php callback function to next page - php

I'm using a widget that allow me to execute a callback php function after some events.
I want to have a php function that will allow me to go to the next page using the GET method.
From
mypage.php?page=1
To
mypage.php?page=2
To
mypage.php?page=3
and so on...
I tought that something like
$page = mysql_real_escape_string($_GET['page']); // ==0 if no $_GET['page']
function next_page($page) {
header('Location: mypage.php?page='.++$page.'');}
I know that using header could be tricky. That might be obvious but I'd prefer something reliable and scalable. Maybe if I could execute a javascript.location script. Any suggestions?

$page = 0;
if(isset($_GET['page']))
$page = intval($_GET['page']);
function next_page($page) {
$page ++;
header('Location: mypage.php?page='.$page);
exit;
}
header shouldn't be considered tricky. You just have to make sure no output has been sent to the browser before using it.

Re-assign $page first then append it:
$page = isset($_GET['page']) ? intval($_GET['page']) : 0;
Then in your function simple call
$page++;
header('Location: http://address-to-page/?page=' . $page);

Related

$page =$_GET["page] (an other post)

I'm learning PHP and i block on a problem. I read posts about this issue but i still do not understand.
This is my code (from index.php):
$page = $_GET['page'];
$page = $_GET['action'];
if ($page == "operation" && $action == "liste"){
include("operationForm.php");
}
if ($page == "produits" && $action == "ajout") {
include('../Produits/AddProductForm.php');
}
When i tried to navigate i come across this message:
(404 Not Found : /Fournisseurs/index.php was not found on this
server).
I really don't see where is the problem. Do you have any tips or tutos for solving this problem ?
$page = $_GET['page'];
$page = $_GET['action'];
You are using the same variable name !
This looks better :P
$page = basename($_GET['page']);
$action = basename($_GET['action']);
As for the 404...
../ means parent folder, it seems the file you want to include is not located there. Be careful when using user input, validation / sanitization is mandatory
$page = $_GET['page'];
$page = $_GET['action'];
You set your variables with the same name. So the second $page is overwrite the first $page.

Strange issue PHP session inside condition

I have this code:
session_start();
$i = 'NO';
if ( $_GET['page'] != 'login' ) {
$_SESSION['redirect'] = 'my-account';
$i = 'YES';
}
The logic says:
allways $_GET['page'] != "login", the block inside IF condition will be skipped...
In a URL like this: www.example.com/?page=login
The first time is OK, $_SESSION['redirect'] has no value
if I reload the page, $i still has the value "NO" (OK)
but $_SESSION['redirect'] now contains the value "my-account"
Currently, this code is everything that is written on my test url
And a strange thing more:
Chrome / Firefox (Windows) and Chrome (Mac) exhibit this behavior
Firefox (Mac) effectively ignores the block
how can it be possible?
Try below code:
<?php
session_start();
$i = 'NO';
$page = $_GET['page'];
if ( isset($page) ) {
if ($page != 'login') {
$_SESSION['redirect'] = 'my-account';
$i = 'YES';
} else {
$_SESSION['redirect'] = '';
}
}
echo $i;
echo $_SESSION['redirect'];
?>
before trying it, clear the session variable
So, your SESSION is getting set even though you think it shouldn't?
Your page is probably getting called anyway - either you have a redirect to it or an auto include, and the browser is then calling it when you yourself call the page because it's trying to load "favicon.ico".

PHP Code Cleaning

Am running the following code to gather some data from my page and store it in my database, however, i need to add some extra functionality to it but i don't seem to be able to do it correctly.
The Code:
// Get Referrer and Page
if (isset($_GET["ref"]))
{
// from javascript
$referer = $_GET["ref"];
$page = ((isset($_SERVER['HTTP_REFERER'])) ? (parse_url($_SERVER['HTTP_REFERER'], PHP_URL_PATH)) : (''));
}
else
{
// from php
$referer = ((isset($_SERVER['HTTP_REFERER'])) ? ($_SERVER['HTTP_REFERER']) : (''));
$page = $_SERVER['PHP_SELF']; // with include via php
}
// Cleanup
if (basename($page) == basename(__FILE__)) $page = "" ;
This script is storing $page as "/site/index.php or /site/about.php", for example. I kinda want it to store it as "Index or About" without the whole /site/ and .php part.
Thanks in advance
Use pathinfo(), for example:
<?php
$page = "/site/index.php";
$page_info = pathinfo($page);
$page_name = $page_info['filename'];
echo $page_name; //output: index
?>

Problem with including files based on (non-defined) variable

i have a PHP site with the following code in it:
<?php
$p = $_GET['p']
include("$p.inc");
?>
Whenever I send a visitor to a page like index.php?p=contact for example I want the file contact.inc to be included. This works fine.
Now I want a certain file to be included (e.g. start.inc) when the visitor is sent to index.php without any GET variables. However, an error message is returned which tells me that $p is undefined (which it logically is).
I tried fixing this problem by using the isset function like so:
<?php
if(!isset($p)) $p = "start";
else $p = $_GET['p'];
include("$p.inc");
?>
but this doesn't work because now $p always contains the string "start" and I can't send the visitor to index.php?p=contact anymore - it will still include start.inc
Can somebody please help me with this issue?
Thanks in advance!
Explicitly specify the allowable values​​, obtained from outside.
<?php
$allowed_pages = array(
'home' => 'home.inc',
'contact' => 'contact.inc',
);
$page = #$_GET['p'];
$file = array_key_exists($page, $allowed_pages) ? $allowed_pages[$page] : $allowed_pages['home'];
include($file);
?>
You should white-list your pages anyway, for security. so:
<?php
$p = $_GET['p']
switch($p){
case 'contact':
include("contact.inc");
break;
default:
include("start.inc");
}
?>
Define your $p variable just like this:
$p = array_key_exists('p', $_GET) ? preg_replace('!\W!', '', $_GET['p']) : 'start';
you're checking $p instead of $_GET['p'] so, as $p is never set, you always land at starting page.
anyway you have to sanitize this variable first.
good practice would be like this (assuming pages stored in a "pagedata" folder and have .php extension):
if(isset($_GET['p'])) {
$p = basename($_GET['p']);
} else {
$p = "start";
}
$fileName = "pagedata/$p.inc.php";
if(is_readable($fileName)) {
include($fileName);
} else {
include("pagedata/404.html");
}
You should prefer an array-map or a switch like Nanne suggested.
At the very least use basename() if you want to keep using the $p variable directly in the include statement. And this is how you could avoid the "error" (which is a debug notice, btw):
<?php
$p = #$_GET["p"] or $p = "start";
$p = preg_replace("/\W+/", "", $p); // minimum filtering
include("./$p.inc");
?>
Thanks to you all!
I combined most of your suggestions to the following piece of code:
<?php
$pages = array(
'start'=>'Start.inc';
'contact'=>'Contact.inc';
'about'=>'About.inc';
};
$p = array_key_exists(#$_GET['p'], $pages) ? preg_replace('!\W!', '', $_GET['p'] : 'start';
$p = ucfirst($p);
$page = "./$p.inc";
if(is_readable($page)) include($page);
else include(./404.);
?>
I particularly like the array-map (as suggested by Alex and mario) for security reasons aswell as the error page idea by Col. Shrapnel.

dynamic include methods

Among the following include methods which is the best to practice and why?
$page = $_GET['page'];
Method 1
$pages = array('home', 'blog', 'about');
if( in_array($page, $pages) )
{
include($page.'.php');
{
else
{
die('Nice Try.');
}
Method 2
if($page = 'home'){
include('home.php');
}else if($page = 'blog'){
include('blog.php');
}else if($page = 'about'){
include('about.php');
}
Method 3
if(str_replace("http://", "gth://", $page) == $page){
include_once $page;
}else{
die('Nice Try.');
}
or any other solutions? I dont prefer method 1 and 2 as it always needs to be updated everytime i add a new page.
extending/maintaining the first way is easiest, second way is worse. third way is no way to go, as it relies on user input to require pages... it is going to be a security hole
I believe that the first one is the best of the lot. You can try the second one, but it's for the freshers. And the third one is a BIG NO, because any fresher hacker could hack your "if" condition, & more loopholes will start creeping in.
As for your problem, on adding a new page to the array, every time a new page is created, for the first method, I have one solution:-
Let's say you're putting all the new pages in one folder "abc". Now just write one file code as the following, to read all the files / pages existing in that folder:-
<?php
$page = $_GET['page'];
$pages = array();
/**
* If you are using all the pages existing in the current folder you are in,
* then use the below variable as:-
* $path = ".";
*/
$path = 'abc/'; // Change the Path here, related to this Folder name
$handle = opendir($path);
while (($file = readdir($handle)) !== false) {
$pages[] = $file;
}
closedir($handle);
if( in_array($page, $pages) ) {
include($page.'.php');
}
else {
die('Nice Try.');
}
?>
So you see that the array is getting filled up dynamically, without the need to mention all the pages you create every time. And you are using the first method only. And keep the including pages in one separate folder, which you will need to include every time, in other main pages.
Hope it helps.

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