How to Achieve Seamless Error Logging in PHP?

Error Logging: A Seamless Solution

The Problem with error_log

While error_log provides a straightforward way to log errors, it lacks flexibility and can lead to maintenance challenges if the log file path needs to be changed across multiple files or classes.

A Solution with trigger_error and set_error_handler

To overcome these limitations, consider using trigger_error to raise errors and set_error_handler to log them. trigger_error allows you to generate standard PHP errors, while set_error_handler provides a custom callback to handle the error logging. This approach:

• Maintains Standard PHP Interface: trigger_error uses predefined error levels, ensuring compatibility with all PHP installations.
• Centralizes Error Handling: The set_error_handler callback allows you to define a single, customizable error-logging process.
• Decouples Error Handling from Application Code: The application code is responsible for triggering errors, while the logging logic resides in a dedicated error handler, improving code readability and maintainability.

Example Implementation

<code class="php">// Define the error handler function
function errorHandler($errno, $errstr, $errfile, $errline, $errcontext) {
    // Perform error handling actions, such as logging errors
}

// Set the custom error handler
set_error_handler('errorHandler');</code>

Handling Exceptions with set_exception_handler

Similar to error handling, use set_exception_handler to define a callback function for handling exceptions. Exceptions can be handled in various ways:

• Catch and Fix: Resolve the exception within the current code block and continue execution.
• Append and Re-Throw: Append additional information to the exception and re-throw it for further handling at a higher level.
• Bubble Up: Allow the exception to propagate up the call stack to be handled by a higher-level exception handler.

Usage Examples

Errors

<code class="php">// Raise an E_USER_NOTICE error
trigger_error('Disk space is low.', E_USER_NOTICE);

// Raise an E_USER_ERROR fatal error
trigger_error('Cannot continue due to fatal error.', E_USER_ERROR);</code>

Exceptions

Catch and Fix:

<code class="php">try {
    // Code that may throw an exception
} catch (Exception $e) {
    // Resolve the exception and continue
}</code>

Append and Re-Throw:

<code class="php">try {
    // Code that may throw an exception
} catch (Exception $e) {
    // Add context and re-throw
    throw new Exception('Additional context: ' . $context, 0, $e);
}</code>

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