From 6cccaebf64c62d314fb0fe70b36d24542541bf5c Mon Sep 17 00:00:00 2001
From: Erik Dubbelboer <erik@dubbelboer.com>
Date: Sun, 1 Dec 2019 09:44:21 +0100
Subject: [PATCH] Fix parsing relative URLs starting with // (#702)

* Fix parsing relative URLs starting with //

* Improve test
---
 uri.go      | 11 ++++++++---
 uri_test.go |  6 ++++++
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/uri.go b/uri.go
index 21ab3ae..80e5bf3 100644
--- a/uri.go
+++ b/uri.go
@@ -263,9 +263,14 @@ func (u *URI) Parse(host, uri []byte) {
 func (u *URI) parse(host, uri []byte, isTLS bool) {
 	u.Reset()
 
-	scheme, host, uri := splitHostURI(host, uri)
-	u.scheme = append(u.scheme, scheme...)
-	lowercaseBytes(u.scheme)
+	if len(host) == 0 || bytes.Contains(uri, strColonSlashSlash) {
+		scheme, newHost, newURI := splitHostURI(host, uri)
+		u.scheme = append(u.scheme, scheme...)
+		lowercaseBytes(u.scheme)
+		host = newHost
+		uri = newURI
+	}
+
 	if isTLS {
 		u.scheme = append(u.scheme[:0], strHTTPS...)
 	}
diff --git a/uri_test.go b/uri_test.go
index c90b4e1..06d7526 100644
--- a/uri_test.go
+++ b/uri_test.go
@@ -345,6 +345,12 @@ func TestURIParse(t *testing.T) {
 	// http:// in query params
 	testURIParse(t, &u, "aaa.com", "/foo?bar=http://google.com",
 		"http://aaa.com/foo?bar=http://google.com", "aaa.com", "/foo", "/foo", "bar=http://google.com", "")
+
+	testURIParse(t, &u, "aaa.com", "//relative",
+		"http://aaa.com/relative", "aaa.com", "/relative", "//relative", "", "")
+
+	testURIParse(t, &u, "", "//aaa.com//absolute",
+		"http://aaa.com/absolute", "aaa.com", "/absolute", "//absolute", "", "")
 }
 
 func testURIParse(t *testing.T, u *URI, host, uri,