Add async Content-Length computation when using form-data - #953

how does form.getLength get the length of the form? if it's buffering the entire form in to memory then we can't really take this as a default.

getLength()

We can see here: _lengthRetrievers how node-form-data computes the length. I don't think that the data is loaded in memory.

ok, the code is pretty obfuscated but it looks like it has some built in length retrievers for each stream that gets added to it. when those streams are known it can compute the length (if it has a .path property it'll fs.stat the path).

I believe it errors when it doesn't understand the stream. In that case, you'll need to modify this patch so that when getLength's callback gets an error you just opt out of setting the length rather than actually emit an error in the stream.

I updated the PR.

(I updated my comment clarify. The problem was obviously not caused by async)

There is a problem when the stream is created before the execution of the request.
Here is an example that explains the problem:

function doRequest (stream) {
  var r = request.post('http://requestb.in/1baaynt1', function (err, httpResponse, body) {
    if (err) {
      throw err;
    }
    console.log(httpResponse, body);
  });
  var form = r.form();
  form.append('file', stream);
}

// works
var stream = fs.createReadStream('test.jpg');
doRequest(stream);

// not works
var stream = fs.createReadStream('test.jpg');
setTimeout(function () {
  doRequest(stream);
}, 100);

I don't really know what happens but I continue to investigate... Any idea?

(In my case, I createReadStream before passing into multiple async.waterfall.)

@mikeal Any thought ?

what version of node?

Ok. Works great with v0.11.13 but not with v0.10.29.
Do you know what has changed in node stream behavior ?

Rebase done. Travis build in error caused by #951

Sorry this one took so long, I was busy with NodeConf :)

Thanks for merging and your trust :)

FYI... I ran into this same issue. We use Akamai. File uploads work fine locally, but not in production. Using the fix in this pull request resolved the issue. When will this get published?

Thanks!