Readability improvement of Connection::connect

- Added a private isErrorResponse method to check if response is of -ERR
- Created some Exception factory methods to centralise/standardise Exceptions and their messages

Fixes repejota#57

Author: anthonysterling

src/Nats/Connection.php

@@ -202,7 +202,7 @@ private function getStream($address, $timeout)
         stream_set_timeout($fp, $seconds, $microseconds);
 
         if (!$fp) {
-            throw new \Exception($errstr, $errno);
+            throw Exception::forStreamSocketClientError($errstr, $errno);
         }
 
         return $fp;
@@ -239,16 +239,16 @@ public function connect($timeout = null)
         $msg = 'CONNECT '.$this->options;
         $this->send($msg);
         $connect_response = $this->receive();
-        if (strpos($connect_response, '-ERR')!== false) {
-            throw new \Exception("Failing connection: $connect_response");
+
+        if ($this->isErrorResponse($connect_response)) {
+            throw Exception::forFailedConnection($connect_response);
         }
 
         $this->ping();
         $ping_response = $this->receive();
-        if ($ping_response !== "PONG") {
-            if (strpos($ping_response, '-ERR')!== false) {
-                throw new \Exception("Failing on first ping: $ping_response");
-            }
+
+        if ($this->isErrorResponse($ping_response)) {
+            throw Exception::forFailedPing($ping_response);
         }
     }
 
@@ -391,14 +391,14 @@ private function handleMSG($line)
         $msg = new Message($subject, $payload, $sid, $this);
 
         if (!isset($this->subscriptions[$sid])) {
-            throw new Exception('subscription not found');
+            throw Exception::forSubscriptionNotFound($sid);
         }
 
         $func = $this->subscriptions[$sid];
         if (is_callable($func)) {
             $func($msg);
         } else {
-            throw new Exception('not callable');
+            throw Exception::forSubscriptionCallbackInvalid($sid);
         }
 
         return;
@@ -504,4 +504,15 @@ public function streamSocket()
     {
         return $this->streamSocket;
     }
+
+    /**
+     * Indicates whether $response is an error response.
+     *
+     * @param string $response The Nats Server response.
+     * @return boolean
+     */
+    private function isErrorResponse($response)
+    {
+        return false !== strpos('-ERR', $response);
+    }
 }

src/Nats/Exception.php

@@ -6,5 +6,59 @@
  */
 class Exception extends \Exception
 {
+    /**
+     * Creates an Exception for a failed connection.
+     *
+     * @param string $response The failed error response.
+     * @return Nats\Exception
+     */
+    public static function forFailedConnection($response)
+    {
+        return new static(sprintf('Failed to connect: %s', $response));
+    }
 
+    /**
+     * Creates an Exception for a failed PING response.
+     *
+     * @param string $response The failed PING response.
+     * @return Nats\Exception
+     */
+    public static function forFailedPing($response)
+    {
+        return new static(sprintf('Failed to ping: %s', $response));
+    }
+
+    /**
+     * Creates an Exception for an invalid Subscription Identifier (sid).
+     *
+     * @param string $subscription The Subscription Identifier (sid).
+     * @return Nats\Exception
+     */
+    public static function forSubscriptionNotFound($subscription)
+    {
+        return new static(sprintf('Subscription not found: %s', $subscription));
+    }
+
+    /**
+     * Creates an Exception for an invalid Subscription Identifier (sid) callback.
+     *
+     * @param string $subscription The Subscription Identifier (sid).
+     * @return Nats\Exception
+     */
+    public static function forSubscriptionCallbackInvalid($subscription)
+    {
+        return new static(sprintf('Subscription callback is invalid: %s', $subscription));
+    }
+
+    /**
+     * Creates an Exception for the failed creation of a Stream Socket Client.
+     *
+     * @param string  $message The system level error message.
+     * @param integer $code    The system level error code.
+     * @return Nats\Exception
+     */
+    public static function forStreamSocketClientError($message, $code)
+    {
+        return new static(sprintf('A Stream Socket Client could not be created: (%d) %s', $code, $message), $code);
+    }
 }

test/ConnectionTest.php

@@ -158,7 +158,6 @@ function ($message) use ($contentLen) {
 
             $i++;
         } while ($i < 100);
-
     }
 
     /**