Last modified: 2014-09-23 19:54:56 UTC
We've kicked this idea around for some time but haven't yet implemented it.
It would be great to have a nice little daemon for doing image resizes safely:
* No more ImageMagick shell-character-exploit or buffer-overflow scares
* Reduce and unify library and subprogram dependencies for application servers
(vs varying versions of ImageMagick, librsvg, libart/cairo, freetype, etc)
* Integrate a nice SVG renderer like Batik
* Potential to isolate CPU and memory usage by running on separate boxes
* downscale PNG -> PNG
* downscale JPEG -> JPEG
* downscale GIF -> GIF
* rasterize SVG -> PNG
* The SVG renderer must be used in a restricted mode: a SVG must not be able to
include resources loadeded from disk or the network, as this could be a security
* Any alpha-transparent PNGs must set the background color chunk to white
to avoid weird unexpected colors in old versions of IE.
* Application servers should be able to communicate with the daemon by a
standard, easy to integrate protocol such as HTTP. A simple REST interface
is preferred over XML-RPC or SOAP.
* If in Java, should be possible to compile with Eclipse compiler and run
with GNU Classpath and an open-source VM, even if we use another VM in
production for performance preferences.
I'd like to see also:
* Better control over output format (grayscale staying grayscale, avoiding
wasted bandwidth etc)
* If possible, 'safe' memory usage for resizes of large PNGs as well as JPEGs.
Loading a 10kx10k pixel bitmap into memory to make a 100x100 thumbnail doesn't always end well.
* Other file formats welcome.
There are two main possibilities for data transfer:
* POST an upload of the source file, and receive the data back. MediaWiki
will deal with reading the file from disk and saving the thumbnail back.
* Send and receive pathnames (or partial pathnames). Daemon will handle
disk access, and simply return a file references.
The path references are likely more efficient, but may require sanitizing
some comments posted here: http://lists.wikimedia.org/pipermail/wikitech-l/2009-April/042693.html
Zhe Wu wrote code to solve this problem for a 2009 GSoC project.
Zhe's status email: http://lists.wikimedia.org/pipermail/wikitech-l/2009-August/044586.html
Zhe's code: https://github.com/wuzhe/imgserve
Install instructions: http://pypi.python.org/pypi/imgserve
Created attachment 14118 [details]
The repo was deleted from GitHub but is still available on pypi (190 downloads last month): attaching the package here in case it disappears there too.
Created attachment 14119 [details]