gedankenstuecke/oh_data_uploader

var file, response;
var xhr = new XMLHttpRequest();
var put_xhr = new XMLHttpRequest();
var finish_xhr = new XMLHttpRequest();
var count = 0;

function startUpload() {
  var uploaded = false;
  file_metadata.forEach(function(file) {
    var files = document.getElementById('file_'+file.pk).files;
    uploaded = uploaded || files.length;
  });
  if (!uploaded) {
    alert("Please select some files");
    return;
  }
  var replacement = '<div class="progress"><div class="progress-bar progress-bar-striped active" role="progressbar" aria-valuenow="45" aria-valuemin="0" aria-valuemax="100" style="width: 45%"></div></div>';
  $("#infotext").replaceWith('<div id="upload_form">' + replacement + '</div>');
  for (var i = 0; i < file_metadata.length; i++) {
      fle = file_metadata[i];
      count++;
      var data = fle.fields;
      var metadata = {'tags': JSON.parse(data.tags), 'description': data.description};
      metadata = JSON.stringify(metadata);
      fle = document.getElementById('file_'+fle.pk).files[0];
      uploadFile(fle,metadata);
  }
}

function uploadFile(fle,metadata) {
  makeRequest({
    method: 'POST',
    url: "https://www.openhumans.org/api/direct-sharing/project/files/upload/direct/?access_token="+access_token,
    headers: {
      "Content-type": "application/x-www-form-urlencoded"
    },
    params: 'project_member_id='+member_id+'&filename='+fle.name+'&metadata='+metadata
  })
  .then(function (responseText) {
    response = JSON.parse(responseText);
    makeRequest({
      method: 'PUT',
      url: response.url,
      response_type: 'text',
      params: fle,
      headers: {
        'Content-type': ''
      }
    })
    .then(function(response1) {
      response = JSON.parse(responseText);
      makeRequest({
        method: 'POST',
        url: "https://www.openhumans.org/api/direct-sharing/project/files/upload/complete/?access_token="+access_token,
        params: 'project_member_id='+member_id+'&file_id='+response.id,
        headers: {
          "Content-type": "application/x-www-form-urlencoded"
        }
      });
      if(count == file_metadata.length) {
        doneUpload();
      }
    })
    .catch(function (err) {
      console.error('ERROR in PUT', err.statusText);
    });
  })
  .catch(function (err) {
    console.error('Error in POST', err.statusText);
  });
}

function makeRequest (opts) {
  return new Promise(function (resolve, reject) {
    var xhr = new XMLHttpRequest();
    xhr.open(opts.method, opts.url);
    xhr.onload = function () {
      if (this.status >= 200 && this.status < 300) {
        resolve(xhr.response);
      } else {
        reject({
          status: this.status,
          statusText: xhr.statusText
        });
      }
    };
    xhr.onerror = function () {
      reject({
        status: this.status,
        statusText: xhr.statusText
      });
    };
    if (opts.headers) {
      Object.keys(opts.headers).forEach(function (key) {
        xhr.setRequestHeader(key, opts.headers[key]);
      });
    };
    if (opts.response_type) {
      xhr.responseType = opts.response_type
    }

    var params = opts.params;
    xhr.send(params);
  });
}

function doneUpload() {
  var done = "<h3>Upload successful.</h3>";
  $("#upload_form").replaceWith('<div id="upload_form">'+done+'</div>');
}