Automatically version your Javascript files with Subversion
17 Feb
We’ve already talked about serving static files in a good way. This post can be read as a follow-up to the Particletree article “Automatically Version Your CSS and JavaScript Files“.
A little excerpt of the article (read it!): When serving static files like .js or .css, the idea is having them cached by the client (a.k.a. browser) for a very long time (let’s say 10 years). But if we modify one of this static files, we need a way for the client to get the new version downloaded again. With that in mind we introduce the “version” of the file in the name, either with mod_rewrite (or similar), either in the querystring as a parameter. Changing the version number will get the browser think is a new file, and get it downloaded again.
But as said, read the Particletree article, is a lot better explained there.
Version
Now the thing is how to determine that version number for each static file. Obviously the idea is not having it done by hand, and that’s why in the Particletree article they use the filemtime() function, to get the last modification timestamp for the file.
Although it’s a first option, personally I don’t like it so much. That would imply a disk access each time an uncached static file is requested, and even we can avoid that disk access saving the timestamps in a include file… Why not use the repository version itself?
The staticVersions.py script
And here’s my humbly contribution. Is a Python script that scans the specified folders for static files (js and css), and returns a PHP array with the name of the files and its version in the Subversion repository, that is, when the last change happened.
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