PHP — Check PHP Code for Syntax Errors without running the code
I know that by using eval($code_to_check); we can check if this value equals FALSE and if so, we can stop execution of the script. However, the problem I’m facing is that I am unable to define a function, because it gets called twice. it gets processed with the eval() check to be sure there are no syntax errors and than processes the function again, but shows an error that states that it can NOT REDECLARE this function, as it is already being declared in the eval’d function. How can I make it so that we don’t declare things in the EVAL’d function, or perhaps, we can undeclare everything that was declared in the eval() function before we actually do call it. Anyways, here is what I’m working with so far. Could use some help, cause I am getting a «CAN NOT REDECLARE FUNCTION» when $content (which is php code) has a function within it.
// PHP Syntax errors? if (!@eval('return true;' . $content)) < // Error found in PHP somewhere. Call error function and return out of here! call_user_func_array($code_error['function'], $code_error['params']); return; >else Can anyone please help me here? Thanks guys, you are all so very helpful here! You all deserve a GOLD MEDAL, but I believe the Olympics are now over and this isn’t quite a sport yet. Ok, I am attempting my own answer here, and wondering if this will still catch errors and allow for functions to be created at the same time without calling these functions twice. Is this a proper way of doing this?? Can anyone see any possible problems in this code? I am echoing the $eval_code if no syntax errors detected. is this fine to do?
$eval_code = @eval($content); // PHP Syntax errors? if ($eval_code === FALSE) < call_user_func_array($code_error['function'], $code_error['params']); return; >else
Смотрите также
I keep seeing qualification lists for error types/error-nums as arrays; In user notes and in the manual itself. For example, in this manual entry’s example, when trying to seperate behavior for the variable trace in the error report:
// set of errors for which a var trace will be saved
$user_errors = array( E_USER_ERROR , E_USER_WARNING , E_USER_NOTICE );
if ( in_array ( $errno , $user_errors )) //. whatever
>
//. ?>
I was under the impression that PHP error code values where bitwise flag values. Wouldn’t bitwise masking be better? So I propose a slightly better way:
$user_errors = E_USER_ERROR | E_USER_WARNING | E_USER_NOTICE ;
if ( $errno & $user_errors ) //. whatever
>
//. ?>
Or for those of you who don’t like the idea of using an integer as the condition in an if statement:
if (( $errno & $user_errors ) > 0 ) //. whatever
>
?>
I think that’s much more efficient than using _yet another_ array() constuct and an in_array().
If I am wrong, and the E_* constants aren’t supposed to be used in this fashion (ie, the constans aren’t guaranteed to be bitwise, which would be odd since that’s how they’re setup in the php.ini file), then delete me. I just don’t see why one should be using arrays when bitwise comparisons will work, considering the bitwise method should be MUCH more efficient.
Although the root user writes to the files ‘error_log’ and ‘access_log’, the Apache user has to own the file referenced by ‘error_log = filename’ or no log entries will be written.
; From php.ini
; Log errors to specified file.
error_log = /usr/local/apache/logs/php.errors
-rw-r—r— 1 nobody root 27K Jan 27 16:58 php.errors
PHP5 only (only tested with php5.0).
If you, for some reason, prefer exceptions over errors and have your custom error handler (set_error_handler) wrap the error into an exception you have to be careful with your script.
Because if you, instead of just calling the exception handler, throws the exception, and having a custom exception handler (set_exception_handler). And an error is being triggered inside that exception handler, you will get a weird error:
«Fatal error: Exception thrown without a stack frame in Unknown on line 0»
This error is not particulary informative, is it? 🙂
This example below will cause this error.
class PHPErrorException extends Exception
private $context = null ;
public function __construct
( $code , $message , $file , $line , $context = null )
parent :: __construct ( $message , $code );
$this -> file = $file ;
$this -> line = $line ;
$this -> context = $context ;
>
>;
function error_handler ( $code , $message , $file , $line ) throw new PHPErrorException ( $code , $message , $file , $line );
>
function exception_handler ( Exception $e )
<
$errors = array(
E_USER_ERROR => «User Error» ,
E_USER_WARNING => «User Warning» ,
E_USER_NOTICE => «User Notice» ,
);
echo $errors [ $e -> getCode ()]. ‘: ‘ . $e -> getMessage (). ‘ in ‘ . $e -> getFile ().
‘ on line ‘ . $e -> getLine (). «\n» ;
echo $e -> getTraceAsString ();
>
set_error_handler ( ‘error_handler’ );
set_exception_handler ( ‘exception_handler’ );
// Throw exception with an /unkown/ error code.
throw new Exception ( ‘foo’ , 0 );
?>
There are however, easy fix for this as it’s only cause is sloppy code.
Like one, directly call exception_handler from error_handler instead of throwing an exception. Not only does it remedy this problem, but it’s also faster. Though this will cause a `regular` unhandled exception being printed and if only «designed» error messages are intended, this is not the ultimate solution.
So, what is there to do? Make sure the code in exception_handlers doesn’t cause any errors! In this case a simple isset() would have solved it.
If you are using PHP as an Apache module, your default behavior may be to write PHP error messages to Apache’s error log. This is because the error_log .ini directive may be set equal to «error_log» which is also the name of Apache’s error log. I think this is intentional.
However, you can separate Apache errors from PHP errors if you wish by simply setting a different value for error_log. I write mine in the /var/log folder.
Note the example code listed here calls date() every time this is called. If you have a complex source base which calls the custom error handler often, it can end up taking quite a bit of time. I ran a profiler on som code and discovered that 50% of the time was spent in the date function in this error handler.
When configuring your error log file in php.ini, you can use an absolute path or a relative path. A relative path will be resolved based on the location of the generating script, and you’ll get a log file in each directory you have scripts in. If you want all your error messages to go to the same file, use an absolute path to the file.
In some application development methodologies, there is the concept of an application root directory, indicated by «/» (even on Windows). However, PHP does not seem to have this concept, and using a «/» as the initial character in a log file path produces weird behavior on Windows.
If you are running on Windows and have set, in php.ini:
You will get some, but not all, error messages. The file will appear at
and contain internally generated error messages, making it appear that error logging is working. However, log messages requested by error_log() do NOT appear here, or anywhere else, making it appear that the code containing them did not get processed.
Apparently on Windows the internally generated errors will interpret «/» as «C:\» (or possibly a different drive if you have Windows installed elsewhere — I haven’t tested this). However, the error_log process apparently can’t find «/» — understandably enough — and the message is dropped silently.
It is totally possible to use debug_backtrace() inside an error handling function. Here, take a look:
function errorHandler ( $errno , $errstr , $errfile , $errline , $errcontext )
echo ‘Into ‘ . __FUNCTION__ . ‘() at line ‘ . __LINE__ .
«\n\n—ERRNO—\n» . print_r ( $errno , true ).
«\n\n—ERRSTR—\n» . print_r ( $errstr , true ).
«\n\n—ERRFILE—\n» . print_r ( $errfile , true ).
«\n\n—ERRLINE—\n» . print_r ( $errline , true ).
«\n\n—ERRCONTEXT—\n» . print_r ( $errcontext , true ).
«\n\nBacktrace of errorHandler()\n» .
print_r ( debug_backtrace (), true );
>
function a ( )
//echo «a()’s backtrace\n».print_r( debug_backtrace(), true);
asdfasdf ; // oops
>
function b ()
//echo «b()’s backtrace\n».print_r( debug_backtrace(), true);
a ();
>
Into errorhandler() at line 9
—ERRSTR—
Use of undefined constant asdfasdf — assumed ‘asdfasdf’
Backtrace of errorHandler()
Array
(
[0] => Array
(
[function] => errorhandler
[args] => Array
(
[0] => 8
[1] => Use of undefined constant asdfasdf — assumed ‘asdfasdf’
[2] => /home/theotek/test-1.php
[3] => 23
[4] => Array
(
)
(
[file] => /home/theotek/test-1.php
[line] => 23
[function] => a
) [2] => Array
(
[file] => /home/theotek/test-1.php
[line] => 30
[function] => a
[args] => Array
(
) [3] => Array
(
[file] => /home/theotek/test-1.php
[line] => 33
[function] => b
[args] => Array
(
)
So, the first member of the backtrace’s array is not really surprising, except from the missing «file» and «line» members.
The second member of the backtrace seem the be a hook inside the zend engine that is used to trigger the error.
Other members are the normal backtrace.
Check a PHP file for syntax errors
I’m attempting to build an auditing feature into my application that will check for various code quality issues. One of the things I would like to do is check certain PHP files for syntax errors. I was going to use php_check_syntax() but it has been removed in PHP 5.0.5. I’ve tried using exec() statements but it isn’t outputting anything. I’ve added a date to make sure exec() is working:
string 'before' (length=6) string '' (length=0) array (size=0) empty string 'Thu Feb 6 10:42:35 PST 2014' (length=28) array (size=1) 0 => string 'Thu Feb 6 10:42:35 PST 2014' (length=28) Did you check the command directly first? (To make sure the path is correct, and that the php command works correctly)
check php error logs and add the following to the top of php file error_reporting(E_ALL | E_NOTICE | E_STRICT | E_WARNING); @ini_set(‘display_errors’, 1);
if it is working from the terminal and not through your web server, be sure that exec is enabled. Maybe you are running in safe mode?
4 Answers 4
check web-server configuration. places like this: disable_functions=»». after var_dump($output) starts to return an array check for errors in array to eliminate further errors like correct path to php.
use this to eliminate some other possibilities:
$output="just before exec"; var_dump($output); exec('php -l /path/to/file.php', $output); var_dump($output); echo exec('php -l /path/to/file.php'); Upd: Updated question shows exec works. It may be your *nix like platform hides the error output. a way to redirect it to add to the command 2>&1 it will redirect error output into standard output
$to_run = '/path/to/bin/php -l /path/to/file 2>&1'; $output ="" ; //init var_dump(exec($to_run, $output)); if you have root access on the platform you may even use tools like strace to debug some complicated cases.
'/path/to/bin/strace -o/path/to/strace.log php -l /path/to/file.php' UPD: var_dump(exec(‘php -l ‘ . FILE .’ 2>&1′, $output)); // error redirection for a unix platform