Gmail contactlist reader with Google Oauth API will helps us to read the contact list of our friends with Google authenticate method.These days it is very important to share,invites ,sending email through many application with your friend list .So the Google Oauth will solve this requirement.

First of all you have to signup with Google to your application reads the Gmail contact list.For signup you application on Google check here.

Gmail Contact list reader with Oauth Api

When you register your application with Google you will get one Consumer key  and secret key. Then you have to download the Gmail contactlist reader Google Oauth API config file. Gmailconfig.

When you get the Google API keys and config file then you can start the integration of Gmail Oauth API with php. First you have to create a php file for user interface and have the following codes.Also make sure you created a folder with Gmail_api in your file structure.

<?php
session_start();
require_once('Gmail_api/Gmailconfig.php');
$cuncumer_key='YOUR_CONSUMER_KEY';
$cunsumer_secret='SECRET_KEY';
$argarray = $argv[0];
$debug = 0; // Set to 1 for verbose debugging output
$callback    =    "http://www.yourdomain.com/gmail_callback.php";
$oauth =new GmailOath($cuncumer_key, $cunsumer_secret, $argarray, $debug, $callback);
//echo $oauth->oauth_cunsumer_secret;
$getcontact=new GmailGetContacts();
$accrss_token=$getcontact->get_request_token($oauth, false, true, true);
$_SESSION['oauth_token']        =    $accrss_token['oauth_token'];
$_SESSION['oauth_token_secret']    =    $accrss_token['oauth_token_secret'];
$urls_ = "https://www.google.com/accounts/OAuthAuthorizeToken?oauth_token=".$oauth->rfc3986_decode($accrss_token['oauth_token']);
$gmail_link =  '<a href="'.$urls_.'">Gmail Contacts</a>';
echo $gmail_link;
?>

When you create these file it will get the Google Oauth user authentication but in the above file you are already give one call back file so next step is to create gmail_callback.php and have the following codes.

<?php
session_start();
require_once('Gmail_api/Gmailconfig.php');
$cuncumer_key='CONSUMER_KEY';
$cunsumer_secret='SECRET_KEY';
$argarray = $argv[0];
$debug = 0; // Set to 1 for verbose debugging output
$callback = "http://www.yourdomain.com/gmail_callback.php";
$oauth =new GmailOath($cuncumer_key, $cunsumer_secret, $argarray, $debug, $callback);
$getcontact_access=new GmailGetContacts();
/////////////////////////////////////////////////////////////////////////////////////////////////////////
// Get the access token using HTTP GET and HMAC-SHA1 signature
$request_token=$oauth->rfc3986_decode($_GET['oauth_token']);
$request_token_secret=$oauth->rfc3986_decode($_SESSION['oauth_token_secret']);
$oauth_verifier= $oauth->rfc3986_decode($_GET['oauth_verifier']);
$retarr = $getcontact_access->get_access_token($oauth,$request_token, $request_token_secret,$oauth_verifier, false, true, true);
////////////////////////////////////////////////////////////////////
$access_token=$oauth->rfc3986_decode($retarr['oauth_token']);
//echo "Access token :".$access_token;
//echo "<br />";
$access_token_secret=$oauth->rfc3986_decode($retarr['oauth_token_secret']);
//echo "access token sectet :".$access_token_secret;
//echo "<br />";
$contac_list= $getcontact_access->callcontact($oauth, $access_token, $access_token_secret, false, true);
$gmailList = "";
foreach($contac_list as $k => $value)
{
$user_full_name = $value['title']['$t'];
foreach($value['gd$email'] as $email)
{
//echo $email["address"]."<br/>";$user_full_name."<".$email["address"].">";
$gmailList.= "<div><span>".$user_full_name."</span><span>".$email["address"]."</span></div>";
}
}
//$full_string = implode(",",$gmailList);
echo $gmailList;
?>

For your reference check here. Also make sure you are running the application on the registered application url other wise it will not authenticate eg: (when your application registered with http://yourdomain.com and try to access with http://www.yourdomain.com then it will not works Google or any other Oauth methods.). for clearing the work flow from Google check here

Google Oauth APi  more

Also you can play on the Google play ground for Oauth check here.