PHP Custom error handling function

Basic error handling: Using the Die () function
The first example shows a simple script that opens a text file:

The code is as follows	Copy Code
<?php $file =fopen ("Welcome.txt", "R"); ?>

If the file does not exist, you will get an error similar to this:

Warning:fopen (Welcome.txt) [function.fopen]: failed to open stream:
No such file or directory in c:webfoldertest.php on line 2 to prevent users from getting similar error messages, we detect the existence of the file before accessing the file:

The code is as follows	Copy Code
<?php if (!file_exists ("Welcome.txt")) { Die ("File not Found"); } Else { $file =fopen ("Welcome.txt", "R"); } ?>

Now, if the file doesn't exist, you get an error message like this:

File not found is more efficient than previous code because it employs a simple error-handling mechanism that terminates the script after the error.

However, simply terminating the script is not always the right approach. Let's look at the alternate PHP functions for handling errors.

Now let's look at a custom error handler

The code is as follows

Copy Code

function MyErrorHandler ($errno, $errstr, $errfile, $errline) { if (!) ( Error_reporting () & $errno)) {return;} Switch ($errno) { Case E_USER_ERROR: echo "<b>my error</b> [$errno] $errstr <br/>"; echo "Error line: $errline in file: $errfile <br/>"; echo "PHP version:". Php_version. " (" . Php_os. ") <br/> "; Break Case e_user_warning: echo "<b>my warning</b> [$errno] $errstr <br/>"; Break Case E_user_notice: echo "<b>my notice</b> [$errno] $errstr <br/>"; Break Default echo "Unknown error type: [$errno] $errstr <br/>"; Break } return true; } function Trigger_test ($age) {//Throw error test functions if ($age <= 0 | | $age > 999) trigger_error ("Age not valid: $age years old", E_user_error); if ($age <) trigger_error ("Underage: $age-Year-old", e_user_warning); if ($age > && $age <) trigger_error ("Slightly older: $age years old", E_user_notice); } If you are simply handling errors in a simple and uniform way: $errorHandler = Set_error_handler ("MyErrorHandler"); Trigger_test (1000);//will throw an error level function Myerror ($errno, $errstr, $errfile, $errline) { Print_r (Func_get_args ()); Specific processing methods } function mywarning ($errno, $errstr, $errfile, $errline) { Print_r (Func_get_args ()); Specific processing methods } function Myntice ($errno, $errstr, $errfile, $errline) { Print_r (Func_get_args ()); Specific processing methods }

If you want to handle different error levels separately:

The code is as follows	Copy Code
Set_error_handler (' Myerror ', e_user_error); Set_exception_handler (' mywarning ', e_user_warning); Set_exception_handler (' Myntice ', e_user_notice);

Trigger_error (' intentionally throwing a mistake, or a very serious one! ', e_user_error);

Below also enclose some PHP error code detailed

Parameters	Description
Error_level	Necessary. Sets the error reporting level for user-defined errors. Must be a number of values. See table below: Error reporting level.
Error_message	Necessary. Specify error messages for user-defined errors.
Error_file	Optional. Specify the name of the file in which the error occurred.
Error_line	Optional. The line number that sets the error to occur.
Error_context	Optional. Specify an array that contains each variable that was used when the error occurred and their values.

Error Reporting level
These error reporting levels are different types of errors that the error handlers are designed to handle:

value	Constants	Description
2	E_warning	Non-fatal run-time error. Script execution is not paused.
8	E_notice	Run-time notice. The script found that an error might occur, but it may also occur when the script is running correctly.
256	E_user_error	Fatal user-generated error. This is similar to the e_error that programmers use PHP function Trigger_error () settings.
512	E_user_warning	A non-fatal user-generated warning. This is similar to the e_warning that programmers use PHP function Trigger_error () settings.
1024	E_user_notice	User-generated notifications. This is similar to the e_notice that programmers use PHP function Trigger_error () settings.
4096	E_recoverable_error	A fatal error that can be caught. Similar to E_error, but can be captured by user-defined handlers. (see Set_error_handler ())
8191	E_all	All errors and warnings, except for level e_strict. (In PHP 6.0,e_strict is part of E_all)