[feature] Upload base64 or dataURL use QiNiu.

Author: wangxiao

lib/file.js

@@ -45,6 +45,30 @@ module.exports = function(AV) {
     return chunks.join("");
   };
 
+
+  var dataURItoBlob = function(dataURI, type) {
+    // convert base64/URLEncoded data component to raw binary data held in a string
+    var byteString;
+
+    // 传入的 base64，不是 dataURL
+    if (dataURI.indexOf('base64') < 0) {
+      byteString = atob(dataURI);
+    } else if (dataURI.split(',')[0].indexOf('base64') >= 0) {
+      byteString = atob(dataURI.split(',')[1]);
+    } else {
+      byteString = unescape(dataURI.split(',')[1]);
+    }
+    // separate out the mime component
+    var mimeString = type || dataURI.split(',')[0].split(':')[1].split(';')[0];
+
+    // write the bytes of the string to a typed array
+    var ia = new Uint8Array(byteString.length);
+    for (var i = 0; i < byteString.length; i ++) {
+        ia[i] = byteString.charCodeAt(i);
+    }
+    return new Blob([ia], {type:mimeString});
+  };
+
   // A list of file extensions to mime types as found here:
   // http://stackoverflow.com/questions/58510/using-net-how-can-you-find-the-
   //     mime-type-of-a-file-based-on-the-file-signature
@@ -330,6 +354,7 @@ module.exports = function(AV) {
       this._metaData.size = data.length;
     } else if (data && data.base64) {
       this._source = AV.Promise.as(data.base64, guessedType);
+      this._isBase64 = true;
     } else if (data && data.blob) {
       this._source = AV.Promise.as(data.blob, guessedType);
       this._isBlob = true;
@@ -557,11 +582,15 @@ module.exports = function(AV) {
       var self = this;
       if (!self._previousSave) {
         if(self._source) {
-          if (this._isBlob || this._isFileObject) {
+          if (self._isBlob || self._isFileObject || self._isBase64) {
             // TODO: remove this code and use qiniu SDK
             var dataFormat;
             self._previousSave = self._source.then(function(data, type) {
-              dataFormat = data;
+              if (self._isBase64) {
+                dataFormat = dataURItoBlob(data, type);
+              } else {
+                dataFormat = data;
+              }
               return self._qiniuToken(type);
             }).then(function(response) {
               self._url = response.url;