Add support for optional queryParams.

modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/GoClientCodegen.java

@@ -301,6 +301,11 @@ public void postProcessParameter(CodegenParameter parameter){
         StringBuilder sb = new StringBuilder(parameter.paramName);
         sb.setCharAt(0, Character.toUpperCase(firstChar));
         parameter.vendorExtensions.put("x-exportParamName", sb.toString());
+
+	// Dates are not a primitive. Not sure how this is getting flagged as such.
+	if (parameter.isDate != null|| parameter.isDateTime != null || parameter.isFile != null) {
+            parameter.isPrimitiveType = Boolean.FALSE;
+        }
     }
 
 

modules/swagger-codegen/src/main/resources/go/api.mustache

@@ -34,10 +34,10 @@ func New{{classname}}WithBasePath(basePath string) *{{classname}} {
  * {{summary}}{{#notes}}
  * {{notes}}{{/notes}}
  *
-{{#allParams}} * @param {{paramName}} {{description}}
-{{/allParams}} * @return {{#returnType}}{{^isListContainer}}*{{/isListContainer}}{{{returnType}}}{{/returnType}}{{^returnType}}void{{/returnType}}
+{{#allParams}} * @param {{paramName}}{{^required}}{{#isPrimitiveType}}(nil){{/isPrimitiveType}}{{/required}} {{description}} 
+{{/allParams}} * @return {{#returnType}}{{^isListContainer}}*{{/isListContainer}}{{{returnType}}}{{/returnType}}{{^returnType}}nil{{/returnType}}
  */
-func (a {{{classname}}}) {{{nickname}}}({{#allParams}}{{paramName}} {{{dataType}}}{{#hasMore}}, {{/hasMore}}{{/allParams}}) ({{#returnType}}{{^isListContainer}}*{{/isListContainer}}{{{returnType}}}, {{/returnType}}*APIResponse, error) {
+func (a {{{classname}}}) {{{nickname}}}({{#allParams}}{{paramName}} {{#required}}{{{dataType}}}{{/required}}{{^required}}{{#isPrimitiveType}}interface{}{{/isPrimitiveType}}{{^isPrimitiveType}}{{{dataType}}}{{/isPrimitiveType}}{{/required}}{{#hasMore}}, {{/hasMore}}{{/allParams}}) ({{#returnType}}{{^isListContainer}}*{{/isListContainer}}{{{returnType}}}, {{/returnType}}*APIResponse, error) {
 
 	var localVarHttpMethod = strings.ToUpper("{{httpMethod}}")
 	// create path and map variables
@@ -79,21 +79,30 @@ func (a {{{classname}}}) {{{nickname}}}({{#allParams}}{{paramName}} {{{dataType}
 	for key := range a.Configuration.DefaultHeader {
 		localVarHeaderParams[key] = a.Configuration.DefaultHeader[key]
 	}
+
+{{#allParams}}
+{{^required}}
+{{#isPrimitiveType}}
+	if err := a.Configuration.APIClient.typeCheckParameter({{paramName}}, "{{{dataType}}}", "{{paramName}}"); err != nil {
+		return {{#returnType}}nil, {{/returnType}} nil, err
+	}
+{{/isPrimitiveType}}
+{{/required}}
+{{/allParams}}
 	{{#hasQueryParams}}
 	{{#queryParams}}
+	{{^required}}
+	if {{paramName}} != nil {
+    {{/required}}
 	{{#isListContainer}}
-	var collectionFormat = "{{#collectionFormat}}{{collectionFormat}}{{/collectionFormat}}"
-	if collectionFormat == "multi" {
-		for _, value := range {{paramName}} {
-			localVarQueryParams.Add("{{baseName}}", value)
-		}
-	} else {
-		localVarQueryParams.Add("{{baseName}}", a.Configuration.APIClient.ParameterToString({{paramName}}, collectionFormat))
-	}
+		localVarQueryParams.Add("{{baseName}}", a.Configuration.APIClient.parameterToString({{paramName}}, "{{collectionFormat}}"))
 	{{/isListContainer}}
 	{{^isListContainer}}
-		localVarQueryParams.Add("{{baseName}}", a.Configuration.APIClient.ParameterToString({{paramName}}, ""))
+		localVarQueryParams.Add("{{baseName}}", a.Configuration.APIClient.parameterToString({{paramName}}, ""))
 	{{/isListContainer}}
+    {{^required}}
+	}
+    {{/required}}
 	{{/queryParams}}
 	{{/hasQueryParams}}
 
@@ -120,7 +129,7 @@ func (a {{{classname}}}) {{{nickname}}}({{#allParams}}{{paramName}} {{{dataType}
 {{#hasHeaderParams}}
 {{#headerParams}}
 	// header params "{{baseName}}"
-	localVarHeaderParams["{{baseName}}"] = a.Configuration.APIClient.ParameterToString({{paramName}}, "")
+	localVarHeaderParams["{{baseName}}"] = a.Configuration.APIClient.parameterToString({{paramName}}, "")
 {{/headerParams}}
 {{/hasHeaderParams}}
 {{#hasFormParams}}
@@ -131,7 +140,7 @@ func (a {{{classname}}}) {{{nickname}}}({{#allParams}}{{paramName}} {{{dataType}
 	localVarFileName = file.Name()
 {{/isFile}}
 {{^isFile}}
-	localVarFormParams["{{paramName}}"] = a.Configuration.APIClient.ParameterToString({{paramName}}, "")
+	localVarFormParams["{{paramName}}"] = a.Configuration.APIClient.parameterToString({{paramName}}, "")
 {{/isFile}}
 {{/formParams}}
 {{/hasFormParams}}

modules/swagger-codegen/src/main/resources/go/api_client.mustache

@@ -8,6 +8,7 @@ import (
 	"reflect"
 	"strings"
 	"net/url"
+    "errors"
 	"io/ioutil"
 	"github.com/go-resty/resty"
 )
@@ -79,22 +80,38 @@ func (c *APIClient) CallAPI(path string, method string,
 	return nil, fmt.Errorf("invalid method %v", method)
 }
 
-func (c *APIClient) ParameterToString(obj interface{},collectionFormat string) string {
-	if reflect.TypeOf(obj).String() == "[]string" {
-		switch	collectionFormat {
-		case "pipes":
-			return strings.Join(obj.([]string), "|")
-		case "ssv":
-			return strings.Join(obj.([]string), " ")
-		case "tsv":
-			return strings.Join(obj.([]string), "\t")	
-		case "csv" :
-			return strings.Join(obj.([]string), ",")
-		}
+func (c *APIClient) parameterToString(obj interface{}, collectionFormat string) string {
+	delimiter := ""
+	switch collectionFormat {
+	case "pipes":
+		delimiter = "|"
+	case "ssv":
+		delimiter = " "
+	case "tsv":
+		delimiter = "\t"
+	case "csv":
+		delimiter = ","
+	}
+
+	if reflect.TypeOf(obj).Kind() == reflect.Slice {
+		return strings.Trim(strings.Replace(fmt.Sprint(obj), " ", delimiter, -1), "[]")
 	}
 
 	return fmt.Sprintf("%v", obj)
 }
+// Verify optional parameters are of the correct type.
+func (c *APIClient) typeCheckParameter(obj interface{}, expected string, name string) error {
+    // Make sure there is an object.
+    if obj == nil {
+        return nil    
+    }
+
+    // Check the type is as expected.
+	if reflect.TypeOf(obj).String() != expected {
+        return errors.New(fmt.Sprintf("Expected %s to be of type %s but received %s.", name, expected, reflect.TypeOf(obj).String()))
+	}
+	return nil
+}
 
 func (c *APIClient) prepareClient() *resty.Client {
 

samples/client/petstore/go/go-petstore/README.md

@@ -24,6 +24,7 @@ Class | Method | HTTP request | Description
 *FakeApi* | [**TestClientModel**](docs/FakeApi.md#testclientmodel) | **Patch** /fake | To test \"client\" model
 *FakeApi* | [**TestEndpointParameters**](docs/FakeApi.md#testendpointparameters) | **Post** /fake | Fake endpoint for testing various parameters 假端點 偽のエンドポイント 가짜 엔드 포인트 
 *FakeApi* | [**TestEnumParameters**](docs/FakeApi.md#testenumparameters) | **Get** /fake | To test enum parameters
+*Fake_classname_tags123Api* | [**TestClassname**](docs/Fake_classname_tags123Api.md#testclassname) | **Patch** /fake_classname_test | To test class name in snake case
 *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

samples/client/petstore/go/go-petstore/api_client.go

@@ -29,7 +29,7 @@ import (
 	"reflect"
 	"strings"
 	"net/url"
-	"io/ioutil"
+    "errors"
 	"github.com/go-resty/resty"
 )
 
@@ -100,22 +100,38 @@ func (c *APIClient) CallAPI(path string, method string,
 	return nil, fmt.Errorf("invalid method %v", method)
 }
 
-func (c *APIClient) ParameterToString(obj interface{},collectionFormat string) string {
-	if reflect.TypeOf(obj).String() == "[]string" {
-		switch	collectionFormat {
-		case "pipes":
-			return strings.Join(obj.([]string), "|")
-		case "ssv":
-			return strings.Join(obj.([]string), " ")
-		case "tsv":
-			return strings.Join(obj.([]string), "\t")	
-		case "csv" :
-			return strings.Join(obj.([]string), ",")
-		}
+func (c *APIClient) parameterToString(obj interface{}, collectionFormat string) string {
+	delimiter := ""
+	switch collectionFormat {
+	case "pipes":
+		delimiter = "|"
+	case "ssv":
+		delimiter = " "
+	case "tsv":
+		delimiter = "\t"
+	case "csv":
+		delimiter = ","
+	}
+
+	if reflect.TypeOf(obj).Kind() == reflect.Slice {
+		return strings.Trim(strings.Replace(fmt.Sprint(obj), " ", delimiter, -1), "[]")
 	}
 
 	return fmt.Sprintf("%v", obj)
 }
+// Verify optional parameters are of the correct type.
+func (c *APIClient) typeCheckParameter(obj interface{}, expected string, name string) error {
+    // Make sure there is an object.
+    if obj == nil {
+        return nil    
+    }
+
+    // Check the type is as expected.
+	if reflect.TypeOf(obj).String() != expected {
+        return errors.New(fmt.Sprintf("Expected %s to be of type %s but received %s.", name, expected, reflect.TypeOf(obj).String()))
+	}
+	return nil
+}
 
 func (c *APIClient) prepareClient() *resty.Client {
 
@@ -129,7 +145,7 @@ func (c *APIClient) prepareClient() *resty.Client {
 	if c.config.Timeout != nil {
 		rClient.SetTimeout(*c.config.Timeout)
 	}
-	rClient.SetLogger(ioutil.Discard)
+
 	return rClient
 }
 

samples/client/petstore/go/go-petstore/docs/FakeApi.md

@@ -37,7 +37,7 @@ No authorization required
 [[Back to top]](#) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to Model list]](../README.md#documentation-for-models) [[Back to README]](../README.md)
 
 # **TestEndpointParameters**
-> TestEndpointParameters($number, $double, $patternWithoutDelimiter, $byte_, $integer, $int32_, $int64_, $float, $string_, $binary, $date, $dateTime, $password)
+> TestEndpointParameters($number, $double, $patternWithoutDelimiter, $byte_, $integer, $int32_, $int64_, $float, $string_, $binary, $date, $dateTime, $password, $callback)
 
 Fake endpoint for testing various parameters 假端點 偽のエンドポイント 가짜 엔드 포인트 
 
@@ -58,9 +58,10 @@ Name | Type | Description  | Notes
  **float** | **float32**| None | [optional] 
  **string_** | **string**| None | [optional] 
  **binary** | **string**| None | [optional] 
- **date** | **time.Time**| None | [optional] 
- **dateTime** | **time.Time**| None | [optional] 
+ **date** | [**time.Time**](.md)| None | [optional] 
+ **dateTime** | [**time.Time**](.md)| None | [optional] 
  **password** | **string**| None | [optional] 
+ **callback** | **string**| None | [optional] 
 
 ### Return type
 
@@ -106,8 +107,8 @@ No authorization required
 
 ### HTTP request headers
 
- - **Content-Type**: application/json
- - **Accept**: application/json
+ - **Content-Type**: */*
+ - **Accept**: */*
 
 [[Back to top]](#) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to Model list]](../README.md#documentation-for-models) [[Back to README]](../README.md)
 

samples/client/petstore/go/go-petstore/docs/Fake_classname_tags123Api.md

@@ -0,0 +1,36 @@
+# \Fake_classname_tags123Api
+
+All URIs are relative to *http://petstore.swagger.io/v2*
+
+Method | HTTP request | Description
+------------- | ------------- | -------------
+[**TestClassname**](Fake_classname_tags123Api.md#TestClassname) | **Patch** /fake_classname_test | To test class name in snake case
+
+
+# **TestClassname**
+> Client TestClassname($body)
+
+To test class name in snake case
+
+
+### Parameters
+
+Name | Type | Description  | Notes
+------------- | ------------- | ------------- | -------------
+ **body** | [**Client**](Client.md)| client model | 
+
+### Return type
+
+[**Client**](Client.md)
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+ - **Content-Type**: application/json
+ - **Accept**: application/json
+
+[[Back to top]](#) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to Model list]](../README.md#documentation-for-models) [[Back to README]](../README.md)
+