Login a user during the callback

loginUser.php

/**
 * login the user
 * should receive the information from twitter/oauth if login was successful
 *
 * @param string $oauthtoken
 * @param string $oauthVerifier
 * @return boolean
 */
public function loginUser($oauthtoken, $oauthVerifier) {

	try {
		// create a new twitterOauth object with the temporary oauth_token and oauth_verifier
		$this->twitterOAuth = new TwitterOAuth($this->consumerKey, $this->consumerSecret, $oauthtoken, $oauthVerifier);
		
		// get the real oauth_token and oauth_verififer via curl
		$tokenCredentials = $this->twitterOAuth->getAccessToken($oauthVerifier);

		// create the new object with the real oauth_token and oauth_secret.
		$this->twitterOAuth = new TwitterOAuth(
				$this->consumerKey, $this->consumerSecret,
				$tokenCredentials['oauth_token'], $tokenCredentials['oauth_token_secret']);

		// get some informations about the logged in user and verify that everything worked
		$twitterInfo = $this->twitterOAuth->get('account/verify_credentials');

		if (isset($twitterInfo->errors)) {
			// add some error handling
			return FALSE;
		}

		// do something with the data or store it in a session
		return TRUE;

	} catch (\Exception $e) {
		// do some exception handling
		return FALSE;
	}

}