From 083bb50d44fe559dafdc0977d85a8105e2a279b0 Mon Sep 17 00:00:00 2001
From: Olivier Bellone <ob@stripe.com>
Date: Wed, 14 Nov 2018 16:49:12 +0100
Subject: [PATCH] Reuse curl handle

---
 lib/HttpClient/CurlClient.php | 74 +++++++++++++++++++++++++++++++----
 1 file changed, 67 insertions(+), 7 deletions(-)

diff --git a/lib/HttpClient/CurlClient.php b/lib/HttpClient/CurlClient.php
index 3d2474c25b..4431c7a9bd 100644
--- a/lib/HttpClient/CurlClient.php
+++ b/lib/HttpClient/CurlClient.php
@@ -40,6 +40,10 @@ public static function instance()
 
     protected $userAgentInfo;
 
+    protected $enablePersistentConnections = true;
+
+    protected $curlHandle = null;
+
     /**
      * CurlClient constructor.
      *
@@ -60,6 +64,11 @@ public function __construct($defaultOptions = null, $randomGenerator = null)
         $this->initUserAgentInfo();
     }
 
+    public function __destruct()
+    {
+        $this->closeCurlHandle();
+    }
+
     public function initUserAgentInfo()
     {
         $curlVersion = curl_version();
@@ -79,6 +88,22 @@ public function getUserAgentInfo()
         return $this->userAgentInfo;
     }
 
+    /**
+     * @return boolean
+     */
+    public function getEnablePersistentConnections()
+    {
+        return $this->enablePersistentConnections;
+    }
+
+    /**
+     * @param boolean $enable
+     */
+    public function setEnablePersistentConnections($enable)
+    {
+        $this->enablePersistentConnections = $enable;
+    }
+
     // USER DEFINED TIMEOUTS
 
     const DEFAULT_TIMEOUT = 80;
@@ -216,17 +241,19 @@ private function executeRequestWithRetries($opts, $absUrl)
             $rcode = 0;
             $errno = 0;
 
-            $curl = curl_init();
-            curl_setopt_array($curl, $opts);
-            $rbody = curl_exec($curl);
+            $this->resetCurlHandle();
+            curl_setopt_array($this->curlHandle, $opts);
+            $rbody = curl_exec($this->curlHandle);
 
             if ($rbody === false) {
-                $errno = curl_errno($curl);
-                $message = curl_error($curl);
+                $errno = curl_errno($this->curlHandle);
+                $message = curl_error($this->curlHandle);
             } else {
-                $rcode = curl_getinfo($curl, CURLINFO_HTTP_CODE);
+                $rcode = curl_getinfo($this->curlHandle, CURLINFO_HTTP_CODE);
+            }
+            if (!$this->getEnablePersistentConnections()) {
+                $this->closeCurlHandle();
             }
-            curl_close($curl);
 
             if ($this->shouldRetry($errno, $rcode, $numRetries)) {
                 $numRetries += 1;
@@ -338,4 +365,37 @@ private function sleepTime($numRetries)
 
         return $sleepSeconds;
     }
+
+    /**
+     * Initializes the curl handle. If already initialized, the handle is closed first.
+     */
+    private function initCurlHandle()
+    {
+        $this->closeCurlHandle();
+        $this->curlHandle = curl_init();
+    }
+
+    /**
+     * Closes the curl handle if initialized. Do nothing if already closed.
+     */
+    private function closeCurlHandle()
+    {
+        if (!is_null($this->curlHandle)) {
+            curl_close($this->curlHandle);
+            $this->curlHandle = null;
+        }
+    }
+
+    /**
+     * Resets the curl handle. If the handle is not already initialized, or if persistent
+     * connections are disabled, the handle is reinitialized instead.
+     */
+    private function resetCurlHandle()
+    {
+        if (!is_null($this->curlHandle) && $this->getEnablePersistentConnections()) {
+            curl_reset($this->curlHandle);
+        } else {
+            $this->initCurlHandle();
+        }
+    }
 }