Mobile Browser detection and redirection

[HaLo2FrEeEk]

Ok, I've done a little research on this subject and I've come up with 2 good methods. The first uses a PHP script that detects the $_SERVER['HTTP_USER_AGENT'] variable and parses it for information that might indicate that the browser is a mobile one. This works well, I tested it with my Motorola Droid with Android 2.0.1 and it successfully reported not only that I was on a mobile browser, but also that I was on an android device.

However, I learned about another way, using a similar concept. Mod_Rewrite. I've done some searching and uncovered a few mod rewrite commands that will redirect a mobile browser, but I haven't tried any of them, mostly because I've got other RewriteRules already present on my site.

My main question is what is going to be the best method? Logic leans toward Mod_Rewrite because it occurs before the page is even loaded, meaning I won't have to even run the PHP script in the first place.

My second question, if I do go with Mod_Rewrite, will the RewriteCond's and RewriteRules interfere with the ones I already have implemented? The ones I have right now are things to redirect from subfolders to subdomains where I've moved files to keep organized, or to rewrite dynamic pages with parameters to static-looking pages.

I don't want those to be disrupted, but I want all mobile browsers to be redirected to the mobile version of the site.

Can someone help me out?

I should also note that I'm not very good at the Regular Expressions used in Mod Rewrite, so I might need help with that, too.

[Atli]

Hey.

RewriteRules are executed in a sequence, just as any code, so if you place your rule for redirecting mobiles in front of the others, and then stop the execution, it should not interfere with your old rules.

For instance, something like this should be perfectly fine:
(Note, this is just an example. I didn't test it.)

# Silently redirect IE to another version of the site
RewriteCond %{HTTP_USER_AGENT} MSIE
RewriteRule ^(.*)$ broken.php?$1 [L,NC]
 
# Redirect Android somewhere else
RewriteCond %{HTTP_USER_AGENT} Android
RewriteRule ^(.*)$ android.php?$1 [R=301,L,NC]
 
# And put your old redirects here
RewriteRule ^search/([^/]*)/?$ search.php?keyword=$1 [L]
RewriteRule ^blog/(\d+)/? blog.php?id=$1 [L]
# etc...

Also, just to put it out there...
I would be careful in redirecting all mobile browsers from your main site. Some of them may well prefer to view the standard site rather than the mobile one.
Personally, I would consider it a better tactic to detect mobile browsers using PHP, and add a sort of splash-screen, offering them a link to the mobile version.

[HaLo2FrEeEk]

I fully plan to redirect all detectable mobile browsers to the mobile site, then provide a link to the full version if the user so desires. That's another thing, how would I go about allowing the user back into the mobile site if I'm doing a redirect? Cookies?

[mlynn]

I offer the following article in answer to your question... I created it to show an example of how to redirect users based on their device / browser to unique instances of your web content. The example also includes a mechanism for allowing users to specify a preference for / view other site versions.

http://www.mlynn.org/2010/06/mobile-...tion-with-php/

Enjoy!