How to get a Google API token - token

Question

I need to get the Google validation token to use with Google APIs, but my code does not work.
$client_id = '495225261106.apps.googleusercontent.com';
$client_secret = urlencode('MY_SECRET_CDE');
$redirect_uri = urlencode('http://MYPAGE.net/test.php');
//$grant_type = urlencode('authorization_code'); //it does not work either.
$grant_type = 'authorization_code';
$post_string = "code=4/P7q7W91a-oMsCeLvIaQm6bTrgtp6&client_id={$client_id}&client_secret={$client_secret}&redirect_uri={$redirect_uri}&grant_type={$grant_type}";
//echo_key_value('post_string',$post_string);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, 'https://accounts.google.com/o/oauth2/token');
curl_setopt($ch, CURLOPT_POSTFIELDS, $post_string);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
$result = curl_exec($ch); // Execute the HTTP command
$errmsg = curl_error($ch);
if($errmsg) echo $errmsg;
The output is:
{"error":"invalid_grant"}

Answer 1

You may find it easier to use Google APIs, especially OAuth stuff, via one of the official client libraries.
Here's a link to the PHP one: http://code.google.com/p/google-api-php-client/
And a link to the docs on OAuth 2.0 with the library (with some great example code): http://code.google.com/p/google-api-php-client/wiki/OAuth2

Answer 2

Don't you have to put " curl_setopt($ch, CURLOPT_POST, true); " before using postfields? Mine is working and except that and I didn't used urlencode on my secret, it's the same

Answer 3

Setup Instructions
Go to the Google Developers Console
https://console.developers.google.com/project Select your project or
create a new one (and then select it)
Enable the API for your
project In the sidebar on the left, expand APIs & auth > APIs Search
for "drive" Click on "Drive API" click the blue "Enable API" button
Create a service account for your project In the sidebar on the left,
expand APIs & auth > Credentials Click blue "Add credentials" button
Select the "Service account" option
Select "Furnish a new private
key" checkbox Select the "JSON" key type option
Click blue "Create"
button your JSON key file is generated and downloaded to your machine
(it is the only copy!)
open the json file and save your private key to a file called rsa
note your service account's email address
(also available in the JSON key file) Share the doc (or docs) with
your service account using the email noted above
based on information from ( a fantastic doc )
https://developers.google.com/identity/protocols/OAuth2ServiceAccount#delegatingauthority
for a list of possible API scopes set
https://developers.google.com/identity/protocols/googlescopes#sheetsv4
for a purely bash based solution
#!/bin/bash
client_email='your client email'
scope='https://www.googleapis.com/auth/spreadsheets.readonly'
jwt1=`echo -n '{"alg":"RS256","typ":"JWT"}' | openssl base64 -e`
exp=$(($(date +%s)+3600))
iat=$(date +%s)
jwt2=`echo -n '{\
"iss":"'"$client_email"'",\
"scope":"'"$scope"'",\
"aud":"https://accounts.google.com/o/oauth2/token",\
"exp":'$exp',\
"iat":'$iat'}' | openssl base64 -e`
jwt3=`echo -n "$jwt1.$jwt2" | tr -d '\n' | tr -d '=' | tr '/+' '_-'`
jwt4=`echo -n "$jwt3" | openssl sha -sha256 -sign rsa | openssl base64 -e`
jwt5=`echo -n "$jwt4" | tr -d '\n' | tr -d '=' | tr '/+' '_-'`
echo $jwt3
echo $jwt5
curl -H -vvv "Content-type: application/x-www-form-urlencoded" -X POST "https://accounts.google.com/o/oauth2/token" -d \
"grant_type=urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Ajwt-bearer&assertion=$jwt3.$jwt5"
for a javascript nodejs based solution see
https://gist.github.com/cloverbox/5ce51a1d8889da9045c5b128a3a2502f