Error 400 Your Request Is Invalid.

This is my View


 <div class="clear doc-buttons" style="padding-left: 2%; margin-top: 9px;">

	<?php

	$app_id = 'APP_ID';

	$app_secret = 'SECRET KEY';

	$return_url = 'example.com/project/event/customer/main/return';

	$dialog_url = "facebook.com/dialog/oauth?client_id=".$app_id . "&redirect_uri=".urlencode($return_url)."&scope=email,read_stream,create_event";

	?>		                  		

				                <a href="<?php echo $dialog_url; ?>" class="btn btn-s-md  btn-facebook">Import from <strong>facebook</strong></a><br>

				               <small class="text-muted text-uc">Import From Facebook</small>         

				          </div>

This is my controller


public function actionReturn() {

		include (YiiBase::getPathOfAlias('webroot') . '/facebook-php-sdk/src/base_facebook.php');

		include (YiiBase::getPathOfAlias('webroot') . '/facebook-php-sdk/src/facebook.php');

		


		$app_id = 'APPID';


		$app_secret = 'SECRET KEY';


		$return_url = 'localhost/project/event/customer/main/return';

		

		if ($_SERVER['REQUEST_METHOD'] == 'POST' && isset($_POST['code'])) {

			$code = $_POST['code'];

		}


		include (YiiBase::getPathOfAlias('webroot') . '/facebook-php-sdk/src/fb_ca_chain_bundle.crt');

		//provide the path where you have stored the facebook API


		$token_url = "graph.facebook.com/oauth/access_token?client_id=" . $app_id . "&redirect_uri=" . urlencode($return_url) . "&client_secret=" . $app_secret . "&code=" . $code . "&scope=email,read_stream,create_event";


		//Getting access_token using curl method


		$c = curl_init($token_url);


		curl_setopt($c, CURLOPT_HTTPGET, true);


		curl_setopt($c, CURLOPT_FRESH_CONNECT, true);


		curl_setopt($c, CURLOPT_RETURNTRANSFER, true);


		curl_setopt($c, CURLOPT_SSL_VERIFYPEER, TRUE);


		curl_setopt($c, CURLOPT_CAINFO, $cert);


		$output = curl_exec($c);


		if ($output === false) {


			curl_close($c);


			return false;


		}

		curl_close($c);


		$curltoken = explode('&', $output);


		$token = explode('=', $curltoken[0]);


		foreach ($token as $singletoken) {

			$oneToken = $singletoken;

		}

		echo $oneToken . '<br/>';


		if (empty($oneToken)) {

			echo 'Something went wrong';

			//here redirect back to the page throwing error “No Facebook Connection”…


		}

		//Facebook API function to get the event details from FB


		$facebook = new Facebook( array('appId' => $appid, 'secret' => $secret, 'cookie' => true));


		$attachment = array('access_token' => $oneToken, 'limit' => 100);


		$container = array();

		try {


			$user = $facebook -> api('/me', 'GET', $attachment);

			echo "Your Detail is ";

			print_r($user);


			$events = $facebook -> api('/me/events', 'GET', $attachment);


			if (!empty($events) && !empty($events['data'])) {

				echo "$events is not empty";

				foreach ($events['data'] as $event) {


					$objResult = $facebook -> api($event['id'], 'GET', $attachment);


					if (!empty($objResult)) {

						echo "$objResult is not empty";

						$fevent = new stdClass();


						$fevent -> id = $objResult['id'];


						$fevent -> EventName = $objResult['name'];


						$fevent -> EventDescription = $objResult['description'];


						$fevent -> EventStartDate = isset($objResult['start_time']) ? strtotime($objResult['start_time']) : time();


						$fevent -> EventEndDate = isset($objResult['end_time']) ? strtotime($objResult['end_time']) : time() + 7200;


						$fevent -> EventHost = isset($objResult['owner']['name']) ? $objResult['owner']['name'] : "";


						$fevent -> Location = isset($objResult['location']) ? $objResult['location'] : "";


						$fevent -> LocationStreet = isset($objResult['venue']['street']) ? $objResult['venue']['street'] : "";


						$fevent -> LocationCity = isset($objResult['venue']['city']) ? $objResult['venue']['city'] : "";


						$fevent -> LocationState = isset($objResult['venue']['state']) ? $objResult['venue']['state'] : "";


						$fevent -> LocationCountry = isset($objResult['venue']['country']) ? $objResult['venue']['country'] : "";


						$fevent -> LocationLat = isset($objResult['venue']['latitude']) ? $objResult['venue']['latitude'] : "";


						$fevent -> LocationLon = isset($objResult['venue']['longitude']) ? $objResult['venue']['longitude'] : "";


						$eventList[] = $fevent;


					}


				}


			}


		} catch (Exception $e) {

			//here redirect back to the page throwing Exception error – $e->getMessage()…

			print_r($e);

		}

		print_r($eventList);

		if (!empty($eventList)) {//array of list obtained from the previous step


			//foreach ($eventList as $event) {

			print_r($eventList);


			//}

		} else {


		}

	}

Now When i click on the link Import from facebook the action opens a login page and user gets logged in but when facebook returns the result on the $return_url it Gives the

[b]

Error 400

Your request is invalid.

[/b]

Is there any one please help me THANXX IN ADVANCE