Make JSON error handling logic reusable

refs #2728

library/Icinga/Exception/Json/JsonDecodeException.php

@@ -0,0 +1,11 @@
+<?php
+/* Icinga Web 2 | (c) 2017 Icinga Development Team | GPLv2+ */
+
+namespace Icinga\Exception\Json;
+
+/**
+ * Exception thrown by {@link \Icinga\Util\Json::decode()} on failure
+ */
+class JsonDecodeException extends JsonException
+{
+}

library/Icinga/Exception/Json/JsonEncodeException.php

@@ -0,0 +1,11 @@
+<?php
+/* Icinga Web 2 | (c) 2017 Icinga Development Team | GPLv2+ */
+
+namespace Icinga\Exception\Json;
+
+/**
+ * Exception thrown by {@link \Icinga\Util\Json::encode()} on failure
+ */
+class JsonEncodeException extends JsonException
+{
+}

library/Icinga/Exception/Json/JsonException.php

@@ -0,0 +1,13 @@
+<?php
+/* Icinga Web 2 | (c) 2017 Icinga Development Team | GPLv2+ */
+
+namespace Icinga\Exception\Json;
+
+use Icinga\Exception\IcingaException;
+
+/**
+ * Exception thrown by {@link \Icinga\Util\Json} on failure
+ */
+abstract class JsonException extends IcingaException
+{
+}

library/Icinga/Util/Json.php

@@ -0,0 +1,80 @@
+<?php
+/* Icinga Web 2 | (c) 2017 Icinga Development Team | GPLv2+ */
+
+namespace Icinga\Util;
+
+use Icinga\Exception\Json\JsonDecodeException;
+use Icinga\Exception\Json\JsonEncodeException;
+
+/**
+ * Wrap {@link json_encode()} and {@link json_decode()} with error handling
+ */
+class Json
+{
+    /**
+     * {@link json_encode()} wrapper
+     *
+     * @param   mixed   $value
+     * @param   int     $options
+     * @param   int     $depth
+     *
+     * @return  string
+     * @throws  JsonEncodeException
+     */
+    public static function encode($value, $options = 0, $depth = 512)
+    {
+        $encoded = json_encode($value, $options, $depth);
+        if (json_last_error() !== JSON_ERROR_NONE) {
+            throw new JsonEncodeException('%s: %s', static::lastErrorMsg(), var_export($value, true));
+        }
+        return $encoded;
+    }
+
+    /**
+     * {@link json_decode()} wrapper
+     *
+     * @param   string  $json
+     * @param   bool    $assoc
+     * @param   int     $depth
+     * @param   int     $options
+     *
+     * @return  mixed
+     * @throws  JsonDecodeException
+     */
+    public static function decode($json, $assoc = false, $depth = 512, $options = 0)
+    {
+        $decoded = json_decode($json, $assoc, $depth, $options);
+        if (json_last_error() !== JSON_ERROR_NONE) {
+            throw new JsonDecodeException('%s: %s', static::lastErrorMsg(), var_export($json, true));
+        }
+        return $decoded;
+    }
+
+    /**
+     * {@link json_last_error_msg()} replacement for PHP < 5.5.0
+     *
+     * @return string
+     */
+    protected static function lastErrorMsg()
+    {
+        if (version_compare(PHP_VERSION, '5.5.0', '>=')) {
+            return json_last_error_msg();
+        }
+
+        // All possible error codes before PHP 5.5.0 (except JSON_ERROR_NONE)
+        switch (json_last_error()) {
+            case JSON_ERROR_DEPTH:
+                return 'Maximum stack depth exceeded';
+            case JSON_ERROR_STATE_MISMATCH:
+                return 'State mismatch (invalid or malformed JSON)';
+            case JSON_ERROR_CTRL_CHAR:
+                return 'Control character error, possibly incorrectly encoded';
+            case JSON_ERROR_SYNTAX:
+                return 'Syntax error';
+            case JSON_ERROR_UTF8:
+                return 'Malformed UTF-8 characters, possibly incorrectly encoded';
+            default:
+                return 'Unknown error';
+        }
+    }
+}

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

@@ -4,11 +4,11 @@
 namespace Icinga\Module\Monitoring\Command\Transport;
 
 use Icinga\Application\Logger;
+use Icinga\Exception\Json\JsonDecodeException;
 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;
 
 /**

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

@@ -1,55 +0,0 @@
-<?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

@@ -5,7 +5,7 @@ namespace Icinga\Module\Monitoring\Web\Rest;
 
 use Exception;
 use Icinga\Application\Logger;
-use Icinga\Module\Monitoring\Exception\JsonDecodeException;
+use Icinga\Util\Json;
 
 /**
  * REST Request
@@ -262,12 +262,6 @@ class RestRequest
             fclose($stream);
         }
 
-        $response = @json_decode($result, true);
+        return Json::decode($result, true);
-
-        if ($response === null) {
-            throw new JsonDecodeException($result);
-        }
-
-        return $response;
     }
 }