Making Reposado Client aware

Apple’s Software Update service has the ability to offer the “correct” catalog to a client that requests simply “index.sucatalog”. This ability was first added with OS X Server 10.6.6, and involved the use of Apache’s mod_rewrite.

This feature is handy, as it greatly simplifies client configuration. You no longer need to take client OS version into consideration when setting the CatalogURL for the client.

Lion Server’s Software Update service has a similar capability, but this is done via a CGI instead.

Since Reposado doesn’t handle the web-serving part of offering Apple software updates, Reposado itself cannot provide a similar feature: instead you must configure your web server to do URL rewrites, or write your own CGI to provide this functionality.

mod_rewrite example
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If you are using Apache2 as your webserver, you may be able to configure mod_rewrite to return the “correct” OS-specific sucatalog:

Here is an example .htaccess file you could place at the root of your Reposado repo:

(This requires Apache2 to be configured to actually pay attention to mod_rewite rules in .htaccess files. See your Apache and mod_rewrite documentation for details.)

(Note that the format for these rules is specific for use in an .htaccess file. The rules would need to be changed if in the main Apache config file.)

(Other web servers such as Nginx support URL rewriting; the specifics are slightly different, but the general concepts are similar.)

Testing

The current version of Reposado can help you test your URL rewrites. When catalogs are written out to disk, a key named “_CatalogName” is added to the catalog with the base filename of the catalog. This allows you to verify that the catalog being returned is the one you expect.

For example, I want to test that I’m getting the Lion catalog:

% curl –user-agent “Darwin/11.4.0” http://su.example.com/index_testing.sucatalog > /tmp/testing
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 1024k 100 1024k 0 0 25.1M 0 –:–:– –:–:– –:–:– 32.2M

% tail -5 /tmp/testing

_CatalogName
index-lion-snowleopard-leopard.merged-1_testing.sucatalog
The _CatalogName is “index-lion-snowleopard-leopard.merged-1_testing.sucatalog”, which is what I expect.

I can repeat the test for Snow Leopard, this time against the “release” branch:

% curl –user-agent “Darwin/10.8.0” http://su.example.com/index_release.sucatalog > /tmp/release
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 912k 100 912k 0 0 29.7M 0 –:–:– –:–:– –:–:– 31.8M

% tail -5 /tmp/release

_CatalogName
index-leopard-snowleopard.merged-1_release.sucatalog

Conclusion

Adding URL rewriting to your Reposado web server configuration makes client configuration much simpler, as you no longer have to worry about which OS the client is running.

NOTE

As the URL is being rewritten on the fly, if you goto the url in a browser you will get a 404 error.

I have added the following to the .htaccess file so that I can at least see a catalog in Safari to verify the server is running.

htaccess