no universal redirection function - why?

VisionsOfCody

Hi all
first post on this forum!

I'm a relative newbie in php have a very general question concerning redirection in php:

why isn't there a function like getURL() (in Flash ActionScript) that can be used anywhere and at any time and in any conditions to go to a new php page?

It seems (and i may be well wrong here, lol) that header location CAN'T be used sometimes (you get that "headers already sent" message), some people output a javascript Location function and others use a META REFRESH.

There's probably a REALLY good reason why this function doesn't exist (or maybe it does!) - can anyone enlighten me? 😕

thanks 😃

shamly

The error message "headers already sent", by the header function only if something is outputted before the header function.
So if you want to use the header location function, then make sure that there is nothing echoed in the page before the header location.

superwormy

It's not a limit of PHP, its a limit of HTTP protocol, so don't blame the Zend people.

HTTP is a stateless protocol, basically you make a request, the server sends back HTML, and closes the connection, and it's done. HTTP dictates that the first output that MUST be sent are HTTP headers, telling the brower what to expect so it knows how to handle the data it's getting.

Flash Actionscript is an ENTIRELY different situation, being that it's client side, doesn't have anything to do with HTTP headers, etc. etc.

If you plan ahead and write decent code there should never be a time when header ("Location: "); cannot be used... but then again, if you plan ahead most of the time you don't need to redirect people like this anyway... you can include() files most times instead. If you think about it, header("Location: "); really isn't very efficient, since you are causing the client to have to issue ANOTHER GET request to whatever server you are redirecting to.

VisionsOfCody

thanks - far be it from me to criticize the folks at Zend - it was a question arising more out of my own ignorance
It seems I'll have to make better use of the include() function ...
thanks for your explanation

😃

stolzyboy

or if you want to use the header() function anywhere in the page, you can use

<?
ob_start();
?>

at the top of the page and that will allow headers to be placed anywhere on your page