Practical mod_perl

Appendix A. mod_perl Recipes

This appendix acts as a mini-cookbook for mod_perl. As we’ve mentioned many times in this book, the mod_perl mailing list is a terrific resource for anyone working with mod_perl. Many very useful code snippets and neat techniques have been posted to the mod_perl mailing list. In this appendix, we present the techniques that you will find most useful in your day-to-day mod_perl programming.

Emulating the Authentication Mechanism

You can authenticate users with your own mechanism (instead of the standard one) but still make Apache think that the user was authenticated by the standard mechanism. Set the username with:

$r->connection->user('username');

Now you can use this information, for example, during logging, so that you can have your “username” passed as if it was transmitted to Apache through HTTP authentication.

Reusing Data from POST Requests

What happens if you need to access the POSTed data more than once. For example, suppose you need to reuse it in subsequent handlers of the same request? POSTed data comes directly from the socket, and at the low level data can be read from a socket only once. You have to store it to make it available for reuse.

But what do you do with large multipart file uploads? Because POSTed data is not all read in one clump, it’s a problem that’s not easy to solve in a general way. A transparent way to do this is to switch the request method from POST to GET and store the POST data in the query string. The handler in Example ...