The key to handling errors and exceptions in PHP is to distinguish error types, use try/catch to catch exceptions, set up a global processor and record logs. 1. Differentiate error types: including Notice, Warning, Fatal error, Parse error and Exception, each requires different processing methods; 2. Use the try/catch block to catch exceptions, recommend to catch specific types, and finally execute cleaning code; 3. Set the global error handler through set_exception_handler(), set_error_handler() and register_shutdown_function() to centrally manage; 4. The production environment should turn off error display, use logging instead (such as Monolog or error_log()), and regularly monitor logs to ensure security and maintainability.

When working with PHP, handling errors and exceptions properly is cruel for building stable and maintained applications. The key is to not only catch problems when they happen but also to log them and respond in a way that doesn't expose sensitive information to end users.

Understand the Different Types of Errors

PHP has several types of errors, and knowing the difference helps you handle them correctly:

• Notices : These are minor issues, like trying to access an undefined variable. They don't break execution but should be fixed during development.
• Warnings : More serious than notices — for example, trying to include a non-existent file. Execution continues, but something is off.
• Errors (Fatal errors) : These stop script execution immediately. For example, calling a non-existent function or instantiating a class that doesn't exist.
• Parse errors : Syntax mistakes in your code, like a missing semicolon. These also stop execution entirely.
• Exceptions : Thrown explicitly using throw new Exception() and can be caught with try/catch blocks.

Understanding which type of issue you're dealing with determinations how you should respond — whether it's logging, displaying a message, or gracefully recovering.

Use Try/Catch for Exceptions

Exceptions in PHP are meant for exceptional circumstances — things that shouldn't normally happen during regular execution. You can throw and catch them using try/catch blocks.

For example:

 try {
    // Code that might throw an exception
    if ($somethingGoesWrong) {
        throw new Exception("Something went wrong!");
    }
} catch (Exception $e) {
    // Handle the exception
    echo "Caught exception: " . $e->getMessage();
}

Some tips:

• Always catch specific exception types instead of the general Exception class if possible.
• Don't silently swallow exceptions unless there's a good reason.
• Use finally blocks for cleanup code that must run regardless of an exception being thrown or caught.

This approach gives you control over error flow and allows graceful degradation or fallback logic.

Set Up Global Error and Exception Handlers

Instead of scattering error checks throughout your code, you can define global handlers for uncaught exceptions and errors:

• Use set_exception_handler() to handle uncaught exceptions.
• Use set_error_handler() to convert traditional errors into exceptions (or handle them directly).
• Register a shutdown function with register_shutdown_function() to catch fatal errors.

A basic setup might look like this:

 set_exception_handler(function($exception) {
    echo "Uncaught exception: " . $exception->getMessage();
});

set_error_handler(function($errno, $errstr, $errfile, $errline) {
    // Log or handle warnings/Notices here
    error_log("Error: [$errno] $errstr - $errfile:$errline");
});

This centralizes error handling and makes debugging easier across your entire application.

Log Errors — Don't Display Them Publicly

In production environments, always log errors instead of displaying them to users. Expposing error messages can reveal sensitive system details to attackers.

You can configure this in php.ini :

 display_errors = Off
log_errors = On
error_log = /path/to/your/error.log

If you're not using a framework that already handles logging, consider using tools like:

• Monolog (great for custom apps)
• Built-in error_log() function
• Syslog integration for server-level monitoring

Also, make sure to rotate logs and monitor them regularly — otherwise, even perfect logging won't help you fix issues quickly.

Basically that's it. Handling errors and exceptions well in PHP isn't just about preventing crashes — it's about making your app more predictable, debuggable, and secure.

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