使用cURL访问REST API时发生无限循环，是什么原因引起的？

Question

I am trying to write a connector using cURL to connect to a REST API.

The first step the user have to do is creates a session using createSession() . This will send a POST call to the API with a username and a password. The API will respond with a sessionId, a cookie value and couple of custom header.

The session is only valid for 3 minutes after each valid request. If I make a request after the session has expired I will get http error code 401 which indicates that the user is unauthorized to make the request because the sessionId is invalid or timed out.

Instead of asking the user to login again manually, I would like to automatically reconnect by calling the createSession() method when I get error 401. The reason why I need to do this because the sessionId is save in the client cookies and so the client does not know if the session is expired or active. My code will try to call methods using the sessionId that is saved in the cookies weather it is active or expired.

The API will renew the session 3 minutes each time a request is made as long as the session is still active. The only time I will need to reconnect is only when the user have not made a request for 3 minutes.

The issue that I am running into is when I try to reconnnect, I go into an infinite loop that I can't figure out how to stop it.

Here is my code

<?php namespace API;

/**
 * ICWS API
 *
 * @package ICWS
 */
class ICWS {

    private $_myAppName = 'ICWS API connector';
    private $_authenticationType = 'Basic'; //Not used yet
    private $_languageID = 'en-US';
    private $_protocol = 'http';
    private $_sessionIdKey = 'sessionId';
    private $_interactionIdKey = 'interactionIdKey';
    private $_maxLoginAttempts = 3;
    private $_loginAttempts = 0;
    private $_debug = false;

    //No need to edit beyond this line
    private $_isSubscribledToQueue = false;
    private $_alternateHostList = array();
    private $_interactionId = 0;

    private $_queueType = 1;
    private $_userID;
    private $_password;
    private $_workstation;
    private $_queueName;
    private $_cainfo;
    private $_baseURL;
    private $_csrfToken;
    private $_sessionId;
    private $_ININ_ICWS_CSRF_Token;
    private $_Location;
    private $_subscriptionId;
    private $_curlHeader;
    private $_requestFile;

    public function __construct($config)
    {

        //Make sure cURL is enabled on the server
        if(!is_callable('curl_init')){
            throw new ApiException('cURL is disabled on this server. Before making API calls cURL extension must be enabled.');
        }

        //Make sure all required config are set
        if(    !isset($config['host']) || empty($config['host'])
            || !isset($config['port']) || empty($config['port'])
            || !isset($config['userID']) || empty($config['userID'])
            || !isset($config['password']) || empty($config['password'])
            || !isset($config['workstation']) || empty($config['workstation'])
        ){
            throw new ApiException('Host, Port, userID, password, workstation are required!');
        }

        $this->_userID = $config['userID'];
        $this->_password = $config['password'];
        $this->_workstation = $config['workstation'];

        //override the default queueType
        if( isset($config['queueType']) && !empty($config['queueType']) ){
            $this->_queueType = $config['queueType'];
        }       

        //override the default queueName
        if( isset($config['queueName']) && !empty($config['queueName']) ){
            $this->_queueName = $config['queueName'];
        }

        //override the default appName
        if( isset($config['appName']) && !empty($config['appName']) ){
            $this->_myAppName = $config['appName'];
        }

        //override the default session Key
        if( isset($config['sessionKey']) && !empty($config['sessionKey']) ){
            $this->_sessionKey = $config['sessionKey'];
        }

        //override the default protocol
        if( isset($config['isSecured']) && $config['isSecured'] == true){

            if(!isset($config['cainfo']) || empty($config['cainfo'])){
                throw new ApiException('To enable SSL you must provide CA Info file (.cert)');
            } else {
                $this->_protocol = 'https';
                $this->cainfo = $config['cainfo'];
            }
        }

        //override the default server Language
        if( isset($config['languageID']) && !empty($config['languageID']) ){
            $this->_languageID = $config['languageID'];
        }

        //override the default debug mode
        if( isset($config['debug']) && !empty($config['debug']) ){
            $this->_debug = $config['debug'];
        }

        //override the default authentication type
        if( isset($config['authenticationType']) && !empty($config['authenticationType']) ){
            $this->_authenticationType = $config['authenticationType'];
        }

        //set the sessionId if it already exists
        if( isset( $_COOKIE[$this->_sessionIdKey] ) && !empty( $_COOKIE[$this->_sessionIdKey] )){
            $this->_sessionId = $_COOKIE[$this->_sessionIdKey];
        }

        //set the _interactionIdKey if it already exists
        if( isset( $_COOKIE[$this->_interactionIdKey] ) && !empty( $_COOKIE[$this->_interactionIdKey] )){
            $this->_interactionId = $this->_bigint($_COOKIE[$this->_interactionIdKey]);

        }

        if(isset($_COOKIE['ININ-ICWS-CSRF-Token']) && !empty($_COOKIE['ININ-ICWS-CSRF-Token'])){
            $this->_ININ_ICWS_CSRF_Token = $_COOKIE['ININ-ICWS-CSRF-Token'];
        }


        $this->_baseURL = $this->_protocol . '://' . $config['host'] . ':' . $config['port'] . '/icws/';
        $this->_subscriptionId = $this->_userID;        
    }

    /**
    * Authentication the user and generated a sessionId
    *
    * @param string $userID
    * @param string $password
    * @param boolean $forceNewSession
    * @catch exception
    * @return void
    */  
    public function createSession($forceNewSession = false){

        if( !empty($this->_sessionId) && ! $forceNewSession ){
            return;
        }

        if($forceNewSession){
            $this->destroySession();
        }

        $this->_requestFile = 'connection';
        $type = 'urn:inin.com:connection:icAuthConnectionRequestSettings';

        $data = array('__type' => $type,
                      'applicationName' => $this->_myAppName,
                      'userID' => $this->_userID,
                      'password' => $this->_password);

        $this->_curlHeader = array('Accept-Language: ' . $this->_languageID,
                                   'Content-Type: application/json');
        $httpCode = 0;

        try {
            $data = $this->_processRequest('POST', 'connection', $data, $httpCode, false);

            if($this->_debug){
                new showVar($data, false, 'HTTP Code: ' . $httpCode);
            }

            $this->_csrfToken = $data['csrfToken'];
            $this->_sessionId = $data['sessionId'];
            $this->_alternateHostList = $data['alternateHostList'];

            if(!empty($this->_sessionId)){
                setCookie($this->_sessionIdKey, $this->_sessionId);
                $this->_loginAttempts = 0;
            }

        } catch (\Exception  $e){
            $this->_displayError($e);
        }
    }

    /**
    * Destroy the IC session
    *
    * @return void
    */      
    public function destroySession(){

        //destroy the sessionId
        $this->_sessionId = NULL;
        $this->_destroy($this->_sessionIdKey);

        //destroy the sessionId
        $this->_interactionIdKey = 0;
        $this->_destroy($this->_interactionIdKey);  

        //destroy the CSRF-Token
        $this->_ININ_ICWS_CSRF_Token = NULL;
        $this->_destroy('ININ-ICWS-CSRF-Token');    

    }   

    /**
    * Calls any Method after a session is created
    *
    * @param string $method GET/POST/PUT
    * @param string $uri 
    * @param array $data
    * @catch exception
    * @return array or false
    */
    private function _sendRequest($method, $uri, $data = false, &$httpCode = 0){

        if( !$this->_sessionId ){
            return false;
        }

        $uri = $this->_sessionId . '/' . $uri;
        $return = false;
        //,'Cookie: ' . $this->_ININ_ICWS_Cookie
        $this->_curlHeader = array('ININ-ICWS-CSRF-Token: ' . $this->_ININ_ICWS_CSRF_Token,
                                   'ININ-ICWS-Session-ID: ' . $this->_sessionId,
                                   'Content-Type: application/json');

        try {
            $return = $this->_processRequest($method, $uri, $data, $httpCode);
        } catch (\Exception  $e){
            $this->_displayError($e);
        } finally {
            return $return;
        }       
    }

    /**
    * Handle the cURL call to the API
    *
    * @throws ApiException
    * @param string $method GET/POST/PUT
    * @param string $uri 
    * @param array $data
    * @param array &$httpCode
    * @return array
    */  
    private function _processRequest($method, $uri, $data = false, &$httpCode = NULL, $allowReconnect = true)
    {

        $ch = curl_init();
        $url = $this->_baseURL . $uri;

        if( 
               ($method == 'POST' || $method == 'PUT') 
            && $data
        ){
            $jsonString = json_encode($data);
            curl_setopt( $ch, CURLOPT_POSTFIELDS, $jsonString );

        }

        if($method == 'POST'){
            curl_setopt($ch, CURLOPT_POST, true);
        } elseif( $method == 'PUT'){
            curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'PUT');
        } else {
            if ($data){
                $url = sprintf("%s?%s", $url, http_build_query($data));
            }
        }   

        //set the URL
        curl_setopt($ch, CURLOPT_URL, $url);

        //disable the use of cached connection
        curl_setopt($ch, CURLOPT_FRESH_CONNECT, true);

        //return the respond from the API
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

        //return the HEADER respond from the API
        curl_setopt($ch, CURLOPT_HEADER, true);

        //add custom headers
        if(!empty($this->_curlHeader)){
            curl_setopt($ch, CURLOPT_HTTPHEADER, $this->_curlHeader);
        }

        //add the cookie value

        $cookiesFile = 'icwsCookies';
        curl_setopt($ch, CURLOPT_COOKIEJAR, $cookiesFile); // write
        curl_setopt($ch, CURLOPT_COOKIEFILE, $cookiesFile); // read


        //enable SSL
        if( $this->_protocol == 'https' ){
            curl_setopt($ch, CURLOPT_CAINFO, $this->_cainfo);
            curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);
            curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, true);
        }

        //send the request to the API
        $respond = curl_exec($ch);
        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);  

        //throw cURL exception
        if($respond === false){
            $errorNo = curl_errno($ch);
            $errorMessage = curl_error($ch);

            throw new ApiException($errorMessage, $errorNo);
        }   

        list($header, $body) = explode("\r\n\r\n", $respond, 2);

        if($uri == 'connection'){
            $this->_handleReceivedHeaders($header);
        }

        //if user gets unauthorized error attempt to login as long as the attempt are under 3
        if($httpCode == 401 && $allowReconnect){

            if( $this->_loginAttempts > $this->_maxLoginAttempts){
                throw new ApiException('All Attempts to create a session have been used! Please check your credentials and try again');
            } else {
                $this->_reconnect($method, $uri, $data);
            }

        }

        //convert respond to an array
        return json_decode($body, true);
    }

    /**
    * Reconnect to the Api and generate a new sessionId
    *
    * @return boolean
    */              
    private function _reconnect($method, $uri, $data){

        $this->createSession(true);
        $httpCode = 0;
        $this->_processRequest($method, $uri, $data, $httpCode);

        if($httpCode == 200 || $httpCode == 201){
            return true;
        }

        return false;

    }

    /**
    * Get the cookie HTTP headers and set them as cookie
    *
    * @param array $httpRespond
    * @return void
    */  
    private function _handleReceivedHeaders($httpRespond){

        $header = $this->_http_parse_headers($httpRespond);

        //set the ININ-ICWS-CSRF-Token value
        if( isset($header['ININ-ICWS-CSRF-Token']) ){
            $this->_ININ_ICWS_CSRF_Token = $header['ININ-ICWS-CSRF-Token'];
            setCookie('ININ-ICWS-CSRF-Token', $this->_ININ_ICWS_CSRF_Token);
        }       

    }

    /**
    * Checks if the API return an error
    *
    * @param array $result
    * @return boolean
    */  
    private function _hasAPIError($result){
        if(    isset($result['errorId']) && !empty($result['errorId'])
            && isset($result['message']) && !empty($result['message'])
        ){          
            return true;
        }

        return false;       
    }

    /**
    * Displays the exception details
    *
    * @param ApiException $e
    */  
    private function _displayError(ApiException $e){
        echo 'Error Number: ' . $e->getCode() . "<br>";
        echo $e->getMessage() . "<br><br>";     
    }

     /**
     * convert cURL header into an array
     *
     * @param string $raw_headers
     * @return array
     */ 
    private function _http_parse_headers($raw_headers)
    {
        $headers = array();
        $key = '';

        foreach(explode("\n", $raw_headers) as $i => $h)
        {
            $h = explode(':', $h, 2);

            if (isset($h[1])){
                if (!isset($headers[$h[0]])){
                    $headers[$h[0]] = trim($h[1]);
                } elseif (is_array($headers[$h[0]])){
                    $headers[$h[0]] = array_merge($headers[$h[0]], array(trim($h[1]))); // [+]
                } else {
                    $headers[$h[0]] = array_merge(array($headers[$h[0]]), array(trim($h[1]))); // [+]
                }

                $key = $h[0];
            } else {
                if (substr($h[0], 0, 1) == "\t"){
                    $headers[$key] .= "\r\n\t".trim($h[0]);
                } elseif (!$key){
                    $headers[0] = trim($h[0]);trim($h[0]);
                }
            }
        }

        return $headers;
    }

    /**
    * return a valid numeric value
    *
    * @param string $val
    * @return big integer
    */      
    private function _bigint($val){

        $val = filter_var($val, FILTER_SANITIZE_NUMBER_INT);

        if(empty($val)){
            $val = 0;
        }
        return $val;

    }   

    /**
    * Destroy a cookie
    * @return void
    */
    private function _destroy($name){

        setcookie($name, null);
        unset($_COOKIE[$name]);
    }
}

?>

This snipit below is where I am trying reconnect to the API. which is causing the loop for some reason.

        if($httpCode == 401 && $allowReconnect){

            if( $this->_loginAttempts > $this->_maxLoginAttempts){
                throw new ApiException('All Attempts to create a session have been used! Please check your credentials and try again');
            } else {
                $this->_reconnect($method, $uri, $data);
            }

        }

Here is a summary of my code. a session is created via $this->createSession(true); then multiple _processRequests() methods are called at different time. If a the _processRequests() method return 401 then $this->createSession(true); is called until it return code 201 or 200 or the $this->createSession(true); is called more than 3 times then I will need to quite. the problem is even when $this->createSession(true); return code 200 or 201 it keeps looping and it does not stop

The cause of the loop is that _processRequests() calls itself infinite when error 401 is reached. It does not recognize that the second calls returns 201.

Answer 1

In _reconnect method:

$this->createSession(true);

In createSession method:

$data = $this->_processRequest('POST', 'connection', $data, $httpCode, false);

In _processRequest method:

//if user gets unauthorized error attempt to login as long as the attempt are under 3
if($httpCode == 401 && $allowReconnect){

    if( $this->_loginAttempts > $this->_maxLoginAttempts){
        throw new ApiException('All Attempts to create a session have been used! Please check your credentials and try again');
    } else {
        $this->_reconnect($method, $uri, $data);
    }

}

My guess is that you got an unauthorized error, and since you're never incrementing $this->_loginAttempts anywhere in the code, it can't never be greater than $this->_maxLoginAttempts , so the code will call again the _reconnect mehtod, causing it to enter in an infinite loop.