fipamo/brain/tools/utilities/DataUtils.js

export const REQUEST_TYPE_POST = "POST";
export const REQUEST_TYPE_GET = "GET";
export const REQUEST_TYPE_PUT = "PUT";
export const REQUEST_TYPE_DELETE = "DELETE";
export const CONTENT_TYPE_JSON = 'json';
export const CONTENT_TYPE_FORM = 'x-www-form-urlencoded';
import EventEmitter from '../events/EventEmitter.jsx';
import * as DataEvent from '../events/DataEvent.jsx';
class DataUtils extends EventEmitter {
  //--------------------------
  // constructor
  //--------------------------
  constructor() {
    super();
    var self = this;
  }
  //--------------------------
  // methods
  //--------------------------
  request(requestURL, eventType, requestType = REQUEST_TYPE_GET, contentType = CONTENT_TYPE_JSON, requestData = null) {
    var self = this;
    return new Promise(function(resolve, reject) {
      var request = new XMLHttpRequest();
      request.upload.onprogress = self.handleLoadProgress;
      request.open(requestType, requestURL, true);
      request.onload = function(e) {
        if (request.status == 200) {
          resolve({
            request,
            eventType
          });
        } else {
          reject({
            request,
            eventType
          });
        }
        ;
      };
      if (requestType == REQUEST_TYPE_PUT || requestType == REQUEST_TYPE_POST) {
        switch (contentType) {
          case CONTENT_TYPE_JSON:
            request.setRequestHeader("Content-type", "application/" + contentType);
            request.send(JSON.stringify(requestData));
            break;
          case CONTENT_TYPE_FORM:
            request.send(requestData);
            break;
        }
      } else {
        request.send();
      }
    })
  }
  imgLoad(url) {
    'use strict';
    // Create new promise with the Promise() constructor;
    // This has as its argument a function with two parameters, resolve and reject
    return new Promise(function(resolve, reject) {
      // Standard XHR to load an image
      var request = new XMLHttpRequest();
      request.open('GET', url);
      request.responseType = 'blob';
      // When the request loads, check whether it was successful
      request.onload = function() {
        if (request.status === 200) {
          // If successful, resolve the promise by passing back the request response
          resolve(request.response);
        } else {
          // If it fails, reject the promise with a error message
          reject(new Error('Image didn\'t load successfully; error code:' + request.statusText));
        }
      };
      request.onerror = function() {
        // Also deal with the case when the entire request fails to begin with
        // This is probably a network error, so reject the promise with an appropriate message
        reject(new Error('There was a network error.'));
      };
      // Send the request
      request.send();
    });
  }
  loadImage(src) {
    'use strict';
    let self = this;
    return new Promise(function(resolve, reject) {
      // Get a reference to the body element, and create a new image object
      var body = document.querySelector('body'),
        myImage = new Image();
      myImage.crossOrigin = ""; // or "anonymous"
      // Call the function with the URL we want to load, but then chain the
      // promise then() method on to the end of it. This contains two callbacks
      self.imgLoad(src).then(function(response) {
        // The first runs when the promise resolves, with the request.reponse specified within the resolve() method.
        var imageURL = window.URL.createObjectURL(response);
        resolve(imageURL);
      //$('background-content').setStyle('background-image', 'url('+imageURL+')') //myImage.src = imageURL;
      //console.log(imageURL);
      //body.appendChild(myImage);
      // The second runs when the promise is rejected, and logs the Error specified with the reject() method.
      }, function(Error) {
        reject(Error)
      });
    });
  }
  //--------------------------
  // event handlers
  //--------------------------
  handleLoadProgress(e) {
    var percentComplete = Math.ceil((e.loaded / e.total) * 100);
  //console.log(percentComplete);
  }
}
export default DataUtils;