


Detailed explanation of how to obtain PHP error logs, detailed explanation of how to obtain PHP logs_PHP tutorial
Detailed explanation of how to obtain PHP error logs, detailed explanation of how to obtain PHP logs
There are many ways to obtain error logs in PHP. Let me give you a brief introduction to how to obtain such logs. How to solve the problem, I will show you through the code below, I hope it can help you.
<?php error_reporting (0); register_shutdown_function($err = 'my_error_handler') OR set_error_handler($err,E_ALL); // 同时注册两个函数. // 函数参数错误 $original = unserialize ( array(423142,2134234)); // 不可对0除 echo 1/0; // 不存在的数组索引 echo $_GET['aa']; // 不存在的常量 PHP_E; // 不存在的变量 echo $var; // 函数参数错误 strlen(array(2434)); // 函数参数错误 md5(array(1)); // 用户自定义错误 trigger_error('safdds',E_USER_NOTICE); // 不存在的函数 php中断 // tes(); // 不存在的方法 php中断 $ts = new afsd(); function my_error_handler($errno=0 ,$errstr=0 , $errfile=0 ,$errline=0){ if($errno && $errfile){ if(true){ $earr = array(); $earr['type'] = $errno; $earr['message'] = $errstr; $earr['file'] = $errfile; $earr['line'] = $errline; } }else{ $earr = error_get_last(); } echo '<pre class="brush:php;toolbar:false">'; print_r($earr); return array(); }
For PHP errors, we must have a clear understanding of the types, when they are triggered, and what the return value is.
If we do not distinguish between warnings, errors, suggestions, prompts and other detailed types, then we can understand that there are two types of PHP error types:
One is forced interrupt program error. Such as error, method does not exist, etc. Insufficient memory, timeout
One type is a non-interrupting error. Such as warnings, prompt these
To obtain the interrupt program error, you need to use the register_shutdown_function function, register a memory function, and then obtain the error information. This method can only obtain the first error line. For example, when there are multiple non-existent functions, it can only obtain That mistake the first time. This actually has advantages, you fix one and it will move to the next one.
For non-interruptive errors, if you use:register_shutdown_function, it will become extremely difficult to operate. You can only get the first prompt or warning. At this time, we need set_error_handler. Every time the error level constants are touched, the error function will be called once. You can also get the error log inside. However, this function will inherit the error_get_last function, so you will find that error_get_last returns empty, all passed in by parameters.
Using the two functions together, you can get 99% of the errors in the program. For PHP programs, this is a lighter relief.
Try running the above example.
By combining code and text, we organize the methods of obtaining error logs in PHP. I hope it will be helpful to everyone who encounters such problems in future work.

Reasons for PHPSession failure include configuration errors, cookie issues, and session expiration. 1. Configuration error: Check and set the correct session.save_path. 2.Cookie problem: Make sure the cookie is set correctly. 3.Session expires: Adjust session.gc_maxlifetime value to extend session time.

Methods to debug session problems in PHP include: 1. Check whether the session is started correctly; 2. Verify the delivery of the session ID; 3. Check the storage and reading of session data; 4. Check the server configuration. By outputting session ID and data, viewing session file content, etc., you can effectively diagnose and solve session-related problems.

Multiple calls to session_start() will result in warning messages and possible data overwrites. 1) PHP will issue a warning, prompting that the session has been started. 2) It may cause unexpected overwriting of session data. 3) Use session_status() to check the session status to avoid repeated calls.

Configuring the session lifecycle in PHP can be achieved by setting session.gc_maxlifetime and session.cookie_lifetime. 1) session.gc_maxlifetime controls the survival time of server-side session data, 2) session.cookie_lifetime controls the life cycle of client cookies. When set to 0, the cookie expires when the browser is closed.

The main advantages of using database storage sessions include persistence, scalability, and security. 1. Persistence: Even if the server restarts, the session data can remain unchanged. 2. Scalability: Applicable to distributed systems, ensuring that session data is synchronized between multiple servers. 3. Security: The database provides encrypted storage to protect sensitive information.

Implementing custom session processing in PHP can be done by implementing the SessionHandlerInterface interface. The specific steps include: 1) Creating a class that implements SessionHandlerInterface, such as CustomSessionHandler; 2) Rewriting methods in the interface (such as open, close, read, write, destroy, gc) to define the life cycle and storage method of session data; 3) Register a custom session processor in a PHP script and start the session. This allows data to be stored in media such as MySQL and Redis to improve performance, security and scalability.

SessionID is a mechanism used in web applications to track user session status. 1. It is a randomly generated string used to maintain user's identity information during multiple interactions between the user and the server. 2. The server generates and sends it to the client through cookies or URL parameters to help identify and associate these requests in multiple requests of the user. 3. Generation usually uses random algorithms to ensure uniqueness and unpredictability. 4. In actual development, in-memory databases such as Redis can be used to store session data to improve performance and security.

Managing sessions in stateless environments such as APIs can be achieved by using JWT or cookies. 1. JWT is suitable for statelessness and scalability, but it is large in size when it comes to big data. 2.Cookies are more traditional and easy to implement, but they need to be configured with caution to ensure security.


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