How to debug a php website

Common debugging methods

##Debug by printing information from the browser

Method

Add echo, var_dump, print_r and exit to the code and view the output in the browser.

Advantages and Disadvantages

Advantages:

Simple, easy to use, no need to install plug-ins (recommended learning:

PHP Programming from entry to proficiency)

For code written by yourself, or a framework you are familiar with, you can use this method

Disadvantages:

For multi-branch logic, you need to add a lot of code or try many times

For unfamiliar logic, the complete execution process cannot be reflected.

It is possible to omit debugging statements in the project

Unable to single-step execution

When debugging, in order to format the output variables, you often need to implement your own dump( in the project ) function. Using Composer, the dump() function in the symfony/var-dumper package can be installed globally so that it can be used by all projects without modifying the project.

Use Xdebug for debugging

. When PHP runs a script, it sends debugging information to the IDE through the Xdebug plug-in and receives control signals from the IDE.

You need to install and enable Xdebug for PHP, and then set up the IDE's Xdebug plug-in so that the two can communicate.

Advantages and Disadvantages

Supports single-step debugging and acquisition of arbitrary variable values

Complex configuration, requires IDE installation plug-in

Support To cooperate with the browser, the request needs to carry the XDEBUG_SESSION_START parameter

Debug through the console terminal (CLI mode)

For non-web applications, such as scheduled tasks or unit tests , you can debug directly on the console.

Open the command line terminal in PhpStorm through the Alt F12 shortcut key. However, because only one terminal can be displayed in the IDE, the debugging terminal after debugging is turned on will cover the command line terminal, so it is better to open a separate command line terminal (you can use a DOS window or PowerShell under Windows).

Method and principle

Web applications debug requests through GET/POST/Cookie parameter flags, while non-web applications enable debugging by setting environment variables in the command line terminal. .

Two steps:

Set the environment variable XDEBUG_CONFIG="idekey=session_name". This idekey needs to be the same as the idekey set in the Xdebug section of php.ini.

Execute the script in the command line terminal. When executed, the debug terminal of the IDE will be evoked, allowing single-step debugging, and the output results will be displayed in the command line terminal in real time

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