PHP readfile() and large files

Question

When using readfile() -- using PHP on Apache -- is the file immediately read into Apache\'s output buffer and the PHP script execution completed, or does the PHP script exec

Answer 1

You may still have PHP output buffering active while performing the readfile(). Check that with:

if (ob_get_level()) ob_end_clean();

or

while (ob_get_level()) ob_end_clean();

This way theonly remaining output Buffer should be apache's Output Buffer, see SendBufferSize for apache tweaks.

EDIT

You can also have a look at mod_xsendfile (an SO post on such usage, PHP + apache + x-sendfile), so that you simply tell the web server you have done the security check and that now he can deliver the file.