result.operation is nil when calling AFMotion::JSON.get

[larsudengaard]

After upgrading to the latest version of RubyMotion, the following code does not work anymore, because result.operation is 'nil'.

We are using RubyMotion v2.9 and AFMotion 0.9.0. The problem started occurring when we upgrade RubyMotion from v2.3 to v2.9.

  def initAndGet(url)
    @isFailed = false
    request = self.createRequest url
    AFMotion::JSON.get(request) do |result|
      handleResponse(request, result)
    end
  end

  def handle_response(request, result)
    response = result.operation.response
    if response
      if (response.statusCode() >= 200 and response.statusCode() <= 299)
        onSuccess(result, response)
      else
        onError(result, response.statusCode())
        @isFailed = true
      end
    else
      onConnectionError(request)
    end

    @delegate.request_done(self) if @delegate and @delegate.respond_to? :request_done
    onDone
  end

[clayallsopp]

• request (returned from createRequest) is a String right?
• So if you downgrade to v2.3, run this code with no changes, it works?
• Is it possible to upload a reproducible example? Have you tried running AFMotion's requests against other endpoints than whatever request is?

[larsudengaard]

No, actually it create and NSMutableURLRequest

  def createRequest(url)
    request = NSMutableURLRequest.requestWithURL(NSURL.URLWithString(url),
                                                 cachePolicy: NSURLRequestReloadIgnoringLocalCacheData,
                                                 timeoutInterval: 300)

    apiVersion = NSBundle.mainBundle.objectForInfoDictionaryKey('ApiVersion')
    request.setValue(apiVersion, forHTTPHeaderField: 'ApiVersion')

    request
  end

I think the problem is how the AFMotion::Operation::JSON.for_request closes over the variable operation.
In AFMotion::Operation::HTTP.for_request you initiate the operation variable before closing over it in the succes and failure blocks. Im am no expert on how closures work in ruby though :-)

Reimplementing AFMotion::Operation::JSON.for_request to look more like the HTTP.for_request solves the problem for me:

  def json_get_request(request, &callback)
    operation = AFJSONRequestOperation.alloc.initWithRequest(request)
    operation.setCompletionBlockWithSuccess(
        lambda { |operation, responseObject|
          result = AFMotion::HTTPResult.new(operation, responseObject, nil)
          callback.call(result)
        },
        failure: lambda {|operation, error|
          result = AFMotion::HTTPResult.new(operation, nil, error)
          callback.call(result)
        }
    )
    operation
  end

[larsudengaard]

And to answer your questions: :-)

request (returned from createRequest) is a String right?
No, NSMutableRequest
So if you downgrade to v2.3, run this code with no changes, it works?
Yes
Is it possible to upload a reproducible example? Have you tried running AFMotion's requests against other endpoints than whatever request is?
I think i might how found a fix for the problem, see the above comment. If not, I will try and make a reproducible example tonight (CET).

[clayallsopp]

Ah I see; yeah the code-paths when passing NSURLRequests aren't very well tested. If your fix works, definitely submit a pull request! (with a test, preferably :) )

[larsudengaard]

What is the alternative method? :-)
I'll try and get around making a pull-request (and test ;-)) tonight.

[clayallsopp]

The alternative method is to passing a String, which will get converted to an NSURLRequest: https://github.com/usepropeller/afmotion/blob/master/lib/afmotion/http.rb#L7. Somehow I guess this triggers a different memory behavior than simply passing one =\