Error and Exception Handling in PHP

Error and exception handling helps in detecting, managing, and debugging runtime problems safely.

Error Logging

Error logging stores error messages in a log file instead of showing to users.

Enable Error Logging

log_errors = On
error_log = error.log

Log Error Manually

error_log("Custom Error Message");

Exam Definition: Error logging records errors for debugging and monitoring.

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Configuration Directives (php.ini)

Example

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

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PHP’s Exception Class

PHP provides a built-in Exception class to handle runtime issues.

Basic Exception Handling

try {
   throw new Exception("Error Occurred");
}
catch(Exception $e){
   echo $e->getMessage();
}

Common Exception Methods

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Throw New Exception

Exceptions are raised using the throw keyword.

function checkAge($age){
   if($age < 18){
      throw new Exception("Not Eligible");
   }
   return "Eligible";
}

Usage

try{
   echo checkAge(15);
}
catch(Exception $e){
   echo $e->getMessage();
}

Exam Line: throw is used to generate exceptions manually.

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Custom Exceptions

Custom exceptions are created by extending the Exception class.

Example: Custom Exception

class MyException extends Exception {
   public function errorMsg(){
      return "Custom Error: ".$this->getMessage();
   }
}

Using Custom Exception

try{
   throw new MyException("Invalid Operation");
}
catch(MyException $e){
   echo $e->errorMsg();
}

Exam Tip: Custom exceptions provide application-specific error handling.

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Difference: Error vs Exception

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Advantages of Exception Handling

• Clean error handling
• Better debugging
• Secure applications
• Prevents system crash
• Improves maintainability