Handle invalid Icinga 2 API response types

refs #2728

modules/monitoring/library/Monitoring/Command/Transport/ApiCommandTransport.php

@@ -8,6 +8,7 @@ use Icinga\Module\Monitoring\Command\IcingaApiCommand;
 use Icinga\Module\Monitoring\Command\IcingaCommand;
 use Icinga\Module\Monitoring\Command\Renderer\IcingaApiCommandRenderer;
 use Icinga\Module\Monitoring\Exception\CommandTransportException;
+use Icinga\Module\Monitoring\Exception\JsonDecodeException;
 use Icinga\Module\Monitoring\Web\Rest\RestRequest;
 
 /**
@@ -193,12 +194,18 @@ class ApiCommandTransport implements CommandTransportInterface
             $this->getHost(),
             $this->getPort()
         );
+
+        try {
             $response = RestRequest::post($this->getUriFor($command->getEndpoint()))
                 ->authenticateWith($this->getUsername(), $this->getPassword())
                 ->sendJson()
                 ->noStrictSsl()
                 ->setPayload($command->getData())
                 ->send();
+        } catch (JsonDecodeException $e) {
+            throw new CommandTransportException('Got invalid JSON response from the Icinga 2 API: %s', $e->getMessage());
+        }
+
         if (isset($response['error'])) {
             throw new CommandTransportException(
                 'Can\'t send external Icinga command: %u %s',

modules/monitoring/library/Monitoring/Exception/JsonDecodeException.php

@@ -0,0 +1,55 @@
+<?php
+/* Icinga Web 2 | (c) 2017 Icinga Development Team | GPLv2+ */
+
+namespace Icinga\Module\Monitoring\Exception;
+
+use Icinga\Exception\IcingaException;
+
+/**
+ * Exception thrown if {@link json_decode()} fails
+ */
+class JsonDecodeException extends IcingaException
+{
+    /**
+     * JsonDecodeException constructor
+     *
+     * @param   string      $invalidJson    The JSON string caused this error
+     * @param   int|null    $jsonError      Error code (from {@link json_last_error()}) or null for the last occurred error
+     */
+    public function __construct($invalidJson, $jsonError = null)
+    {
+        if ($jsonError === null) {
+            $msg = version_compare(PHP_VERSION, '5.5.0', '>=')
+                ? json_last_error_msg()
+                : $this->errorCodeToMessage(json_last_error());
+        } else {
+            $msg = $this->errorCodeToMessage($jsonError);
+        }
+
+        parent::__construct('%s: %s', $msg, $invalidJson);
+    }
+
+    /**
+     * Convert the given error code (from {@link json_last_error()}) to a human readable error message
+     *
+     * @param   int     $jsonError
+     * @return  string
+     */
+    protected function errorCodeToMessage($jsonError)
+    {
+        switch ($jsonError) {
+            case JSON_ERROR_DEPTH:
+                return 'The maximum stack depth has been exceeded';
+            case JSON_ERROR_CTRL_CHAR:
+                return 'Control character error, possibly incorrectly encoded';
+            case JSON_ERROR_STATE_MISMATCH:
+                return 'Invalid or malformed JSON';
+            case JSON_ERROR_SYNTAX:
+                return 'Syntax error';
+            case JSON_ERROR_UTF8:
+                return 'Malformed UTF-8 characters, possibly incorrectly encoded';
+            default:
+                return 'An error occured when parsing a JSON string';
+        }
+    }
+}

modules/monitoring/library/Monitoring/Web/Rest/RestRequest.php

@@ -5,6 +5,7 @@ namespace Icinga\Module\Monitoring\Web\Rest;
 
 use Exception;
 use Icinga\Application\Logger;
+use Icinga\Module\Monitoring\Exception\JsonDecodeException;
 
 /**
  * REST Request
@@ -264,30 +265,7 @@ class RestRequest
         $response = @json_decode($result, true);
 
         if ($response === null) {
-            if (version_compare(PHP_VERSION, '5.5.0', '>=')) {
+            throw new JsonDecodeException($result);
-                throw new Exception(json_last_error_msg());
-            } else {
-                switch (json_last_error()) {
-                    case JSON_ERROR_DEPTH:
-                        $msg = 'The maximum stack depth has been exceeded';
-                        break;
-                    case JSON_ERROR_CTRL_CHAR:
-                        $msg = 'Control character error, possibly incorrectly encoded';
-                        break;
-                    case JSON_ERROR_STATE_MISMATCH:
-                        $msg = 'Invalid or malformed JSON';
-                        break;
-                    case JSON_ERROR_SYNTAX:
-                        $msg = 'Syntax error';
-                        break;
-                    case JSON_ERROR_UTF8:
-                        $msg = 'Malformed UTF-8 characters, possibly incorrectly encoded';
-                        break;
-                    default:
-                        $msg = 'An error occured when parsing a JSON string';
-                }
-                throw new Exception($msg);
-            }
         }
 
         return $response;