Need Regular Expression to match name/value pairs in different formats

Question

I'm pulling in ASP/VBScript configuration files via PHP Curl to do some file processing and want to return some values.

The strings look like this:

config1 = ""  
config2 = "VALUE:1:0:9" 'strange value comment 
otherconfig = False 
yetanotherconfig = False 'some comment

Basically, its name value pairs separated by equal signs, with a value optionally enclosed within quotation marks followed optionally by a comment.

I want to return the actual VALUE (False, VALUE:1:0:9, etc..) in ONE matching group regardless of the format the string is in.

Here's the pattern i'm passing to preg_match so far:

$pattern = '/\s*'.$configname.'\s*\=\s*(\".*?\"|.*?\r)/'

$configname is the name of the specific configuration i'm looking for, so I pass it in with a variable.

I'm still getting parentheses included back with the value (instead of the value itself) and i'm getting comments returned with the value as well.

Any help is appreciated!

Answer 1

Returning matching value in ONE matching group if difficult because of the double quotes alternative. Back references can help:

$pattern = '/\s*'.$configname.'\s*=\s*("?)(?<value>.*?)\1\s*[\'$]/'

should do the trick. Then use $result['value'] .

Explained in english it does:

• I skip the spaces identifier spaces = spaces (easy)
• may match a " referenced as \\1 (the first capture parenthesis)
• match any char not greedily referenced as value
• match \\1 (so " if there was one before, or nothing if not)
• may match some spaces
• must match a starting comment ' or an end of line

Without back references:

$pattern = '/\s*'.$configname.'\s*=\s*(?:"(.*?)"|(.*?)\s*[\'$])/'

More efficient but value is in $result[1] or $result[2] .

Understand your mistakes:

• You need \\ only to protect the string quote itself (here simple quote) or to avoid a preg reserved char to be interpreted (as . , ^ , $ ...)
• End of line is marked as $ , not \\r or \\n
• You never avoided the commentary

Answer 2

\\r is going to match a CR character (carriage return). You're essentially saying I want to match "???????" or ????????[carriage return]

Of course you'll get the apostrophe, you've matched it. You'll have to strip these things off.

patter = '/\\s*'.$configname.'\\s*\\=\\s*(\\")(.*?)(?(1)\\"|)\\s*/'

Answer 3

This one will work:

$pattern = '/
    \s*
    # name
    (?P<name>.*?)
    # =
    \s*=\s*
    # value
    (?P<val>
        "(?P<quoted>([^"]|\\\\"|\\\\\\\\)*)"
        |(?P<raw>.*?)
    )
    # comment
    \s*(?P<comment>\'.*)?
$/xm';

This will match every key=value pair in the input string, instead of just a specific one.

The regex takes care for quotes and escaped quotes ( \\" ) in quoted values (eg "foo\\"bar" ).

Use it with a function like this:

function parse_config($string) {
    $pattern = '/
        \s*
        # name
        (?P<name>.*?)
        # =
        \s*=\s*
        # value
        (?P<val>
            "(?P<quoted>([^"]|\\\\"|\\\\\\\\)*)"
            |(?P<raw>.*?)
        )
        # comment
        \s*(?P<comment>\'.*)?
    $/xm';

    preg_match_all($pattern, $string, $matches, PREG_SET_ORDER);

    $config = array();
    foreach($matches as $match) {
        $name = $match['name'];
        if (!empty($match['quoted'])) {
            $value = str_replace(array('\\"','\\\\'), array('"','\\'), $match['quoted']);
        } else if (isset($match['raw'])) {
            $value = $match['raw'];
        } else {
            $value = '';
        }
        $config[$name] = $value;
    }

    return $config;
}

Example:

$string = "a = b\n
c=\"d\\\"e\\\\fgh\" ' comment";

$config = parse_config($string);

// output:

array('a' => 'b', 'c' => 'd"e\fgh');

Other example:

$string = <<<EOF
config1 = ""
config2 = "VALUE:1:0:9" 'strange value comment
otherconfig = False
yetanotherconfig = False 'some comment
EOF;

print_r(parse_config($string));

// output:

Array
(
    [config1] => 
    [config2] => VALUE:1:0:9
    [otherconfig] => False
    [yetanotherconfig] => False
)