Extract data from part JSON and part HTTP response - php

Question

I'm working with an API, using cURL I have received a set of data.
The data appears to be half HTTP request and half JSON. I'm not sure why it's mixed but essentially I get this response when I do a var_dump:
string(873) "HTTP/1.1 200 OK cache-control: no-cache, no-store, must-revalidate, pre-check=0, post-check=0 content-length: 153 content-type: application/json;charset=utf-8 date: Mon, 10 Nov 2014 10:58:49 UTC expires: Tue, 31 Mar 1981 05:00:00 GMT last-modified: Mon, 10 Nov 2014 10:58:49 GMT ml: A pragma: no-cache server: tsa_b set-cookie: guest_id=v1%3A141561712923128379; Domain=.twitter.com; Path=/; Expires=Wed, 09-Nov-2016 10:58:49 UTC status: 200 OK strict-transport-security: max-age=631138519 x-connection-hash: 57175e4dba3d726bebb399072c225958 x-content-type-options: nosniff x-frame-options: SAMEORIGIN x-transaction: 2e4b8e053e615c75 x-ua-compatible: IE=edge,chrome=1 x-xss-protection: 1; mode=block {"token_type":"bearer","access_token":"AAAAAAAAAAAAAAAAAAAAAMVfbQAAAAAAK7qYRQOgdZ771TrJ6pZ7nugCwVQ%3DLKcongtwy3lcBDbPSEreC9DfhJk3Gm7qyQInqhFAxYvo1clv4S"}"
That's the full data back. It's got HTTP info at the beginning and then part JSON at the end.
The only bit I need from this is the access_token data.
If it was just JSON then I could use json_decode to get the access_token out but because it's got all the HTTP info at the beginning json_decode cannot understand it and gives the result NULL.
How can I remove the HTTP part so I can just grab the access_token data?
ETA: my request is made through cURL, so the var I'm dumping out is $response
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL,$auth_url);
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, "grant_type=client_credentials");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$header = curl_setopt($ch, CURLOPT_HEADER, 1);
$result = curl_exec($ch);
curl_close($ch);
The result I receive roughly matches the expected result given in the Twitter documentation so I don't think the data is corrupt/incorrect: https://dev.twitter.com/oauth/reference/post/oauth2/token

Answer 1

Switch of header output and remove
$header = curl_setopt($ch, CURLOPT_HEADER, 1);
or replace with
curl_setopt($ch, CURLOPT_HEADER, false);

Answer 2

$a='HTTP/1.1 200 OK cache-control: no-cache, no-store, must-revalidate, pre-check=0, post-check=0 content-length: 153 content-type: application/json;charset=utf-8 date: Mon, 10 Nov 2014 10:58:49 UTC expires: Tue, 31 Mar 1981 05:00:00 GMT last-modified: Mon, 10 Nov 2014 10:58:49 GMT ml: A pragma: no-cache server: tsa_b set-cookie: guest_id=v1%3A141561712923128379; Domain=.twitter.com; Path=/; Expires=Wed, 09-Nov-2016 10:58:49 UTC status: 200 OK strict-transport-security: max-age=631138519 x-connection-hash: 57175e4dba3d726bebb399072c225958 x-content-type-options: nosniff x-frame-options: SAMEORIGIN x-transaction: 2e4b8e053e615c75 x-ua-compatible: IE=edge,chrome=1 x-xss-protection: 1; mode=block {"token_type":"bearer","access_token":"AAAAAAAAAAAAAAAAAAAAAMVfbQAAAAAAK7qYRQOgdZ771TrJ6pZ7nugCwVQ%3DLKcongtwy3lcBDbPSEreC9DfhJk3Gm7qyQInqhFAxYvo1clv4S"}"';
preg_match("/\{.*\}/",$a,$m);
$ja=json_decode($m[0]);
var_dump($ja,$m);
output:
object(stdClass)[1]
public 'token_type' => string 'bearer' (length=6)
public 'access_token' => string 'AAAAAAAAAAAAAAAAAAAAAMVfbQAAAAAAK7qYRQOgdZ771TrJ6pZ7nugCwVQ%3DLKcongtwy3lcBDbPSEreC9DfhJk3Gm7qyQInqhFAxYvo1clv4S' (length=112)