From 167bbe514f9808bc1e03804311b39f463a0a76fe Mon Sep 17 00:00:00 2001
From: Andrew Ivchenkov <and.ivchenkov@gmail.com>
Date: Mon, 1 Apr 2019 15:44:21 +0300
Subject: [PATCH] Detailed error

---
 src/UrlConverter.php | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/UrlConverter.php b/src/UrlConverter.php
index f5d8a40..9cbf355 100644
--- a/src/UrlConverter.php
+++ b/src/UrlConverter.php
@@ -53,7 +53,8 @@ private function parseUrl($ampUrl)
     private function signPath($path)
     {
         if (!@openssl_sign($path, $signature, $this->privateKey, OPENSSL_ALGO_SHA256)) {
-            throw new AmpCacheException("Failed to sign the $path");
+            $error = openssl_error_string();
+            throw new AmpCacheException("Failed to sign the $path: $error");
         }
         return $this->base64encode($signature);
     }