Add error messages returned from InfluxDB to curl driver exceptions

This provides more useful error messages than just the HTTP status
code, if available (especially useful in case of bad requests)

Author: pprkut

src/InfluxDB/Driver/Curl.php

@@ -29,6 +29,9 @@ class Curl implements DriverInterface, QueryDriverInterface
     /** @var array */
     protected $lastRequestInfo;
 
+    /** @var mixed */
+    protected $lastResponse;
+
     /**
      * Build the Curl driver from a dsn
      * Examples:
@@ -124,7 +127,13 @@ public function isSuccess()
         $statusCode = $this->lastRequestInfo['http_code'];
 
         if (!in_array($statusCode, [200, 204], true)) {
-            throw new Exception('Request failed with HTTP Code ' . $statusCode);
+            $json = json_decode($this->lastResponse);
+
+            if (json_last_error() == JSON_ERROR_NONE && isset($json->error)) {
+                throw new Exception('Request failed with HTTP Code ' . $statusCode . ': ' . $json->error);
+            } else {
+                throw new Exception('Request failed with HTTP Code ' . $statusCode);
+            }
         }
 
         return true;
@@ -152,18 +161,17 @@ protected function execute($url, $curlOptions = [])
         curl_setopt($ch, CURLOPT_URL, $this->dsn . '/' . $url);
         curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
 
-        $result = curl_exec($ch);
+        $this->lastResponse = curl_exec($ch);
         $this->lastRequestInfo = curl_getinfo($ch);
 
-        if ($result === false) {
+        if ($this->lastResponse === false) {
             // in case of total failure - socket/port is closed etc
             throw new Exception('Request failed! curl_errno: ' . curl_errno($ch));
         }
 
-
         curl_close($ch);
 
-        return $result;
+        return $this->lastResponse;
     }
 
     /**
@@ -203,4 +211,4 @@ public function getDsn()
     {
         return $this->dsn;
     }
-}
+}

tests/unit/Driver/CurlTest.php

@@ -217,6 +217,23 @@ public function testIsSuccessThrowsExceptionOnHttpError()
             $driver->isSuccess();
         }
 
+        /**
+         * @expectedException \InfluxDB\Driver\Exception
+         * @expectedExceptionMessage Request failed with HTTP Code 401: authorization failed
+         */
+        public function testIsSuccessThrowsExceptionWithResponseErrorMessage()
+        {
+            $driver = new Curl('http://localhost:8086');
+
+            static::$MOCK_INFO = ['http_code' => 401];
+            static::$MOCK_RESPONSE = '{"error":"authorization failed"}';
+            $driver->setParameters(['url' => 'write?something']);
+
+            $driver->write(['data']);
+
+            $driver->isSuccess();
+        }
+
         /**
          * @expectedException \InfluxDB\Driver\Exception
          * @expectedExceptionMessage Request failed! curl_errno: 999