In the process of developing web applications using the thinkphp framework, sometimes we encounter some jump problems, such as repeated jumps. This situation usually occurs when using the redirect function in the Controller, which will automatically perform a 302 jump, and then cause repeated jump problems.
So how should we solve this problem?
First of all, we need to understand the concept of 302 jump. When a web application receives a request, if it needs to make a jump, it will return a response header with status code 302 and set a Location attribute in the response header to tell the browser which new URI to redirect to. When the browser receives this response header, it will automatically send a new request for a new URI, which is a 302 jump.
So why does the problem of repeated jumps occur when using the redirect function of thinkphp?
Actually, this problem is caused by the session mechanism of the thinkphp framework. When we use thinkphp's Session class to store some data, it will automatically perform a session_start() operation on each request. When performing the session_start() operation, a response header similar to "Set-Cookie:PHPSESSID=xxxxxxxxxxxxxxx" will be returned, telling the browser that a cookie named "PHPSESSID" needs to be set. When the browser receives this response header, it will automatically include this cookie in the request header. When the server receives a request with the same PHPSESSID, it will think that this is the same session, so it will not redirect, but directly return the previous response header, resulting in repeated jumps.
There are two ways to solve this problem, we can use any of them to solve the problem.
Method 1: When using the redirect function, add the second parameter to tell the function not to perform a 302 jump, but to jump directly to the specified URI. You can use the following code:
$this->redirect('/index/index', [], 302, ['Pragma'=>'no-cache']);
The fourth parameter is to set the Pragma attribute of the response header, which prohibits the browser from caching the current page, thereby avoiding problems caused by caching.
Method 2: When using the Session class, add a line of code to tell the Session class not to automatically perform the session_start() operation, but to perform the session_start() operation manually. You can use the following code:
session('PHPSESSID', $_COOKIE['PHPSESSID']);
The code here is to manually assign the cookie sent by the browser to PHPSESSID, so that the Session class thinks that the current session is the same session, thereby avoiding the problem of repeated jumps.
To summarize, the repeated jump problem is caused by the session mechanism of the thinkphp framework. The way to solve this problem is to add the Pragma attribute to the redirect function, or use the Session class to manually perform the session_start() operation.
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