Pass `contentType` from `.write` to `form.append`

[amurchick]

Sometime needs direct assign of content-type when write file to seaweedfs.

To do this - simply change line https://github.com/atroo/node-weedfs/blob/master/lib/weedfs.js#L83:

form.append("file", stream ? stream : file[i]);

to:

form.append("file", stream ? stream : file[i], opts);

And this allowed assign content-type like this:

weed.write('./file', {contentType: 'image/png'})

[phal0r]

Hi @amurchick ,

what is your scenario for submitting the contentType to weed?

Since an array can be passed to the write function, the general options which are appended as querystring to be send to weed are the wrong place. A cleaner solution would be to pass an object instead of a plain buffer like so:

weed.write({
    file: buffer or path or stream,
    contentType: 'image/png'
});

Then we could also support filename and knownLength options provided by form-append

{
    filename: 'unicycle.jpg',
    contentType: 'image/jpg',
    knownLength: 19806
}