Detailed explanation of debugging skills in PHP language development

In PHP language development, debugging skills are a very important part. Debugging is an essential process in development, which can help us find defects and errors in the program. In this article, we will explain in detail the debugging skills in PHP language development to help developers develop more efficiently.

1. Using the var_dump() and print_r() functions

In the PHP language, the var_dump() and print_r() functions are one of the most commonly used debugging tools. Both of these functions can help us output the value of the variable on the web page to directly see whether the program can execute normally.

Among them, the var_dump() function can print out the detailed information of a variable, including type, length, value, etc. The print_r() function will only print the value of the variable, but it will also format the results according to a certain format.

For example, we can use the following code:

<?php
    $arr = array('a', 'b', 'c');
    var_dump($arr);
    print_r($arr);
?>

The output result is:

array(3) {
  [0]=>
  string(1) "a"
  [1]=>
  string(1) "b"
  [2]=>
  string(1) "c"
}
Array ( [0] => a [1] => b [2] => c )

2. Use the phpinfo() function

phpinfo The () function can output the current PHP version number, configuration information, extended information, etc., which is very useful for viewing PHP settings during debugging. We can enter the following code into the web page:

<?php
    phpinfo();
?>

and then visit the web page to display the current PHP detailed information.

3. Control error reporting

PHP provides multiple levels of error reporting. We can modify the php.ini file or use the ini_set() function in the code. set up.

Among them, the error_reporting() function can be used to control the error reporting level. For example, we can use the following code to display only error information:

<?php
    error_reporting(E_ERROR);
?>

You can also use the ini_set() function to set the corresponding parameters. is 0, which means that PHP will not output any error information:

<?php
    ini_set("display_errors", 0);
?>

Controlling the error reporting level can help us better locate errors in the program, especially when processing sensitive information, we do not want any errors to occur information.

4. Using log files

When developing, we can output the error information and debugging information of the program to a file instead of displaying it directly on the web page. This prevents others from seeing our debugging information and better protects the security of the program. We can use PHP's built-in functions such as error_log() or third-party libraries to achieve this purpose.

For example, we can use the following code to record the error message of the program:

<?php
    $error = "Error: xyz";
    error_log($error, 3, "/path/to/log/file.log");
?>

It should be noted that we need to set the log file path and ensure that the log file is writable.

5. Use Xdebug extension

debug. Xdebug can be installed in PHP as an extension without requiring any modifications to the code.

Xdebug provides many useful debugging tools, such as breakpoint debugging, viewing the value of variables, viewing function call stacks, etc. We only need to enable the Xdebug extension in the PHP configuration file, and then install the Xdebug plug-in in the IDE to use it.

Summary

The above are some common debugging techniques in PHP language development. These techniques can help us better locate errors in the program and improve development efficiency. Of course, different projects and developers may require different debugging tools and methods, and we need to choose and use them according to the actual situation.

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