Auto-generated proxy doesn't work with endpoints which return actual file content. about autorest

[ogail]

@centur thanks for reporting this, can you please attach sample Swagger for the repro?

[centur]

check this gist https://gist.github.com/centur/953490b7c5b48c74fc99 - I've edited it a bit to remove unrelated bits.
The method in question is "/api/items/{id}" - for Get signature it always generates deserialization logic.

My current fix for this specific item is to edit proxy manually after each proxy generation and add condition to avoid de-serialization logic in case of application/octet-stream response type.

    // Deserialize Response
            if (statusCode == HttpStatusCode.OK)
            {
                if (Equals(httpResponse.Content.Headers.ContentType, new MediaTypeHeaderValue("application/octet-stream")))
                {
                    result.Body = responseContent;
                }
                else
                {
                    string resultModel = default(string);
                    JToken responseDoc = null;
                    if (string.IsNullOrEmpty(responseContent) == false)
                    {
                        responseDoc = JToken.Parse(responseContent);
                    }
                    if (responseDoc != null)
                    {
                        resultModel = responseDoc.ToString(Newtonsoft.Json.Formatting.Indented);
                    }
                    result.Body = resultModel;
                }
            }

[stankovski]

@centur thank you for filing this. We were able to repro the issue. As far as the spec goes, however, you should specify the return type to be a file or to have a property of a file and use the appropriate MIME in produces. For example:

"produces": [
          "application/octet-stream"
        ],

and

  "definitions": {
    "Object": {
      "type": "file"
    },

[centur]

@stankovski thanks, I've fixed produces section. Can you please elaborate a bit on definitions example?

If I understood this correctly - I can't just replace "type":"file" of Object definition (other methods will break as they are also using Object).

Can I just set that inside inline response (not sure yet how to do this with Swashbuckle :) but will find out) with "type":"file" like this:

 "responses": {
          "200": {
            "description": "OK",
            "schema": {
              "type": "file"
            }
          }
        },

Is this correct ?

[stankovski]

Yep, that should work.

[centur]

Sorry for the delay: I've got correct swagger definition for the file but it actually got worse :(
We have this definition

...
"/api/items/{id}": {
      "get": {
        "tags": [
          "Items"
        ],
        "summary": "Download a specific File by Id.",
        "operationId": "Items_DownloadFile",
        "consumes": [],
        "produces": [
          "application/octet-stream"
        ],
        "parameters": [
          {
            "name": "id",
            "in": "path",
            "description": "String ID of the File",
            "required": true,
            "type": "string"
          }
        ],
        "responses": {
          "200": {
            "description": "OK",
            "schema": {
              "type": "file"
            }
          }
        },
        "deprecated": false
      }
  }
...

With "application/octet-stream" in produces section, AutoRest doesn't generate proxy at all

PS D:\Projects\Tools> .\AutoRest.DocX.ps1
error: [FATAL] Error generating service model: The given key was not present in the dictionary.
Finished generating CSharp code for D:\Projects\Tools\Docx.swagger.json.

If I get rid of application/octet-stream and switch it back to

"produces": [
          "application/json",
          "text/json",
          "application/xml",
          "text/xml"
        ],

but keep

"responses": {
          "200": {
            "description": "OK",
            "schema": {
              "type": "file"
            }
          }
        },

Code which is generated by AutoRest is broken (see inline comments for specific errrors):

public async Task<HttpOperationResponse<Stream>> DownloadFileWithOperationResponseAsync(string id, CancellationToken cancellationToken = default(System.Threading.CancellationToken))
        {
/*Removed unrelated parts*/
 // Deserialize Response
            if (statusCode == HttpStatusCode.OK)
            {
                Stream resultModel = default(System.IO.Stream);
                JToken responseDoc = null;
                if (string.IsNullOrEmpty(responseContent) == false)
                {
                    responseDoc = JToken.Parse(responseContent);
                }
                if (responseDoc != null)
                {
// Got Error: Cannot implicitly convert type 'string' to 'System.IO.Stream' here
                    resultModel = ((string)responseDoc);
                }
                result.Body = resultModel;
            }

So I'm currently switching back to the old fix we had. Hope this will be resolved soon.
AutoRest version is 0.9.7 as latest publicly released one.

[stankovski]

Implemented in #186

[hovsepm]

Fixed in Release 0.10.0 - nuget, chocolatey, github

[centur]

Great, thank you