Merge pull request #277 from aayusharyan/patch-3

Add new functionality to calculate chunk size dynamically

Author: AidasK

README.md

@@ -102,7 +102,7 @@ Available configuration options are:
 * `target` The target URL for the multipart POST request. This can be a string or a function. If a
 function, it will be passed a FlowFile, a FlowChunk and isTest boolean (Default: `/`)
 * `singleFile` Enable single file upload. Once one file is uploaded, second file will overtake existing one, first one will be canceled. (Default: false)
-* `chunkSize` The size in bytes of each uploaded chunk of data. The last uploaded chunk will be at least this size and up to two the size, see [Issue #51](https://github.com/23/resumable.js/issues/51) for details and reasons. (Default: `1*1024*1024`)
+* `chunkSize` The size in bytes of each uploaded chunk of data. This can be a number or a function. If a function, it will be passed a FlowFile. The last uploaded chunk will be at least this size and up to two the size, see [Issue #51](https://github.com/23/resumable.js/issues/51) for details and reasons. (Default: `1*1024*1024`, 1MB)
 * `forceChunkSize` Force all chunks to be less or equal than chunkSize. Otherwise, the last chunk will be greater than or equal to `chunkSize`. (Default: `false`)
 * `simultaneousUploads` Number of simultaneous uploads (Default: `3`)
 * `fileParameterName` The name of the multipart POST parameter to use for the file chunk  (Default: `file`)

src/flow.js

@@ -12,7 +12,7 @@
    * Flow.js is a library providing multiple simultaneous, stable and
    * resumable uploads via the HTML5 File API.
    * @param [opts]
-   * @param {number} [opts.chunkSize]
+   * @param {number|Function} [opts.chunkSize]
    * @param {bool} [opts.forceChunkSize]
    * @param {number} [opts.simultaneousUploads]
    * @param {bool} [opts.singleFile]
@@ -750,6 +750,12 @@
      * @type {string}
      */
     this.uniqueIdentifier = (uniqueIdentifier === undefined ? flowObj.generateUniqueIdentifier(file) : uniqueIdentifier);
+                        
+    /**
+     * Size of Each Chunk
+     * @type {number}
+     */
+    this.chunkSize = 0;
 
     /**
      * List of chunks
@@ -938,8 +944,9 @@
       // Rebuild stack of chunks from file
       this._prevProgress = 0;
       var round = this.flowObj.opts.forceChunkSize ? Math.ceil : Math.floor;
+      this.chunkSize = evalOpts(this.flowObj.opts.chunkSize, this);
       var chunks = Math.max(
-        round(this.size / this.flowObj.opts.chunkSize), 1
+        round(this.size / this.chunkSize), 1
       );
       for (var offset = 0; offset < chunks; offset++) {
         this.chunks.push(
@@ -1153,7 +1160,7 @@
      * Size of a chunk
      * @type {number}
      */
-    this.chunkSize = this.flowObj.opts.chunkSize;
+    this.chunkSize = this.fileObj.chunkSize;
 
     /**
      * Chunk start byte in a file
@@ -1267,7 +1274,7 @@
     getParams: function () {
       return {
         flowChunkNumber: this.offset + 1,
-        flowChunkSize: this.flowObj.opts.chunkSize,
+        flowChunkSize: this.chunkSize,
         flowCurrentChunkSize: this.endByte - this.startByte,
         flowTotalSize: this.fileObj.size,
         flowIdentifier: this.fileObj.uniqueIdentifier,