"Can parse content" answer for `undefined` mediaType

[Schoonology]

I'm happy to submit a pull request solving this problem, but I want to talk through the design first.

The server I'm currently working on is getting some bad JSON requests. I cannot change the client, so I have to work with what I've got. That said, it's not providing a Content-Type header, so the Request's mediaType property is undefined. That, in turn, makes its canParseContent property true, and parseContent tries to handle the content as if it's application/x-www-form-urlencoded.

Questions:

• What should canParseContent be in this situation?
• If we continue to try to parse content without a Content-Type, should we try { JSON.parse(...) } as a part of our guessing game?
• Should Request have a configurable "defaultContentType" to attempt if it's undefined?

[mjackson]

When the Content-Type header is missing a mach.Request should only assume the request is application/x-www-form-urlencoded (and therefore parseable) if it's a POST, which I assume you're getting. If this is the case then I'd like to leave the behavior of canParseContent as-is since this is the default behavior of web browsers submitting forms.

If your only problem is that the request is missing the Content-Type header, my recommended would be to force mach to use its JSON parser on the request content. You can do this by manually set the Content-Type in your request handler, e.g.:

function (request) {
  // Force mach to handle the request as JSON.
  request.headers['Content-Type'] = 'application/json';

  return request.parseContent().then(function (params) {
    // The client gave us valid JSON.
    return 200;
  }, function (error) {
    // The request body failed to parse as JSON. Maybe it's not valid?
    return 403;
  });
}

It might be a good idea to put this in a middleware.

function enforceJson(app) {
  return function (request) {
    var headers = request.headers;
    if (!headers['Content-Type']) headers['Content-Type'] = 'application/json';
    return request.call(app);
  }
}

Does that help?

[mjackson]

@Schoonology Just following up on this. Did I answer your question?

[Schoonology]

Thanks for following up on this. You definitely answered the question, and I think I wound up doing something similar. It's on a personal project I haven't been able to visit for a while (hence the radio silence), but I'll take a look tonight.

I'll confirm that your expectations match what I was experiencing, and close or comment appropriately.

[Schoonology]

For posterity, the solution above solves the problem nicely. An alternative approach is to build middleware that always parses the content as JSON within said middleware:

stack.use(function (app) {
  return function (request) {
    return mach.utils.bufferStream(request.content)
      .then(function (body) {
        try {
          request.body = JSON.parse(String(body))
        } catch(e) {
          request.body = {}
        }

        return request.call(app)
      })
  }
})