Json: wrap json_encode to emit errors

refs #1445

library/Director/Core/Json.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace Icinga\Module\Director\Core;
+
+use Icinga\Module\Director\Exception\JsonEncodeException;
+
+class Json
+{
+    public static function encode($string)
+    {
+        $result = json_encode($string);
+
+        if ($result === false) {
+            throw JsonEncodeException::forLastJsonError();
+        }
+
+        return $result;
+    }
+}

library/Director/Core/RestApiClient.php

@@ -141,7 +141,7 @@ class RestApiClient
         }
 
         if ($body !== null) {
-            $body = json_encode($body);
+            $body = Json::encode($body);
             $headers[] = 'Content-Type: application/json';
         }
 

library/Director/Exception/JsonEncodeException.php

@@ -0,0 +1,7 @@
+<?php
+
+namespace Icinga\Module\Director\Exception;
+
+class JsonEncodeException extends JsonException
+{
+}

library/Director/Exception/JsonException.php

@@ -0,0 +1,57 @@
+<?php
+
+namespace Icinga\Module\Director\Exception;
+
+use Icinga\Exception\IcingaException;
+
+class JsonException extends IcingaException
+{
+    public static function forLastJsonError($msg = null)
+    {
+        if ($msg === null) {
+            return new static(static::getJsonErrorMessage(json_last_error()));
+        } else {
+            $args = func_get_args();
+            $args[0] = $msg . ': ' . static::getJsonErrorMessage(json_last_error());
+            return call_user_func_array('static::__construct', $args);
+        }
+    }
+
+    public static function getJsonErrorMessage($code)
+    {
+        $map = [
+            JSON_ERROR_DEPTH => 'The maximum stack depth has been exceeded',
+            JSON_ERROR_CTRL_CHAR => 'Control character error, possibly incorrectly encoded',
+            JSON_ERROR_STATE_MISMATCH => 'Invalid or malformed JSON',
+            JSON_ERROR_SYNTAX => 'Syntax error',
+            JSON_ERROR_UTF8 => 'Malformed UTF-8 characters, possibly incorrectly encoded'
+        ];
+        if (array_key_exists($code, $map)) {
+            return $map[$code];
+        }
+
+        if (PHP_VERSION_ID >= 50500) {
+            $map = [
+                JSON_ERROR_RECURSION => 'One or more recursive references in the value to be encoded',
+                JSON_ERROR_INF_OR_NAN => 'One or more NAN or INF values in the value to be encoded',
+                JSON_ERROR_UNSUPPORTED_TYPE => 'A value of a type that cannot be encoded was given',
+            ];
+            if (array_key_exists($code, $map)) {
+                return $map[$code];
+            }
+        }
+
+        if (PHP_VERSION_ID >= 70000) {
+            $map = [
+                JSON_ERROR_INVALID_PROPERTY_NAME => 'A property name that cannot be encoded was given',
+                JSON_ERROR_UTF16 => 'Malformed UTF-16 characters, possibly incorrectly encoded',
+            ];
+
+            if (array_key_exists($code, $map)) {
+                return $map[$code];
+            }
+        }
+
+        return 'An error occured when parsing a JSON string';
+    }
+}