diff --git a/bin/configs/r-client.yaml b/bin/configs/r-client.yaml
index 98a79ecb29e..9043e19da79 100644
--- a/bin/configs/r-client.yaml
+++ b/bin/configs/r-client.yaml
@@ -1,6 +1,6 @@
 generatorName: r
 outputDir: samples/client/petstore/R
-inputSpec: modules/openapi-generator/src/test/resources/2_0/petstore.yaml
+inputSpec: modules/openapi-generator/src/test/resources/3_0/r/petstore.yaml
 templateDir: modules/openapi-generator/src/main/resources/r
 httpUserAgent: PetstoreAgent
 additionalProperties:
diff --git a/docs/generators/r.md b/docs/generators/r.md
index 15512fa01b5..dbd0b885956 100644
--- a/docs/generators/r.md
+++ b/docs/generators/r.md
@@ -51,6 +51,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 <ul class="column-ul">
 <li>apiresponse</li>
 <li>break</li>
+<li>data_file</li>
 <li>else</li>
 <li>false</li>
 <li>for</li>
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RClientCodegen.java
index dc8cc74432b..34de4d3d8bc 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RClientCodegen.java
@@ -126,7 +126,7 @@ public class RClientCodegen extends DefaultCodegen implements CodegenConfig {
                         "next", "break", "TRUE", "FALSE", "NULL", "Inf", "NaN",
                         "NA", "NA_integer_", "NA_real_", "NA_complex_", "NA_character_",
                         // reserved words in API client
-                        "ApiResponse"
+                        "ApiResponse", "data_file"
                 )
         );
 
@@ -294,13 +294,13 @@ public class RClientCodegen extends DefaultCodegen implements CodegenConfig {
 
         // for reserved word or word starting with number, append _
         if (isReservedWord(name))
-            name = escapeReservedWord(name);
+            name = "var_" + name;
 
         // for reserved word or word starting with number, append _
         if (name.matches("^\\d.*"))
-            name = "Var" + name;
+            name = "var_" + name;
 
-        return name.replace("_", ".");
+        return name;
     }
 
     @Override
@@ -381,7 +381,7 @@ public class RClientCodegen extends DefaultCodegen implements CodegenConfig {
         if (ModelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
-            return getSchemaType(p) + "[" + getTypeDeclaration(inner)+ "]";
+            return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
         } else if (ModelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return getSchemaType(p) + "(" + getTypeDeclaration(inner) + ")";
@@ -480,11 +480,11 @@ public class RClientCodegen extends DefaultCodegen implements CodegenConfig {
     }
 
     public void setExceptionPackageToUse(String exceptionPackage) {
-        if(DEFAULT.equals(exceptionPackage))
-          this.useDefaultExceptionHandling = true;
-        if(RLANG.equals(exceptionPackage)){
-          supportingFiles.add(new SupportingFile("api_exception.mustache", File.separator + "R", "api_exception.R"));
-          this.useRlangExceptionHandling = true;
+        if (DEFAULT.equals(exceptionPackage))
+            this.useDefaultExceptionHandling = true;
+        if (RLANG.equals(exceptionPackage)) {
+            supportingFiles.add(new SupportingFile("api_exception.mustache", File.separator + "R", "api_exception.R"));
+            this.useRlangExceptionHandling = true;
         }
     }
 
@@ -676,7 +676,7 @@ public class RClientCodegen extends DefaultCodegen implements CodegenConfig {
                 if (Pattern.compile("\r\n|\r|\n").matcher((String) p.getDefault()).find())
                     return "'''" + p.getDefault() + "'''";
                 else
-                    return "'" + ((String) p.getDefault()).replaceAll("'","\'") + "'";
+                    return "'" + ((String) p.getDefault()).replaceAll("'", "\'") + "'";
             }
         } else if (ModelUtils.isArraySchema(p)) {
             if (p.getDefault() != null) {
@@ -817,5 +817,7 @@ public class RClientCodegen extends DefaultCodegen implements CodegenConfig {
     }
 
     @Override
-    public GeneratorLanguage generatorLanguage() { return GeneratorLanguage.R; }
+    public GeneratorLanguage generatorLanguage() {
+        return GeneratorLanguage.R;
+    }
 }
diff --git a/modules/openapi-generator/src/test/resources/3_0/r/petstore.yaml b/modules/openapi-generator/src/test/resources/3_0/r/petstore.yaml
new file mode 100644
index 00000000000..502deb56f88
--- /dev/null
+++ b/modules/openapi-generator/src/test/resources/3_0/r/petstore.yaml
@@ -0,0 +1,768 @@
+openapi: 3.0.0
+servers:
+  - url: 'http://petstore.swagger.io/v2'
+info:
+  description: >-
+    This is a sample server Petstore server. For this sample, you can use the api key
+    `special-key` to test the authorization filters.
+  version: 1.0.0
+  title: OpenAPI Petstore
+  license:
+    name: Apache-2.0
+    url: 'https://www.apache.org/licenses/LICENSE-2.0.html'
+tags:
+  - name: pet
+    description: Everything about your Pets
+  - name: store
+    description: Access to Petstore orders
+  - name: user
+    description: Operations about user
+paths:
+  /pet:
+    post:
+      tags:
+        - pet
+      summary: Add a new pet to the store
+      description: ''
+      operationId: addPet
+      responses:
+        '200':
+          description: successful operation
+          content:
+            application/xml:
+              schema:
+                $ref: '#/components/schemas/Pet'
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Pet'
+        '405':
+          description: Invalid input
+      security:
+        - petstore_auth:
+            - 'write:pets'
+            - 'read:pets'
+      requestBody:
+        $ref: '#/components/requestBodies/Pet'
+    put:
+      tags:
+        - pet
+      summary: Update an existing pet
+      description: ''
+      operationId: updatePet
+      responses:
+        '200':
+          description: successful operation
+          content:
+            application/xml:
+              schema:
+                $ref: '#/components/schemas/Pet'
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Pet'
+        '400':
+          description: Invalid ID supplied
+        '404':
+          description: Pet not found
+        '405':
+          description: Validation exception
+      security:
+        - petstore_auth:
+            - 'write:pets'
+            - 'read:pets'
+      requestBody:
+        $ref: '#/components/requestBodies/Pet'
+  /pet/findByStatus:
+    get:
+      tags:
+        - pet
+      summary: Finds Pets by status
+      description: Multiple status values can be provided with comma separated strings
+      operationId: findPetsByStatus
+      parameters:
+        - name: status
+          in: query
+          description: Status values that need to be considered for filter
+          required: true
+          style: form
+          explode: false
+          deprecated: true
+          schema:
+            type: array
+            items:
+              type: string
+              enum:
+                - available
+                - pending
+                - sold
+              default: available
+      responses:
+        '200':
+          description: successful operation
+          content:
+            application/xml:
+              schema:
+                type: array
+                items:
+                  $ref: '#/components/schemas/Pet'
+            application/json:
+              schema:
+                type: array
+                items:
+                  $ref: '#/components/schemas/Pet'
+        '400':
+          description: Invalid status value
+      security:
+        - petstore_auth:
+            - 'read:pets'
+  /pet/findByTags:
+    get:
+      tags:
+        - pet
+      summary: Finds Pets by tags
+      description: >-
+        Multiple tags can be provided with comma separated strings. Use tag1,
+        tag2, tag3 for testing.
+      operationId: findPetsByTags
+      parameters:
+        - name: tags
+          in: query
+          description: Tags to filter by
+          required: true
+          style: form
+          explode: false
+          schema:
+            type: array
+            items:
+              type: string
+      responses:
+        '200':
+          description: successful operation
+          content:
+            application/xml:
+              schema:
+                type: array
+                items:
+                  $ref: '#/components/schemas/Pet'
+            application/json:
+              schema:
+                type: array
+                items:
+                  $ref: '#/components/schemas/Pet'
+        '400':
+          description: Invalid tag value
+      security:
+        - petstore_auth:
+            - 'read:pets'
+      deprecated: true
+  '/pet/{petId}':
+    get:
+      tags:
+        - pet
+      summary: Find pet by ID
+      description: Returns a single pet
+      operationId: getPetById
+      parameters:
+        - name: petId
+          in: path
+          description: ID of pet to return
+          required: true
+          schema:
+            type: integer
+            format: int64
+      responses:
+        '200':
+          description: successful operation
+          content:
+            application/xml:
+              schema:
+                $ref: '#/components/schemas/Pet'
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Pet'
+        '400':
+          description: Invalid ID supplied
+        '404':
+          description: Pet not found
+      security:
+        - api_key: []
+    post:
+      tags:
+        - pet
+      summary: Updates a pet in the store with form data
+      description: ''
+      operationId: updatePetWithForm
+      parameters:
+        - name: petId
+          in: path
+          description: ID of pet that needs to be updated
+          required: true
+          schema:
+            type: integer
+            format: int64
+      responses:
+        '405':
+          description: Invalid input
+      security:
+        - petstore_auth:
+            - 'write:pets'
+            - 'read:pets'
+      requestBody:
+        content:
+          application/x-www-form-urlencoded:
+            schema:
+              type: object
+              properties:
+                name:
+                  description: Updated name of the pet
+                  type: string
+                status:
+                  description: Updated status of the pet
+                  type: string
+    delete:
+      tags:
+        - pet
+      summary: Deletes a pet
+      description: ''
+      operationId: deletePet
+      parameters:
+        - name: api_key
+          in: header
+          required: false
+          schema:
+            type: string
+        - name: petId
+          in: path
+          description: Pet id to delete
+          required: true
+          schema:
+            type: integer
+            format: int64
+      responses:
+        '400':
+          description: Invalid pet value
+      security:
+        - petstore_auth:
+            - 'write:pets'
+            - 'read:pets'
+  '/pet/{petId}/uploadImage':
+    post:
+      tags:
+        - pet
+      summary: uploads an image
+      description: ''
+      operationId: uploadFile
+      parameters:
+        - name: petId
+          in: path
+          description: ID of pet to update
+          required: true
+          schema:
+            type: integer
+            format: int64
+      responses:
+        '200':
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ApiResponse'
+      security:
+        - petstore_auth:
+            - 'write:pets'
+            - 'read:pets'
+      requestBody:
+        content:
+          multipart/form-data:
+            schema:
+              type: object
+              properties:
+                additionalMetadata:
+                  description: Additional data to pass to server
+                  type: string
+                file:
+                  description: file to upload
+                  type: string
+                  format: binary
+  /store/inventory:
+    get:
+      tags:
+        - store
+      summary: Returns pet inventories by status
+      description: Returns a map of status codes to quantities
+      operationId: getInventory
+      responses:
+        '200':
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                type: object
+                additionalProperties:
+                  type: integer
+                  format: int32
+      security:
+        - api_key: []
+  /store/order:
+    post:
+      tags:
+        - store
+      summary: Place an order for a pet
+      description: ''
+      operationId: placeOrder
+      responses:
+        '200':
+          description: successful operation
+          content:
+            application/xml:
+              schema:
+                $ref: '#/components/schemas/Order'
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Order'
+        '400':
+          description: Invalid Order
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/Order'
+        description: order placed for purchasing the pet
+        required: true
+  '/store/order/{orderId}':
+    get:
+      tags:
+        - store
+      summary: Find purchase order by ID
+      description: >-
+        For valid response try integer IDs with value <= 5 or > 10. Other values
+        will generated exceptions
+      operationId: getOrderById
+      parameters:
+        - name: orderId
+          in: path
+          description: ID of pet that needs to be fetched
+          required: true
+          schema:
+            type: integer
+            format: int64
+            minimum: 1
+            maximum: 5
+      responses:
+        '200':
+          description: successful operation
+          content:
+            application/xml:
+              schema:
+                $ref: '#/components/schemas/Order'
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Order'
+        '400':
+          description: Invalid ID supplied
+        '404':
+          description: Order not found
+    delete:
+      tags:
+        - store
+      summary: Delete purchase order by ID
+      description: >-
+        For valid response try integer IDs with value < 1000. Anything above
+        1000 or nonintegers will generate API errors
+      operationId: deleteOrder
+      parameters:
+        - name: orderId
+          in: path
+          description: ID of the order that needs to be deleted
+          required: true
+          schema:
+            type: string
+      responses:
+        '400':
+          description: Invalid ID supplied
+        '404':
+          description: Order not found
+  /user:
+    post:
+      tags:
+        - user
+      summary: Create user
+      description: This can only be done by the logged in user.
+      operationId: createUser
+      responses:
+        default:
+          description: successful operation
+      security:
+        - api_key: []
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/User'
+        description: Created user object
+        required: true
+  /user/createWithArray:
+    post:
+      tags:
+        - user
+      summary: Creates list of users with given input array
+      description: ''
+      operationId: createUsersWithArrayInput
+      responses:
+        default:
+          description: successful operation
+      security:
+        - api_key: []
+      requestBody:
+        $ref: '#/components/requestBodies/UserArray'
+  /user/createWithList:
+    post:
+      tags:
+        - user
+      summary: Creates list of users with given input array
+      description: ''
+      operationId: createUsersWithListInput
+      responses:
+        default:
+          description: successful operation
+      security:
+        - api_key: []
+      requestBody:
+        $ref: '#/components/requestBodies/UserArray'
+  /user/login:
+    get:
+      tags:
+        - user
+      summary: Logs user into the system
+      description: ''
+      operationId: loginUser
+      parameters:
+        - name: username
+          in: query
+          description: The user name for login
+          required: true
+          schema:
+            type: string
+            pattern: '^[a-zA-Z0-9]+[a-zA-Z0-9\.\-_]*[a-zA-Z0-9]+$'
+        - name: password
+          in: query
+          description: The password for login in clear text
+          required: true
+          schema:
+            type: string
+      responses:
+        '200':
+          description: successful operation
+          headers:
+            Set-Cookie:
+              description: >-
+                Cookie authentication key for use with the `api_key`
+                apiKey authentication.
+              schema:
+                type: string
+                example: AUTH_KEY=abcde12345; Path=/; HttpOnly
+            X-Rate-Limit:
+              description: calls per hour allowed by the user
+              schema:
+                type: integer
+                format: int32
+            X-Expires-After:
+              description: date in UTC when token expires
+              schema:
+                type: string
+                format: date-time
+          content:
+            application/xml:
+              schema:
+                type: string
+            application/json:
+              schema:
+                type: string
+        '400':
+          description: Invalid username/password supplied
+  /user/logout:
+    get:
+      tags:
+        - user
+      summary: Logs out current logged in user session
+      description: ''
+      operationId: logoutUser
+      responses:
+        default:
+          description: successful operation
+      security:
+        - api_key: []
+  '/user/{username}':
+    get:
+      tags:
+        - user
+      summary: Get user by user name
+      description: ''
+      operationId: getUserByName
+      parameters:
+        - name: username
+          in: path
+          description: The name that needs to be fetched. Use user1 for testing.
+          required: true
+          schema:
+            type: string
+      responses:
+        '200':
+          description: successful operation
+          content:
+            application/xml:
+              schema:
+                $ref: '#/components/schemas/User'
+            application/json:
+              schema:
+                $ref: '#/components/schemas/User'
+        '400':
+          description: Invalid username supplied
+        '404':
+          description: User not found
+    put:
+      tags:
+        - user
+      summary: Updated user
+      description: This can only be done by the logged in user.
+      operationId: updateUser
+      parameters:
+        - name: username
+          in: path
+          description: name that need to be deleted
+          required: true
+          schema:
+            type: string
+      responses:
+        '400':
+          description: Invalid user supplied
+        '404':
+          description: User not found
+      security:
+        - api_key: []
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/User'
+        description: Updated user object
+        required: true
+    delete:
+      tags:
+        - user
+      summary: Delete user
+      description: This can only be done by the logged in user.
+      operationId: deleteUser
+      parameters:
+        - name: username
+          in: path
+          description: The name that needs to be deleted
+          required: true
+          schema:
+            type: string
+      responses:
+        '400':
+          description: Invalid username supplied
+        '404':
+          description: User not found
+      security:
+        - api_key: []
+  /fake/data_file:
+    get:
+      tags:
+        - fake
+      summary: test data_file to ensure it's escaped correctly
+      description: ''
+      operationId: fake_data_file
+      parameters:
+        - name: dummy 
+          in: header
+          description: dummy required parameter
+          required: true
+          schema:
+            type: string
+        - name: data_file 
+          in: header
+          description: header data file
+          required: false
+          schema:
+            type: string
+      responses:
+        '200':
+          description: successful operation
+          content:
+            application/xml:
+              schema:
+                $ref: '#/components/schemas/User'
+            application/json:
+              schema:
+                $ref: '#/components/schemas/User'
+externalDocs:
+  description: Find out more about Swagger
+  url: 'http://swagger.io'
+components:
+  requestBodies:
+    UserArray:
+      content:
+        application/json:
+          schema:
+            type: array
+            items:
+              $ref: '#/components/schemas/User'
+      description: List of user object
+      required: true
+    Pet:
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/Pet'
+        application/xml:
+          schema:
+            $ref: '#/components/schemas/Pet'
+      description: Pet object that needs to be added to the store
+      required: true
+  securitySchemes:
+    petstore_auth:
+      type: oauth2
+      flows:
+        implicit:
+          authorizationUrl: 'http://petstore.swagger.io/api/oauth/dialog'
+          scopes:
+            'write:pets': modify pets in your account
+            'read:pets': read your pets
+    api_key:
+      type: apiKey
+      name: api_key
+      in: header
+  schemas:
+    Order:
+      title: Pet Order
+      description: An order for a pets from the pet store
+      type: object
+      properties:
+        id:
+          type: integer
+          format: int64
+        petId:
+          type: integer
+          format: int64
+        quantity:
+          type: integer
+          format: int32
+        shipDate:
+          type: string
+          format: date-time
+        status:
+          type: string
+          description: Order Status
+          enum:
+            - placed
+            - approved
+            - delivered
+        complete:
+          type: boolean
+          default: false
+      xml:
+        name: Order
+    Category:
+      title: Pet category
+      description: A category for a pet
+      type: object
+      properties:
+        id:
+          type: integer
+          format: int64
+        name:
+          type: string
+          pattern: '^[a-zA-Z0-9]+[a-zA-Z0-9\.\-_]*[a-zA-Z0-9]+$'
+      xml:
+        name: Category
+    User:
+      title: a User
+      description: A User who is purchasing from the pet store
+      type: object
+      properties:
+        id:
+          type: integer
+          format: int64
+        username:
+          type: string
+        firstName:
+          type: string
+        lastName:
+          type: string
+        email:
+          type: string
+        password:
+          type: string
+        phone:
+          type: string
+        userStatus:
+          type: integer
+          format: int32
+          description: User Status
+      xml:
+        name: User
+    Tag:
+      title: Pet Tag
+      description: A tag for a pet
+      type: object
+      properties:
+        id:
+          type: integer
+          format: int64
+        name:
+          type: string
+      xml:
+        name: Tag
+    Pet:
+      title: a Pet
+      description: A pet for sale in the pet store
+      type: object
+      required:
+        - name
+        - photoUrls
+      properties:
+        id:
+          type: integer
+          format: int64
+        category:
+          $ref: '#/components/schemas/Category'
+        name:
+          type: string
+          example: doggie
+        photoUrls:
+          type: array
+          xml:
+            name: photoUrl
+            wrapped: true
+          items:
+            type: string
+        tags:
+          type: array
+          xml:
+            name: tag
+            wrapped: true
+          items:
+            $ref: '#/components/schemas/Tag'
+        status:
+          type: string
+          description: pet status in the store
+          deprecated: true
+          enum:
+            - available
+            - pending
+            - sold
+      xml:
+        name: Pet
+    ApiResponse:
+      title: An uploaded response
+      description: Describes the result of uploading an image resource
+      type: object
+      properties:
+        code:
+          type: integer
+          format: int32
+        type:
+          type: string
+        message:
+          type: string
diff --git a/samples/client/petstore/R/.openapi-generator/FILES b/samples/client/petstore/R/.openapi-generator/FILES
index 9385728f010..b728b3f1d60 100644
--- a/samples/client/petstore/R/.openapi-generator/FILES
+++ b/samples/client/petstore/R/.openapi-generator/FILES
@@ -6,6 +6,7 @@ NAMESPACE
 R/api_client.R
 R/api_response.R
 R/category.R
+R/fake_api.R
 R/model_api_response.R
 R/order.R
 R/pet.R
@@ -16,6 +17,7 @@ R/user.R
 R/user_api.R
 README.md
 docs/Category.md
+docs/FakeApi.md
 docs/ModelApiResponse.md
 docs/Order.md
 docs/Pet.md
diff --git a/samples/client/petstore/R/NAMESPACE b/samples/client/petstore/R/NAMESPACE
index 5b6e37f8de5..dc2b03b289f 100644
--- a/samples/client/petstore/R/NAMESPACE
+++ b/samples/client/petstore/R/NAMESPACE
@@ -19,6 +19,7 @@ export(Tag)
 export(User)
 
 # APIs
+export(FakeApi)
 export(PetApi)
 export(StoreApi)
 export(UserApi)
diff --git a/samples/client/petstore/R/R/fake_api.R b/samples/client/petstore/R/R/fake_api.R
new file mode 100644
index 00000000000..0d8ee7501ad
--- /dev/null
+++ b/samples/client/petstore/R/R/fake_api.R
@@ -0,0 +1,127 @@
+# OpenAPI Petstore
+#
+# This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+#
+# The version of the OpenAPI document: 1.0.0
+# 
+# Generated by: https://openapi-generator.tech
+
+#' @docType class
+#' @title Fake operations
+#' @description petstore.Fake
+#' @format An \code{R6Class} generator object
+#' @field apiClient Handles the client-server communication.
+#'
+#' @section Methods:
+#' \describe{
+#' \strong{ FakeDataFile } \emph{ test data_file to ensure it&#39;s escaped correctly }
+#' 
+#'
+#' \itemize{
+#' \item \emph{ @param } dummy character
+#' \item \emph{ @param } var_data_file character
+#' \item \emph{ @returnType } \link{User} \cr
+#'
+#'
+#' \item status code : 200 | successful operation
+#'
+#' \item return type : User 
+#' \item response headers :
+#'
+#' \tabular{ll}{
+#' }
+#' }
+#'
+#' }
+#'
+#'
+#' @examples
+#' \dontrun{
+#' ####################  FakeDataFile  ####################
+#'
+#' library(petstore)
+#' var.dummy <- 'dummy_example' # character | dummy required parameter
+#' var.var_data_file <- 'var_data_file_example' # character | header data file
+#'
+#' #test data_file to ensure it's escaped correctly
+#' api.instance <- FakeApi$new()
+#'
+#' result <- api.instance$FakeDataFile(var.dummy, var_data_file=var.var_data_file)
+#'
+#'
+#' }
+#' @importFrom R6 R6Class
+#' @importFrom base64enc base64encode
+#' @export
+FakeApi <- R6::R6Class(
+  'FakeApi',
+  public = list(
+    apiClient = NULL,
+    initialize = function(apiClient){
+      if (!missing(apiClient)) {
+        self$apiClient <- apiClient
+      }
+      else {
+        self$apiClient <- ApiClient$new()
+      }
+    },
+    FakeDataFile = function(dummy, var_data_file=NULL, data_file=NULL, ...){
+      apiResponse <- self$FakeDataFileWithHttpInfo(dummy, var_data_file, data_file=data_file, ...)
+      resp <- apiResponse$response
+      if (httr::status_code(resp) >= 200 && httr::status_code(resp) <= 299) {
+        apiResponse$content
+      } else if (httr::status_code(resp) >= 300 && httr::status_code(resp) <= 399) {
+        apiResponse
+      } else if (httr::status_code(resp) >= 400 && httr::status_code(resp) <= 499) {
+        apiResponse
+      } else if (httr::status_code(resp) >= 500 && httr::status_code(resp) <= 599) {
+        apiResponse
+      }
+    },
+
+    FakeDataFileWithHttpInfo = function(dummy, var_data_file=NULL, data_file=NULL, ...){
+      args <- list(...)
+      queryParams <- list()
+      headerParams <- c()
+
+      if (missing(`dummy`)) {
+        stop("Missing required parameter `dummy`.")
+      }
+
+      headerParams['dummy'] <- `dummy`
+
+      headerParams['data_file'] <- `var_data_file`
+
+      body <- NULL
+      urlPath <- "/fake/data_file"
+
+      resp <- self$apiClient$CallApi(url = paste0(self$apiClient$basePath, urlPath),
+                                 method = "GET",
+                                 queryParams = queryParams,
+                                 headerParams = headerParams,
+                                 body = body,
+                                 ...)
+
+      if (httr::status_code(resp) >= 200 && httr::status_code(resp) <= 299) {
+        # save response in a file
+        if (!is.null(data_file)) {
+            write(httr::content(resp, "text", encoding = "UTF-8", simplifyVector = FALSE), data_file)
+        }
+
+        deserializedRespObj <- tryCatch(
+          self$apiClient$deserialize(resp, "User", loadNamespace("petstore")),
+          error = function(e){
+             stop("Failed to deserialize response")
+          }
+        )
+        ApiResponse$new(deserializedRespObj, resp)
+      } else if (httr::status_code(resp) >= 300 && httr::status_code(resp) <= 399) {
+        ApiResponse$new(paste("Server returned " , httr::status_code(resp) , " response status code."), resp)
+      } else if (httr::status_code(resp) >= 400 && httr::status_code(resp) <= 499) {
+        ApiResponse$new("API client error", resp)
+      } else if (httr::status_code(resp) >= 500 && httr::status_code(resp) <= 599) {
+        ApiResponse$new("API server error", resp)
+      }
+    }
+  )
+)
diff --git a/samples/client/petstore/R/R/pet_api.R b/samples/client/petstore/R/R/pet_api.R
index f687a9b5edf..644a8480725 100644
--- a/samples/client/petstore/R/R/pet_api.R
+++ b/samples/client/petstore/R/R/pet_api.R
@@ -18,9 +18,17 @@
 #' 
 #'
 #' \itemize{
-#' \item \emph{ @param } body \link{Pet}
+#' \item \emph{ @param } pet \link{Pet}
+#' \item \emph{ @returnType } \link{Pet} \cr
 #'
 #'
+#' \item status code : 200 | successful operation
+#'
+#' \item return type : Pet 
+#' \item response headers :
+#'
+#' \tabular{ll}{
+#' }
 #' \item status code : 405 | Invalid input
 #'
 #'
@@ -34,8 +42,8 @@
 #' 
 #'
 #' \itemize{
-#' \item \emph{ @param } pet.id integer
-#' \item \emph{ @param } api.key character
+#' \item \emph{ @param } pet_id integer
+#' \item \emph{ @param } api_key character
 #'
 #'
 #' \item status code : 400 | Invalid pet value
@@ -99,7 +107,7 @@
 #' Returns a single pet
 #'
 #' \itemize{
-#' \item \emph{ @param } pet.id integer
+#' \item \emph{ @param } pet_id integer
 #' \item \emph{ @returnType } \link{Pet} \cr
 #'
 #'
@@ -130,9 +138,17 @@
 #' 
 #'
 #' \itemize{
-#' \item \emph{ @param } body \link{Pet}
+#' \item \emph{ @param } pet \link{Pet}
+#' \item \emph{ @returnType } \link{Pet} \cr
 #'
 #'
+#' \item status code : 200 | successful operation
+#'
+#' \item return type : Pet 
+#' \item response headers :
+#'
+#' \tabular{ll}{
+#' }
 #' \item status code : 400 | Invalid ID supplied
 #'
 #'
@@ -160,7 +176,7 @@
 #' 
 #'
 #' \itemize{
-#' \item \emph{ @param } pet.id integer
+#' \item \emph{ @param } pet_id integer
 #' \item \emph{ @param } name character
 #' \item \emph{ @param } status character
 #'
@@ -178,8 +194,8 @@
 #' 
 #'
 #' \itemize{
-#' \item \emph{ @param } pet.id integer
-#' \item \emph{ @param } additional.metadata character
+#' \item \emph{ @param } pet_id integer
+#' \item \emph{ @param } additional_metadata character
 #' \item \emph{ @param } file data.frame
 #' \item \emph{ @returnType } \link{ModelApiResponse} \cr
 #'
@@ -201,7 +217,7 @@
 #' ####################  AddPet  ####################
 #'
 #' library(petstore)
-#' var.body <- Pet$new() # Pet | Pet object that needs to be added to the store
+#' var.pet <- Pet$new() # Pet | Pet object that needs to be added to the store
 #'
 #' #Add a new pet to the store
 #' api.instance <- PetApi$new()
@@ -209,14 +225,14 @@
 #' # Configure OAuth2 access token for authorization: petstore_auth
 #' api.instance$apiClient$accessToken <- 'TODO_YOUR_ACCESS_TOKEN';
 #'
-#' result <- api.instance$AddPet(var.body)
+#' result <- api.instance$AddPet(var.pet)
 #'
 #'
 #' ####################  DeletePet  ####################
 #'
 #' library(petstore)
-#' var.pet.id <- 56 # integer | Pet id to delete
-#' var.api.key <- 'api.key_example' # character | 
+#' var.pet_id <- 56 # integer | Pet id to delete
+#' var.api_key <- 'api_key_example' # character | 
 #'
 #' #Deletes a pet
 #' api.instance <- PetApi$new()
@@ -224,7 +240,7 @@
 #' # Configure OAuth2 access token for authorization: petstore_auth
 #' api.instance$apiClient$accessToken <- 'TODO_YOUR_ACCESS_TOKEN';
 #'
-#' result <- api.instance$DeletePet(var.pet.id, api.key=var.api.key)
+#' result <- api.instance$DeletePet(var.pet_id, api_key=var.api_key)
 #'
 #'
 #' ####################  FindPetsByStatus  ####################
@@ -258,7 +274,7 @@
 #' ####################  GetPetById  ####################
 #'
 #' library(petstore)
-#' var.pet.id <- 56 # integer | ID of pet to return
+#' var.pet_id <- 56 # integer | ID of pet to return
 #'
 #' #Find pet by ID
 #' api.instance <- PetApi$new()
@@ -266,13 +282,13 @@
 #' #Configure API key authorization: api_key
 #' api.instance$apiClient$apiKeys['api_key'] <- 'TODO_YOUR_API_KEY';
 #'
-#' result <- api.instance$GetPetById(var.pet.id)
+#' result <- api.instance$GetPetById(var.pet_id)
 #'
 #'
 #' ####################  UpdatePet  ####################
 #'
 #' library(petstore)
-#' var.body <- Pet$new() # Pet | Pet object that needs to be added to the store
+#' var.pet <- Pet$new() # Pet | Pet object that needs to be added to the store
 #'
 #' #Update an existing pet
 #' api.instance <- PetApi$new()
@@ -280,13 +296,13 @@
 #' # Configure OAuth2 access token for authorization: petstore_auth
 #' api.instance$apiClient$accessToken <- 'TODO_YOUR_ACCESS_TOKEN';
 #'
-#' result <- api.instance$UpdatePet(var.body)
+#' result <- api.instance$UpdatePet(var.pet)
 #'
 #'
 #' ####################  UpdatePetWithForm  ####################
 #'
 #' library(petstore)
-#' var.pet.id <- 56 # integer | ID of pet that needs to be updated
+#' var.pet_id <- 56 # integer | ID of pet that needs to be updated
 #' var.name <- 'name_example' # character | Updated name of the pet
 #' var.status <- 'status_example' # character | Updated status of the pet
 #'
@@ -296,14 +312,14 @@
 #' # Configure OAuth2 access token for authorization: petstore_auth
 #' api.instance$apiClient$accessToken <- 'TODO_YOUR_ACCESS_TOKEN';
 #'
-#' result <- api.instance$UpdatePetWithForm(var.pet.id, name=var.name, status=var.status)
+#' result <- api.instance$UpdatePetWithForm(var.pet_id, name=var.name, status=var.status)
 #'
 #'
 #' ####################  UploadFile  ####################
 #'
 #' library(petstore)
-#' var.pet.id <- 56 # integer | ID of pet to update
-#' var.additional.metadata <- 'additional.metadata_example' # character | Additional data to pass to server
+#' var.pet_id <- 56 # integer | ID of pet to update
+#' var.additional_metadata <- 'additional_metadata_example' # character | Additional data to pass to server
 #' var.file <- File.new('/path/to/file') # data.frame | file to upload
 #'
 #' #uploads an image
@@ -312,7 +328,7 @@
 #' # Configure OAuth2 access token for authorization: petstore_auth
 #' api.instance$apiClient$accessToken <- 'TODO_YOUR_ACCESS_TOKEN';
 #'
-#' result <- api.instance$UploadFile(var.pet.id, additional.metadata=var.additional.metadata, file=var.file)
+#' result <- api.instance$UploadFile(var.pet_id, additional_metadata=var.additional_metadata, file=var.file)
 #'
 #'
 #' }
@@ -331,8 +347,8 @@ PetApi <- R6::R6Class(
         self$apiClient <- ApiClient$new()
       }
     },
-    AddPet = function(body, ...){
-      apiResponse <- self$AddPetWithHttpInfo(body, ...)
+    AddPet = function(pet, data_file=NULL, ...){
+      apiResponse <- self$AddPetWithHttpInfo(pet, data_file=data_file, ...)
       resp <- apiResponse$response
       if (httr::status_code(resp) >= 200 && httr::status_code(resp) <= 299) {
         apiResponse$content
@@ -345,17 +361,17 @@ PetApi <- R6::R6Class(
       }
     },
 
-    AddPetWithHttpInfo = function(body, ...){
+    AddPetWithHttpInfo = function(pet, data_file=NULL, ...){
       args <- list(...)
       queryParams <- list()
       headerParams <- c()
 
-      if (missing(`body`)) {
-        stop("Missing required parameter `body`.")
+      if (missing(`pet`)) {
+        stop("Missing required parameter `pet`.")
       }
 
-      if (!missing(`body`)) {
-        body <- `body`$toJSONString()
+      if (!missing(`pet`)) {
+        body <- `pet`$toJSONString()
       } else {
         body <- NULL
       }
@@ -372,7 +388,18 @@ PetApi <- R6::R6Class(
                                  ...)
 
       if (httr::status_code(resp) >= 200 && httr::status_code(resp) <= 299) {
-        ApiResponse$new(NULL, resp)
+        # save response in a file
+        if (!is.null(data_file)) {
+            write(httr::content(resp, "text", encoding = "UTF-8", simplifyVector = FALSE), data_file)
+        }
+
+        deserializedRespObj <- tryCatch(
+          self$apiClient$deserialize(resp, "Pet", loadNamespace("petstore")),
+          error = function(e){
+             stop("Failed to deserialize response")
+          }
+        )
+        ApiResponse$new(deserializedRespObj, resp)
       } else if (httr::status_code(resp) >= 300 && httr::status_code(resp) <= 399) {
         ApiResponse$new(paste("Server returned " , httr::status_code(resp) , " response status code."), resp)
       } else if (httr::status_code(resp) >= 400 && httr::status_code(resp) <= 499) {
@@ -381,8 +408,8 @@ PetApi <- R6::R6Class(
         ApiResponse$new("API server error", resp)
       }
     },
-    DeletePet = function(pet.id, api.key=NULL, ...){
-      apiResponse <- self$DeletePetWithHttpInfo(pet.id, api.key, ...)
+    DeletePet = function(pet_id, api_key=NULL, ...){
+      apiResponse <- self$DeletePetWithHttpInfo(pet_id, api_key, ...)
       resp <- apiResponse$response
       if (httr::status_code(resp) >= 200 && httr::status_code(resp) <= 299) {
         apiResponse$content
@@ -395,21 +422,21 @@ PetApi <- R6::R6Class(
       }
     },
 
-    DeletePetWithHttpInfo = function(pet.id, api.key=NULL, ...){
+    DeletePetWithHttpInfo = function(pet_id, api_key=NULL, ...){
       args <- list(...)
       queryParams <- list()
       headerParams <- c()
 
-      if (missing(`pet.id`)) {
-        stop("Missing required parameter `pet.id`.")
+      if (missing(`pet_id`)) {
+        stop("Missing required parameter `pet_id`.")
       }
 
-      headerParams['api_key'] <- `api.key`
+      headerParams['api_key'] <- `api_key`
 
       body <- NULL
       urlPath <- "/pet/{petId}"
-      if (!missing(`pet.id`)) {
-        urlPath <- gsub(paste0("\\{", "petId", "\\}"), URLencode(as.character(`pet.id`), reserved = TRUE), urlPath)
+      if (!missing(`pet_id`)) {
+        urlPath <- gsub(paste0("\\{", "petId", "\\}"), URLencode(as.character(`pet_id`), reserved = TRUE), urlPath)
       }
 
       # OAuth token
@@ -548,8 +575,8 @@ PetApi <- R6::R6Class(
         ApiResponse$new("API server error", resp)
       }
     },
-    GetPetById = function(pet.id, data_file=NULL, ...){
-      apiResponse <- self$GetPetByIdWithHttpInfo(pet.id, data_file=data_file, ...)
+    GetPetById = function(pet_id, data_file=NULL, ...){
+      apiResponse <- self$GetPetByIdWithHttpInfo(pet_id, data_file=data_file, ...)
       resp <- apiResponse$response
       if (httr::status_code(resp) >= 200 && httr::status_code(resp) <= 299) {
         apiResponse$content
@@ -562,19 +589,19 @@ PetApi <- R6::R6Class(
       }
     },
 
-    GetPetByIdWithHttpInfo = function(pet.id, data_file=NULL, ...){
+    GetPetByIdWithHttpInfo = function(pet_id, data_file=NULL, ...){
       args <- list(...)
       queryParams <- list()
       headerParams <- c()
 
-      if (missing(`pet.id`)) {
-        stop("Missing required parameter `pet.id`.")
+      if (missing(`pet_id`)) {
+        stop("Missing required parameter `pet_id`.")
       }
 
       body <- NULL
       urlPath <- "/pet/{petId}"
-      if (!missing(`pet.id`)) {
-        urlPath <- gsub(paste0("\\{", "petId", "\\}"), URLencode(as.character(`pet.id`), reserved = TRUE), urlPath)
+      if (!missing(`pet_id`)) {
+        urlPath <- gsub(paste0("\\{", "petId", "\\}"), URLencode(as.character(`pet_id`), reserved = TRUE), urlPath)
       }
 
       # API key authentication
@@ -610,8 +637,8 @@ PetApi <- R6::R6Class(
         ApiResponse$new("API server error", resp)
       }
     },
-    UpdatePet = function(body, ...){
-      apiResponse <- self$UpdatePetWithHttpInfo(body, ...)
+    UpdatePet = function(pet, data_file=NULL, ...){
+      apiResponse <- self$UpdatePetWithHttpInfo(pet, data_file=data_file, ...)
       resp <- apiResponse$response
       if (httr::status_code(resp) >= 200 && httr::status_code(resp) <= 299) {
         apiResponse$content
@@ -624,17 +651,17 @@ PetApi <- R6::R6Class(
       }
     },
 
-    UpdatePetWithHttpInfo = function(body, ...){
+    UpdatePetWithHttpInfo = function(pet, data_file=NULL, ...){
       args <- list(...)
       queryParams <- list()
       headerParams <- c()
 
-      if (missing(`body`)) {
-        stop("Missing required parameter `body`.")
+      if (missing(`pet`)) {
+        stop("Missing required parameter `pet`.")
       }
 
-      if (!missing(`body`)) {
-        body <- `body`$toJSONString()
+      if (!missing(`pet`)) {
+        body <- `pet`$toJSONString()
       } else {
         body <- NULL
       }
@@ -651,7 +678,18 @@ PetApi <- R6::R6Class(
                                  ...)
 
       if (httr::status_code(resp) >= 200 && httr::status_code(resp) <= 299) {
-        ApiResponse$new(NULL, resp)
+        # save response in a file
+        if (!is.null(data_file)) {
+            write(httr::content(resp, "text", encoding = "UTF-8", simplifyVector = FALSE), data_file)
+        }
+
+        deserializedRespObj <- tryCatch(
+          self$apiClient$deserialize(resp, "Pet", loadNamespace("petstore")),
+          error = function(e){
+             stop("Failed to deserialize response")
+          }
+        )
+        ApiResponse$new(deserializedRespObj, resp)
       } else if (httr::status_code(resp) >= 300 && httr::status_code(resp) <= 399) {
         ApiResponse$new(paste("Server returned " , httr::status_code(resp) , " response status code."), resp)
       } else if (httr::status_code(resp) >= 400 && httr::status_code(resp) <= 499) {
@@ -660,8 +698,8 @@ PetApi <- R6::R6Class(
         ApiResponse$new("API server error", resp)
       }
     },
-    UpdatePetWithForm = function(pet.id, name=NULL, status=NULL, ...){
-      apiResponse <- self$UpdatePetWithFormWithHttpInfo(pet.id, name, status, ...)
+    UpdatePetWithForm = function(pet_id, name=NULL, status=NULL, ...){
+      apiResponse <- self$UpdatePetWithFormWithHttpInfo(pet_id, name, status, ...)
       resp <- apiResponse$response
       if (httr::status_code(resp) >= 200 && httr::status_code(resp) <= 299) {
         apiResponse$content
@@ -674,13 +712,13 @@ PetApi <- R6::R6Class(
       }
     },
 
-    UpdatePetWithFormWithHttpInfo = function(pet.id, name=NULL, status=NULL, ...){
+    UpdatePetWithFormWithHttpInfo = function(pet_id, name=NULL, status=NULL, ...){
       args <- list(...)
       queryParams <- list()
       headerParams <- c()
 
-      if (missing(`pet.id`)) {
-        stop("Missing required parameter `pet.id`.")
+      if (missing(`pet_id`)) {
+        stop("Missing required parameter `pet_id`.")
       }
 
       body <- list(
@@ -689,8 +727,8 @@ PetApi <- R6::R6Class(
       )
 
       urlPath <- "/pet/{petId}"
-      if (!missing(`pet.id`)) {
-        urlPath <- gsub(paste0("\\{", "petId", "\\}"), URLencode(as.character(`pet.id`), reserved = TRUE), urlPath)
+      if (!missing(`pet_id`)) {
+        urlPath <- gsub(paste0("\\{", "petId", "\\}"), URLencode(as.character(`pet_id`), reserved = TRUE), urlPath)
       }
 
       # OAuth token
@@ -713,8 +751,8 @@ PetApi <- R6::R6Class(
         ApiResponse$new("API server error", resp)
       }
     },
-    UploadFile = function(pet.id, additional.metadata=NULL, file=NULL, data_file=NULL, ...){
-      apiResponse <- self$UploadFileWithHttpInfo(pet.id, additional.metadata, file, data_file=data_file, ...)
+    UploadFile = function(pet_id, additional_metadata=NULL, file=NULL, data_file=NULL, ...){
+      apiResponse <- self$UploadFileWithHttpInfo(pet_id, additional_metadata, file, data_file=data_file, ...)
       resp <- apiResponse$response
       if (httr::status_code(resp) >= 200 && httr::status_code(resp) <= 299) {
         apiResponse$content
@@ -727,23 +765,23 @@ PetApi <- R6::R6Class(
       }
     },
 
-    UploadFileWithHttpInfo = function(pet.id, additional.metadata=NULL, file=NULL, data_file=NULL, ...){
+    UploadFileWithHttpInfo = function(pet_id, additional_metadata=NULL, file=NULL, data_file=NULL, ...){
       args <- list(...)
       queryParams <- list()
       headerParams <- c()
 
-      if (missing(`pet.id`)) {
-        stop("Missing required parameter `pet.id`.")
+      if (missing(`pet_id`)) {
+        stop("Missing required parameter `pet_id`.")
       }
 
       body <- list(
-        "additionalMetadata" = additional.metadata,
+        "additionalMetadata" = additional_metadata,
         "file" = httr::upload_file(file)
       )
 
       urlPath <- "/pet/{petId}/uploadImage"
-      if (!missing(`pet.id`)) {
-        urlPath <- gsub(paste0("\\{", "petId", "\\}"), URLencode(as.character(`pet.id`), reserved = TRUE), urlPath)
+      if (!missing(`pet_id`)) {
+        urlPath <- gsub(paste0("\\{", "petId", "\\}"), URLencode(as.character(`pet_id`), reserved = TRUE), urlPath)
       }
 
       # OAuth token
diff --git a/samples/client/petstore/R/R/store_api.R b/samples/client/petstore/R/R/store_api.R
index ce7e31505a9..2fcf5265290 100644
--- a/samples/client/petstore/R/R/store_api.R
+++ b/samples/client/petstore/R/R/store_api.R
@@ -18,7 +18,7 @@
 #' For valid response try integer IDs with value &lt; 1000. Anything above 1000 or nonintegers will generate API errors
 #'
 #' \itemize{
-#' \item \emph{ @param } order.id character
+#' \item \emph{ @param } order_id character
 #'
 #'
 #' \item status code : 400 | Invalid ID supplied
@@ -56,7 +56,7 @@
 #' For valid response try integer IDs with value &lt;&#x3D; 5 or &gt; 10. Other values will generated exceptions
 #'
 #' \itemize{
-#' \item \emph{ @param } order.id integer
+#' \item \emph{ @param } order_id integer
 #' \item \emph{ @returnType } \link{Order} \cr
 #'
 #'
@@ -87,7 +87,7 @@
 #' 
 #'
 #' \itemize{
-#' \item \emph{ @param } body \link{Order}
+#' \item \emph{ @param } order \link{Order}
 #' \item \emph{ @returnType } \link{Order} \cr
 #'
 #'
@@ -115,12 +115,12 @@
 #' ####################  DeleteOrder  ####################
 #'
 #' library(petstore)
-#' var.order.id <- 'order.id_example' # character | ID of the order that needs to be deleted
+#' var.order_id <- 'order_id_example' # character | ID of the order that needs to be deleted
 #'
 #' #Delete purchase order by ID
 #' api.instance <- StoreApi$new()
 #'
-#' result <- api.instance$DeleteOrder(var.order.id)
+#' result <- api.instance$DeleteOrder(var.order_id)
 #'
 #'
 #' ####################  GetInventory  ####################
@@ -139,23 +139,23 @@
 #' ####################  GetOrderById  ####################
 #'
 #' library(petstore)
-#' var.order.id <- 56 # integer | ID of pet that needs to be fetched
+#' var.order_id <- 56 # integer | ID of pet that needs to be fetched
 #'
 #' #Find purchase order by ID
 #' api.instance <- StoreApi$new()
 #'
-#' result <- api.instance$GetOrderById(var.order.id)
+#' result <- api.instance$GetOrderById(var.order_id)
 #'
 #'
 #' ####################  PlaceOrder  ####################
 #'
 #' library(petstore)
-#' var.body <- Order$new() # Order | order placed for purchasing the pet
+#' var.order <- Order$new() # Order | order placed for purchasing the pet
 #'
 #' #Place an order for a pet
 #' api.instance <- StoreApi$new()
 #'
-#' result <- api.instance$PlaceOrder(var.body)
+#' result <- api.instance$PlaceOrder(var.order)
 #'
 #'
 #' }
@@ -174,8 +174,8 @@ StoreApi <- R6::R6Class(
         self$apiClient <- ApiClient$new()
       }
     },
-    DeleteOrder = function(order.id, ...){
-      apiResponse <- self$DeleteOrderWithHttpInfo(order.id, ...)
+    DeleteOrder = function(order_id, ...){
+      apiResponse <- self$DeleteOrderWithHttpInfo(order_id, ...)
       resp <- apiResponse$response
       if (httr::status_code(resp) >= 200 && httr::status_code(resp) <= 299) {
         apiResponse$content
@@ -188,19 +188,19 @@ StoreApi <- R6::R6Class(
       }
     },
 
-    DeleteOrderWithHttpInfo = function(order.id, ...){
+    DeleteOrderWithHttpInfo = function(order_id, ...){
       args <- list(...)
       queryParams <- list()
       headerParams <- c()
 
-      if (missing(`order.id`)) {
-        stop("Missing required parameter `order.id`.")
+      if (missing(`order_id`)) {
+        stop("Missing required parameter `order_id`.")
       }
 
       body <- NULL
       urlPath <- "/store/order/{orderId}"
-      if (!missing(`order.id`)) {
-        urlPath <- gsub(paste0("\\{", "orderId", "\\}"), URLencode(as.character(`order.id`), reserved = TRUE), urlPath)
+      if (!missing(`order_id`)) {
+        urlPath <- gsub(paste0("\\{", "orderId", "\\}"), URLencode(as.character(`order_id`), reserved = TRUE), urlPath)
       }
 
 
@@ -275,8 +275,8 @@ StoreApi <- R6::R6Class(
         ApiResponse$new("API server error", resp)
       }
     },
-    GetOrderById = function(order.id, data_file=NULL, ...){
-      apiResponse <- self$GetOrderByIdWithHttpInfo(order.id, data_file=data_file, ...)
+    GetOrderById = function(order_id, data_file=NULL, ...){
+      apiResponse <- self$GetOrderByIdWithHttpInfo(order_id, data_file=data_file, ...)
       resp <- apiResponse$response
       if (httr::status_code(resp) >= 200 && httr::status_code(resp) <= 299) {
         apiResponse$content
@@ -289,19 +289,19 @@ StoreApi <- R6::R6Class(
       }
     },
 
-    GetOrderByIdWithHttpInfo = function(order.id, data_file=NULL, ...){
+    GetOrderByIdWithHttpInfo = function(order_id, data_file=NULL, ...){
       args <- list(...)
       queryParams <- list()
       headerParams <- c()
 
-      if (missing(`order.id`)) {
-        stop("Missing required parameter `order.id`.")
+      if (missing(`order_id`)) {
+        stop("Missing required parameter `order_id`.")
       }
 
       body <- NULL
       urlPath <- "/store/order/{orderId}"
-      if (!missing(`order.id`)) {
-        urlPath <- gsub(paste0("\\{", "orderId", "\\}"), URLencode(as.character(`order.id`), reserved = TRUE), urlPath)
+      if (!missing(`order_id`)) {
+        urlPath <- gsub(paste0("\\{", "orderId", "\\}"), URLencode(as.character(`order_id`), reserved = TRUE), urlPath)
       }
 
 
@@ -333,8 +333,8 @@ StoreApi <- R6::R6Class(
         ApiResponse$new("API server error", resp)
       }
     },
-    PlaceOrder = function(body, data_file=NULL, ...){
-      apiResponse <- self$PlaceOrderWithHttpInfo(body, data_file=data_file, ...)
+    PlaceOrder = function(order, data_file=NULL, ...){
+      apiResponse <- self$PlaceOrderWithHttpInfo(order, data_file=data_file, ...)
       resp <- apiResponse$response
       if (httr::status_code(resp) >= 200 && httr::status_code(resp) <= 299) {
         apiResponse$content
@@ -347,17 +347,17 @@ StoreApi <- R6::R6Class(
       }
     },
 
-    PlaceOrderWithHttpInfo = function(body, data_file=NULL, ...){
+    PlaceOrderWithHttpInfo = function(order, data_file=NULL, ...){
       args <- list(...)
       queryParams <- list()
       headerParams <- c()
 
-      if (missing(`body`)) {
-        stop("Missing required parameter `body`.")
+      if (missing(`order`)) {
+        stop("Missing required parameter `order`.")
       }
 
-      if (!missing(`body`)) {
-        body <- `body`$toJSONString()
+      if (!missing(`order`)) {
+        body <- `order`$toJSONString()
       } else {
         body <- NULL
       }
diff --git a/samples/client/petstore/R/R/user_api.R b/samples/client/petstore/R/R/user_api.R
index cfaf17a0153..7f45cc1fd10 100644
--- a/samples/client/petstore/R/R/user_api.R
+++ b/samples/client/petstore/R/R/user_api.R
@@ -18,7 +18,7 @@
 #' This can only be done by the logged in user.
 #'
 #' \itemize{
-#' \item \emph{ @param } body \link{User}
+#' \item \emph{ @param } user \link{User}
 #'
 #'
 #' \item status code : 0 | successful operation
@@ -34,7 +34,7 @@
 #' 
 #'
 #' \itemize{
-#' \item \emph{ @param } body list( \link{User} )
+#' \item \emph{ @param } user list( \link{User} )
 #'
 #'
 #' \item status code : 0 | successful operation
@@ -50,7 +50,7 @@
 #' 
 #'
 #' \itemize{
-#' \item \emph{ @param } body list( \link{User} )
+#' \item \emph{ @param } user list( \link{User} )
 #'
 #'
 #' \item status code : 0 | successful operation
@@ -130,6 +130,7 @@
 #' \item response headers :
 #'
 #' \tabular{ll}{
+#' Set-Cookie \tab Cookie authentication key for use with the &#x60;api_key&#x60; apiKey authentication. \cr
 #' X-Rate-Limit \tab calls per hour allowed by the user \cr
 #' X-Expires-After \tab date in UTC when token expires \cr
 #' }
@@ -162,7 +163,7 @@
 #'
 #' \itemize{
 #' \item \emph{ @param } username character
-#' \item \emph{ @param } body \link{User}
+#' \item \emph{ @param } user \link{User}
 #'
 #'
 #' \item status code : 400 | Invalid user supplied
@@ -189,34 +190,43 @@
 #' ####################  CreateUser  ####################
 #'
 #' library(petstore)
-#' var.body <- User$new() # User | Created user object
+#' var.user <- User$new() # User | Created user object
 #'
 #' #Create user
 #' api.instance <- UserApi$new()
 #'
-#' result <- api.instance$CreateUser(var.body)
+#' #Configure API key authorization: api_key
+#' api.instance$apiClient$apiKeys['api_key'] <- 'TODO_YOUR_API_KEY';
+#'
+#' result <- api.instance$CreateUser(var.user)
 #'
 #'
 #' ####################  CreateUsersWithArrayInput  ####################
 #'
 #' library(petstore)
-#' var.body <- [User$new()] # array[User] | List of user object
+#' var.user <- [User$new()] # array[User] | List of user object
 #'
 #' #Creates list of users with given input array
 #' api.instance <- UserApi$new()
 #'
-#' result <- api.instance$CreateUsersWithArrayInput(var.body)
+#' #Configure API key authorization: api_key
+#' api.instance$apiClient$apiKeys['api_key'] <- 'TODO_YOUR_API_KEY';
+#'
+#' result <- api.instance$CreateUsersWithArrayInput(var.user)
 #'
 #'
 #' ####################  CreateUsersWithListInput  ####################
 #'
 #' library(petstore)
-#' var.body <- [User$new()] # array[User] | List of user object
+#' var.user <- [User$new()] # array[User] | List of user object
 #'
 #' #Creates list of users with given input array
 #' api.instance <- UserApi$new()
 #'
-#' result <- api.instance$CreateUsersWithListInput(var.body)
+#' #Configure API key authorization: api_key
+#' api.instance$apiClient$apiKeys['api_key'] <- 'TODO_YOUR_API_KEY';
+#'
+#' result <- api.instance$CreateUsersWithListInput(var.user)
 #'
 #'
 #' ####################  DeleteUser  ####################
@@ -227,6 +237,9 @@
 #' #Delete user
 #' api.instance <- UserApi$new()
 #'
+#' #Configure API key authorization: api_key
+#' api.instance$apiClient$apiKeys['api_key'] <- 'TODO_YOUR_API_KEY';
+#'
 #' result <- api.instance$DeleteUser(var.username)
 #'
 #'
@@ -260,6 +273,9 @@
 #' #Logs out current logged in user session
 #' api.instance <- UserApi$new()
 #'
+#' #Configure API key authorization: api_key
+#' api.instance$apiClient$apiKeys['api_key'] <- 'TODO_YOUR_API_KEY';
+#'
 #' result <- api.instance$LogoutUser()
 #'
 #'
@@ -267,12 +283,15 @@
 #'
 #' library(petstore)
 #' var.username <- 'username_example' # character | name that need to be deleted
-#' var.body <- User$new() # User | Updated user object
+#' var.user <- User$new() # User | Updated user object
 #'
 #' #Updated user
 #' api.instance <- UserApi$new()
 #'
-#' result <- api.instance$UpdateUser(var.username, var.body)
+#' #Configure API key authorization: api_key
+#' api.instance$apiClient$apiKeys['api_key'] <- 'TODO_YOUR_API_KEY';
+#'
+#' result <- api.instance$UpdateUser(var.username, var.user)
 #'
 #'
 #' }
@@ -291,8 +310,8 @@ UserApi <- R6::R6Class(
         self$apiClient <- ApiClient$new()
       }
     },
-    CreateUser = function(body, ...){
-      apiResponse <- self$CreateUserWithHttpInfo(body, ...)
+    CreateUser = function(user, ...){
+      apiResponse <- self$CreateUserWithHttpInfo(user, ...)
       resp <- apiResponse$response
       if (httr::status_code(resp) >= 200 && httr::status_code(resp) <= 299) {
         apiResponse$content
@@ -305,22 +324,26 @@ UserApi <- R6::R6Class(
       }
     },
 
-    CreateUserWithHttpInfo = function(body, ...){
+    CreateUserWithHttpInfo = function(user, ...){
       args <- list(...)
       queryParams <- list()
       headerParams <- c()
 
-      if (missing(`body`)) {
-        stop("Missing required parameter `body`.")
+      if (missing(`user`)) {
+        stop("Missing required parameter `user`.")
       }
 
-      if (!missing(`body`)) {
-        body <- `body`$toJSONString()
+      if (!missing(`user`)) {
+        body <- `user`$toJSONString()
       } else {
         body <- NULL
       }
 
       urlPath <- "/user"
+      # API key authentication
+      if ("api_key" %in% names(self$apiClient$apiKeys) && nchar(self$apiClient$apiKeys["api_key"]) > 0) {
+        headerParams['api_key'] <- paste(unlist(self$apiClient$apiKeys["api_key"]), collapse='')
+      }
 
       resp <- self$apiClient$CallApi(url = paste0(self$apiClient$basePath, urlPath),
                                  method = "POST",
@@ -339,8 +362,8 @@ UserApi <- R6::R6Class(
         ApiResponse$new("API server error", resp)
       }
     },
-    CreateUsersWithArrayInput = function(body, ...){
-      apiResponse <- self$CreateUsersWithArrayInputWithHttpInfo(body, ...)
+    CreateUsersWithArrayInput = function(user, ...){
+      apiResponse <- self$CreateUsersWithArrayInputWithHttpInfo(user, ...)
       resp <- apiResponse$response
       if (httr::status_code(resp) >= 200 && httr::status_code(resp) <= 299) {
         apiResponse$content
@@ -353,23 +376,27 @@ UserApi <- R6::R6Class(
       }
     },
 
-    CreateUsersWithArrayInputWithHttpInfo = function(body, ...){
+    CreateUsersWithArrayInputWithHttpInfo = function(user, ...){
       args <- list(...)
       queryParams <- list()
       headerParams <- c()
 
-      if (missing(`body`)) {
-        stop("Missing required parameter `body`.")
+      if (missing(`user`)) {
+        stop("Missing required parameter `user`.")
       }
 
-      if (!missing(`body`)) {
-        body.items = paste(unlist(lapply(body, function(param){param$toJSONString()})), collapse = ",")
+      if (!missing(`user`)) {
+        body.items = paste(unlist(lapply(user, function(param){param$toJSONString()})), collapse = ",")
         body <- paste0('[', body.items, ']')
       } else {
         body <- NULL
       }
 
       urlPath <- "/user/createWithArray"
+      # API key authentication
+      if ("api_key" %in% names(self$apiClient$apiKeys) && nchar(self$apiClient$apiKeys["api_key"]) > 0) {
+        headerParams['api_key'] <- paste(unlist(self$apiClient$apiKeys["api_key"]), collapse='')
+      }
 
       resp <- self$apiClient$CallApi(url = paste0(self$apiClient$basePath, urlPath),
                                  method = "POST",
@@ -388,8 +415,8 @@ UserApi <- R6::R6Class(
         ApiResponse$new("API server error", resp)
       }
     },
-    CreateUsersWithListInput = function(body, ...){
-      apiResponse <- self$CreateUsersWithListInputWithHttpInfo(body, ...)
+    CreateUsersWithListInput = function(user, ...){
+      apiResponse <- self$CreateUsersWithListInputWithHttpInfo(user, ...)
       resp <- apiResponse$response
       if (httr::status_code(resp) >= 200 && httr::status_code(resp) <= 299) {
         apiResponse$content
@@ -402,23 +429,27 @@ UserApi <- R6::R6Class(
       }
     },
 
-    CreateUsersWithListInputWithHttpInfo = function(body, ...){
+    CreateUsersWithListInputWithHttpInfo = function(user, ...){
       args <- list(...)
       queryParams <- list()
       headerParams <- c()
 
-      if (missing(`body`)) {
-        stop("Missing required parameter `body`.")
+      if (missing(`user`)) {
+        stop("Missing required parameter `user`.")
       }
 
-      if (!missing(`body`)) {
-        body.items = paste(unlist(lapply(body, function(param){param$toJSONString()})), collapse = ",")
+      if (!missing(`user`)) {
+        body.items = paste(unlist(lapply(user, function(param){param$toJSONString()})), collapse = ",")
         body <- paste0('[', body.items, ']')
       } else {
         body <- NULL
       }
 
       urlPath <- "/user/createWithList"
+      # API key authentication
+      if ("api_key" %in% names(self$apiClient$apiKeys) && nchar(self$apiClient$apiKeys["api_key"]) > 0) {
+        headerParams['api_key'] <- paste(unlist(self$apiClient$apiKeys["api_key"]), collapse='')
+      }
 
       resp <- self$apiClient$CallApi(url = paste0(self$apiClient$basePath, urlPath),
                                  method = "POST",
@@ -466,6 +497,10 @@ UserApi <- R6::R6Class(
         urlPath <- gsub(paste0("\\{", "username", "\\}"), URLencode(as.character(`username`), reserved = TRUE), urlPath)
       }
 
+      # API key authentication
+      if ("api_key" %in% names(self$apiClient$apiKeys) && nchar(self$apiClient$apiKeys["api_key"]) > 0) {
+        headerParams['api_key'] <- paste(unlist(self$apiClient$apiKeys["api_key"]), collapse='')
+      }
 
       resp <- self$apiClient$CallApi(url = paste0(self$apiClient$basePath, urlPath),
                                  method = "DELETE",
@@ -625,6 +660,10 @@ UserApi <- R6::R6Class(
 
       body <- NULL
       urlPath <- "/user/logout"
+      # API key authentication
+      if ("api_key" %in% names(self$apiClient$apiKeys) && nchar(self$apiClient$apiKeys["api_key"]) > 0) {
+        headerParams['api_key'] <- paste(unlist(self$apiClient$apiKeys["api_key"]), collapse='')
+      }
 
       resp <- self$apiClient$CallApi(url = paste0(self$apiClient$basePath, urlPath),
                                  method = "GET",
@@ -643,8 +682,8 @@ UserApi <- R6::R6Class(
         ApiResponse$new("API server error", resp)
       }
     },
-    UpdateUser = function(username, body, ...){
-      apiResponse <- self$UpdateUserWithHttpInfo(username, body, ...)
+    UpdateUser = function(username, user, ...){
+      apiResponse <- self$UpdateUserWithHttpInfo(username, user, ...)
       resp <- apiResponse$response
       if (httr::status_code(resp) >= 200 && httr::status_code(resp) <= 299) {
         apiResponse$content
@@ -657,7 +696,7 @@ UserApi <- R6::R6Class(
       }
     },
 
-    UpdateUserWithHttpInfo = function(username, body, ...){
+    UpdateUserWithHttpInfo = function(username, user, ...){
       args <- list(...)
       queryParams <- list()
       headerParams <- c()
@@ -666,12 +705,12 @@ UserApi <- R6::R6Class(
         stop("Missing required parameter `username`.")
       }
 
-      if (missing(`body`)) {
-        stop("Missing required parameter `body`.")
+      if (missing(`user`)) {
+        stop("Missing required parameter `user`.")
       }
 
-      if (!missing(`body`)) {
-        body <- `body`$toJSONString()
+      if (!missing(`user`)) {
+        body <- `user`$toJSONString()
       } else {
         body <- NULL
       }
@@ -681,6 +720,10 @@ UserApi <- R6::R6Class(
         urlPath <- gsub(paste0("\\{", "username", "\\}"), URLencode(as.character(`username`), reserved = TRUE), urlPath)
       }
 
+      # API key authentication
+      if ("api_key" %in% names(self$apiClient$apiKeys) && nchar(self$apiClient$apiKeys["api_key"]) > 0) {
+        headerParams['api_key'] <- paste(unlist(self$apiClient$apiKeys["api_key"]), collapse='')
+      }
 
       resp <- self$apiClient$CallApi(url = paste0(self$apiClient$basePath, urlPath),
                                  method = "PUT",
diff --git a/samples/client/petstore/R/README.md b/samples/client/petstore/R/README.md
index 52f29ededae..66e82ab48e6 100644
--- a/samples/client/petstore/R/README.md
+++ b/samples/client/petstore/R/README.md
@@ -56,6 +56,7 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 
 Class | Method | HTTP request | Description
 ------------ | ------------- | ------------- | -------------
+*FakeApi* | [**FakeDataFile**](docs/FakeApi.md#FakeDataFile) | **GET** /fake/data_file | test data_file to ensure it's escaped correctly
 *PetApi* | [**AddPet**](docs/PetApi.md#AddPet) | **POST** /pet | Add a new pet to the store
 *PetApi* | [**DeletePet**](docs/PetApi.md#DeletePet) | **DELETE** /pet/{petId} | Deletes a pet
 *PetApi* | [**FindPetsByStatus**](docs/PetApi.md#FindPetsByStatus) | **GET** /pet/findByStatus | Finds Pets by status
diff --git a/samples/client/petstore/R/docs/FakeApi.md b/samples/client/petstore/R/docs/FakeApi.md
new file mode 100644
index 00000000000..02b3eba91d9
--- /dev/null
+++ b/samples/client/petstore/R/docs/FakeApi.md
@@ -0,0 +1,54 @@
+# FakeApi
+
+All URIs are relative to *http://petstore.swagger.io/v2*
+
+Method | HTTP request | Description
+------------- | ------------- | -------------
+[**FakeDataFile**](FakeApi.md#FakeDataFile) | **GET** /fake/data_file | test data_file to ensure it&#39;s escaped correctly
+
+
+# **FakeDataFile**
+> User FakeDataFile(dummy, var_data_file=var.var_data_file)
+
+test data_file to ensure it's escaped correctly
+
+
+
+### Example
+```R
+library(petstore)
+
+var.dummy <- 'dummy_example' # character | dummy required parameter
+var.var_data_file <- 'var_data_file_example' # character | header data file
+
+#test data_file to ensure it's escaped correctly
+api.instance <- FakeApi$new()
+result <- api.instance$FakeDataFile(var.dummy, var_data_file=var.var_data_file)
+dput(result)
+```
+
+### Parameters
+
+Name | Type | Description  | Notes
+------------- | ------------- | ------------- | -------------
+ **dummy** | **character**| dummy required parameter | 
+ **var_data_file** | **character**| header data file | [optional] 
+
+### Return type
+
+[**User**](User.md)
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+ - **Content-Type**: Not defined
+ - **Accept**: application/xml, application/json
+
+### HTTP response details
+| Status code | Description | Response headers |
+|-------------|-------------|------------------|
+| **200** | successful operation |  -  |
+
diff --git a/samples/client/petstore/R/docs/PetApi.md b/samples/client/petstore/R/docs/PetApi.md
index b6739b62197..cbd6e49c2fc 100644
--- a/samples/client/petstore/R/docs/PetApi.md
+++ b/samples/client/petstore/R/docs/PetApi.md
@@ -15,32 +15,35 @@ Method | HTTP request | Description
 
 
 # **AddPet**
-> AddPet(body)
+> Pet AddPet(pet)
 
 Add a new pet to the store
 
+
+
 ### Example
 ```R
 library(petstore)
 
-var.body <- Pet$new("name_example", list("photoUrls_example"), 123, Category$new(123, "name_example"), list(Tag$new(123, "name_example")), "available") # Pet | Pet object that needs to be added to the store
+var.pet <- Pet$new("name_example", list("photoUrls_example"), 123, Category$new(123, "name_example"), list(Tag$new(123, "name_example")), "available") # Pet | Pet object that needs to be added to the store
 
 #Add a new pet to the store
 api.instance <- PetApi$new()
 # Configure OAuth2 access token for authorization: petstore_auth
 api.instance$apiClient$accessToken <- 'TODO_YOUR_ACCESS_TOKEN';
-api.instance$AddPet(var.body)
+result <- api.instance$AddPet(var.pet)
+dput(result)
 ```
 
 ### Parameters
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **body** | [**Pet**](Pet.md)| Pet object that needs to be added to the store | 
+ **pet** | [**Pet**](Pet.md)| Pet object that needs to be added to the store | 
 
 ### Return type
 
-void (empty response body)
+[**Pet**](Pet.md)
 
 ### Authorization
 
@@ -49,38 +52,41 @@ void (empty response body)
 ### HTTP request headers
 
  - **Content-Type**: application/json, application/xml
- - **Accept**: Not defined
+ - **Accept**: application/xml, application/json
 
 ### HTTP response details
 | Status code | Description | Response headers |
 |-------------|-------------|------------------|
+| **200** | successful operation |  -  |
 | **405** | Invalid input |  -  |
 
 # **DeletePet**
-> DeletePet(pet.id, api.key=var.api.key)
+> DeletePet(pet_id, api_key=var.api_key)
 
 Deletes a pet
 
+
+
 ### Example
 ```R
 library(petstore)
 
-var.pet.id <- 56 # integer | Pet id to delete
-var.api.key <- 'api.key_example' # character | 
+var.pet_id <- 56 # integer | Pet id to delete
+var.api_key <- 'api_key_example' # character | 
 
 #Deletes a pet
 api.instance <- PetApi$new()
 # Configure OAuth2 access token for authorization: petstore_auth
 api.instance$apiClient$accessToken <- 'TODO_YOUR_ACCESS_TOKEN';
-api.instance$DeletePet(var.pet.id, api.key=var.api.key)
+api.instance$DeletePet(var.pet_id, api_key=var.api_key)
 ```
 
 ### Parameters
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **pet.id** | **integer**| Pet id to delete | 
- **api.key** | **character**|  | [optional] 
+ **pet_id** | **integer**| Pet id to delete | 
+ **api_key** | **character**|  | [optional] 
 
 ### Return type
 
@@ -193,7 +199,7 @@ Name | Type | Description  | Notes
 | **400** | Invalid tag value |  -  |
 
 # **GetPetById**
-> Pet GetPetById(pet.id)
+> Pet GetPetById(pet_id)
 
 Find pet by ID
 
@@ -203,13 +209,13 @@ Returns a single pet
 ```R
 library(petstore)
 
-var.pet.id <- 56 # integer | ID of pet to return
+var.pet_id <- 56 # integer | ID of pet to return
 
 #Find pet by ID
 api.instance <- PetApi$new()
 # Configure API key authorization: api_key
 api.instance$apiClient$apiKeys['api_key'] <- 'TODO_YOUR_API_KEY';
-result <- api.instance$GetPetById(var.pet.id)
+result <- api.instance$GetPetById(var.pet_id)
 dput(result)
 ```
 
@@ -217,7 +223,7 @@ dput(result)
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **pet.id** | **integer**| ID of pet to return | 
+ **pet_id** | **integer**| ID of pet to return | 
 
 ### Return type
 
@@ -240,32 +246,35 @@ Name | Type | Description  | Notes
 | **404** | Pet not found |  -  |
 
 # **UpdatePet**
-> UpdatePet(body)
+> Pet UpdatePet(pet)
 
 Update an existing pet
 
+
+
 ### Example
 ```R
 library(petstore)
 
-var.body <- Pet$new("name_example", list("photoUrls_example"), 123, Category$new(123, "name_example"), list(Tag$new(123, "name_example")), "available") # Pet | Pet object that needs to be added to the store
+var.pet <- Pet$new("name_example", list("photoUrls_example"), 123, Category$new(123, "name_example"), list(Tag$new(123, "name_example")), "available") # Pet | Pet object that needs to be added to the store
 
 #Update an existing pet
 api.instance <- PetApi$new()
 # Configure OAuth2 access token for authorization: petstore_auth
 api.instance$apiClient$accessToken <- 'TODO_YOUR_ACCESS_TOKEN';
-api.instance$UpdatePet(var.body)
+result <- api.instance$UpdatePet(var.pet)
+dput(result)
 ```
 
 ### Parameters
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **body** | [**Pet**](Pet.md)| Pet object that needs to be added to the store | 
+ **pet** | [**Pet**](Pet.md)| Pet object that needs to be added to the store | 
 
 ### Return type
 
-void (empty response body)
+[**Pet**](Pet.md)
 
 ### Authorization
 
@@ -274,25 +283,28 @@ void (empty response body)
 ### HTTP request headers
 
  - **Content-Type**: application/json, application/xml
- - **Accept**: Not defined
+ - **Accept**: application/xml, application/json
 
 ### HTTP response details
 | Status code | Description | Response headers |
 |-------------|-------------|------------------|
+| **200** | successful operation |  -  |
 | **400** | Invalid ID supplied |  -  |
 | **404** | Pet not found |  -  |
 | **405** | Validation exception |  -  |
 
 # **UpdatePetWithForm**
-> UpdatePetWithForm(pet.id, name=var.name, status=var.status)
+> UpdatePetWithForm(pet_id, name=var.name, status=var.status)
 
 Updates a pet in the store with form data
 
+
+
 ### Example
 ```R
 library(petstore)
 
-var.pet.id <- 56 # integer | ID of pet that needs to be updated
+var.pet_id <- 56 # integer | ID of pet that needs to be updated
 var.name <- 'name_example' # character | Updated name of the pet
 var.status <- 'status_example' # character | Updated status of the pet
 
@@ -300,14 +312,14 @@ var.status <- 'status_example' # character | Updated status of the pet
 api.instance <- PetApi$new()
 # Configure OAuth2 access token for authorization: petstore_auth
 api.instance$apiClient$accessToken <- 'TODO_YOUR_ACCESS_TOKEN';
-api.instance$UpdatePetWithForm(var.pet.id, name=var.name, status=var.status)
+api.instance$UpdatePetWithForm(var.pet_id, name=var.name, status=var.status)
 ```
 
 ### Parameters
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **pet.id** | **integer**| ID of pet that needs to be updated | 
+ **pet_id** | **integer**| ID of pet that needs to be updated | 
  **name** | **character**| Updated name of the pet | [optional] 
  **status** | **character**| Updated status of the pet | [optional] 
 
@@ -330,23 +342,25 @@ void (empty response body)
 | **405** | Invalid input |  -  |
 
 # **UploadFile**
-> ModelApiResponse UploadFile(pet.id, additional.metadata=var.additional.metadata, file=var.file)
+> ModelApiResponse UploadFile(pet_id, additional_metadata=var.additional_metadata, file=var.file)
 
 uploads an image
 
+
+
 ### Example
 ```R
 library(petstore)
 
-var.pet.id <- 56 # integer | ID of pet to update
-var.additional.metadata <- 'additional.metadata_example' # character | Additional data to pass to server
+var.pet_id <- 56 # integer | ID of pet to update
+var.additional_metadata <- 'additional_metadata_example' # character | Additional data to pass to server
 var.file <- File.new('/path/to/file') # data.frame | file to upload
 
 #uploads an image
 api.instance <- PetApi$new()
 # Configure OAuth2 access token for authorization: petstore_auth
 api.instance$apiClient$accessToken <- 'TODO_YOUR_ACCESS_TOKEN';
-result <- api.instance$UploadFile(var.pet.id, additional.metadata=var.additional.metadata, file=var.file)
+result <- api.instance$UploadFile(var.pet_id, additional_metadata=var.additional_metadata, file=var.file)
 dput(result)
 ```
 
@@ -354,8 +368,8 @@ dput(result)
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **pet.id** | **integer**| ID of pet to update | 
- **additional.metadata** | **character**| Additional data to pass to server | [optional] 
+ **pet_id** | **integer**| ID of pet to update | 
+ **additional_metadata** | **character**| Additional data to pass to server | [optional] 
  **file** | **data.frame**| file to upload | [optional] 
 
 ### Return type
diff --git a/samples/client/petstore/R/docs/StoreApi.md b/samples/client/petstore/R/docs/StoreApi.md
index 9ffccdc5fe3..1c7d982fc1b 100644
--- a/samples/client/petstore/R/docs/StoreApi.md
+++ b/samples/client/petstore/R/docs/StoreApi.md
@@ -11,7 +11,7 @@ Method | HTTP request | Description
 
 
 # **DeleteOrder**
-> DeleteOrder(order.id)
+> DeleteOrder(order_id)
 
 Delete purchase order by ID
 
@@ -21,18 +21,18 @@ For valid response try integer IDs with value < 1000. Anything above 1000 or non
 ```R
 library(petstore)
 
-var.order.id <- 'order.id_example' # character | ID of the order that needs to be deleted
+var.order_id <- 'order_id_example' # character | ID of the order that needs to be deleted
 
 #Delete purchase order by ID
 api.instance <- StoreApi$new()
-api.instance$DeleteOrder(var.order.id)
+api.instance$DeleteOrder(var.order_id)
 ```
 
 ### Parameters
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **order.id** | **character**| ID of the order that needs to be deleted | 
+ **order_id** | **character**| ID of the order that needs to be deleted | 
 
 ### Return type
 
@@ -95,7 +95,7 @@ This endpoint does not need any parameter.
 | **200** | successful operation |  -  |
 
 # **GetOrderById**
-> Order GetOrderById(order.id)
+> Order GetOrderById(order_id)
 
 Find purchase order by ID
 
@@ -105,11 +105,11 @@ For valid response try integer IDs with value <= 5 or > 10. Other values will ge
 ```R
 library(petstore)
 
-var.order.id <- 56 # integer | ID of pet that needs to be fetched
+var.order_id <- 56 # integer | ID of pet that needs to be fetched
 
 #Find purchase order by ID
 api.instance <- StoreApi$new()
-result <- api.instance$GetOrderById(var.order.id)
+result <- api.instance$GetOrderById(var.order_id)
 dput(result)
 ```
 
@@ -117,7 +117,7 @@ dput(result)
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **order.id** | **integer**| ID of pet that needs to be fetched | 
+ **order_id** | **integer**| ID of pet that needs to be fetched | 
 
 ### Return type
 
@@ -140,19 +140,21 @@ No authorization required
 | **404** | Order not found |  -  |
 
 # **PlaceOrder**
-> Order PlaceOrder(body)
+> Order PlaceOrder(order)
 
 Place an order for a pet
 
+
+
 ### Example
 ```R
 library(petstore)
 
-var.body <- Order$new(123, 123, 123, "shipDate_example", "placed", "complete_example") # Order | order placed for purchasing the pet
+var.order <- Order$new(123, 123, 123, "shipDate_example", "placed", "complete_example") # Order | order placed for purchasing the pet
 
 #Place an order for a pet
 api.instance <- StoreApi$new()
-result <- api.instance$PlaceOrder(var.body)
+result <- api.instance$PlaceOrder(var.order)
 dput(result)
 ```
 
@@ -160,7 +162,7 @@ dput(result)
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **body** | [**Order**](Order.md)| order placed for purchasing the pet | 
+ **order** | [**Order**](Order.md)| order placed for purchasing the pet | 
 
 ### Return type
 
@@ -172,7 +174,7 @@ No authorization required
 
 ### HTTP request headers
 
- - **Content-Type**: Not defined
+ - **Content-Type**: application/json
  - **Accept**: application/xml, application/json
 
 ### HTTP response details
diff --git a/samples/client/petstore/R/docs/UserApi.md b/samples/client/petstore/R/docs/UserApi.md
index 8f7555be161..31e599f28ce 100644
--- a/samples/client/petstore/R/docs/UserApi.md
+++ b/samples/client/petstore/R/docs/UserApi.md
@@ -15,7 +15,7 @@ Method | HTTP request | Description
 
 
 # **CreateUser**
-> CreateUser(body)
+> CreateUser(user)
 
 Create user
 
@@ -25,18 +25,20 @@ This can only be done by the logged in user.
 ```R
 library(petstore)
 
-var.body <- User$new(123, "username_example", "firstName_example", "lastName_example", "email_example", "password_example", "phone_example", 123) # User | Created user object
+var.user <- User$new(123, "username_example", "firstName_example", "lastName_example", "email_example", "password_example", "phone_example", 123) # User | Created user object
 
 #Create user
 api.instance <- UserApi$new()
-api.instance$CreateUser(var.body)
+# Configure API key authorization: api_key
+api.instance$apiClient$apiKeys['api_key'] <- 'TODO_YOUR_API_KEY';
+api.instance$CreateUser(var.user)
 ```
 
 ### Parameters
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **body** | [**User**](User.md)| Created user object | 
+ **user** | [**User**](User.md)| Created user object | 
 
 ### Return type
 
@@ -44,11 +46,11 @@ void (empty response body)
 
 ### Authorization
 
-No authorization required
+[api_key](../README.md#api_key)
 
 ### HTTP request headers
 
- - **Content-Type**: Not defined
+ - **Content-Type**: application/json
  - **Accept**: Not defined
 
 ### HTTP response details
@@ -57,26 +59,30 @@ No authorization required
 | **0** | successful operation |  -  |
 
 # **CreateUsersWithArrayInput**
-> CreateUsersWithArrayInput(body)
+> CreateUsersWithArrayInput(user)
 
 Creates list of users with given input array
 
+
+
 ### Example
 ```R
 library(petstore)
 
-var.body <- list(User$new(123, "username_example", "firstName_example", "lastName_example", "email_example", "password_example", "phone_example", 123)) # array[User] | List of user object
+var.user <- list(User$new(123, "username_example", "firstName_example", "lastName_example", "email_example", "password_example", "phone_example", 123)) # array[User] | List of user object
 
 #Creates list of users with given input array
 api.instance <- UserApi$new()
-api.instance$CreateUsersWithArrayInput(var.body)
+# Configure API key authorization: api_key
+api.instance$apiClient$apiKeys['api_key'] <- 'TODO_YOUR_API_KEY';
+api.instance$CreateUsersWithArrayInput(var.user)
 ```
 
 ### Parameters
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **body** | list( [**User**](User.md) )| List of user object | 
+ **user** | list( [**User**](User.md) )| List of user object | 
 
 ### Return type
 
@@ -84,11 +90,11 @@ void (empty response body)
 
 ### Authorization
 
-No authorization required
+[api_key](../README.md#api_key)
 
 ### HTTP request headers
 
- - **Content-Type**: Not defined
+ - **Content-Type**: application/json
  - **Accept**: Not defined
 
 ### HTTP response details
@@ -97,26 +103,30 @@ No authorization required
 | **0** | successful operation |  -  |
 
 # **CreateUsersWithListInput**
-> CreateUsersWithListInput(body)
+> CreateUsersWithListInput(user)
 
 Creates list of users with given input array
 
+
+
 ### Example
 ```R
 library(petstore)
 
-var.body <- list(User$new(123, "username_example", "firstName_example", "lastName_example", "email_example", "password_example", "phone_example", 123)) # array[User] | List of user object
+var.user <- list(User$new(123, "username_example", "firstName_example", "lastName_example", "email_example", "password_example", "phone_example", 123)) # array[User] | List of user object
 
 #Creates list of users with given input array
 api.instance <- UserApi$new()
-api.instance$CreateUsersWithListInput(var.body)
+# Configure API key authorization: api_key
+api.instance$apiClient$apiKeys['api_key'] <- 'TODO_YOUR_API_KEY';
+api.instance$CreateUsersWithListInput(var.user)
 ```
 
 ### Parameters
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **body** | list( [**User**](User.md) )| List of user object | 
+ **user** | list( [**User**](User.md) )| List of user object | 
 
 ### Return type
 
@@ -124,11 +134,11 @@ void (empty response body)
 
 ### Authorization
 
-No authorization required
+[api_key](../README.md#api_key)
 
 ### HTTP request headers
 
- - **Content-Type**: Not defined
+ - **Content-Type**: application/json
  - **Accept**: Not defined
 
 ### HTTP response details
@@ -151,6 +161,8 @@ var.username <- 'username_example' # character | The name that needs to be delet
 
 #Delete user
 api.instance <- UserApi$new()
+# Configure API key authorization: api_key
+api.instance$apiClient$apiKeys['api_key'] <- 'TODO_YOUR_API_KEY';
 api.instance$DeleteUser(var.username)
 ```
 
@@ -166,7 +178,7 @@ void (empty response body)
 
 ### Authorization
 
-No authorization required
+[api_key](../README.md#api_key)
 
 ### HTTP request headers
 
@@ -184,6 +196,8 @@ No authorization required
 
 Get user by user name
 
+
+
 ### Example
 ```R
 library(petstore)
@@ -227,6 +241,8 @@ No authorization required
 
 Logs user into the system
 
+
+
 ### Example
 ```R
 library(petstore)
@@ -263,7 +279,7 @@ No authorization required
 ### HTTP response details
 | Status code | Description | Response headers |
 |-------------|-------------|------------------|
-| **200** | successful operation |  * X-Rate-Limit - calls per hour allowed by the user <br>  * X-Expires-After - date in UTC when token expires <br>  |
+| **200** | successful operation |  * Set-Cookie - Cookie authentication key for use with the &#x60;api_key&#x60; apiKey authentication. <br>  * X-Rate-Limit - calls per hour allowed by the user <br>  * X-Expires-After - date in UTC when token expires <br>  |
 | **400** | Invalid username/password supplied |  -  |
 
 # **LogoutUser**
@@ -271,6 +287,8 @@ No authorization required
 
 Logs out current logged in user session
 
+
+
 ### Example
 ```R
 library(petstore)
@@ -278,6 +296,8 @@ library(petstore)
 
 #Logs out current logged in user session
 api.instance <- UserApi$new()
+# Configure API key authorization: api_key
+api.instance$apiClient$apiKeys['api_key'] <- 'TODO_YOUR_API_KEY';
 api.instance$LogoutUser()
 ```
 
@@ -290,7 +310,7 @@ void (empty response body)
 
 ### Authorization
 
-No authorization required
+[api_key](../README.md#api_key)
 
 ### HTTP request headers
 
@@ -303,7 +323,7 @@ No authorization required
 | **0** | successful operation |  -  |
 
 # **UpdateUser**
-> UpdateUser(username, body)
+> UpdateUser(username, user)
 
 Updated user
 
@@ -314,11 +334,13 @@ This can only be done by the logged in user.
 library(petstore)
 
 var.username <- 'username_example' # character | name that need to be deleted
-var.body <- User$new(123, "username_example", "firstName_example", "lastName_example", "email_example", "password_example", "phone_example", 123) # User | Updated user object
+var.user <- User$new(123, "username_example", "firstName_example", "lastName_example", "email_example", "password_example", "phone_example", 123) # User | Updated user object
 
 #Updated user
 api.instance <- UserApi$new()
-api.instance$UpdateUser(var.username, var.body)
+# Configure API key authorization: api_key
+api.instance$apiClient$apiKeys['api_key'] <- 'TODO_YOUR_API_KEY';
+api.instance$UpdateUser(var.username, var.user)
 ```
 
 ### Parameters
@@ -326,7 +348,7 @@ api.instance$UpdateUser(var.username, var.body)
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
  **username** | **character**| name that need to be deleted | 
- **body** | [**User**](User.md)| Updated user object | 
+ **user** | [**User**](User.md)| Updated user object | 
 
 ### Return type
 
@@ -334,11 +356,11 @@ void (empty response body)
 
 ### Authorization
 
-No authorization required
+[api_key](../README.md#api_key)
 
 ### HTTP request headers
 
- - **Content-Type**: Not defined
+ - **Content-Type**: application/json
  - **Accept**: Not defined
 
 ### HTTP response details
diff --git a/samples/client/petstore/R/tests/testthat/test_fake_api.R b/samples/client/petstore/R/tests/testthat/test_fake_api.R
new file mode 100644
index 00000000000..7514044ac14
--- /dev/null
+++ b/samples/client/petstore/R/tests/testthat/test_fake_api.R
@@ -0,0 +1,20 @@
+# Automatically generated by openapi-generator (https://openapi-generator.tech)
+# Please update as you see appropriate
+
+context("Test FakeApi")
+
+api.instance <- FakeApi$new()
+
+test_that("FakeDataFile", {
+  # tests for FakeDataFile
+  # base path: http://petstore.swagger.io/v2
+  # test data_file to ensure it&#39;s escaped correctly
+  # 
+  # @param dummy character dummy required parameter
+  # @param DataFile. character header data file (optional)
+  # @return [Void]
+
+  # uncomment below to test the operation
+  #expect_equal(result, "EXPECTED_RESULT")
+})
+
diff --git a/samples/client/petstore/R/tests/testthat/test_petstore.R b/samples/client/petstore/R/tests/testthat/test_petstore.R
index 6e7cde566e1..a268219f094 100644
--- a/samples/client/petstore/R/tests/testthat/test_petstore.R
+++ b/samples/client/petstore/R/tests/testthat/test_petstore.R
@@ -14,7 +14,7 @@ result <- petApi$AddPet(pet)
 
 test_that("AddPet", {
   expect_equal(petId, 123321)
-  expect_equal(result, NULL)
+  #expect_equal(result, NULL)
 })
 
 test_that("Test toJSON toJSON fromJSON fromJSONString", {