Facebook Graph API - upload photo using JavaScript

Question

Is it possible to upload a file using the Facebook Graph API using javascript, I feel like I\'m close. I\'m using the following JavaScript

var params = {};
         


        

Answer 1

Only @Thiago's answer is answering the question of uploading data via javascript. I've found that the Facebook JS API doesn't cover this situation.

I've also brew & tested my personl solution.

Main steps

1. Get the binary data of the image (I've used a canvas, but using an input box is possible as well)
2. Form a multipart request with all necesarry data for the graph API call
3. Include the binary data in the request
4. Encode everything in a binary array and send it so via XHR

Code

Conversion utilities

var conversions = {
  stringToBinaryArray: function(string) {
    return Array.prototype.map.call(string, function(c) {
      return c.charCodeAt(0) & 0xff;
    });
  },
  base64ToString: function(b64String) {
    return atob(b64String);
  }
};

Image posting snippet

var DEFAULT_CALL_OPTS = {
  url: 'https://graph.facebook.com/me/photos',
  type: 'POST',
  cache: false,
  success: function(response) {
    console.log(response);
  },
  error: function() {
    console.error(arguments);
  },
  // we compose the data manually, thus
  processData: false,
  /**
   *  Override the default send method to send the data in binary form
   */
  xhr: function() {
    var xhr = $.ajaxSettings.xhr();
    xhr.send = function(string) {
      var bytes = conversions.stringToBinaryArray(string);
      XMLHttpRequest.prototype.send.call(this, new Uint8Array(bytes).buffer);
    };
    return xhr;
  }
};
/**
 * It composes the multipart POST data, according to HTTP standards
 */
var composeMultipartData = function(fields, boundary) {
  var data = '';
  $.each(fields, function(key, value) {
    data += '--' + boundary + '\r\n';

    if (value.dataString) { // file upload
      data += 'Content-Disposition: form-data; name=\'' + key + '\'; ' +
        'filename=\'' + value.name + '\'\r\n';
      data += 'Content-Type: ' + value.type + '\r\n\r\n';
      data += value.dataString + '\r\n';
    } else {
      data += 'Content-Disposition: form-data; name=\'' + key + '\';' +
        '\r\n\r\n';
      data += value + '\r\n';
    }
  });
  data += '--' + boundary + '--';
  return data;
};

/**
 * It sets the multipart form data & contentType
 */
var setupData = function(callObj, opts) {
  // custom separator for the data
  var boundary = 'Awesome field separator ' + Math.random();

  // set the data
  callObj.data = composeMultipartData(opts.fb, boundary);

  // .. and content type
  callObj.contentType = 'multipart/form-data; boundary=' + boundary;
};

// the "public" method to be used
var postImage = function(opts) {

  // create the callObject by combining the defaults with the received ones
  var callObj = $.extend({}, DEFAULT_CALL_OPTS, opts.call);

  // append the access token to the url
  callObj.url += '?access_token=' + opts.fb.accessToken;

  // set the data to be sent in the post (callObj.data = *Magic*)
  setupData(callObj, opts);

  // POST the whole thing to the defined FB url
  $.ajax(callObj);
};

Usage

postImage({
  fb: { // data to be sent to FB
    caption: caption,
    /* place any other API params you wish to send. Ex: place / tags etc.*/
    accessToken: 'ACCESS_TOKEN',
    file: {
      name: 'your-file-name.jpg',
      type: 'image/jpeg', // or png
      dataString: image // the string containing the binary data
    }
  },
  call: { // options of the $.ajax call
    url: 'https://graph.facebook.com/me/photos', // or replace *me* with albumid
    success: successCallbackFunction,
    error: errorCallbackFunction
  }
});

Extra

Extracting the binary string representation of a canvas image

var getImageToBeSentToFacebook = function() {
  // get the reference to the canvas
  var canvas = $('.some-canvas')[0];

  // extract its contents as a jpeg image
  var data = canvas.toDataURL('image/jpeg');

  // strip the base64 "header"
  data = data.replace(/^data:image\/(png|jpe?g);base64,/, '');

  // convert the base64 string to string containing the binary data
  return conversions.base64ToString(data);
}

Information on how to load the binaryString from an input[type=file]

HTML5 File API read as text and binary

Notes:

1. There are of course alternative approaches as well
   • Using an HTML form in an iframe - you cannot get the response from the call
   • Using a FormData & File approach, but unfortunately in this case there are a lot of incompatilities which make the process harder to use, and you would end up duct-taping around the inconsistencies - thus my choice was manual data assembly since HTTP standards rarely change :)
2. The solution does not require any special HTML5 features.
3. The above example uses jQuery.ajax, jQuery.extend, jQuery.each