file/js/file.js

file.js revision 4751573f6062da85435e345520a7525e91a897ea
   /**
    * The File class provides a wrapper for a file pointer, either through an HTML5
    * implementation or as a reference to a file pointer stored in Flash. The File wrapper
    * also implements the mechanics for uploading a file and tracking its progress.
    * @module File
    */
   /**
    * The class provides a wrapper for a file pointer.
    * @class File
    * @extends Base
    * @constructor
    */
   var Lang = Y.Lang,
       Bind = Y.bind,
       Win = Y.config.win;

   var YFile = function(o) {

       var file = null;

       if (Y.File.isValidFile(o)) {
           file = o;
       }
       else if (Y.File.isValidFile(o.file)) {
           file = o.file;
       }

       YFile.superclass.constructor.apply(this, arguments);

       if (file && Y.File.canUpload()) {
          if (!this.get("file")) {
              this._set("file", file);
          }
          if (!this.get("html5")) {
          this._set("html5", true);
          }
          if (!this.get("name")) {
          this._set("name", file.name || file.fileName);
          }
          if (this.get("size") != (file.size || file.fileSize)) {
          this._set("size", file.size || file.fileSize);
          }
          if (!this.get("type")) {
          this._set("type", file.type);
          }
          if (file.hasOwnProperty("lastModifiedDate") && !this.get("dateModified")) {
              this._set("dateModified", file.lastModifiedDate);
          }
       }
   };


   Y.extend(YFile, Y.Base, {

       initializer : function (cfg) {
           if (!this.get("id")) {
               this._set("id", Y.guid("file"));
           }
       },

       _uploadEventHandler: function (event) {


           switch (event.type) {
               case "progress":
                  this.fire("uploadprogress", {originEvent: event,
                                              bytesLoaded: event.loaded,
                                              bytesTotal: this.get("size"),
                                              percentLoaded: Math.min(100, Math.round(10000*event.loaded/this.get("size"))/100)
                                              });
                  this._set("bytesUploaded", event.loaded);
                  break;

               case "load":
                   this.fire("uploadcomplete", {originEvent: event,
                                                data: event.target.responseText});
                   var xhrupload = this.get("xhr").upload,
                       xhr = this.get("xhr"),
                       boundEventHandler = this.get("boundEventHandler");

                   xhrupload.removeEventListener ("progress", boundEventHandler);
                   xhrupload.removeEventListener ("error", boundEventHandler);
                   xhrupload.removeEventListener ("abort", boundEventHandler);
                   xhr.removeEventListener ("load", boundEventHandler);
                   xhr.removeEventListener ("readystatechange", boundEventHandler);

                   this._set("xhr", null);
                  break;

               case "error":
                  Y.log("An error has occurred: " + status + ", " + statusText);
                  this.fire("uploaderror", {originEvent: event,
                                                 status: xhr.status,
                                                 statusText: xhr.statusText});
                  break;

               case "abort":
                  this.fire("uploadcancel", {originEvent: event});
                  break;

               case "readystatechange":
                  this.fire("readystatechange", {readyState: event.target.readyState,
                                                 originEvent: event});
                  break;
           }
       },

  /**
   * Starts the upload of a specific file.
   *
   * @method startUpload
   * @param url {String} The URL to upload the file to.
   * @param parameters {Object} (optional) A set of key-value pairs to send as variables along with the file upload HTTP request.
   * @param fileFieldName {String} (optional) The name of the POST variable that should contain the uploaded file ('Filedata' by default)
   * @return {Boolean} This method always returns true.
   */

       startUpload: function(url, parameters, fileFieldName) {
        if (this.get("html5")) {
           this._set("bytesUploaded", 0);
           //console.log ("Initializing xhr");

                this._set("xhr", new XMLHttpRequest());
                this._set("boundEventHandler", Bind(this._uploadEventHandler, this));

                var uploadData = new FormData(),
                    fileField = fileFieldName || "Filedata",
                    xhr = this.get("xhr"),
                    xhrupload = this.get("xhr").upload,
                    boundEventHandler = this.get("boundEventHandler");

        //   console.log ("Appending data to xhr");

           Y.each(parameters, function (value, key) {uploadData.append(key, value);});
           uploadData.append(fileField, this.get("file"));

         //  console.log ("Adding event listeners");


            xhrupload.addEventListener ("progress", boundEventHandler, false);
            xhrupload.addEventListener ("error", boundEventHandler, false);
            xhrupload.addEventListener ("abort", boundEventHandler, false);

            xhr.addEventListener ("load", boundEventHandler, false);
            xhr.addEventListener ("readystatechange", boundEventHandler, false);

         //  console.log ("Initiating upload");

            xhr.open("POST", url, true);
            xhr.send(uploadData);

         //   console.log(xhr);
            this.fire("uploadstart", {xhr: xhr});
        }
       },
  /**
   * Cancels the upload of a specific file, if currently in progress.
   *
   * @method cancelUpload
   */
       cancelUpload: function () {
           xhr.abort();
       },


   }, {

       NAME: 'file',

       ATTRS: {

       html5: {
           readOnly: true,
           value: false
       },

       id: {
           writeOnce: "initOnly",
           value: null
       },

       size: {
           writeOnce: "initOnly",
           value: 0
       },

       name: {
           writeOnce: "initOnly",
           value: null
       },

       dateCreated: {
           writeOnce: "initOnly",
           value: null
       },

       dateModified: {
           writeOnce: "initOnly",
           value: null
       },

       bytesUploaded: {
           readOnly: true,
           value: 0
       },

       type: {
           writeOnce: "initOnly",
           value: null
       },

       file: {
           writeOnce: "initOnly",
           value: null
       },

       uploader: {
           writeOnce: "initOnly",
           value: null
       },
       xhr: {
           readOnly: true,
           value: null
       },

       boundEventHandler: {
           readOnly: true,
           value: null
       }
       },
  /**
   * Checks whether a specific native file instance is valid
   *
   * @method isValidFile
   * @param file {File} A native File() instance.
   */
       isValidFile: function (file) {
           return (Win && Win.File && file instanceof File);
       },

  /**
   * Checks whether the browser has a native upload capability
   * via XMLHttpRequest Level 2.
   *
   * @method canUpload
   */
       canUpload: function () {
           return (Win && Win.FormData && Win.XMLHttpRequest);
       },

       FOO: "BAR"
   });

   Y.File = YFile;