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';
import * as DataEvent from '../events/DataEvent';
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;