[csharp][csharp-netcore] Fix Fileupload for Request Bodies for RestSharp and HttpClient libraries (#9010)

* Fix Request Body File Upload for RestSharp and csharp-netcore

* Update Samples

* Fix missing using and update samples

* Enable upload test

* Fix form data and file upload handling for httpclient, update samples

modules/openapi-generator/src/main/resources/csharp-netcore/ApiClient.mustache

@@ -330,6 +330,20 @@ namespace {{packageName}}.Client
             }
 
             if (options.Data != null)
+            {
+                if (options.Data is Stream stream)
+                {
+                    var contentType = "application/octet-stream";
+                    if (options.HeaderParameters != null)
+                    {
+                        var contentTypes = options.HeaderParameters["Content-Type"];
+                        contentType = contentTypes[0];
+                    }
+
+                    var bytes = ClientUtils.ReadAsBytes(stream);
+                    request.AddParameter(contentType, bytes, ParameterType.RequestBody);
+                }
+                else
                 {
                     if (options.HeaderParameters != null)
                     {
@@ -351,6 +365,7 @@ namespace {{packageName}}.Client
 
                     request.AddJsonBody(options.Data);
                 }
+            }
 
             if (options.FileParameters != null)
             {

modules/openapi-generator/src/main/resources/csharp-netcore/libraries/httpclient/ApiClient.mustache

@@ -24,6 +24,7 @@ using ErrorEventArgs = Newtonsoft.Json.Serialization.ErrorEventArgs;
 using System.Net.Http;
 {{/useWebRequest}}
 using System.Net.Http;
+using System.Net.Http.Headers;
 {{#supportsRetry}}
 using Polly;
 {{/supportsRetry}}
@@ -214,6 +215,32 @@ namespace {{packageName}}.Client
     {{/reUseHttpClient}}
         }
 
+        /// Prepares multipart/form-data content
+        {{! TODO: Add handling of improper usage }}
+        HttpContent PrepareMultipartFormDataContent(RequestOptions options)
+        {
+            string boundary = "---------" + Guid.NewGuid().ToString().ToUpperInvariant();
+            var multipartContent = new MultipartFormDataContent(boundary);
+            foreach (var formParameter in options.FormParameters)
+            {
+                multipartContent.Add(new StringContent(formParameter.Value), formParameter.Key);
+            }
+
+            if (options.FileParameters != null && options.FileParameters.Count > 0)
+            {
+                foreach (var fileParam in options.FileParameters)
+                {
+                    var fileStream = fileParam.Value as FileStream;
+                    var fileStreamName = fileStream != null ? System.IO.Path.GetFileName(fileStream.Name) : null;
+                    var content = new StreamContent(fileParam.Value);
+                    content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
+                    multipartContent.Add(content, fileParam.Key,
+                        fileStreamName ?? "no_file_name_provided");
+                }
+            }
+            return multipartContent;
+        }
+
         /// <summary>
         /// Provides all logic for constructing a new HttpRequestMessage.
         /// At this point, all information for querying the service is known. Here, it is simply
@@ -270,51 +297,44 @@ namespace {{packageName}}.Client
 
             List<Tuple<HttpContent, string, string>> contentList = new List<Tuple<HttpContent, string, string>>();
 
-            if (options.FormParameters != null && options.FormParameters.Count > 0)
+            string contentType = null;
+            if (options.HeaderParameters != null && options.HeaderParameters.ContainsKey("Content-Type"))
             {
-                contentList.Add(new Tuple<HttpContent, string, string>(new FormUrlEncodedContent(options.FormParameters), null, null));
+                var contentTypes = options.HeaderParameters["Content-Type"];
+                contentType = contentTypes.FirstOrDefault();
             }
 
+            {{!// TODO Add error handling in case of improper usage}}
+            if (contentType == "multipart/form-data")
+            {
+                request.Content = PrepareMultipartFormDataContent(options);
+            }
+            else if (contentType == "application/x-www-form-urlencoded")
+            {
+                request.Content = new FormUrlEncodedContent(options.FormParameters);
+            }
+            else
+            {
                 if (options.Data != null)
+                {
+                    if (options.Data is Stream s)
+                    {
+                        contentType ??= "application/octet-stream";
+
+                        var streamContent = new StreamContent(s);
+                        streamContent.Headers.ContentType = new MediaTypeHeaderValue(contentType);
+                        request.Content = streamContent;
+                    }
+                    else
                     {
                         var serializer = new CustomJsonCodec(SerializerSettings, configuration);
-                contentList.Add(
+                        request.Content = new StringContent(serializer.Serialize(options.Data), new UTF8Encoding(),
-                    new Tuple<HttpContent, string, string>(new StringContent(serializer.Serialize(options.Data), new UTF8Encoding(), "application/json"), null, null));
+                            "application/json");
                     }
-
-            if (options.FileParameters != null && options.FileParameters.Count > 0)
-            {
-                foreach (var fileParam in options.FileParameters)
-                {
-                    var bytes = ClientUtils.ReadAsBytes(fileParam.Value);
-                    var fileStream = fileParam.Value as FileStream;
-                    contentList.Add(new Tuple<HttpContent, string, string>(new ByteArrayContent(bytes), fileParam.Key,
-                        fileStream?.Name ?? "no_file_name_provided"));
                 }
             }
 
-            if (contentList.Count > 1)
-            {
-                string boundary = "---------" + Guid.NewGuid().ToString().ToUpperInvariant();
-                var multipartContent = new MultipartFormDataContent(boundary);
-                foreach (var content in contentList)
-                {
-                   if(content.Item2 != null)
-                   {
-                     multipartContent.Add(content.Item1, content.Item2, content.Item3);
-                   }
-                   else
-                   {
-                     multipartContent.Add(content.Item1);
-                   }
-                }
 
-                request.Content = multipartContent;
-            }
-            else
-            {
-                request.Content = contentList.FirstOrDefault()?.Item1;
-            }
 
             // TODO provide an alternative that allows cookies per request instead of per API client
             if (options.Cookies != null && options.Cookies.Count > 0)

samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/src/Org.OpenAPITools.Test/Api/PetApiTests.cs

@@ -284,7 +284,7 @@ namespace Org.OpenAPITools.Test
         /// <summary>
         /// Test UploadFile
         /// </summary>
-        [Fact (Skip = "file upload not working for httpclient yet")]
+        [Fact]
         public void UploadFileTest()
         {
             Assembly _assembly = Assembly.GetExecutingAssembly();

samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/src/Org.OpenAPITools/Client/ApiClient.cs

@@ -26,6 +26,7 @@ using Newtonsoft.Json;
 using Newtonsoft.Json.Serialization;
 using ErrorEventArgs = Newtonsoft.Json.Serialization.ErrorEventArgs;
 using System.Net.Http;
+using System.Net.Http.Headers;
 using Polly;
 
 namespace Org.OpenAPITools.Client
@@ -202,6 +203,31 @@ namespace Org.OpenAPITools.Client
             _baseUrl = basePath;
         }
 
+        /// Prepares multipart/form-data content
+        HttpContent PrepareMultipartFormDataContent(RequestOptions options)
+        {
+            string boundary = "---------" + Guid.NewGuid().ToString().ToUpperInvariant();
+            var multipartContent = new MultipartFormDataContent(boundary);
+            foreach (var formParameter in options.FormParameters)
+            {
+                multipartContent.Add(new StringContent(formParameter.Value), formParameter.Key);
+            }
+
+            if (options.FileParameters != null && options.FileParameters.Count > 0)
+            {
+                foreach (var fileParam in options.FileParameters)
+                {
+                    var fileStream = fileParam.Value as FileStream;
+                    var fileStreamName = fileStream != null ? System.IO.Path.GetFileName(fileStream.Name) : null;
+                    var content = new StreamContent(fileParam.Value);
+                    content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
+                    multipartContent.Add(content, fileParam.Key,
+                        fileStreamName ?? "no_file_name_provided");
+                }
+            }
+            return multipartContent;
+        }
+
         /// <summary>
         /// Provides all logic for constructing a new HttpRequestMessage.
         /// At this point, all information for querying the service is known. Here, it is simply
@@ -258,51 +284,43 @@ namespace Org.OpenAPITools.Client
 
             List<Tuple<HttpContent, string, string>> contentList = new List<Tuple<HttpContent, string, string>>();
 
-            if (options.FormParameters != null && options.FormParameters.Count > 0)
+            string contentType = null;
+            if (options.HeaderParameters != null && options.HeaderParameters.ContainsKey("Content-Type"))
             {
-                contentList.Add(new Tuple<HttpContent, string, string>(new FormUrlEncodedContent(options.FormParameters), null, null));
+                var contentTypes = options.HeaderParameters["Content-Type"];
+                contentType = contentTypes.FirstOrDefault();
             }
 
+            if (contentType == "multipart/form-data")
+            {
+                request.Content = PrepareMultipartFormDataContent(options);
+            }
+            else if (contentType == "application/x-www-form-urlencoded")
+            {
+                request.Content = new FormUrlEncodedContent(options.FormParameters);
+            }
+            else
+            {
                 if (options.Data != null)
+                {
+                    if (options.Data is Stream s)
+                    {
+                        contentType ??= "application/octet-stream";
+
+                        var streamContent = new StreamContent(s);
+                        streamContent.Headers.ContentType = new MediaTypeHeaderValue(contentType);
+                        request.Content = streamContent;
+                    }
+                    else
                     {
                         var serializer = new CustomJsonCodec(SerializerSettings, configuration);
-                contentList.Add(
+                        request.Content = new StringContent(serializer.Serialize(options.Data), new UTF8Encoding(),
-                    new Tuple<HttpContent, string, string>(new StringContent(serializer.Serialize(options.Data), new UTF8Encoding(), "application/json"), null, null));
+                            "application/json");
                     }
-
-            if (options.FileParameters != null && options.FileParameters.Count > 0)
-            {
-                foreach (var fileParam in options.FileParameters)
-                {
-                    var bytes = ClientUtils.ReadAsBytes(fileParam.Value);
-                    var fileStream = fileParam.Value as FileStream;
-                    contentList.Add(new Tuple<HttpContent, string, string>(new ByteArrayContent(bytes), fileParam.Key,
-                        fileStream?.Name ?? "no_file_name_provided"));
                 }
             }
 
-            if (contentList.Count > 1)
-            {
-                string boundary = "---------" + Guid.NewGuid().ToString().ToUpperInvariant();
-                var multipartContent = new MultipartFormDataContent(boundary);
-                foreach (var content in contentList)
-                {
-                   if(content.Item2 != null)
-                   {
-                     multipartContent.Add(content.Item1, content.Item2, content.Item3);
-                   }
-                   else
-                   {
-                     multipartContent.Add(content.Item1);
-                   }
-                }
 
-                request.Content = multipartContent;
-            }
-            else
-            {
-                request.Content = contentList.FirstOrDefault()?.Item1;
-            }
 
             // TODO provide an alternative that allows cookies per request instead of per API client
             if (options.Cookies != null && options.Cookies.Count > 0)

samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Client/ApiClient.cs

@@ -330,6 +330,20 @@ namespace Org.OpenAPITools.Client
             }
 
             if (options.Data != null)
+            {
+                if (options.Data is Stream stream)
+                {
+                    var contentType = "application/octet-stream";
+                    if (options.HeaderParameters != null)
+                    {
+                        var contentTypes = options.HeaderParameters["Content-Type"];
+                        contentType = contentTypes[0];
+                    }
+
+                    var bytes = ClientUtils.ReadAsBytes(stream);
+                    request.AddParameter(contentType, bytes, ParameterType.RequestBody);
+                }
+                else
                 {
                     if (options.HeaderParameters != null)
                     {
@@ -351,6 +365,7 @@ namespace Org.OpenAPITools.Client
 
                     request.AddJsonBody(options.Data);
                 }
+            }
 
             if (options.FileParameters != null)
             {

samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Client/ApiClient.cs

@@ -330,6 +330,20 @@ namespace Org.OpenAPITools.Client
             }
 
             if (options.Data != null)
+            {
+                if (options.Data is Stream stream)
+                {
+                    var contentType = "application/octet-stream";
+                    if (options.HeaderParameters != null)
+                    {
+                        var contentTypes = options.HeaderParameters["Content-Type"];
+                        contentType = contentTypes[0];
+                    }
+
+                    var bytes = ClientUtils.ReadAsBytes(stream);
+                    request.AddParameter(contentType, bytes, ParameterType.RequestBody);
+                }
+                else
                 {
                     if (options.HeaderParameters != null)
                     {
@@ -351,6 +365,7 @@ namespace Org.OpenAPITools.Client
 
                     request.AddJsonBody(options.Data);
                 }
+            }
 
             if (options.FileParameters != null)
             {

samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Client/ApiClient.cs

@@ -329,6 +329,20 @@ namespace Org.OpenAPITools.Client
             }
 
             if (options.Data != null)
+            {
+                if (options.Data is Stream stream)
+                {
+                    var contentType = "application/octet-stream";
+                    if (options.HeaderParameters != null)
+                    {
+                        var contentTypes = options.HeaderParameters["Content-Type"];
+                        contentType = contentTypes[0];
+                    }
+
+                    var bytes = ClientUtils.ReadAsBytes(stream);
+                    request.AddParameter(contentType, bytes, ParameterType.RequestBody);
+                }
+                else
                 {
                     if (options.HeaderParameters != null)
                     {
@@ -350,6 +364,7 @@ namespace Org.OpenAPITools.Client
 
                     request.AddJsonBody(options.Data);
                 }
+            }
 
             if (options.FileParameters != null)
             {

samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Client/ApiClient.cs

@@ -330,6 +330,20 @@ namespace Org.OpenAPITools.Client
             }
 
             if (options.Data != null)
+            {
+                if (options.Data is Stream stream)
+                {
+                    var contentType = "application/octet-stream";
+                    if (options.HeaderParameters != null)
+                    {
+                        var contentTypes = options.HeaderParameters["Content-Type"];
+                        contentType = contentTypes[0];
+                    }
+
+                    var bytes = ClientUtils.ReadAsBytes(stream);
+                    request.AddParameter(contentType, bytes, ParameterType.RequestBody);
+                }
+                else
                 {
                     if (options.HeaderParameters != null)
                     {
@@ -351,6 +365,7 @@ namespace Org.OpenAPITools.Client
 
                     request.AddJsonBody(options.Data);
                 }
+            }
 
             if (options.FileParameters != null)
             {