jQuery.twFile

This jQuery plugin provides access to the local file system (for documents loaded from a file:// URI) to load and save file contents from the browser.

The code is based on TiddlyWiki's self-saving capabilities.

Note that the TiddlySaver applet is required on Opera and WebKit-based browsers (Safari, Chrome). The applet has to be present in the same folder as the respective HTML document.

Source

The source code is currently hosted in TiddlyWiki's Subversion repository.

Feedback is welcome.

API Summary

• $.twFile.load(filePath): load contents from file

• $.twFile.save(filePath, content): save contents to file

• $.twFile.copy(dest, source): duplicate existing file

  N.B.: This is not supported on all browsers.

• $.twFile.convertUriToLocalPath(filePath): normalizes specified absolute file path

N.B.: All file paths must be absolute (e.g. /tmp/foo.txt or C:\temp\foo.txt).

(full documentation in the code comments)

Limitations

• plugin unavailable until document.ready handlers have completed

  Since the TiddlySaver applet cannot be injected synchronously into the document, this is done asynchronously during document.ready processing.

  This means that the plugin is not guaranteed to work properly until after all these handlers have completed.

• currently unreliable UTF-8 support on Internet Explorer

  The plugin is designed to work with UTF-8 encoded text files. However, support in Internet Explorer is broken, and can only reliably save files that are encoded with the ANSI subset of UTF-8. In the case of HTML files, this problem can often be avoided by using HTML entity encodings.

Internals

Internally, the plugin uses four separate drivers to implement the functionality on different browsers:

• activeX: uses the FileSystemObject built into Internet Explorer 5 and above
• mozilla: uses the XUL libraries built into Firefox
• tiddlySaver: uses a custom Java applet that works on Safari, Chrome and Opera
• javaLiveConnect: uses an ancient (and slow) binding technology to call Java runtime library routines directly - only works on Opera

Demo

Download this document (and TiddlySaver if necessary) and open it from the local disk.

This demo illustrates self-saving capabilities by passing document.location.href to $.twFile.convertUriToLocalPath, using the return value in load and save functions.