ASP.Net Core File badly handled in csharp-dotnet2 client

Start with the csharp-dotnet2 generated client and trace ApiClient.CallApi through ApiClient.Deserialize for a response declared as type file. Reproduce the GetVersionFile request using the supplied Swagger definition and generation command with a ZIP containing a NUL byte. Done means the generated client preserves the complete binary response instead of truncating it at the NUL.

Description

Code for downloading files generated by swagger-codegen (csharp) is wrong. It may work in most cases, but it cuts my .zip file after \0.

Code generated with swagger-codegen:

        public System.IO.Stream GetVersionFile (int? versionId)
        {
            // verify the required parameter 'versionId' is set
            if (versionId == null) throw new ApiException(400, "Missing required parameter 'versionId' when calling GetVersionFile");
    
            var path = "/api/Versions/{versionId}/File";
            path = path.Replace("{format}", "json");
            path = path.Replace("{" + "versionId" + "}", ApiClient.ParameterToString(versionId));
    
            var queryParams = new Dictionary<String, String>();
            var headerParams = new Dictionary<String, String>();
            var formParams = new Dictionary<String, String>();
            var fileParams = new Dictionary<String, FileParameter>();
            String postBody = null;
    
                                                    
            // authentication setting, if any
            String[] authSettings = new String[] { "Bearer" };
    
            // make the HTTP request
            IRestResponse response = (IRestResponse) ApiClient.CallApi(path, Method.GET, queryParams, postBody, headerParams, formParams, fileParams, authSettings);
    
            if (((int)response.StatusCode) >= 400)
                throw new ApiException ((int)response.StatusCode, "Error calling GetVersionFile: " + response.Content, response.Content);
            else if (((int)response.StatusCode) == 0)
                throw new ApiException ((int)response.StatusCode, "Error calling GetVersionFile: " + response.ErrorMessage, response.ErrorMessage);
    
            return (System.IO.Stream) ApiClient.Deserialize(response.Content, typeof(System.IO.Stream), response.Headers);
        }

response.Length has bigger value than response.Content.Length because there is a \0 in my .zip file. Then the response.Content is passed to File.WriteAllText. There is no length specified so my file is smaller than it is supposed to be. It's a easy fix in generated code, but it's a huge waste of time to do this every time after generating the client code.

Swagger-codegen version

swagger-codegen-cli-3.0.11

Swagger declaration file content or url

(for YAML code) or

...
			"get": {
				"tags": [ "Applications" ],
				"summary": "Version file download",
				"operationId": "GetVersionFile",
				"consumes": [],
				"produces": [ "application/octet-stream" ],
				"parameters": [
					{
						"name": "versionId",
						"in": "path",
						"description": "Version ID",
						"required": true,
						"type": "integer",
						"format": "int32"
					}
				],
				"responses": {
					"200": {
						"description": "Success",
						"schema": { "type": "file" }
					}
				}
			}
...

Command line used for generation

java -jar swagger-codegen-cli-3.0.11.jar generate -l csharp-dotnet2 -i http://localhost:9220/swagger/v2/swagger.json

Steps to reproduce

Create a controler in ASP.Net Core that returns File. Example:

	[HttpGet("Versions/{versionId}/File")]
	[Produces("application/octet-stream")]
	[ProducesResponseType(200, Type = typeof(FileStreamResult))]
	public async Task<IActionResult> GetVersionFile(int versionId)
	{
		try
		{
			ApplicationVersion applicationVersion = await ApplicationService.GetVersion(versionId);
			var stream = await ApplicationService.GetVersionFileStream(versionId);
			return File(stream, "application/octet-stream", applicationVersion.FileName);
		}
		catch (InvalidOperationException)
		{
			return NotFound();
		}
	}

Add mapping in startup.

...
	c.MapType<FileStreamResult>(() => new Schema { Type = "file" });
...

Generate csharp-dotnet2 client and run your method.