[Go] Parse int arrays and respect the 'required' property (#9120)

* Added int arrays parsing in parameters. Respect the 'required' property.

* Replaced spaces with tabs

* Generate samples with new spacing

* Removed unused import

* Merged with latest master

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractGoCodegen.java

@@ -311,16 +311,17 @@ public abstract class AbstractGoCodegen extends DefaultCodegen implements Codege
 
     @Override
     public String toApiFilename(String name) {
+        final String apiName;
         // replace - with _ e.g. created-at => created_at
-        name = name.replaceAll("-", "_"); // FIXME: a parameter should not be assigned. Also declare the methods parameters as 'final'.
-
+        String api = name.replaceAll("-", "_");
         // e.g. PetApi.go => pet_api.go
-        name = "api_" + underscore(name);
-        if (isReservedFilename(name)) {
-            LOGGER.warn(name + ".go with suffix (reserved word) cannot be used as filename. Renamed to " + name + "_.go");
-            name += "_";
+        api = "api_" + underscore(api);
+        if (isReservedFilename(api)) {
+            LOGGER.warn(name + ".go with suffix (reserved word) cannot be used as filename. Renamed to " + api + "_.go");
+            api += "_";
         }
-        return name;
+        apiName = api;
+        return apiName;
     }
 
     /**
@@ -807,7 +808,7 @@ public abstract class AbstractGoCodegen extends DefaultCodegen implements Codege
             return; // skip if GO_POST_PROCESS_FILE env variable is not defined
         }
 
-        // only procees the following type (or we can simply rely on the file extension to check if it's a Go file)
+        // only process the following type (or we can simply rely on the file extension to check if it's a Go file)
         Set<String> supportedFileType = new HashSet<String>(
                 Arrays.asList(
                         "supporting-mustache",

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/GoServerCodegen.java

@@ -235,10 +235,8 @@ public class GoServerCodegen extends AbstractGoCodegen {
         // override imports to only include packages for interface parameters
         imports.clear();
 
-        boolean addedOptionalImport = false;
         boolean addedTimeImport = false;
         boolean addedOSImport = false;
-        boolean addedReflectImport = false;
         for (CodegenOperation operation : operations) {
             for (CodegenParameter param : operation.allParams) {
                 // import "os" if the operation uses files
@@ -247,7 +245,7 @@ public class GoServerCodegen extends AbstractGoCodegen {
                     addedOSImport = true;
                 }
 
-                // import "time" if the operation has a required time parameter.
+                // import "time" if the operation has a required time parameter
                 if (param.required) {
                     if (!addedTimeImport && "time.Time".equals(param.dataType)) {
                         imports.add(createMapping("import", "time"));

modules/openapi-generator/src/main/resources/go-server/controller-api.mustache

@@ -16,7 +16,7 @@ type {{classname}}Controller struct {
 
 // New{{classname}}Controller creates a default api controller
 func New{{classname}}Controller(s {{classname}}Servicer) Router {
-	return &{{classname}}Controller{ service: s }
+	return &{{classname}}Controller{service: s}
 }
 
 // Routes returns all of the api route for the {{classname}}Controller
@@ -34,11 +34,18 @@ func (c *{{classname}}Controller) Routes() Routes {
 // {{nickname}} - {{{summary}}}
 func (c *{{classname}}Controller) {{nickname}}(w http.ResponseWriter, r *http.Request) {
 	{{#hasFormParams}}
-	err := r.ParseForm()
-	if err != nil {
+	{{#isMultipart}}
+	if err := r.ParseMultipartForm(32 << 20); err != nil {
 		w.WriteHeader(http.StatusBadRequest)
 		return
 	}
+	{{/isMultipart}}
+	{{^isMultipart}}
+	if err := r.ParseForm(); err != nil {
+		w.WriteHeader(http.StatusBadRequest)
+		return
+	}
+	{{/isMultipart}}
 	{{/hasFormParams}}
 	{{#hasPathParams}}
 	params := mux.Vars(r)
@@ -49,14 +56,14 @@ func (c *{{classname}}Controller) {{nickname}}(w http.ResponseWriter, r *http.Re
 	{{#allParams}}
 	{{#isPathParam}}
 	{{#isLong}}
-	{{paramName}}, err := parseInt64Parameter(params["{{baseName}}"])
+	{{paramName}}, err := parseInt64Parameter(params["{{baseName}}"], {{required}})
 	if err != nil {
 		w.WriteHeader(http.StatusBadRequest)
 		return
 	}
-    {{/isLong}}
+	{{/isLong}}
 	{{#isInteger}}
-	{{paramName}}, err := parseInt32Parameter(params["{{baseName}}"])
+	{{paramName}}, err := parseInt32Parameter(params["{{baseName}}"], {{required}})
 	if err != nil {
 		w.WriteHeader(http.StatusBadRequest)
 		return
@@ -69,14 +76,14 @@ func (c *{{classname}}Controller) {{nickname}}(w http.ResponseWriter, r *http.Re
 	{{/isPathParam}}
 	{{#isQueryParam}}
 	{{#isLong}}
-	{{paramName}}, err := parseInt64Parameter(query.Get("{{baseName}}"))
+	{{paramName}}, err := parseInt64Parameter(query.Get("{{baseName}}"), {{required}})
 	if err != nil {
 		w.WriteHeader(http.StatusBadRequest)
 		return
 	}
 	{{/isLong}}
 	{{#isInteger}}
-	{{paramName}}, err := parseInt32Parameter(query.Get("{{baseName}}"))
+	{{paramName}}, err := parseInt32Parameter(query.Get("{{baseName}}"), {{required}})
 	if err != nil {
 		w.WriteHeader(http.StatusBadRequest)
 		return
@@ -98,24 +105,26 @@ func (c *{{classname}}Controller) {{nickname}}(w http.ResponseWriter, r *http.Re
 	{{/isLong}}
 	{{/isQueryParam}}
 	{{#isFormParam}}
-	{{#isFile}}
-	{{#isArray}}
-	{{paramName}}, err := ReadFormFilesToTempFiles(r, "{{baseName}}"){{/isArray}}{{^isArray}}{{paramName}}, err := ReadFormFileToTempFile(r, "{{baseName}}")
+	{{#isFile}}{{#isArray}}
+	{{paramName}}, err := ReadFormFilesToTempFiles(r, "{{baseName}}"){{/isArray}}{{^isArray}}
+	{{paramName}}, err := ReadFormFileToTempFile(r, "{{baseName}}")
 	{{/isArray}}
 	if err != nil {
 		w.WriteHeader(http.StatusBadRequest)
 		return
 	}
 	{{/isFile}}
-	{{#isLong}}
-	{{paramName}}, err := parseInt64Parameter( r.FormValue("{{baseName}}"))
+	{{#isLong}}{{#isArray}}
+	{{paramName}}, err := parseInt64ArrayParameter(r.FormValue("{{baseName}}"), ",", {{required}}){{/isArray}}{{^isArray}}
+	{{paramName}}, err := parseInt64Parameter(r.FormValue("{{baseName}}"), {{required}}){{/isArray}}
 	if err != nil {
 		w.WriteHeader(http.StatusBadRequest)
 		return
 	}
 	{{/isLong}}
-	{{#isInteger}}
-	{{paramName}}, err := parseInt32Parameter( r.FormValue("{{baseName}}"))
+	{{#isInteger}}{{#isArray}}
+	{{paramName}}, err := parseInt32ArrayParameter(r.FormValue("{{baseName}}"), ",", {{required}}){{/isArray}}{{^isArray}}
+	{{paramName}}, err := parseInt32Parameter(r.FormValue("{{baseName}}"), {{required}}){{/isArray}}
 	if err != nil {
 		w.WriteHeader(http.StatusBadRequest)
 		return
@@ -139,12 +148,12 @@ func (c *{{classname}}Controller) {{nickname}}(w http.ResponseWriter, r *http.Re
 	{{/isBodyParam}}
 	{{/allParams}}
 	result, err := c.service.{{nickname}}(r.Context(){{#allParams}}, {{#isBodyParam}}*{{/isBodyParam}}{{paramName}}{{/allParams}})
-	//If an error occured, encode the error with the status code
+	// If an error occurred, encode the error with the status code
 	if err != nil {
 		EncodeJSONResponse(err.Error(), &result.Code,{{#addResponseHeaders}} result.Headers,{{/addResponseHeaders}} w)
 		return
 	}
-	//If no error, encode the body and the result code
+	// If no error, encode the body and the result code
 	EncodeJSONResponse(result.Body, &result.Code,{{#addResponseHeaders}} result.Headers,{{/addResponseHeaders}} w)
 
 }{{/operation}}{{/operations}}

modules/openapi-generator/src/main/resources/go-server/routers.mustache

@@ -3,22 +3,24 @@ package {{packageName}}
 
 import (
 	"encoding/json"
+	"errors"
+	"github.com/gorilla/mux"
+	{{#featureCORS}}
+	"github.com/gorilla/handlers"
+	{{/featureCORS}}
 	"io/ioutil"
 	"mime/multipart"
 	"net/http"
 	"os"
 	"strconv"
-	{{#featureCORS}}
-	"github.com/gorilla/handlers"
-	{{/featureCORS}}
-	"github.com/gorilla/mux"
+	"strings"
 )
 
 // A Route defines the parameters for an api endpoint
 type Route struct {
-	Name        string
-	Method      string
-	Pattern     string
+	Name		string
+	Method	  string
+	Pattern	 string
 	HandlerFunc http.HandlerFunc
 }
 
@@ -30,6 +32,8 @@ type Router interface {
 	Routes() Routes
 }
 
+const errMsgRequiredMissing = "required parameter is missing"
+
 // NewRouter creates a new router for any number of api routers
 func NewRouter(routers ...Router) *mux.Router {
 	router := mux.NewRouter().StrictSlash(true)
@@ -134,17 +138,34 @@ func readFileHeaderToTempFile(fileHeader *multipart.FileHeader) (*os.File, error
 	return file, nil
 }
 
-// parseInt64Parameter parses a string parameter to an int64
-func parseInt64Parameter(param string) (int64, error) {
+// parseInt64Parameter parses a string parameter to an int64.
+func parseInt64Parameter(param string, required bool) (int64, error) {
+	if param == "" {
+		if required {
+			return 0, errors.New(errMsgRequiredMissing)
+		}
+
+		return 0, nil
+	}
+
 	return strconv.ParseInt(param, 10, 64)
 }
 
-// parseInt32Parameter parses a string parameter to an int32
-func parseInt32Parameter(param string) (int32, error) {
+// parseInt32Parameter parses a string parameter to an int32.
+func parseInt32Parameter(param string, required bool) (int32, error) {
+	if param == "" {
+		if required {
+			return 0, errors.New(errMsgRequiredMissing)
+		}
+
+		return 0, nil
+	}
+
 	val, err := strconv.ParseInt(param, 10, 32)
 	if err != nil {
 		return -1, err
 	}
+
 	return int32(val), nil
 }
 
@@ -154,5 +175,54 @@ func parseBoolParameter(param string) (bool, error) {
 	if err != nil {
 		return false, err
 	}
+
 	return bool(val), nil
 }
+
+// parseInt64ArrayParameter parses a string parameter containing array of values to []int64.
+func parseInt64ArrayParameter(param, delim string, required bool) ([]int64, error) {
+	if param == "" {
+		if required {
+			return nil, errors.New(errMsgRequiredMissing)
+		}
+
+		return nil, nil
+	}
+
+	str := strings.Split(param, delim)
+	ints := make([]int64, len(str))
+
+	for i, s := range str {
+		if v, err := strconv.ParseInt(s, 10, 64); err != nil {
+			return nil, err
+		} else {
+			ints[i] = v
+		}
+	}
+
+	return ints, nil
+}
+
+// parseInt32ArrayParameter parses a string parameter containing array of values to []int32.
+func parseInt32ArrayParameter(param, delim string, required bool) ([]int32, error) {
+	if param == "" {
+		if required {
+			return nil, errors.New(errMsgRequiredMissing)
+		}
+
+		return nil, nil
+	}
+
+	str := strings.Split(param, delim)
+	ints := make([]int32, len(str))
+
+	for i, s := range str {
+		if v, err := strconv.ParseInt(s, 10, 32); err != nil {
+			return nil, err
+		} else {
+			ints[i] = int32(v)
+		}
+	}
+
+	return ints, nil
+}

samples/server/petstore/go-api-server/go/api_pet.go

@@ -24,7 +24,7 @@ type PetApiController struct {
 
 // NewPetApiController creates a default api controller
 func NewPetApiController(s PetApiServicer) Router {
-	return &PetApiController{ service: s }
+	return &PetApiController{service: s}
 }
 
 // Routes returns all of the api route for the PetApiController
@@ -89,12 +89,12 @@ func (c *PetApiController) AddPet(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	result, err := c.service.AddPet(r.Context(), *pet)
-	//If an error occured, encode the error with the status code
+	// If an error occurred, encode the error with the status code
 	if err != nil {
 		EncodeJSONResponse(err.Error(), &result.Code, result.Headers, w)
 		return
 	}
-	//If no error, encode the body and the result code
+	// If no error, encode the body and the result code
 	EncodeJSONResponse(result.Body, &result.Code, result.Headers, w)
 
 }
@@ -102,7 +102,7 @@ func (c *PetApiController) AddPet(w http.ResponseWriter, r *http.Request) {
 // DeletePet - Deletes a pet
 func (c *PetApiController) DeletePet(w http.ResponseWriter, r *http.Request) {
 	params := mux.Vars(r)
-	petId, err := parseInt64Parameter(params["petId"])
+	petId, err := parseInt64Parameter(params["petId"], true)
 	if err != nil {
 		w.WriteHeader(http.StatusBadRequest)
 		return
@@ -110,12 +110,12 @@ func (c *PetApiController) DeletePet(w http.ResponseWriter, r *http.Request) {
 
 	apiKey := r.Header.Get("api_key")
 	result, err := c.service.DeletePet(r.Context(), petId, apiKey)
-	//If an error occured, encode the error with the status code
+	// If an error occurred, encode the error with the status code
 	if err != nil {
 		EncodeJSONResponse(err.Error(), &result.Code, result.Headers, w)
 		return
 	}
-	//If no error, encode the body and the result code
+	// If no error, encode the body and the result code
 	EncodeJSONResponse(result.Body, &result.Code, result.Headers, w)
 
 }
@@ -125,12 +125,12 @@ func (c *PetApiController) FindPetsByStatus(w http.ResponseWriter, r *http.Reque
 	query := r.URL.Query()
 	status := strings.Split(query.Get("status"), ",")
 	result, err := c.service.FindPetsByStatus(r.Context(), status)
-	//If an error occured, encode the error with the status code
+	// If an error occurred, encode the error with the status code
 	if err != nil {
 		EncodeJSONResponse(err.Error(), &result.Code, result.Headers, w)
 		return
 	}
-	//If no error, encode the body and the result code
+	// If no error, encode the body and the result code
 	EncodeJSONResponse(result.Body, &result.Code, result.Headers, w)
 
 }
@@ -140,12 +140,12 @@ func (c *PetApiController) FindPetsByTags(w http.ResponseWriter, r *http.Request
 	query := r.URL.Query()
 	tags := strings.Split(query.Get("tags"), ",")
 	result, err := c.service.FindPetsByTags(r.Context(), tags)
-	//If an error occured, encode the error with the status code
+	// If an error occurred, encode the error with the status code
 	if err != nil {
 		EncodeJSONResponse(err.Error(), &result.Code, result.Headers, w)
 		return
 	}
-	//If no error, encode the body and the result code
+	// If no error, encode the body and the result code
 	EncodeJSONResponse(result.Body, &result.Code, result.Headers, w)
 
 }
@@ -153,19 +153,19 @@ func (c *PetApiController) FindPetsByTags(w http.ResponseWriter, r *http.Request
 // GetPetById - Find pet by ID
 func (c *PetApiController) GetPetById(w http.ResponseWriter, r *http.Request) {
 	params := mux.Vars(r)
-	petId, err := parseInt64Parameter(params["petId"])
+	petId, err := parseInt64Parameter(params["petId"], true)
 	if err != nil {
 		w.WriteHeader(http.StatusBadRequest)
 		return
 	}
 
 	result, err := c.service.GetPetById(r.Context(), petId)
-	//If an error occured, encode the error with the status code
+	// If an error occurred, encode the error with the status code
 	if err != nil {
 		EncodeJSONResponse(err.Error(), &result.Code, result.Headers, w)
 		return
 	}
-	//If no error, encode the body and the result code
+	// If no error, encode the body and the result code
 	EncodeJSONResponse(result.Body, &result.Code, result.Headers, w)
 
 }
@@ -178,70 +178,69 @@ func (c *PetApiController) UpdatePet(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	result, err := c.service.UpdatePet(r.Context(), *pet)
-	//If an error occured, encode the error with the status code
+	// If an error occurred, encode the error with the status code
 	if err != nil {
 		EncodeJSONResponse(err.Error(), &result.Code, result.Headers, w)
 		return
 	}
-	//If no error, encode the body and the result code
+	// If no error, encode the body and the result code
 	EncodeJSONResponse(result.Body, &result.Code, result.Headers, w)
 
 }
 
 // UpdatePetWithForm - Updates a pet in the store with form data
 func (c *PetApiController) UpdatePetWithForm(w http.ResponseWriter, r *http.Request) {
-	err := r.ParseForm()
-	if err != nil {
+	if err := r.ParseForm(); err != nil {
 		w.WriteHeader(http.StatusBadRequest)
 		return
 	}
 	params := mux.Vars(r)
-	petId, err := parseInt64Parameter(params["petId"])
+	petId, err := parseInt64Parameter(params["petId"], true)
 	if err != nil {
 		w.WriteHeader(http.StatusBadRequest)
 		return
 	}
 
-	name := r.FormValue("name")
-	status := r.FormValue("status")
+				name := r.FormValue("name")
+				status := r.FormValue("status")
 	result, err := c.service.UpdatePetWithForm(r.Context(), petId, name, status)
-	//If an error occured, encode the error with the status code
+	// If an error occurred, encode the error with the status code
 	if err != nil {
 		EncodeJSONResponse(err.Error(), &result.Code, result.Headers, w)
 		return
 	}
-	//If no error, encode the body and the result code
+	// If no error, encode the body and the result code
 	EncodeJSONResponse(result.Body, &result.Code, result.Headers, w)
 
 }
 
 // UploadFile - uploads an image
 func (c *PetApiController) UploadFile(w http.ResponseWriter, r *http.Request) {
-	err := r.ParseForm()
-	if err != nil {
+	if err := r.ParseMultipartForm(32 << 20); err != nil {
 		w.WriteHeader(http.StatusBadRequest)
 		return
 	}
 	params := mux.Vars(r)
-	petId, err := parseInt64Parameter(params["petId"])
+	petId, err := parseInt64Parameter(params["petId"], true)
 	if err != nil {
 		w.WriteHeader(http.StatusBadRequest)
 		return
 	}
 
-	additionalMetadata := r.FormValue("additionalMetadata")
-file, err := ReadFormFileToTempFile(r, "file")
+				additionalMetadata := r.FormValue("additionalMetadata")
+	
+	file, err := ReadFormFileToTempFile(r, "file")
 	if err != nil {
 		w.WriteHeader(http.StatusBadRequest)
 		return
 	}
-	result, err := c.service.UploadFile(r.Context(), petId, additionalMetadata, file)
-	//If an error occured, encode the error with the status code
+			result, err := c.service.UploadFile(r.Context(), petId, additionalMetadata, file)
+	// If an error occurred, encode the error with the status code
 	if err != nil {
 		EncodeJSONResponse(err.Error(), &result.Code, result.Headers, w)
 		return
 	}
-	//If no error, encode the body and the result code
+	// If no error, encode the body and the result code
 	EncodeJSONResponse(result.Body, &result.Code, result.Headers, w)
 
 }

samples/server/petstore/go-api-server/go/api_store.go

@@ -24,7 +24,7 @@ type StoreApiController struct {
 
 // NewStoreApiController creates a default api controller
 func NewStoreApiController(s StoreApiServicer) Router {
-	return &StoreApiController{ service: s }
+	return &StoreApiController{service: s}
 }
 
 // Routes returns all of the api route for the StoreApiController
@@ -63,12 +63,12 @@ func (c *StoreApiController) DeleteOrder(w http.ResponseWriter, r *http.Request)
 	orderId := params["orderId"]
 	
 	result, err := c.service.DeleteOrder(r.Context(), orderId)
-	//If an error occured, encode the error with the status code
+	// If an error occurred, encode the error with the status code
 	if err != nil {
 		EncodeJSONResponse(err.Error(), &result.Code, result.Headers, w)
 		return
 	}
-	//If no error, encode the body and the result code
+	// If no error, encode the body and the result code
 	EncodeJSONResponse(result.Body, &result.Code, result.Headers, w)
 
 }
@@ -76,12 +76,12 @@ func (c *StoreApiController) DeleteOrder(w http.ResponseWriter, r *http.Request)
 // GetInventory - Returns pet inventories by status
 func (c *StoreApiController) GetInventory(w http.ResponseWriter, r *http.Request) {
 	result, err := c.service.GetInventory(r.Context())
-	//If an error occured, encode the error with the status code
+	// If an error occurred, encode the error with the status code
 	if err != nil {
 		EncodeJSONResponse(err.Error(), &result.Code, result.Headers, w)
 		return
 	}
-	//If no error, encode the body and the result code
+	// If no error, encode the body and the result code
 	EncodeJSONResponse(result.Body, &result.Code, result.Headers, w)
 
 }
@@ -89,19 +89,19 @@ func (c *StoreApiController) GetInventory(w http.ResponseWriter, r *http.Request
 // GetOrderById - Find purchase order by ID
 func (c *StoreApiController) GetOrderById(w http.ResponseWriter, r *http.Request) {
 	params := mux.Vars(r)
-	orderId, err := parseInt64Parameter(params["orderId"])
+	orderId, err := parseInt64Parameter(params["orderId"], true)
 	if err != nil {
 		w.WriteHeader(http.StatusBadRequest)
 		return
 	}
 
 	result, err := c.service.GetOrderById(r.Context(), orderId)
-	//If an error occured, encode the error with the status code
+	// If an error occurred, encode the error with the status code
 	if err != nil {
 		EncodeJSONResponse(err.Error(), &result.Code, result.Headers, w)
 		return
 	}
-	//If no error, encode the body and the result code
+	// If no error, encode the body and the result code
 	EncodeJSONResponse(result.Body, &result.Code, result.Headers, w)
 
 }
@@ -114,12 +114,12 @@ func (c *StoreApiController) PlaceOrder(w http.ResponseWriter, r *http.Request)
 		return
 	}
 	result, err := c.service.PlaceOrder(r.Context(), *order)
-	//If an error occured, encode the error with the status code
+	// If an error occurred, encode the error with the status code
 	if err != nil {
 		EncodeJSONResponse(err.Error(), &result.Code, result.Headers, w)
 		return
 	}
-	//If no error, encode the body and the result code
+	// If no error, encode the body and the result code
 	EncodeJSONResponse(result.Body, &result.Code, result.Headers, w)
 
 }

samples/server/petstore/go-api-server/go/api_user.go

@@ -24,7 +24,7 @@ type UserApiController struct {
 
 // NewUserApiController creates a default api controller
 func NewUserApiController(s UserApiServicer) Router {
-	return &UserApiController{ service: s }
+	return &UserApiController{service: s}
 }
 
 // Routes returns all of the api route for the UserApiController
@@ -89,12 +89,12 @@ func (c *UserApiController) CreateUser(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	result, err := c.service.CreateUser(r.Context(), *user)
-	//If an error occured, encode the error with the status code
+	// If an error occurred, encode the error with the status code
 	if err != nil {
 		EncodeJSONResponse(err.Error(), &result.Code, result.Headers, w)
 		return
 	}
-	//If no error, encode the body and the result code
+	// If no error, encode the body and the result code
 	EncodeJSONResponse(result.Body, &result.Code, result.Headers, w)
 
 }
@@ -107,12 +107,12 @@ func (c *UserApiController) CreateUsersWithArrayInput(w http.ResponseWriter, r *
 		return
 	}
 	result, err := c.service.CreateUsersWithArrayInput(r.Context(), *user)
-	//If an error occured, encode the error with the status code
+	// If an error occurred, encode the error with the status code
 	if err != nil {
 		EncodeJSONResponse(err.Error(), &result.Code, result.Headers, w)
 		return
 	}
-	//If no error, encode the body and the result code
+	// If no error, encode the body and the result code
 	EncodeJSONResponse(result.Body, &result.Code, result.Headers, w)
 
 }
@@ -125,12 +125,12 @@ func (c *UserApiController) CreateUsersWithListInput(w http.ResponseWriter, r *h
 		return
 	}
 	result, err := c.service.CreateUsersWithListInput(r.Context(), *user)
-	//If an error occured, encode the error with the status code
+	// If an error occurred, encode the error with the status code
 	if err != nil {
 		EncodeJSONResponse(err.Error(), &result.Code, result.Headers, w)
 		return
 	}
-	//If no error, encode the body and the result code
+	// If no error, encode the body and the result code
 	EncodeJSONResponse(result.Body, &result.Code, result.Headers, w)
 
 }
@@ -141,12 +141,12 @@ func (c *UserApiController) DeleteUser(w http.ResponseWriter, r *http.Request) {
 	username := params["username"]
 	
 	result, err := c.service.DeleteUser(r.Context(), username)
-	//If an error occured, encode the error with the status code
+	// If an error occurred, encode the error with the status code
 	if err != nil {
 		EncodeJSONResponse(err.Error(), &result.Code, result.Headers, w)
 		return
 	}
-	//If no error, encode the body and the result code
+	// If no error, encode the body and the result code
 	EncodeJSONResponse(result.Body, &result.Code, result.Headers, w)
 
 }
@@ -157,12 +157,12 @@ func (c *UserApiController) GetUserByName(w http.ResponseWriter, r *http.Request
 	username := params["username"]
 	
 	result, err := c.service.GetUserByName(r.Context(), username)
-	//If an error occured, encode the error with the status code
+	// If an error occurred, encode the error with the status code
 	if err != nil {
 		EncodeJSONResponse(err.Error(), &result.Code, result.Headers, w)
 		return
 	}
-	//If no error, encode the body and the result code
+	// If no error, encode the body and the result code
 	EncodeJSONResponse(result.Body, &result.Code, result.Headers, w)
 
 }
@@ -173,12 +173,12 @@ func (c *UserApiController) LoginUser(w http.ResponseWriter, r *http.Request) {
 	username := query.Get("username")
 	password := query.Get("password")
 	result, err := c.service.LoginUser(r.Context(), username, password)
-	//If an error occured, encode the error with the status code
+	// If an error occurred, encode the error with the status code
 	if err != nil {
 		EncodeJSONResponse(err.Error(), &result.Code, result.Headers, w)
 		return
 	}
-	//If no error, encode the body and the result code
+	// If no error, encode the body and the result code
 	EncodeJSONResponse(result.Body, &result.Code, result.Headers, w)
 
 }
@@ -186,12 +186,12 @@ func (c *UserApiController) LoginUser(w http.ResponseWriter, r *http.Request) {
 // LogoutUser - Logs out current logged in user session
 func (c *UserApiController) LogoutUser(w http.ResponseWriter, r *http.Request) {
 	result, err := c.service.LogoutUser(r.Context())
-	//If an error occured, encode the error with the status code
+	// If an error occurred, encode the error with the status code
 	if err != nil {
 		EncodeJSONResponse(err.Error(), &result.Code, result.Headers, w)
 		return
 	}
-	//If no error, encode the body and the result code
+	// If no error, encode the body and the result code
 	EncodeJSONResponse(result.Body, &result.Code, result.Headers, w)
 
 }
@@ -207,12 +207,12 @@ func (c *UserApiController) UpdateUser(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	result, err := c.service.UpdateUser(r.Context(), username, *user)
-	//If an error occured, encode the error with the status code
+	// If an error occurred, encode the error with the status code
 	if err != nil {
 		EncodeJSONResponse(err.Error(), &result.Code, result.Headers, w)
 		return
 	}
-	//If no error, encode the body and the result code
+	// If no error, encode the body and the result code
 	EncodeJSONResponse(result.Body, &result.Code, result.Headers, w)
 
 }

samples/server/petstore/go-api-server/go/routers.go

@@ -11,19 +11,21 @@ package petstoreserver
 
 import (
 	"encoding/json"
+	"errors"
+	"github.com/gorilla/mux"
 	"io/ioutil"
 	"mime/multipart"
 	"net/http"
 	"os"
 	"strconv"
-	"github.com/gorilla/mux"
+	"strings"
 )
 
 // A Route defines the parameters for an api endpoint
 type Route struct {
-	Name        string
-	Method      string
-	Pattern     string
+	Name		string
+	Method	  string
+	Pattern	 string
 	HandlerFunc http.HandlerFunc
 }
 
@@ -35,6 +37,8 @@ type Router interface {
 	Routes() Routes
 }
 
+const errMsgRequiredMissing = "required parameter is missing"
+
 // NewRouter creates a new router for any number of api routers
 func NewRouter(routers ...Router) *mux.Router {
 	router := mux.NewRouter().StrictSlash(true)
@@ -123,17 +127,34 @@ func readFileHeaderToTempFile(fileHeader *multipart.FileHeader) (*os.File, error
 	return file, nil
 }
 
-// parseInt64Parameter parses a string parameter to an int64
-func parseInt64Parameter(param string) (int64, error) {
+// parseInt64Parameter parses a string parameter to an int64.
+func parseInt64Parameter(param string, required bool) (int64, error) {
+	if param == "" {
+		if required {
+			return 0, errors.New(errMsgRequiredMissing)
+		}
+
+		return 0, nil
+	}
+
 	return strconv.ParseInt(param, 10, 64)
 }
 
-// parseInt32Parameter parses a string parameter to an int32
-func parseInt32Parameter(param string) (int32, error) {
+// parseInt32Parameter parses a string parameter to an int32.
+func parseInt32Parameter(param string, required bool) (int32, error) {
+	if param == "" {
+		if required {
+			return 0, errors.New(errMsgRequiredMissing)
+		}
+
+		return 0, nil
+	}
+
 	val, err := strconv.ParseInt(param, 10, 32)
 	if err != nil {
 		return -1, err
 	}
+
 	return int32(val), nil
 }
 
@@ -143,5 +164,54 @@ func parseBoolParameter(param string) (bool, error) {
 	if err != nil {
 		return false, err
 	}
+
 	return bool(val), nil
 }
+
+// parseInt64ArrayParameter parses a string parameter containing array of values to []int64.
+func parseInt64ArrayParameter(param, delim string, required bool) ([]int64, error) {
+	if param == "" {
+		if required {
+			return nil, errors.New(errMsgRequiredMissing)
+		}
+
+		return nil, nil
+	}
+
+	str := strings.Split(param, delim)
+	ints := make([]int64, len(str))
+
+	for i, s := range str {
+		if v, err := strconv.ParseInt(s, 10, 64); err != nil {
+			return nil, err
+		} else {
+			ints[i] = v
+		}
+	}
+
+	return ints, nil
+}
+
+// parseInt32ArrayParameter parses a string parameter containing array of values to []int32.
+func parseInt32ArrayParameter(param, delim string, required bool) ([]int32, error) {
+	if param == "" {
+		if required {
+			return nil, errors.New(errMsgRequiredMissing)
+		}
+
+		return nil, nil
+	}
+
+	str := strings.Split(param, delim)
+	ints := make([]int32, len(str))
+
+	for i, s := range str {
+		if v, err := strconv.ParseInt(s, 10, 32); err != nil {
+			return nil, err
+		} else {
+			ints[i] = int32(v)
+		}
+	}
+
+	return ints, nil
+}