How to handle log errors in PHP?

PHP is a scripting language widely used in web development. It has many application scenarios, such as websites, CMS, backend management systems, etc. As the complexity of the business increases, the possibility of errors will also increase. At this time, system error logs are needed to facilitate developers to troubleshoot problems in a timely manner. Here are some practical experiences and code examples on how to handle logging errors in PHP.

1. Why logs need to be recorded

1. To facilitate troubleshooting

In a production environment, bugs in the application or abnormalities in the server will cause business interruption and affect users experience. Developers need to know the error situation and when the error occurred so that they can fix bugs or handle exceptions more quickly. Therefore, logging is very necessary.

2. Easy to analyze user behavior

Logging can not only record system errors, but also record user behavior, such as user login, registration, page access and other information. By analyzing these logs, we can better understand user preferences and facilitate subsequent product development and promotion.

2. Commonly used log processing methods in PHP

1. Use the built-in error_log

PHP built-in function error_log() can record logs to the specified file Or in the system log, its function prototype is:

bool error_log ( string $message [, int $message_type = 0 [, string $destination [, string $extra_headers ]]] )

• message: required parameter, the error message that needs to be recorded, which can be a string or serialized object data
• message_type: Optional parameter, specifying the type of error record, which are 0 (recorded and sent to PHP's built-in log processor), 1 (sent to the specified mailbox of the mail() function), 2 (recorded to the system log, including the system log) /var/log/message), the default is 0
• destination: Optional parameter, specifies the saving location of the error log. If not specified, it will be recorded to the error_log in php.ini by default
• extra_headers: Optional parameter, only valid when message_type is 1, used to set additional header information for the mail() function

For example, log error information to a local file:

<?php
$error_msg = "This is an error message";

if(!function_exists('write_log')){
    function write_log($msg){
        error_log(date('[Y-m-d H:i:s]') . "    " . $msg . "
", 3, 'error_log.log');
    }
}

write_log($error_msg);
?>

The above code records error information to the local error_log.log file through the customized write_log function.

2. Use third-party log processing libraries

Common log processing libraries include log4php, Monolog, etc. These libraries usually provide more flexible logging solutions and support advanced features such as different levels of logging, log grouping, and log filtering.

For example, use Monolog to process logs:

<?php
require_once 'vendor/autoload.php';

use MonologLogger;
use MonologHandlerStreamHandler;

class LogService {
    private $logger;
    public function __construct () {
        $this->logger = new Logger('my_logger');
        $this->logger->pushHandler(new StreamHandler('logs/error.log', Logger::WARNING));
        $this->logger->pushHandler(new StreamHandler('logs/info.log', Logger::INFO));
    }

    public function error ($message) {
        $this->logger->error($message);
    }

    public function info ($message) {
        $this->logger->info($message);
    }
}

$log_service = new LogService();
$error_msg = "This is an error message";
$log_service->error($error_msg);
?>

The above code uses the Monolog library to define the LogService class, and records different levels of logs to different files through the error and info methods.

3. Complete code example

<?php
require_once 'vendor/autoload.php';

use MonologLogger;
use MonologHandlerStreamHandler;

class LogService {
    private $logger;
    public function __construct () {
        $this->logger = new Logger('my_logger');
        $this->logger->pushHandler(new StreamHandler('logs/error.log', Logger::WARNING));
        $this->logger->pushHandler(new StreamHandler('logs/info.log', Logger::INFO));
    }

    public function error ($message) {
        $this->logger->error($message);
    }

    public function info ($message) {
        $this->logger->info($message);
    }
}

$log_service = new LogService();

//测试记录错误日志
$error_msg = "This is an error message";
$log_service->error($error_msg);

//测试记录info日志
$info_msg = "This is an info message";
$log_service->info($info_msg);

//将错误信息保存到文件
if(!function_exists('write_log')){
    function write_log($msg){
        error_log(date('[Y-m-d H:i:s]') . "    " . $msg . "
", 3, 'error_log.log');
    }
}
write_log($error_msg);
?>

The above code defines a LogService class, uses the Monolog library to record two different levels of logs, and saves them to logs/error.log and logs/info respectively. log file; at the same time, use the write_log function to save the error information to the error_log.log file.

4. Summary

Error logging is an important aspect of program development and maintenance, and can help developers locate and troubleshoot errors in a timely manner. There are many ways to record logs in PHP. You can choose the appropriate solution according to your actual situation. The two methods given above are relatively common methods. I hope they can be helpful to everyone.

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