PHP 7.0.6 Released

    php_check_syntax

    (PHP 5 <= 5.0.4)

    php_check_syntax — Check the PHP syntax of (and execute) the specified file

    Description

    bool php_check_syntax ( string $filename [, string &$error_message ] )

    Performs a syntax (lint) check on the specified filename testing for scripting errors.

    This is similar to using php -l from the commandline except that this function will execute (but not output) the checked filename.

    For example, if a function is defined in filename, this defined function will be available to the file that executed php_check_syntax(), but output from filename will be suppressed.

    Note:

    For technical reasons, this function is deprecated and removed from PHP. Instead, use php -l somefile.php from the commandline.

    Parameters

    filename

    The name of the file being checked.

    error_message

    If the error_message parameter is used, it will contain the error message generated by the syntax check. error_message is passed by reference.

    Return Values

    Returns TRUE if the lint check passed, and FALSE if the link check failed or if filename cannot be opened.

    Changelog

    Version Description
    5.0.5 This function was removed from PHP.
    5.0.3 Calling exit() after php_check_syntax() resulted in a Segfault.
    5.0.1 error_message is passed by reference.

    Examples

    php -l somefile.php

    The above example will output something similar to:

    PHP Parse error: unexpected T_STRING in /tmp/somefile.php on line 81

    See Also

    User Contributed Notes

    kevin at metalaxe dot com
    7 years ago
    I've given it some thought and rewritten my function to take full advantage of the CLI -l option (that's lower L). It requires that you enable error reporting via your own php.ini file (which you should edit the function to apply) otherwise the return result is a worthless "Error parsing".

    Anyway, I hope this is useful for someone. I'm sure it could use improvement, so use at your own risk. Demo here:
    http://kevinpeno.com/projects/php_syntax_check.php

    <?php
    /**
    *    Check Syntax
    *    Performs a Syntax check within a php script, without killing the parser (hopefully)
    *    Do not use this with PHP 5 <= PHP 5.0.4, or rename this function.
    *
    *    @params    string    PHP to be evaluated
    *    @return    array    Parse error info or true for success
    **/
    function php_check_syntax( $php, $isFile=false )
    {
            # Get the string tokens
            $tokens = token_get_all( '<?php '.trim( $php  ));
       
            # Drop our manually entered opening tag
            array_shift( $tokens );
            token_fix( $tokens );

            # Check to see how we need to proceed
        # prepare the string for parsing
            if( isset( $tokens[0][0] ) && $tokens[0][0] === T_OPEN_TAG )
               $evalStr = $php;
        else
                $evalStr = "<?php\n{$php}?>";

        if(     $isFile OR ( $tf = tempnam( NULL, 'parse-' ) AND file_put_contents( $tf, $php ) !== FALSE ) AND $tf = $php )
        {
                # Prevent output
                ob_start();
                system( 'C:\inetpub\PHP\5.2.6\php -c "'.dirname(__FILE__).'/php.ini" -l < '.$php, $ret );
                $output = ob_get_clean();

            if(     $ret !== 0 )
            {
                    # Parse error to report?
                    if( (bool)preg_match( '/Parse error:\s*syntax error,(.+?)\s+in\s+.+?\s*line\s+(\d+)/', $output, $match ) )
                {
                    return array(
                            'line'    =>    (int)$match[2],
                            'msg'    =>    $match[1]
                    );
                }
            }
            return     true;
        }
        return     false;
    }

    //fixes related bugs: 29761, 34782 => token_get_all returns <?php NOT as T_OPEN_TAG
    function token_fix( &$tokens ) {
        if (!    is_array($tokens) || (count($tokens)<2)) {
            return;
        }
           //return of no fixing needed
            if (is_array($tokens[0]) && (($tokens[0][0]==T_OPEN_TAG) || ($tokens[0][0]==T_OPEN_TAG_WITH_ECHO)) ) {
            return;
        }
            //continue
            $p1 = (is_array($tokens[0])?$tokens[0][1]:$tokens[0]);
            $p2 = (is_array($tokens[1])?$tokens[1][1]:$tokens[1]);
            $p3 = '';

        if ((    $p1.$p2 == '<?') || ($p1.$p2 == '<%')) {
                $type = ($p2=='?')?T_OPEN_TAG:T_OPEN_TAG_WITH_ECHO;
                $del = 2;
                //update token type for 3rd part?
                if (count($tokens)>2) {
                    $p3 = is_array($tokens[2])?$tokens[2][1]:$tokens[2];
                    $del = (($p3=='php') || ($p3=='='))?3:2;
                    $type = ($p3=='=')?T_OPEN_TAG_WITH_ECHO:$type;
            }
                //rebuild erroneous token
                $temp = array($type, $p1.$p2.$p3);
            if (    version_compare(phpversion(), '5.2.2', '<' )===false)
                    $temp[] = isset($tokens[0][2])?$tokens[0][2]:'unknown';

                //rebuild
                $tokens[1] = '';
            if (    $del==3) $tokens[2]='';
                $tokens[0] = $temp;
        }
        return;
    }
    ?>
    matt dot nospam at pryor dot org dot uk
    8 years ago
    While developing an app where I have to include PHP files written by a user, I came across the following problem:

    I used "php -l somefile.php" to check the syntax of the file I was about to include and if it passed, I would include it - so far so good. But in some test cases, the file I was including would have other includes/requires inside it. If one of these was invalid, then I would still get the parse error that I was trying to avoid.

    I got round it using this:

    <?php
            function CheckSyntax($fileName, $checkIncludes = true)
        {
                // If it is not a file or we can't read it throw an exception
                if(!is_file($fileName) || !is_readable($fileName))
                throw new     Exception("Cannot read file ".$fileName);
           
                // Sort out the formatting of the filename
                $fileName = realpath($fileName);
           
                // Get the shell output from the syntax check command
                $output = shell_exec('php -l "'.$fileName.'"');
           
                // Try to find the parse error text and chop it off
                $syntaxError = preg_replace("/Errors parsing.*$/", "", $output, -1, $count);
           
                // If the error text above was matched, throw an exception containing the syntax error
                if($count > 0)
                throw new     Exception(trim($syntaxError));
           
                // If we are going to check the files includes
                if($checkIncludes)
            {
                foreach(    GetIncludes($fileName) as $include)
                {
                        // Check the syntax for each include
                        CheckSyntax($include);
                }
            }
        }
       
        function     GetIncludes($fileName)
        {
                // NOTE that any file coming into this function has already passed the syntax check, so
            // we can assume things like proper line terminations
               
                $includes = array();
                // Get the directory name of the file so we can prepend it to relative paths
                $dir = dirname($fileName);
           
                // Split the contents of $fileName about requires and includes
            // We need to slice off the first element since that is the text up to the first include/require
                $requireSplit = array_slice(preg_split('/require|include/i', file_get_contents($fileName)), 1);
           
                // For each match
                foreach($requireSplit as $string)
            {
                    // Substring up to the end of the first line, i.e. the line that the require is on
                    $string = substr($string, 0, strpos($string, ";"));
               
                    // If the line contains a reference to a variable, then we cannot analyse it
                // so skip this iteration
                    if(strpos($string, "$") !== false)
                    continue;
               
                    // Split the string about single and double quotes
                    $quoteSplit = preg_split('/[\'"]/', $string);
               
                    // The value of the include is the second element of the array
                // Putting this in an if statement enforces the presence of '' or "" somewhere in the include
                // includes with any kind of run-time variable in have been excluded earlier
                // this just leaves includes with constants in, which we can't do much about
                    if($include = $quoteSplit[1])
                {
                        // If the path is not absolute, add the dir and separator
                    // Then call realpath to chop out extra separators
                        if(strpos($include, ':') === FALSE)
                            $include = realpath($dir.DIRECTORY_SEPARATOR.$include);
               
                        array_push($includes, $include);
                }
            }
           
            return     $includes;
        }
    ?>

    This checks as many of the includes inside the file as it possibly can without executing anything.
    nicolas dot grekas+php at gmail dot com
    7 years ago
    Hi again, here is my last contribution to the subject : this php_syntax_error() function returns false if there is no syntax error in $code, or an array($message, $line) if there is one (idea borrowed from kevin's code) .

    For exemple, php_syntax_error(' DELIBERTE PHP ERROR; ') returns array('unexpected T_STRING', 1) ;)

    Please note that the dead code sandbox IS important. A "return" at the beginning of the evaluated string can easily be broken: try eval('return; function strlen(){}') versus eval('if(0){function strlen(){}}').

    <?php

    function php_syntax_error($code)
    {
            $braces = 0;
            $inString = 0;

            // First of all, we need to know if braces are correctly balanced.
        // This is not trivial due to variable interpolation which
        // occurs in heredoc, backticked and double quoted strings
            foreach (token_get_all('<?php ' . $code) as $token)
        {
            if (    is_array($token))
            {
                switch (    $token[0])
                {
                case     T_CURLY_OPEN:
                case     T_DOLLAR_OPEN_CURLY_BRACES:
                case     T_START_HEREDOC: ++$inString; break;
                case     T_END_HEREDOC:   --$inString; break;
                }
            }
            else if (    $inString & 1)
            {
                switch (    $token)
                {
                case     '`':
                case     '"': --$inString; break;
                }
            }
            else
            {
                switch (    $token)
                {
                case     '`':
                case     '"': ++$inString; break;

                case     '{': ++$braces; break;
                case     '}':
                    if (    $inString) --$inString;
                    else
                    {
                        --    $braces;
                        if (    $braces < 0) break 2;
                    }

                    break;
                }
            }
        }

            // Display parse error messages and use output buffering to catch them
            $inString = @ini_set('log_errors', false);
            $token = @ini_set('display_errors', true);
            ob_start();

            // If $braces is not zero, then we are sure that $code is broken.
        // We run it anyway in order to catch the error message and line number.

        // Else, if $braces are correctly balanced, then we can safely put
        // $code in a dead code sandbox to prevent its execution.
        // Note that without this sandbox, a function or class declaration inside
        // $code could throw a "Cannot redeclare" fatal error.

            $braces || $code = "if(0){{$code}\n}";

        if (    false === eval($code))
        {
            if (    $braces) $braces = PHP_INT_MAX;
            else
            {
                    // Get the maximum number of lines in $code to fix a border case
                    false !== strpos($code, "\r") && $code = strtr(str_replace("\r\n", "\n", $code), "\r", "\n");
                    $braces = substr_count($code, "\n");
            }

                $code = ob_get_clean();
                $code = strip_tags($code);

                // Get the error message and line number
                if (preg_match("'syntax error, (.+) in .+ on line (\d+)$'s", $code, $code))
            {
                    $code[2] = (int) $code[2];
                    $code = $code[2] <= $braces
                        ? array($code[1], $code[2])
                    : array(    'unexpected $end' . substr($code[1], 14), $braces);
            }
            else     $code = array('syntax error', 0);
        }
        else
        {
                ob_end_clean();
                $code = false;
        }

        @    ini_set('display_errors', $token);
        @    ini_set('log_errors', $inString);

        return     $code;
    }

    ?>
    nicolas dot grekas+php at gmail dot com
    8 years ago
    My previous code was buggy sorry, here is an update (thanks phprockstheworld). I can't find a way to break the dead code sandbox. Who can ?

    <?php

    function eval_syntax($code)
    {
            $braces = 0;
            $inString = 0;

            // We need to know if braces are correctly balanced.
        // This is not trivial due to variable interpolation
        // which occurs in heredoc, backticked and double quoted strings
            foreach (token_get_all('<?php ' . $code) as $token)
        {
            if (    is_array($token))
            {
                switch (    $token[0])
                {
                case     T_CURLY_OPEN:
                case     T_DOLLAR_OPEN_CURLY_BRACES:
                case     T_START_HEREDOC: ++$inString; break;
                case     T_END_HEREDOC:   --$inString; break;
                }
            }
            else if (    $inString & 1)
            {
                switch (    $token)
                {
                case     '`':
                case     '"': --$inString; break;
                }
            }
            else
            {
                switch (    $token)
                {
                case     '`':
                case     '"': ++$inString; break;

                case     '{': ++$braces; break;
                case     '}':
                    if (    $inString) --$inString;
                    else
                    {
                        --    $braces;
                        if (    $braces < 0) return false;
                    }

                    break;
                }
            }
        }

        if (    $braces) return false; // Unbalanced braces would break the eval below
            else
        {
                ob_start(); // Catch potential parse error messages
                $code = eval('if(0){' . $code . '}'); // Put $code in a dead code sandbox to prevent its execution
                ob_end_clean();

            return     false !== $code;
        }
    }
    steve at clickforseo dot com
    1 year ago
    On php syntax checking, a blog that supports a tool I like may be useful as it looks at remote php checking https://jresponse.net/blog/remote-php-syntax-checking-incron/
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