Duplicated content-type on vanilla gateway

[ericholiveira]

Im trying to do a POST to my server i configured my gateway as follows:

import Mappersmith from 'mappersmith';
Mappersmith.Env.USE_PROMISES = true;
var manifest = {
 host: 'http://localhost:3000',
 rules: [
    {
        values: {
            gateway: {
                headers: {
                    'Content-Type': 'application/json'
                }
            }
        }
    }
 ],
 resources: {
   CreateMixData: {
     search: 'post:/search',
     data: '/data'
   }
 }
};
export default Mappersmith.forge(manifest);```

and im calling it as:
```js
API.CreateMixData.search({body:JSON.stringify({category:21})})

The problem is, when i look at the call on chrome the content-type is "Content-Type:application/json, application/json" instead of "Content-Type:application/json" , and for this reason my server dont know how to parse it.

The problem happens on any verb except for GET , and i tracked down the problem to the following method on vanilla-gateway:

_performRequest: function(method) {
    var emulateHTTP = this.shouldEmulateHTTP(method);
    var requestMethod = method;
    var request = new XMLHttpRequest();

    this._configureCallbacks(request);

    if (emulateHTTP) {
      this.body = this.body || {};
      if (typeof this.body === 'object') this.body._method = method;
      requestMethod = 'POST';
    }

    request.open(requestMethod, this.url, true);
    if (emulateHTTP) request.setRequestHeader('X-HTTP-Method-Override', method);

    this._setContentTypeHeader(request); // HERE THE CONTENT-TYPE IS SET
    this._setUserDefinedHeaders(request); // HERE THE CONTENT-TYPE IS SET AGAIN (DUPLICATION)

    var args = [];
    if (this.body !== undefined) {
      args.push(Utils.params(this.body));
    }

    request.send.apply(request, args);
  },

Thanks :)

[tulios]

Hi @ericholiveira, thanks for the report. Can you try to set your header to content-type, all in lowercase?

Maybe this (https://github.com/tulios/mappersmith/blob/master/src/gateway/vanilla-gateway.js#L124) is failing, this is definitely a bug, I'll take a look.

Thanks again.

[ericholiveira]

Ive tried with 'content-type' but still doenst work... actually i think the line of code you highlighted works... the problem is in _setContentTypeHeader you call request.setRequestHeader('Content-Type', contentType); which sets the correct content type... but on the next function call _setUserDefinedHeaders you are just setting all headers again (including content-type) and for this reason it duplicate this header. A simple filter on _setUserDefinedHeaders to avoid setting content-type again should do the trick.

[tulios]

@ericholiveira This is a quick fix but it should work well. I'm planning a major refactor on mappersmith internals. Thanks again!