PHP Error Handling

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What is Error Handling in PHP?

Error handling in PHP is the process of detecting, reporting, and handling errors that occur during script execution. Proper error handling helps developers debug applications, prevent crashes, and improve security.

Types of Errors in PHP

PHP errors are mainly classified into the following types:

1. Notice Errors

• Minor errors

• Do not stop script execution

• Example: Undefined variable

2. Warning Errors

• More serious than notices

• Script continues execution

• Example: Including a missing file

3. Fatal Errors

• Critical errors

• Script execution stops

• Example: Calling an undefined function

Displaying Errors in PHP

Enable error reporting during development.

error_reporting(E_ALL);
ini_set('display_errors', 1);

⚠️ Disable error display in production environments.

Error Logging in PHP

Instead of displaying errors, log them to a file.

ini_set("log_errors", 1);
ini_set("error_log", "errors.log");

Custom Error Handler

You can create your own error handler using set_error_handler().

function customError($errno, $errstr) {
    echo "Error [$errno]: $errstr";
}

set_error_handler("customError");

Exception Handling in PHP

Try–Catch Block

try {
    if (!file_exists("data.txt")) {
        throw new Exception("File not found");
    }
} catch (Exception $e) {
    echo $e->getMessage();
}

Finally Block

try {
    echo "Processing...";
} catch (Exception $e) {
    echo "Error";
} finally {
    echo "Done";
}

Throwing Custom Exceptions

function divide($a, $b) {
    if ($b == 0) {
        throw new Exception("Division by zero");
    }
    return $a / $b;
}

try {
    echo divide(10, 0);
} catch (Exception $e) {
    echo $e->getMessage();
}

Error Handling with die() and exit()

if (!file_exists("config.php")) {
    die("File not found");
}

Error Levels in PHP

Some common error levels:

• E_NOTICE

• E_WARNING

• E_ERROR

• E_ALL

Best Practices for PHP Error Handling

• Enable error reporting only in development

• Log errors instead of displaying them

• Use try-catch for exceptions

• Handle errors gracefully

• Avoid exposing sensitive information

Common Use Cases

• Debugging application issues

• Handling missing files

• Validating user input

• Database error handling

Conclusion

PHP error handling is essential for building stable, secure, and professional applications. Proper handling improves debugging and protects your application from unexpected failures.