Question

PHP redirect inside a script, how?

Asked by: dcrudo

Dear Experts,

I have a script that processes logins...and at the end, depending on what the result is, the client should be redirected
to one page or another, here an example:

if ($g_loginstatus == "Succesfull")
            {
            header("index.php?cmd=summary");
            }

if ($g_loginstatus == "unverified")
            {
            header("index.php?cmd=unverified");
            }

the problem is that this doesn't work, I always get:
"Warning: Cannot modify header information - headers already sent by (output started at /home/.sites/75/site8/web/it/proclogin.php:29) in /home/.sites/75/site8/web/it/proclogin.php"

is there an easy way to redirect clients depending on variables?
(something like <%response.redirect("http://www.site.com")%> in ASP.)

Thank you in advance!

Dave.

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Asked On
2005-03-29 at 14:58:01ID21369051
Tags

php

,

redirect

Topic

PHP Scripting Language

Participating Experts
9
Points
500
Comments
19

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Answers

 

by: mleebPosted on 2005-03-29 at 15:05:06ID: 13657474

All you have to do is place that chunk of code at the top of the page before the "content" starts so it is part of the header and it should work fine.

 

by: dcrudoPosted on 2005-03-29 at 15:10:01ID: 13657504

I cannot put it on top of the page... because I have to process the script first...

the page 'proclogin.php' contains only script...no html....

 

by: cpucciPosted on 2005-03-29 at 18:51:56ID: 13658387

I'm not sure but can't you escape out of your php script and insert a javascript redirect if the condition is met:

<?php

if (this) { ?>

javascript redirect

<?php  } ?>

 

by: matt_mcswainPosted on 2005-03-29 at 19:03:54ID: 13658449

Well, your header should be like:

header('Location: index.php?cmd=summary');
exit();//it's good practive to exit from the script immediately after.

The main issue is, you can't send any output(i.e html) before sending http headers. They have to be sent to the browser first.
Not even a single white-space. Try to keep any script processing that may lead to a redirect above all of your output.

Hope that helps.

 

by: matt_mcswainPosted on 2005-03-29 at 19:08:51ID: 13658472

>>the page 'proclogin.php' contains only script...no html....
OK, well that's good.
>>output started at /home/.sites/75/site8/web/it/proclogin.php:29
What's on line 29?
There's probably an error.

 

by: jericotolentinoPosted on 2005-03-29 at 22:13:01ID: 13659273

Hi,

Correct me if I'm wrong, but I assume you have 3 pages. Your login page, proclogin.php, then index.php (which decides where to send the user).

I don't know how you structured proclogin.php, but maybe this outline would help you.

1. Check if there were actually entries in the form
2. Check if the entries were actually right
3. If entries were right set session variables or cookies
4. If you want to pass variables, now's the time
5. Redirect where applicable

And like the other experts said, put your redirection code before the <head></head> tags.

So in index.php, you'll just have to check the status of the variables with isset and $_GET.

Hope this helps!

;-)

 

by: ReapzPosted on 2005-03-29 at 22:58:15ID: 13659499

You can get around sending headers after output by using the output buffer.

Put ob_start() at the top of your page...

Your Code...

Then put ob_end_flush() at the bottom.

 

by: _Marcel_Posted on 2005-03-29 at 22:58:18ID: 13659500

If you need to rewrite your total script to make sure no output starts, and don't have the time for it, you might want to use an output buffer: ob_start(). This starts the buffer, and will keep all output in it (and not send it to a browser). You can then clear the buffer before redirecting with ob_end_clear(). This is not the most effective way to code, but it might be a quick solution to the problem.

 

by: eeBlueShadowPosted on 2005-03-30 at 01:50:21ID: 13660282

Make sure there are no other errors in the script before the header() line. Any error messages will cause HTML output to start and will mean your redirect will fail

_Blue

 

by: pkphilipPosted on 2005-03-30 at 01:53:22ID: 13660298

The error is most likely either due to a new line character or a space inserted somewhere before <?php or after ?>.

Please check the following:

1. Make sure there is absolutely nothing being sent to the browser before the header() functions are called. This includes spaces. If your code looks like this:

Start here ->
<?php

if ($g_loginstatus == "Succesfull")
          {
          header("index.php?cmd=summary");
          }

if ($g_loginstatus == "unverified")
          {
          header("index.php?cmd=unverified");
          }
?>

<- end here

NOTE: Please notice that I have deliberately left an empty line between "?>" and "<-end here". This is an error and will cause your header redirection to fail with the warning:

"Warning: Cannot modify header information - headers already sent by (output started at /home/.sites/75/site8/web/it/proclogin.php:29) in /home/.sites/75/site8/web/it/proclogin.php"

Make sure there is no space or newlines before <?php or after ?>

 

by: gruntarPosted on 2005-03-30 at 02:06:21ID: 13660359

Just like Reapz said, use ob_start() and ob_end_flush();

Example

<?php
ob_start();

//your code here

ob_end_flush();
?>

That way you don't have to change anything in your script and you won't have problems with headers/redirecting.

Cheers

 

by: dcrudoPosted on 2005-03-30 at 03:12:58ID: 13660669

...i'm now testing the different proposal... but the one that gives less errors is the javascript nested into the php script...

it seems very strange that a powerful language like PHP... doesn't have an easier way to redirect the client... and the few solutions are header dependent...

 

by: gruntarPosted on 2005-03-30 at 03:54:03ID: 13660856

yea, well. Javascript is client side and won't work if javascript is desabled....

>> it seems very strange that a powerful language like PHP... doesn't have an easier way to redirect the client... and the few solutions are header dependent...

I don't think it can get any easyer than that. :) There are tons of functions that can make your coding fast and easy but only if you know that they exist.

Cheers

 

by: eeBlueShadowPosted on 2005-03-30 at 03:54:05ID: 13660857

Can you show us lines 25-32? As matt_mcswain said, your problem is coming from line 29 and you never posted those lines. If there's an error there then fixing it should solve your problem.

_Blue

 

by: dcrudoPosted on 2005-03-30 at 04:11:12ID: 13660970

Line 29 was :

header("index.php?cmd=summary");


I think he tries to send out the header twice...

 

by: gruntarPosted on 2005-03-30 at 04:21:18ID: 13661027

No, not twice just annother header (you can send several headers).

to redirect header should look like this... and don't forget headers bust be sent before any output or use ob_start(); ...

header("Location: http://www.example.com/index.php?cmd=summary");

cheers

 

by: eeBlueShadowPosted on 2005-03-30 at 05:35:10ID: 13661591

Oops, feeling stupid for not noticing that now.

You don't need the entire URL in the header, but you do need to put "Location: " at the start. There are lots of different types of headers, Location is just one of them.

_Blue

 

by: ReapzPosted on 2005-03-30 at 10:07:42ID: 13664319

Doh!...

I'd just suggested using the header() function to someone in another post. Can't believe I didn't notice that lol!

My excuse... was half one in the morning here :)

 

by: dcrudoPosted on 2005-03-30 at 22:10:13ID: 13669026

Dear Experts,

In the end I have choosen to forget about headers...and I will use the javascript solution.

Thank you a lot for your help!

Dave.

20120131-EE-VQP-002

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