Question

So I just got a nasty surprise when I deployed some code I thought I’d tested. It would seem there must be some difference between my test machine and my server. The exact same code, featuring a header redirect, worked perfectly on my test machine and not at all on the server. The redirect on the server simply didn’t happen, leaving a blank page as a result.

The header is called somewhere in the middle of the script – but nothing will have been output yet. It doesn’t output anything until the very end of the script. Long after everything else is run. It buffers everything.

Both server and test machine are running the same PhP version, the same Apache version. Is there something in the configuration files that would allow the header to happen for one and not in the other? Is there something else going on here that would cause it to fail?

EDIT:

Here’s the line that sets the header:

public function setRedirect($url) {
    header('Location: '.$url);
}

And here’s the code that calls that:

$url = new URL('index');
$this->layout->setRedirect($url->toString());

Where URL::toString() always generates a fully qualified domain name, in this case: http://domain/index.php?action=index

I checked both Php and Apache error logs. Nada.

Answer 1

Probably there was some whitespace or other form of output before the header call.

This is only work if you the ini setting output-buffering is on (or if you explicitly start output buffering, but in that case, the redirect should work in both computers).

You can confirm this by turning on error reporting.