FileReader.js

http://bgrins.github.com/filereader.js/

A small library independant wrapper for the JavaScript FileReader interface.

This plugin is open source under the MIT License. It was developed in conjunction with a CSS sprite generator project: http://instantsprite.com.

Specifications

• See http://www.w3.org/TR/FileAPI/#dfn-filereader to read about FileReader.
• See http://www.w3.org/TR/FileAPI/#FileReaderSync to read about FileReaderSync.
• See http://www.w3.org/TR/FileAPI/#event-handler-attributes-section for details on Options/on.* callbacks.

Usage:

FileReaderJS.setupInput(document.getElementById('file-input'), opts);
FileReaderJS.setupDrop(document.getElementById('dropzone'), opts);
FileReaderJS.setupClipboard(document.body, opts);

If you have jQuery:

$("#file-input, #dropzone").fileReaderJS(opts);
$("body").fileClipboard(opts);

FileReaderJS.sync

Use the FileReaderSync object when available to load the files in a separate worker. false by default. This will cause only the load or error events to fire (there will be none of the other ProgressEvents, as the operation is synchronous).

Options

readAsMap: A collection taking key as a string that will be matched with regex against
    file types and the type to read as.  If no match is found, it will use readAsDefault.
    The default map is:
    {
        'image/*': 'DataURL',
        'text/*' : 'Text'
    }
readAsDefault: 'ArrayBuffer' | 'Text' | 'DataURL' (default)
accept: A regex string to match the contenttype of a given file.
        For example: 'image/*' to only accept images.
        on.skip will be called when a file does not match the filter.
dragClass: A CSS class to add onto the element called with setupDrop while dragging
on:
    loadstart: function(e, file) { }
    progress: function(e, file) { }
    load: function(e, file) { }
    abort: function(e, file) { }
    error: function(e, file) { }
    loadend: function(e, file) { }
    beforestart: function(file) { } Called before a file is passed to the FileReader.  Return false to prevent processing.  This is used along with the 'accept' parameter to skip a file (ex: an image is too big to process).  This wouldn't be needed, except that Chrome sometimes crashes when calling abort(): http://code.google.com/p/chromium/issues/detail?id=60979
    skip: function(file) { } Called only when a read has been skipped because of the accept string
    groupstart: function(group) { }
    groupend: function(group) { }

Parameters to events:

e - the native ProgressEvent created by the FileReader

file - an extension of the original File object.  See W3 link above for all native parameters.  Here are the extra fields

file.extra = {
    fileID: a generated int id for this file.
    groupID: the group that it belongs to
    nameNoExtension: 'myImage' instead of 'myImage.png'
    extension: 'png' instead of 'myImage.png'
    prettySize: '46.47' kb instead of 47585 (size field)
}

group: simple grouping of files.  Each time a change event or drop even happens and a FileList is created, and all of these files are stored inside a group object.

    groupID: a generated int id for this group
    files: the FileList associated with the group
    started: the Date the group was recieved as input
    ended: the Date all files in the group finished loading

Any contributions are welcome. Author: Brian Grinstead.