How to display current working copy version of an hg repository on a PHP page

Question

I use Mercurial for most of my projects and when I deploy a web site, I simply just do an hg clone on the production server and hg pull -u from there. What I'd like to do is add a small snippet to my site's footer which displays the current revision number (both decimal and hex) as well as perhaps the current branch. Stack Overflow and BitBucket both do a variation of what I'm looking for.

I briefly tried parsing the output of exec('hg summary'), but I ran into a couple permissions problems before wondering if there was any better way to do it. Is there a better way, or is exec my best option?

Solution

You could use a post-update hook to put the information in a file. In the site's .hg/hgrc you'd put something like this:

[hooks]
post-update = hg id --rev > VERSION ; hg id --id >> VERSION

then you can access that file from inside your php. You'll still need to make sure that the user running the hg pull -u trusts the hgrc file and that the VERSION file has permissions such that the webserver can read it.

Comments

[Tim Henigan]

A good description of the revision can obtained with something like hg log -r . --template "v{latesttag}-{latesttagdistance}-{node|short}\n". This returns a string like "v1.0.0-2-5e51254a" (i.e. 2 commits after tag 1.0.0 with changeset id 5e51254a.

[Jimmy Sawczuk]

Good answer - I like it. Doesn't rely on exec, easy enough to implement. Thanks!

[Thomas Keller]

hg id -r expects an argument, I guess you meant -n?

[Ry4an Brase]

Right you are @tommyd, though Tim Henigan's form is better yet.