diff --git a/bin/openapi3/ruby-client-petstore.sh b/bin/openapi3/ruby-client-petstore.sh
index 76c321582b0..67420ee1df5 100755
--- a/bin/openapi3/ruby-client-petstore.sh
+++ b/bin/openapi3/ruby-client-petstore.sh
@@ -27,6 +27,6 @@ fi
 
 # if you've executed sbt assembly previously it will use that instead.
 export JAVA_OPTS="${JAVA_OPTS} -XX:MaxPermSize=256M -Xmx1024M -DloggerPath=conf/log4j.properties"
-ags="generate -t modules/openapi-generator/src/main/resources/ruby-client -i modules/openapi-generator/src/test/resources/3_0/petstore-with-fake-endpoints-models-for-testing.yaml -g ruby -c bin/ruby-petstore.json -o samples/client/petstore/ruby $@"
+ags="generate -t modules/openapi-generator/src/main/resources/ruby-client -i modules/openapi-generator/src/test/resources/3_0/petstore-with-fake-endpoints-models-for-testing.yaml -g ruby -c bin/ruby-petstore.json -o samples/client/petstore/ruby -DskipFormModel=true $@"
 
 java $JAVA_OPTS -jar $executable $ags
diff --git a/bin/utils/ensure-up-to-date b/bin/utils/ensure-up-to-date
index 7ce762d807e..f7b86a587f9 100755
--- a/bin/utils/ensure-up-to-date
+++ b/bin/utils/ensure-up-to-date
@@ -10,7 +10,7 @@ echo "Please press CTRL+C to stop or the script will continue in 5 seconds."
 sleep 5
 
 # LIST OF SCRIPTS:
-./bin/ruby-client-petstore.sh > /dev/null 2>&1
+./bin/openapi3/ruby-client-petstore.sh > /dev/null 2>&1
 ./bin/java-petstore-all.sh > /dev/null 2>&1
 ./bin/java-jaxrs-petstore-server-all.sh > /dev/null 2>&1
 ./bin/spring-all-pestore.sh > /dev/null 2>&1
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/URLPathUtils.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/URLPathUtils.java
index fdfa6fdfd6b..26030abbe1b 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/URLPathUtils.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/URLPathUtils.java
@@ -168,7 +168,7 @@ public class URLPathUtils {
      */
     public static String getHost(OpenAPI openAPI) {
         if (openAPI.getServers() != null && openAPI.getServers().size() > 0) {
-            return sanitizeUrl(openAPI.getServers().get(0).getUrl());
+            return sanitizeUrl(getServerURL(openAPI.getServers().get(0)).toString());
         }
         return LOCAL_HOST;
     }
diff --git a/modules/openapi-generator/src/main/resources/ruby-client/configuration.mustache b/modules/openapi-generator/src/main/resources/ruby-client/configuration.mustache
index 7c7e1d82dc5..dcfb0004228 100644
--- a/modules/openapi-generator/src/main/resources/ruby-client/configuration.mustache
+++ b/modules/openapi-generator/src/main/resources/ruby-client/configuration.mustache
@@ -219,5 +219,70 @@ module {{moduleName}}
 {{/authMethods}}
       }
     end
+
+    # Returns an array of Server setting
+    def server_settings
+      [
+      {{#servers}}
+        {
+          url: "{{{url}}}",
+          description: "{{{description}}}{{^description}}No descriptoin provided{{/description}}",
+          {{#variables}}
+          {{#-first}}
+          variables: {
+          {{/-first}}
+            {{{name}}}: {
+                description: "{{{description}}}{{^description}}No descriptoin provided{{/description}}",
+                default_value: "{{{defaultValue}}}",
+                {{#enumValues}}
+                {{#-first}}
+                enum_values: [
+                {{/-first}}
+                  "{{{.}}}"{{^-last}},{{/-last}}
+                {{#-last}}
+                ]
+                {{/-last}}
+                {{/enumValues}}
+              }{{^-last}},{{/-last}}
+            {{#-last}}
+            }
+            {{/-last}}
+          {{/variables}}
+        }{{^-last}},{{/-last}}
+      {{/servers}}
+      ]
+    end
+
+    # Returns URL based on server settings
+    #
+    # @param index array index of the server settings
+    # @param variables hash of variable and the corresponding value
+    def server_url(index, variables = {})
+      servers = server_settings
+
+      # check array index out of bound
+      if (index < 0 || index > servers.size)
+        fail ArgumentError "Invalid index #{index} when selecting the server. Must be less than #{servers.size}"
+      end
+
+      server = servers[index]
+      url = server[:url]
+
+      # go through variable and assign a value
+      server[:variables].each do |name, variable|
+        if variables.key?(name)
+          if (server[:variables][name][:enum_values].include? variables[name])
+            url.gsub! "{" + name.to_s + "}", variables[name]
+          else
+            fail ArgumentError, "The variable `#{name}` in the server URL has invalid value #{variables[name]}. Must be #{server[:variables][name][:enum_values]}."
+          end
+        else
+          # use default value
+          url.gsub! "{" + name.to_s + "}", server[:variables][name][:default_value]
+        end
+      end
+
+      url
+    end
   end
 end
diff --git a/modules/openapi-generator/src/test/resources/3_0/petstore-with-fake-endpoints-models-for-testing.yaml b/modules/openapi-generator/src/test/resources/3_0/petstore-with-fake-endpoints-models-for-testing.yaml
index 78ba11aaebc..8614ee5b56e 100644
--- a/modules/openapi-generator/src/test/resources/3_0/petstore-with-fake-endpoints-models-for-testing.yaml
+++ b/modules/openapi-generator/src/test/resources/3_0/petstore-with-fake-endpoints-models-for-testing.yaml
@@ -968,7 +968,28 @@ paths:
               required:
                 - requiredFile
 servers:
-  - url: 'http://petstore.swagger.io:80/v2'
+  - url: 'http://{server}.swagger.io:{port}/v2'
+    description: petstore server
+    variables:
+      server:
+        enum:
+          - 'petstore'
+          - 'qa-petstore'
+          - 'dev-petstore'
+        default: 'petstore'
+      port:
+        enum:
+          - 80
+          - 8080
+        default: 80
+  - url: https://api.gigantic-server.com:8080/{version}
+    description: The production API server
+    variables:
+      version:
+        enum:
+          - 'v1'
+          - 'v2'
+        default: 'v2'
 components:
   requestBodies:
     UserArray:
diff --git a/samples/client/petstore/ruby/docs/FakeApi.md b/samples/client/petstore/ruby/docs/FakeApi.md
index b27a909ce86..a0a9023412d 100644
--- a/samples/client/petstore/ruby/docs/FakeApi.md
+++ b/samples/client/petstore/ruby/docs/FakeApi.md
@@ -58,7 +58,7 @@ No authorization required
 
 ### HTTP request headers
 
- - **Content-Type**: Not defined
+ - **Content-Type**: application/json
  - **Accept**: */*
 
 
@@ -104,7 +104,7 @@ No authorization required
 
 ### HTTP request headers
 
- - **Content-Type**: Not defined
+ - **Content-Type**: application/json
  - **Accept**: */*
 
 
@@ -150,7 +150,7 @@ No authorization required
 
 ### HTTP request headers
 
- - **Content-Type**: Not defined
+ - **Content-Type**: application/json
  - **Accept**: */*
 
 
@@ -196,7 +196,7 @@ No authorization required
 
 ### HTTP request headers
 
- - **Content-Type**: Not defined
+ - **Content-Type**: application/json
  - **Accept**: */*
 
 
diff --git a/samples/client/petstore/ruby/docs/StoreApi.md b/samples/client/petstore/ruby/docs/StoreApi.md
index 2ebdc4ddc0e..464c8dbb854 100644
--- a/samples/client/petstore/ruby/docs/StoreApi.md
+++ b/samples/client/petstore/ruby/docs/StoreApi.md
@@ -185,7 +185,7 @@ No authorization required
 
 ### HTTP request headers
 
- - **Content-Type**: Not defined
+ - **Content-Type**: application/json
  - **Accept**: application/xml, application/json
 
 
diff --git a/samples/client/petstore/ruby/docs/UserApi.md b/samples/client/petstore/ruby/docs/UserApi.md
index ae8f3fad0f1..8981435d9d9 100644
--- a/samples/client/petstore/ruby/docs/UserApi.md
+++ b/samples/client/petstore/ruby/docs/UserApi.md
@@ -53,7 +53,7 @@ No authorization required
 
 ### HTTP request headers
 
- - **Content-Type**: Not defined
+ - **Content-Type**: application/json
  - **Accept**: Not defined
 
 
@@ -95,7 +95,7 @@ No authorization required
 
 ### HTTP request headers
 
- - **Content-Type**: Not defined
+ - **Content-Type**: application/json
  - **Accept**: Not defined
 
 
@@ -137,7 +137,7 @@ No authorization required
 
 ### HTTP request headers
 
- - **Content-Type**: Not defined
+ - **Content-Type**: application/json
  - **Accept**: Not defined
 
 
@@ -353,7 +353,7 @@ No authorization required
 
 ### HTTP request headers
 
- - **Content-Type**: Not defined
+ - **Content-Type**: application/json
  - **Accept**: Not defined
 
 
diff --git a/samples/client/petstore/ruby/lib/petstore/api/fake_api.rb b/samples/client/petstore/ruby/lib/petstore/api/fake_api.rb
index cc1bdddf5ea..9a03e8be6a6 100644
--- a/samples/client/petstore/ruby/lib/petstore/api/fake_api.rb
+++ b/samples/client/petstore/ruby/lib/petstore/api/fake_api.rb
@@ -46,6 +46,8 @@ module Petstore
       header_params = {}
       # HTTP header 'Accept' (if needed)
       header_params['Accept'] = @api_client.select_header_accept(['*/*'])
+      # HTTP header 'Content-Type'
+      header_params['Content-Type'] = @api_client.select_header_content_type(['application/json'])
 
       # form parameters
       form_params = {}
@@ -93,6 +95,8 @@ module Petstore
       header_params = {}
       # HTTP header 'Accept' (if needed)
       header_params['Accept'] = @api_client.select_header_accept(['*/*'])
+      # HTTP header 'Content-Type'
+      header_params['Content-Type'] = @api_client.select_header_content_type(['application/json'])
 
       # form parameters
       form_params = {}
@@ -140,6 +144,8 @@ module Petstore
       header_params = {}
       # HTTP header 'Accept' (if needed)
       header_params['Accept'] = @api_client.select_header_accept(['*/*'])
+      # HTTP header 'Content-Type'
+      header_params['Content-Type'] = @api_client.select_header_content_type(['application/json'])
 
       # form parameters
       form_params = {}
@@ -187,6 +193,8 @@ module Petstore
       header_params = {}
       # HTTP header 'Accept' (if needed)
       header_params['Accept'] = @api_client.select_header_accept(['*/*'])
+      # HTTP header 'Content-Type'
+      header_params['Content-Type'] = @api_client.select_header_content_type(['application/json'])
 
       # form parameters
       form_params = {}
@@ -585,7 +593,7 @@ module Petstore
 
       # query parameters
       query_params = {}
-      query_params[:'enum_query_string_array'] = @api_client.build_collection_param(opts[:'enum_query_string_array'], :csv) if !opts[:'enum_query_string_array'].nil?
+      query_params[:'enum_query_string_array'] = @api_client.build_collection_param(opts[:'enum_query_string_array'], :multi) if !opts[:'enum_query_string_array'].nil?
       query_params[:'enum_query_string'] = opts[:'enum_query_string'] if !opts[:'enum_query_string'].nil?
       query_params[:'enum_query_integer'] = opts[:'enum_query_integer'] if !opts[:'enum_query_integer'].nil?
       query_params[:'enum_query_double'] = opts[:'enum_query_double'] if !opts[:'enum_query_double'].nil?
diff --git a/samples/client/petstore/ruby/lib/petstore/api/store_api.rb b/samples/client/petstore/ruby/lib/petstore/api/store_api.rb
index a7a77e842e7..55d208a244c 100644
--- a/samples/client/petstore/ruby/lib/petstore/api/store_api.rb
+++ b/samples/client/petstore/ruby/lib/petstore/api/store_api.rb
@@ -208,6 +208,8 @@ module Petstore
       header_params = {}
       # HTTP header 'Accept' (if needed)
       header_params['Accept'] = @api_client.select_header_accept(['application/xml', 'application/json'])
+      # HTTP header 'Content-Type'
+      header_params['Content-Type'] = @api_client.select_header_content_type(['application/json'])
 
       # form parameters
       form_params = {}
diff --git a/samples/client/petstore/ruby/lib/petstore/api/user_api.rb b/samples/client/petstore/ruby/lib/petstore/api/user_api.rb
index 95fd5fe257f..bbacd07c453 100644
--- a/samples/client/petstore/ruby/lib/petstore/api/user_api.rb
+++ b/samples/client/petstore/ruby/lib/petstore/api/user_api.rb
@@ -50,6 +50,8 @@ module Petstore
 
       # header parameters
       header_params = {}
+      # HTTP header 'Content-Type'
+      header_params['Content-Type'] = @api_client.select_header_content_type(['application/json'])
 
       # form parameters
       form_params = {}
@@ -98,6 +100,8 @@ module Petstore
 
       # header parameters
       header_params = {}
+      # HTTP header 'Content-Type'
+      header_params['Content-Type'] = @api_client.select_header_content_type(['application/json'])
 
       # form parameters
       form_params = {}
@@ -146,6 +150,8 @@ module Petstore
 
       # header parameters
       header_params = {}
+      # HTTP header 'Content-Type'
+      header_params['Content-Type'] = @api_client.select_header_content_type(['application/json'])
 
       # form parameters
       form_params = {}
@@ -404,6 +410,8 @@ module Petstore
 
       # header parameters
       header_params = {}
+      # HTTP header 'Content-Type'
+      header_params['Content-Type'] = @api_client.select_header_content_type(['application/json'])
 
       # form parameters
       form_params = {}
diff --git a/samples/client/petstore/ruby/lib/petstore/configuration.rb b/samples/client/petstore/ruby/lib/petstore/configuration.rb
index 8811d01ffb9..63b8dce9e59 100644
--- a/samples/client/petstore/ruby/lib/petstore/configuration.rb
+++ b/samples/client/petstore/ruby/lib/petstore/configuration.rb
@@ -226,5 +226,80 @@ module Petstore
           },
       }
     end
+
+    # Returns an array of Server setting
+    def server_settings
+      [
+        {
+          url: "http://{server}.swagger.io:{port}/v2",
+          description: "petstore server",
+          variables: {
+            server: {
+                description: "No descriptoin provided",
+                default_value: "petstore",
+                enum_values: [
+                  "petstore",
+                  "qa-petstore",
+                  "dev-petstore"
+                ]
+              },
+            port: {
+                description: "No descriptoin provided",
+                default_value: "80",
+                enum_values: [
+                  "80",
+                  "8080"
+                ]
+              }
+            }
+        },
+        {
+          url: "https://api.gigantic-server.com:8080/{version}",
+          description: "The production API server",
+          variables: {
+            version: {
+                description: "No descriptoin provided",
+                default_value: "v2",
+                enum_values: [
+                  "v1",
+                  "v2"
+                ]
+              }
+            }
+        }
+      ]
+    end
+
+    # Returns URL based on server settings
+    #
+    # @param index array index of the server settings
+    # @param variables hash of variable and the corresponding value
+    def server_url(index, variables = {})
+      servers = server_settings
+
+      # check array index out of bound
+      if (index < 0 || index > servers.size)
+        fail ArgumentError "Invalid index #{index} when selecting the server. Must be less than #{servers.size}"
+      end
+
+      server = servers[index]
+      url = server[:url]
+
+      # go through variable and assign a value
+      server[:variables].each do |name, variable|
+        if variables.key?(name)
+          if (server[:variables][name][:enum_values].include? variables[name])
+            url.gsub! "{" + name.to_s + "}", variables[name]
+          else
+            fail ArgumentError, "The variable `#{name}` in the server URL has invalid value #{variables[name]}. Must be #{server[:variables][name][:enum_values]}."
+          end
+        else
+          # use default value
+          url.gsub! "{" + name.to_s + "}", server[:variables][name][:default_value]
+        end
+      end
+
+      url
+    end
   end
 end
diff --git a/samples/client/petstore/ruby/lib/petstore/models/body4.rb b/samples/client/petstore/ruby/lib/petstore/models/body4.rb
index 7c0387d9b37..7b0954a6061 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/body4.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/body4.rb
@@ -1,12 +1,12 @@
 =begin
-#Swagger Petstore
+#OpenAPI Petstore
 
 #This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\
 
 OpenAPI spec version: 1.0.0
-Contact: apiteam@swagger.io
-Generated by: https://github.com/swagger-api/swagger-codegen.git
-Swagger Codegen version: 3.0.0-SNAPSHOT
+
+Generated by: https://openapi-generator.tech
+OpenAPI Generator version: 3.3.2-SNAPSHOT
 
 =end
 
@@ -29,7 +29,7 @@ module Petstore
     end
 
     # Attribute type mapping.
-    def self.swagger_types
+    def self.openapi_types
       {
         :'param' => :'String',
         :'param2' => :'String'
@@ -102,7 +102,7 @@ module Petstore
     # @return [Object] Returns the model itself
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
-      self.class.swagger_types.each_pair do |key, type|
+      self.class.openapi_types.each_pair do |key, type|
         if type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the the attribute
           # is documented as an array but the input is not
diff --git a/samples/client/petstore/ruby/lib/petstore/models/format_test.rb b/samples/client/petstore/ruby/lib/petstore/models/format_test.rb
index 98a903e3123..5539c10c6c7 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/format_test.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/format_test.rb
@@ -195,10 +195,6 @@ module Petstore
         invalid_properties.push('invalid value for "byte", byte cannot be nil.')
       end
 
-      if @byte !~ Regexp.new(/^(?:[A-Za-z0-9+\/]{4})*(?:[A-Za-z0-9+\/]{2}==|[A-Za-z0-9+\/]{3}=)?$/)
-        invalid_properties.push('invalid value for "byte", must conform to the pattern /^(?:[A-Za-z0-9+\/]{4})*(?:[A-Za-z0-9+\/]{2}==|[A-Za-z0-9+\/]{3}=)?$/.')
-      end
-
       if @date.nil?
         invalid_properties.push('invalid value for "date", date cannot be nil.')
       end
@@ -234,7 +230,6 @@ module Petstore
       return false if !@double.nil? && @double < 67.8
       return false if !@string.nil? && @string !~ Regexp.new(/[a-z]/i)
       return false if @byte.nil?
-      return false if @byte !~ Regexp.new(/^(?:[A-Za-z0-9+\/]{4})*(?:[A-Za-z0-9+\/]{2}==|[A-Za-z0-9+\/]{3}=)?$/)
       return false if @date.nil?
       return false if @password.nil?
       return false if @password.to_s.length > 64
@@ -326,20 +321,6 @@ module Petstore
       @string = string
     end
 
-    # Custom attribute writer method with validation
-    # @param [Object] byte Value to be assigned
-    def byte=(byte)
-      if byte.nil?
-        fail ArgumentError, 'byte cannot be nil'
-      end
-
-      if byte !~ Regexp.new(/^(?:[A-Za-z0-9+\/]{4})*(?:[A-Za-z0-9+\/]{2}==|[A-Za-z0-9+\/]{3}=)?$/)
-        fail ArgumentError, 'invalid value for "byte", must conform to the pattern /^(?:[A-Za-z0-9+\/]{4})*(?:[A-Za-z0-9+\/]{2}==|[A-Za-z0-9+\/]{3}=)?$/.'
-      end
-
-      @byte = byte
-    end
-
     # Custom attribute writer method with validation
     # @param [Object] password Value to be assigned
     def password=(password)
diff --git a/samples/client/petstore/ruby/spec/configuration_spec.rb b/samples/client/petstore/ruby/spec/configuration_spec.rb
index 45637e30d6d..e7f9eb39727 100644
--- a/samples/client/petstore/ruby/spec/configuration_spec.rb
+++ b/samples/client/petstore/ruby/spec/configuration_spec.rb
@@ -22,4 +22,34 @@ describe Petstore::Configuration do
       end
     end
   end
+
+  describe 'server settings' do
+    it 'should return an array of server settings' do
+      expect(config.auth_settings).not_to be_empty
+    end
+
+    it 'should get the first url' do
+      url = config.server_url(0, server: "dev-petstore", port: "8080")
+      expect(url).to eq("http://dev-petstore.swagger.io:8080/v2")
+    end
+
+    it 'should get the first url with default values' do
+      url = config.server_url(0)
+      expect(url).to eq("http://petstore.swagger.io:80/v2")
+    end
+
+    it 'should get the second url with default values' do
+      url = config.server_url(1)
+      expect(url).to eq("https://api.gigantic-server.com:8080/v2")
+    end
+
+    it 'should get the second url' do
+      url = config.server_url(1, version: "v1")
+      expect(url).to eq("https://api.gigantic-server.com:8080/v1")
+    end
+
+    it 'should raise error due to invalid enum value' do
+      expect{config.server_url(1, version: "v6")}.to raise_error(ArgumentError)
+    end
+  end
 end