From 3aded4a35f50dfa57bf5587696fabd99dbfc0651 Mon Sep 17 00:00:00 2001
From: Mponos George <gmponos@gmail.com>
Date: Sun, 8 Dec 2019 14:44:02 +0200
Subject: [PATCH] Add IDN support for redirects also

---
 src/RedirectMiddleware.php | 37 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)

diff --git a/src/RedirectMiddleware.php b/src/RedirectMiddleware.php
index 5a0edd572..9d5ad6a62 100644
--- a/src/RedirectMiddleware.php
+++ b/src/RedirectMiddleware.php
@@ -2,6 +2,7 @@
 namespace GuzzleHttp;
 
 use GuzzleHttp\Exception\BadResponseException;
+use GuzzleHttp\Exception\InvalidArgumentException;
 use GuzzleHttp\Exception\TooManyRedirectsException;
 use GuzzleHttp\Promise\PromiseInterface;
 use GuzzleHttp\Psr7;
@@ -190,7 +191,41 @@ public function modifyRequest(
             $modify['body'] = '';
         }
 
-        $modify['uri'] = $this->redirectUri($request, $response, $protocols);
+        $uri = $this->redirectUri($request, $response, $protocols);
+
+        if ($uri->getHost() && isset($options['idn_conversion']) && ($options['idn_conversion'] !== false)) {
+            $idnOptions = ($options['idn_conversion'] === true) ? IDNA_DEFAULT : $options['idn_conversion'];
+
+            $asciiHost = idn_to_ascii($uri->getHost(), $idnOptions, INTL_IDNA_VARIANT_UTS46, $info);
+            if ($asciiHost === false) {
+                $errorBitSet = isset($info['errors']) ? $info['errors'] : 0;
+
+                $errorConstants = array_filter(array_keys(get_defined_constants()), function ($name) {
+                    return substr($name, 0, 11) === 'IDNA_ERROR_';
+                });
+
+                $errors = [];
+                foreach ($errorConstants as $errorConstant) {
+                    if ($errorBitSet & constant($errorConstant)) {
+                        $errors[] = $errorConstant;
+                    }
+                }
+
+                $errorMessage = 'IDN conversion failed';
+                if ($errors) {
+                    $errorMessage .= ' (errors: ' . implode(', ', $errors) . ')';
+                }
+
+                throw new InvalidArgumentException($errorMessage);
+            } else {
+                if ($uri->getHost() !== $asciiHost) {
+                    // Replace URI only if the ASCII version is different
+                    $uri = $uri->withHost($asciiHost);
+                }
+            }
+        }
+
+        $modify['uri'] = $uri;
         Psr7\rewind_body($request);
 
         // Add the Referer header if it is told to do so and only