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sigung_q

loading a page in PHP

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What do you mean "load a page?" You can use an include statement to include another PHP script if that's what you're trying to do.

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Hi there Mod. Actually, I'm tring to use the header function to redirect the user based on the conditions of an if / else statement. So far, I only get blank pages. The <a> element in HTML doesn't seem to work with either variables, or if / then statements. Also, I've tried starting a session, and it starts just fine, and remains just as long as the page that started it is up, but as soon as I navgate to another page, it seems to be destroyed. At least none of the $_SESSION[] variables are available anymore. Not sure what's going on, but it seems none of the php built in functions are operating correctly. Any help is much appreciated.

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I guarantee PHP is working correctly, you're just not using it correctly. While there are in fact bugs in PHP, I have never seen someone come with an issue where the problem turns out to be PHP.

 

You need to use session_start on every page, the $_SESSION array does not get populated until you call session_start. When you're sending headers, make sure that you haven't sent any output to the browser yet, or else the header will not work. Using session_start sends a header, so you cannot use session_start after sending output either.

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it would be helpful if you could post some of the code that you're using

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I guarantee PHP is working correctly, you're just not using it correctly. While there are in fact bugs in PHP, I have never seen someone come with an issue where the problem turns out to be PHP.

 

You need to use session_start on every page, the $_SESSION array does not get populated until you call session_start. When you're sending headers, make sure that you haven't sent any output to the browser yet, or else the header will not work. Using session_start sends a header, so you cannot use session_start after sending output either.

Hi Just,

 

OK, so if I "session_start()" on every page, does it retain the variables I assigned in the previous page?

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Davej,

 

I have read that link you gave me before. I followed it to the letter, but as soon as I navigate to another page, the $_SESSION[] variables disappear.

 

Here is the code I am wrestling with:

 

<?php session_start(); $aok = 1; $username = $_POST['uname']; $emailaddrs = $_POST['emaila']; $remailaddrs = $_POST['remaila']; $passwrd = $_POST['pswrd']; $rpasswrd = $_POST['rpswrd']; if ($emailaddrs != $remailaddrs) { $aok = 0; } if ($passwrd != $rpasswrd) { $aok = 0; }if ($aok == 1) { $filename = "c:/load_new_mem/new_mem.nmb"; $fp = fopen($filename, "w") or die("Couldn't open $filename"); fwrite($fp, "$username"); fwrite($fp, "$passwrd"); fwrite($fp, "$emailaddrs"); fclose($fp); exec("c:load_new_memload_new.exe"); if (file_exists('c:load_new_membad_name.bad')) { printf("The user name you entered is not acceptable, please hit the back<br/>"); printf("button and try a different user name.<br/>"); $aok = 0; } if (file_exists('c:load_new_memdup_name.dup')) { printf("The user name you entered is already in use, please hit the back button and try<br/>"); printf("a different user name.<br/>"); $aok = 0; } if (file_exists('c:load_new_membad_pswd.bad')) { printf("The password must be between 6 and 16 characters in length, please hit the<br/>"); printf("back button and fix this.<br/>"); $aok = 0; } if ($aok == 1) { $filename = "c:/load_new_mem/".$username."_pages.pgf"; $fp = fopen($filename, "r") or die("Couldn't open $filename"); $_SESSION['userhome'] = fgets($fp, 256); $_SESSION['userbio1'] = fgets($fp, 256); $_SESSION['userprof'] = fgets($fp, 256); $_SESSION['useracts'] = fgets($fp, 256); fclose($fp); $_SESSION['uservld'] = "yes"; header$_SESSION['userhome']; } }else { if ($emailaddrs != $remailaddrs) { echo "Your emails do not match, please hit the back button and fix this."; } if ($passwrd != $rpasswrd) { echo "Your passwords do not match, please hit the back button and fix this."; } }?>

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please use code tags, the forum supports formatted code in posts.

 

so what's the issue with that code? it seems like it's the code that sets the $_SESSION variables and redirects to a page that doesn't read the $_SESSION variables? If so, we would need to see the missing page of code. To be clear, you need to use session_start() on every page that needs to use $_SESSION.

 

note: you might really want to consider using a database for storing data and handling user registration / login

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header$_SESSION['userhome'];

This isn't going to work at all, and if you have error messages enabled you should see one.

 

When sending a location header you need to use session_write_close() to save the session variables first because the connection will likely be closed before the PHP script begins the session storage method that occurs when a script is done.

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Hmmmmm....... Thanx Foxy, I think this may be the missing puzzle piece. Because (as I understand it), session_start() sends a header, and that would make it and the header() function mutually exclusive. I'll let you know how it turns out.

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session_start() and header() are not mutually exclusive, but both of them must be executed before anything is printed.

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OK, so I simplified the script, and all I get is a blank page when I execute it. It appears that the header() function does not function.

 

<?phpsession_start();session_write_close();if ($_SESSION['uservld'] == "yes") { header($_SESSION['userhome']); }exit;?>

When I perform this script, I get the print out of the session variable:

 

<?phpsession_start();session_write_close();if ($_SESSION['uservld'] == "yes") { printf($_SESSION['userhome']); }exit;?>

 

The print out is:

 

http://www.scontinuum.com/home

 

So the printf() function seems to work, but the header() function does not. Although, I'm sure I'm still missing a piece of the puzzle here.

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The header function works just fine man, you just need to learn how to use it. The header function sends any HTTP header you want to send, that's all it does. The web server already sends several headers for every response, and the header function lets you add your own. That's why you can't use it after sending output, because since the headers go before all output once you send any output it will send all of the headers first and then you can't send any more.

 

You're trying to send an HTTP header that is just a URL. That doesn't mean anything to the browser. If you want to redirect the browser you send a location header with the URL to redirect to. The manual for the header function specifically shows sending location headers as some of the examples:

 

http://www.php.net/manual/en/function.header.php

 

Here's a list of various request and response headers that most browsers will understand:

 

http://en.wikipedia.org/wiki/List_of_HTTP_header_fields

 

And the location header specifically:

 

http://en.wikipedia.org/wiki/HTTP_location

 

In general, you should never assume that the reason your program doesn't work is because the language is broken. That is virtually never the case. If it doesn't work then you probably don't understand what it's doing, which means you need to research what you're using.

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I know I probably sound dumb, but I'm just learning this stuff. So if the seesion_start() sends output, and needs to preceed any other output, and the header() function sends output, and needs to preceed any other output, that tells me that the two functions are mutually exclusive at least on the same page, unless separated by some sort of if/else or case structure. Is this true?

 

Having read through the articles you have cited, has just confused me even more than before. In the end, all I really want to do is retain some variables from a session, and use them as the web page(s) that I send the browser to. Is the header() function the wrong functon to be using? Is ther another one that gets along with session better?

 

example:

 

if A

{

header($_SESSION['gotolinkA']);

}

else

{

header($_SESSION['gotolinkB']);

}

 

This is all I really want to be able to do. It seems simple enough. I have a book as well that describes how to use the header() function, yet it doesn't seem to do whatever I read says it will.

Edited by sigung_q

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I know I probably sound dumb, but I'm just learning this stuff. So if the seesion_start() sends output, and needs to preceed any other output, and the header() function sends output, and needs to preceed any other output, that tells me that the two functions are mutually exclusive at least on the same page, unless separated by some sort of if/else or case structure. Is this true?

No. session_start and header do not send output, they send headers. The HTTP response from the server is composed of response headers and the response body. The headers go first. If you tell PHP to send any output that is not a header, then since the headers need to go before the body it will send all headers and then send the output you told it to send. So if you tell PHP to send output, and then later tell it to send a header, it can't send the headers because they were already sent. Run this code to see that error message:

<?phpini_set('display_errors', 1);error_reporting(E_ALL); session_start(); // sends a header echo 'test<br>'; // sends output header('Some-header: some value'); // causes an error

I have a book as well that describes how to use the header() function, yet it doesn't seem to do whatever I read says it will.

You're not understanding what the header function does. You seem to think that the only thing it does is to redirect a browser. That is not what it does. It is much more general than that. It sends an HTTP response header to the browser, nothing more, nothing less. You *could* send a Location header to tell the browser to redirect, but that's not the only thing it does. When I want to have someone click on a link to a PHP page, and I want that code to generate a CSV file for the person to download instead of looking at it in their browser, I send these headers:

  header('Expires: Mon, 26 Jul 1997 05:00:00 GMT');  header('Last-Modified: ' . gmdate('D,d M YH:i:s') . ' GMT');  header('Cache-Control: must-revalidate, post-check=0, pre-check=0');  header('Pragma: public');  header('Content-Description: File Transfer');  header('Content-type: application/octet-stream');  header('Content-Disposition: attachment; filename="report.csv"');  header('Content-Transfer-Encoding: binary');

There's an Expires header, a Last-Modified header, a Cache-Control header, a Pragma header. All of those are telling the browser not to cache the file. There's a Content-Description header, a Content-Type header, a Content-Disposition header that has the filename that I want the browser to show, and a Content-Transfer-Encoding header. All of those describe the content to the browser. Not a single one of those headers is telling the browser to redirect.A header is composed of 2 parts - a header name followed by a colon and space, and a value. You aren't sending a name. You're just sending a URL and assuming that the browser is going to treat it as a Location header. If you want to redirect the browser then don't just send a URL as a header, send a Location header. The manual page for the header function shows examples doing just that.

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