regex failing with no errors - php

Question

I have the following text in a string called $test:
Content-Type: text/plain
Server: testapp (4.2.1 (x86_64/linux))
Content-Length: 125
{"password":"123","email_address":"","name":"j.doe","username":"jd123"}
I am trying to write a regular expression in php that will return everything after content-length: 125.
Here's what I have so far:
if (preg_match('/^Content\-Length\:[0-9\\n]+([a-zA-Z0-9\{\}\"\:])*/',$test,$result))
{
var_dump($result[1]);
}
I don't get any error messages, but it doesn't find the pattern I've defined in my string.
I've also tried this pattern:
'/^Content\-Length\:[0-9\\n]+([a-zA-Z0-9{}\"\:])*/'
where I tried to remove the escape char infront of the curly braces. But it's still a no go.
Can you tell me what I'm missing?
Thanks.
EDIT 1
my code now looks like this:
<?php
$test = "Content-Type: text/plain
Server: kamailio (4.2.1 (x86_64/linux))
Content-Length: 125
{"password":"test123","email_address":"","name":"j.doe","username":"jd123"}";
//if (preg_match('/Content-Length\:[0-9\\n]*([a-zA-Z0-9{}\"\:])*/',$test,$result))
//{
// var_dump($result);
//}
preg_match('/({.*})/', $str, $matches);
echo $matches[0];
?>
That gives me the following error:
Undefined offset: 0 in /var/www/html/test/test.php on line 31
Line 31 is where I'm trying to echo the matches.

Answer 1

$str = <<<HEREDOC
Content-Type: text/plain
Server: testapp (4.2.1 (x86_64/linux))
Content-Length: 125
{"password":"123","email_address":"","name":"j.doe","username":"jd123"}
HEREDOC;
preg_match('/(\{.*\})/', $str, $matches);
echo $matches[0];
The regex here is simply matching a line that begins with { and ends with }. It's a quick and loose regex, however.

Answer 2

Instead of using a big pattern to match everything (which is timeconsuming) - why not use preg_split to cut your string into two pieces at your desired location?
$string = 'Content-Type: text/plain
Server: testapp (4.2.1 (x86_64/linux))
Content-Length: 125
{"password":"123","email_address":"","name":"j.doe","username":"jd123"}';
$parts = preg_split ("/Content-Length:\s*\d+\s*/", $string);
echo "The string i want is '" . $parts[1] . "'";
Output:
The string i want is '{"password":"123","email_address":"","name":"j.doe","username":"jd123"}'

Answer 3

You can avoid the regex altogether because the HTTP header is always separated from the response body by 2 consecutives line breaks.
list($headers, $body) = explode("\n\n", $string);
Or for windows-style breaks( which by the way are the standard for HTTP headers):
list($headers, $body) = explode("\r\n\r\n", $string);