How to solve the problem that WeChat applet PHP has no session

In the development of WeChat mini programs, data interaction with the back-end server is very critical, because generally in WeChat mini programs, we often need to obtain some data from the back-end, such as user information, product information, etc. As a widely used back-end language, PHP will also be used to develop the back-end interface of WeChat mini programs. However, when using PHP as the back-end language of WeChat applet, we often encounter some problems, such as no session. So, what are the causes of these problems? How to solve it? The following article will provide an in-depth analysis of these issues.

1. What is session?

Before entering the discussion, we first need to understand the basic concept of "session". Session refers to an interactive connection established between a user and the server. Each time the user makes a request, he or she will apply to establish a session, and the server will generate a unique sessionID to identify the connection. The corresponding session information is stored on the server side, and the respective clients are identified through the session ID. In this way, the server can identify a user during an HTTP request. There are generally two storage methods for Session ID, namely Cookie and URL rewriting.

2. Why is there no session in PHP?

Since session is a mechanism used to identify users, why is it missing in PHP? This is mainly because: PHP is a scripting language, and variables and memory are released immediately after each execution. The implementation of session requires the establishment of an "interactive connection" between the client and the server, and the server is required to save session information, generate sessionid and other operations. This information needs to be exchanged and transmitted between the client and the server. Therefore, in order for PHP to use sessions, there must be a special mechanism to ensure the storage and transmission of session information. This mechanism is session memory.

3. How to solve the problem of no session in PHP?

Since session is missing in PHP, how should we solve this problem? In fact, the solution to this problem is very simple. We can use Cookie to simulate the session. The specific method is: set the Cookie to save the session ID, and then save the user's session information on the server side, so that we can achieve the same session-like function. Functional.

In the process of using cookies to implement sessions, you generally need to pay attention to the following points:

1. Set the Cookie domain name to the current domain name, which ensures that all subdomain names under the current domain name are Ability to read cookies.
2. Set the Cookie Path to "/" to ensure that all directories of the entire website can read the Cookie.
3. On the server side, different sessionIDs need to be assigned to different users, and the entire process can be encrypted using technologies such as MD5.
4. When saving session information on the server side, you can use PHP arrays to save it, or you can use other methods such as databases to save it.

To sum up, for the problem that PHP does not have a session in the WeChat applet, we can use Cookie to simulate the session, so that we can achieve the same functions as the session. Of course, in actual development, we also need to flexibly use various technical means according to specific business situations to meet different needs.

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