added ParameterToString method to handle string array issue

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

@@ -92,7 +92,7 @@ func (a {{classname}}) {{nickname}} ({{#allParams}}{{paramName}} {{{dataType}}}{
     
     {{#hasQueryParams}}    
     {{#queryParams}}
-    queryParams["{{vendorExtensions.x-exportParamName}}"] = strings.Join({{paramName}}, ",")
+    queryParams["{{vendorExtensions.x-exportParamName}}"] = a.Configuration.ApiClient.ParameterToString({{paramName}})
     {{/queryParams}}
     {{/hasQueryParams}}
 

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

@@ -4,6 +4,7 @@ import (
     "strings"
     "github.com/go-resty/resty"
     "errors"
+    "reflect"
 )
 
 type ApiClient struct {
@@ -73,6 +74,14 @@ func (c *ApiClient) CallApi(path string, method string,
     return nil, errors.New("Invalid method " + method)
 }
 
+func (c *ApiClient) ParameterToString (obj interface{}) string {
+    if reflect.TypeOf(obj).Len()  > 0 {
+        return strings.Join(obj.([]string), ",")
+    } else{
+        return obj.(string)
+    }
+}
+
 func prepareRequest(postBody interface{},
     headerParams map[string]string,
     queryParams map[string]string,

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

@@ -4,6 +4,7 @@ import (
     "strings"
     "github.com/go-resty/resty"
     "errors"
+    "reflect"
 )
 
 type ApiClient struct {
@@ -73,6 +74,14 @@ func (c *ApiClient) CallApi(path string, method string,
     return nil, errors.New("Invalid method " + method)
 }
 
+func (c *ApiClient) ParameterToString (obj interface{}) string {
+    if reflect.TypeOf(obj).Len()  > 0 {
+        return strings.Join(obj.([]string), ",")
+    } else{
+        return obj.(string)
+    }
+}
+
 func prepareRequest(postBody interface{},
     headerParams map[string]string,
     queryParams map[string]string,

samples/client/petstore/go/go-petstore/pet_api.go

@@ -207,7 +207,7 @@ func (a PetApi) FindPetsByStatus (status []string) ([]Pet, error) {
         headerParams[key] = a.Configuration.DefaultHeader[key]
     }
     
-    queryParams["Status"] = strings.Join(status, ",")
+    queryParams["Status"] = a.Configuration.ApiClient.ParameterToString(status)
 
     // to determine the Content-Type header
     localVarHttpContentTypes := []string {
@@ -277,7 +277,7 @@ func (a PetApi) FindPetsByTags (tags []string) ([]Pet, error) {
         headerParams[key] = a.Configuration.DefaultHeader[key]
     }
     
-    queryParams["Tags"] = strings.Join(tags, ",")
+    queryParams["Tags"] = a.Configuration.ApiClient.ParameterToString(tags)
 
     // to determine the Content-Type header
     localVarHttpContentTypes := []string {
@@ -585,7 +585,7 @@ func (a PetApi) UploadFile (petId int64, additionalMetadata string, file *os.Fil
     }
 
     formParams["AdditionalMetadata"] = additionalMetadata
-    formParams["File"] = file
+    formParams["File"] = file.Name()
 
   var successPayload = new(ApiResponse)
 

samples/client/petstore/go/go-petstore/user_api.go

@@ -380,8 +380,8 @@ func (a UserApi) LoginUser (username string, password string) (string, error) {
         headerParams[key] = a.Configuration.DefaultHeader[key]
     }
     
-    queryParams["Username"] = strings.Join(username, ",")
+    queryParams["Username"] = a.Configuration.ApiClient.ParameterToString(username)
-    queryParams["Password"] = strings.Join(password, ",")
+    queryParams["Password"] = a.Configuration.ApiClient.ParameterToString(password)
 
     // to determine the Content-Type header
     localVarHttpContentTypes := []string {