1. When debugging Laravel applications, you should first check the log file. Open APP_DEBUG=true in the development environment to obtain detailed information; 2. When the database connection fails, check the .env configuration, service status and driver, and use config:clear to test the connection with tinker; 3. Route access issues need to verify spelling, cache, controller path and API prefix; 4. If the view loading fails, you should confirm the correctness of the path, naming specification, cache and Blade syntax errors. Mastering these troubleshooting steps can quickly locate most problems.

Debugging common errors in Laravel applications are not always so mysterious. Many times the problems lie in several common places, such as configuration errors, database connection failures, route matching, or view rendering problems. As long as you master some basic investigation methods and ideas, most problems can be quickly located and solved.

1. Check log files: your first line of defense

By default, Laravel will record error messages in storage/logs/laravel.log . When an error occurs, the first step is not to flip through the code, but to open the log file to see if there are any clues.

• For example, if you see information similar to PDOException: SQLSTATE[HY000] [2002] Connection refused , it means there is a problem with the database connection.
• If it is Class 'App\Models\User' not found error, it may be that the model path is wrong or there is no correct namespace.

suggestion:

• Every time you encounter an error, read the log first.
• The development environment ensures that APP_DEBUG=true in the .env file, so that the browser can also display detailed error messages.

2. Database connection failed? These points need to be checked one by one

Database connection issues are one of the most common problems in Laravel, especially when deploying to a new environment or migrating a project.

Common reasons include:

• Incorrect database username or password
• The database service has not started (especially local development)
• The database configuration is not updated by the .env file
• The wrong database driver was used (such as misusing pgsql instead of mysql )

Operation suggestions:

• Execute php artisan config:clear and php artisan config:cache to ensure that the configuration takes effect.
• Use php artisan tinker and execute \DB::connection()->getPdo(); to test whether the database can be connected successfully.
• Check whether the DB_* configuration item in the .env file is consistent with the database service.

3. Is the route not accessible? Check these places

If you prompt 404 Not Found or Route [xxx] not defined when accessing a route, it is likely that something is wrong with the route definition or call method.

Frequently Asked Questions:

• Route misspelling or inconsistent case (especially when custom routing with Route::get() )
• Forgot to run php artisan route:clear causes cache impact
• Using an unnamed route but trying to call it through route() helper function
• Controller method does not exist or controller path error

suggestion:

• Execute php artisan route:list to view all currently registered routes.
• Make sure the controller files are placed in the correct directory and the namespace is correct (usually App\Http\Controllers ).
• If you are using API routing, note whether the default prefix /api is included in the request URL.

4. View loading failed? Paths and caches are key

Sometimes the page appears blank, or an exception is thrown and the view file cannot be found. At this time, you should start from the following aspects:

• Does the view file exist (is the path correct, such as resources/views/home.blade.php )
• Is the wrong naming method used? For example, view('home') corresponds to home.blade.php
• Caching problem: Sometimes the view is modified but the page has not changed. You can run php artisan view:clear

Tips:

• Blade template syntax errors can also cause the page to be white, such as forgetting to close the tag, PHP syntax errors, etc.
• You can add @dd($variable) to the Blade file to view the variable content and assist in debugging.

Basically that's it. Laravel provides many tools to help us discover problems, the key is to know where to find them. When encountering problems, don’t rush to reinstall them. Check the logs, clear the cache, and verify the configuration step by step. Many problems can be solved easily.

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