HTTP Redirect ?????

Anon

Hi,

I have been looking through tutes and through the manual but I still cannot find one of the most fundamental functionality needed for web page design.

I cannot find the equivalent "redirect" function in PHP. All I need to do is to validate form fields, if the info is incomplete then display message, else if the info is OK then go to another PHP page. The ASP equivalent is 'Response.Redirect "somepage.asp"'

Please help! Its frustrating to know that something so simple can be so difficult.

Thanks

Stuart

reagent

header("Location: mypage.php");

will redir you to mypage.php

Anon

Hi,

I tried the header function but got the following message:

Warning: Cannot add header information - headers already sent by (output started at ~stuartn/sample/TestForm.php:9)

Does this have something to do with the header_sent() function

Thanks

Stuart

reagent

you need to make the call to header() before any ouput is sent to the browser. THIS INCLUDES WHITESPACE IN ANY INCLUDE'D SCRIPTS! Make sure there isn't a single carriage return after any of your ?> tags or that you call the print/echo statements.

headers_sent() won't really help you here, it just checks to see if you have sent any headers..

if you need to do something funky (which you probably don't), check out the output control functions

http://php.net/manual/en/ref.outcontrol.php

good luck!

yelvington

HTTP headers MUST be sent before HTML body.

The error message means that either the structure/flow of your code is wrong, or you have inadvertently let a bit of data "leak," triggering the Web server to send the headers and begin sending the page.

It's pretty easy to let data "leak" from your program. For example, if you begin

<?php

... on the SECOND line of the file, instead of on the first, you have just transmitted a blank CR/LF pair ... as text. Therefore the headers have been sent, and as soon as you try to send any more through header() or setcookie(), you run into the problem.

Anon

Hi again,

I just can't seem grasp this notion. Can you please have a look at the following code and tell me why I am getting errors. The 'if($submit)' and the header() function is not working.

================

<body>
<?php
if ($submit) {
header("Location: otherpage.php");
} else{
?>
<form method="post" action="<?php echo $PHP_SELF?>">
First name:<input type="Text" name="first"><br>
Last name:<input type="Text" name="last"><br>
<input type="Submit" name="submit" value="Submit">
</form>
<?php
} //end else
?>
</body>

========================

Thanks

Stuart

Anon

You have to put the header call ABOVE ALL CODE

ie

if ($submit){header("Location:otherpage.php");} else{

<body>
<form method="post" action="<?php echo $PHP_SELF?>">
First name:<input type="Text" name="first"><br>
Last name:<input type="Text" name="last"><br>
<input type="Submit" name="submit" value="Submit">
</form>
<?php
} //end else
?>
</body>

===========================

does that clear it up a bit for you? Remember headers get sent before any part of the page at all gets sent, any characters at all.

yelvington

Here is your problem

<body>
<?php

Your script MUST begin by jumping immediately into PHP.

Headers MUST be sent before <body> or any other HTML.

Anon

The above posts should answer your question. Take out the <body> tag before you to the redirection.

I finally got what you are trying to do to work, after many false starts. And yes, this is fundamental to web design. Unforunately, sometimes we can all get lost in the nuts & bolts of the language, little snippets here and there, and forget that people are actually trying to get some real work done.

Don't mean to philosophize here, but your question struck a nerve. I compare it to the great C++ vs. Visual Basic debate. I do both types of programming. And usually, when the arguments get going over obscure pointer dereferencing, or some other very esoteric OOP point, I turn to VB and have the solution coded while the C++ geekers are still arguing :-)

Now then, if you find a way to actually reference those variables you want to pass to the next form (after the redirection takes place) please let me know! I am still looking for the solution (in PHP 3). Appending the variables on to the header string seems to work (you can see them go by in the address box) but the new form still seems to know anything about them.

For example, your redirection may look like " . . ./Form2?name="smith" etc.

But doing <? echo $smith ?> on Form2 does nothing. I know the variables must be there (or we are all in deep PHP trouble). But displaying them is another issue.

Hope that helps.

yelvington

Stinger, you should be able to append name=value pairs to redirect URIs. Here is an example of working code from my message board system. It passes the current URI as an argument to the login.php page so that login.php can return the user to the intended context, rather than simply dumping the user into a base context.

// check login, bounce to login page if not
function checklogin()
{
global $REQUEST_URI;
if (! isloggedin() )
header("Location: login.php?returnto=" . basename($REQUEST_URI));
}

kparker

Uhh, in the case of

    ...?name="smith"

you'd want to say

    echo $name;

rather than

    echo $smith;

kparker

Forget the redirect for a moment. If your problem redirect is:

/Form2.php?name=smith

then what happens if you just type:

http://myhost.com/Form2.php?name=smith

into your browser's location bar?

Anon

As I found out from another thread here, nothing at all can happen!

It seems I was under the misconception that I could mix and match .htm and .php files at will. IOW, I thought that by having the php script that processes Form A call Form B (an .htm file) that all the variables from Form A would now be available in Form B.

Well, I guess they are, but Form B, being an .htm file knows nothing about PHP, even if I used the familiar:

<? echo $name; ?>

None of the tutorials that I have make this clear. They just assume that you already know that PHP only works with .php files and that you can ADD your Form stuff as necessary, but not the other way around!

Again, I was so intent on the details that I couldn't see the forest for the trees. If I wrote a tutorial, I would make this very clear at the start, that while you can mix and match PHP and HTML, you can only do this inside a .php file.

Suffice it to say, from now on I will be using .php files about 95% of the time to do my HTML Form development.