Question

I tried to add the command <?php session_start(); ?> before the first line of an index.html – file. Aside from that, the file only contains html statements.
When I noticed that the php-code was not getting interpreted, I changed the ending of the file to index.php, which solved that issue.

Now I am wondering whether what I did is an ugly hack or actually an accepted practice? Is it ok to add a php-prefix to a file that is otherwise html?

Also, I am sadly still getting the following error:
session_start() [function.session-start]: Cannot send session cache limiter - headers already sent . In case my above practice is fine, what causes this error?

Answer 1

What you did is what you’re meant to do.

Filesystem-based webservers, such as Apache and IIS (for the most part) interpret a requested file based on its file extension and process it accordingly. When a user requests a .html file then the server will return the raw bytes of the file, whereas if the user requested a .php file then it will run it through the PHP module or CGI program which generates the desired output.

You can configure your webserver (assuming you’re not on a shared hosting service) to always process .html files with PHP, but it’s better to hide implementation details in your URIs and use URL Rewriting instead (something Apache and IIS7+ have full support for).

With respect to the session_start() error you’re getting – that’s because session_start has to be called before anything is output to the client, which means that the <?php session_start() ?> part has to be at the very start of your document with no plaintext or blank-lines before it. You can have some PHP code before the call, but be sure that the PHP code is not sending any responses or headers.