The key points of debugging Laravel applications include: 1. Turn on debug mode, set APP_DEBUG=true through the .env file to display detailed error information; 2. Use Log::info() and dd() to view variable content; 3. Check storage/logs/laravel.log log files to track exceptions and queries; 4. Enable DB::enableQueryLog() to check SQL query performance problems; 5. Install the Laravel Debugbar plug-in to improve debugging efficiency. These methods can help quickly locate and solve problems in development.
Debugging a Laravel application is actually not difficult. As long as you master a few key points, most problems can be quickly located and solved. Laravel comes with a lot of tools, which can basically cover most of the problems encountered in daily development with some common methods.

Turn on debug mode
First, confirm whether your application has enabled debug mode. This setting is in the .env
file, APP_DEBUG=true
is enabled. After opening, the page will display detailed error information, such as error file, line number, stack trace, etc., which is very helpful for troubleshooting problems.
But it should be noted that the debugging mode must be turned off in the online environment , otherwise it will not only expose sensitive information, but may also bring security risks.

Use Log and dd()
Sometimes the error will not be displayed directly, or you want to see the content of a certain variable, you can use Log::info()
or dd()
at this time.
-
Log::info($variable)
will record the variable content intostorage/logs/laravel.log
file, which is suitable for viewing the status of the variables in the process. -
dd()
is the abbreviation of "dump and die". It will print out variables and terminate the program's running, which is suitable for quickly viewing the current data structure.
Small suggestions: If you are debugging in the API interface, you can use
return response()->json($data)
to output data, which is more intuitive.![]()
View log files
Laravel's logging system is very practical, especially when your code does not report an error but the result is wrong. The default log file is in storage/logs/laravel.log
, which will record exceptions, SQL queries, custom log output and other information during the request process.
You can use the command line to view log updates in real time:
tail -f storage/logs/laravel.log
If you use Monolog or other log extensions, you can also configure log output at different levels (such as error, warning, debug) to facilitate classification processing.
Check database query
Many times performance problems or logic errors come from database operations. Laravel provides query logging function to view the actual SQL execution:
DB::enableQueryLog(); // Perform some query operations $users = User::all(); \Log::info(DB::getQueryLog());
This code will record all executed query statements and binding parameters to help you analyze whether there are N 1 queries, slow queries and other problems.
In addition, it is recommended to use the Laravel Debugbar plug-in to directly see all SQL, view loading time, routing information, etc. of the current page in the browser, and the debugging efficiency is significantly improved.
Basically these commonly used methods. Debugging is not complicated, but it is easy to ignore details, such as cache imperfection, environment configuration errors, dependency version conflicts, etc. When you encounter problems, take it step by step, first look at the log, then check the process, and finally analyze the data. Most of the situations can be solved.
The above is the detailed content of How to debug a Laravel application?. For more information, please follow other related articles on the PHP Chinese website!

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