From 1f2fbac2075a3cb9bc3c8613d2f8b18bd7bf6582 Mon Sep 17 00:00:00 2001
From: Dave Cooper <dave@moodle.com>
Date: Thu, 28 May 2015 15:54:31 +0800
Subject: [PATCH] MDL-49497 curl: Allow configurable User-Agent.

Thanks to Kartik Yadav for assistance with this patch.
---
 lib/filelib.php | 32 +++++++++++++++++++++++++++-----
 1 file changed, 27 insertions(+), 5 deletions(-)

diff --git a/lib/filelib.php b/lib/filelib.php
index b893cf22f98..69d8da0e18d 100644
--- a/lib/filelib.php
+++ b/lib/filelib.php
@@ -2683,7 +2683,8 @@ class curl {
     public $emulateredirects = null;
 
     /** @var array cURL options */
-    private $options;
+    protected $options;
+
     /** @var string Proxy host */
     private $proxy_host = '';
     /** @var string Proxy auth */
@@ -2975,7 +2976,7 @@ class curl {
      * @param array $options
      * @return resource The curl handle
      */
-    private function apply_opt($curl, $options) {
+    protected function apply_opt($curl, $options) {
         // Clean up
         $this->cleanopt();
         // set cookie
@@ -3004,15 +3005,36 @@ class curl {
         }
 
         $this->setopt($options);
-        // reset before set options
+
+        // Reset before set options.
         curl_setopt($curl, CURLOPT_HEADERFUNCTION, array(&$this,'formatHeader'));
-        // set headers
+
+        // Setting the User-Agent based on options provided.
+        $useragent = '';
+
+        if (!empty($options['CURLOPT_USERAGENT'])) {
+            $useragent = $options['CURLOPT_USERAGENT'];
+        } else if (!empty($this->options['CURLOPT_USERAGENT'])) {
+            $useragent = $this->options['CURLOPT_USERAGENT'];
+        } else {
+            $useragent = 'MoodleBot/1.0';
+        }
+
+        // Set headers.
         if (empty($this->header)) {
             $this->setHeader(array(
-                'User-Agent: MoodleBot/1.0',
+                'User-Agent: ' . $useragent,
                 'Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7',
                 'Connection: keep-alive'
                 ));
+        } else if (!in_array('User-Agent: ' . $useragent, $this->header)) {
+            // Remove old User-Agent if one existed.
+            // We have to partial search since we don't know what the original User-Agent is.
+            if ($match = preg_grep('/User-Agent.*/', $this->header)) {
+                $key = array_keys($match)[0];
+                unset($this->header[$key]);
+            }
+            $this->setHeader(array('User-Agent: ' . $useragent));
         }
         curl_setopt($curl, CURLOPT_HTTPHEADER, $this->header);