From 45271807b25bc042a0fc2206b2f41c0b827c15b8 Mon Sep 17 00:00:00 2001
From: Matthias Kruk <m@m10k.eu>
Date: Sat, 22 Jan 2022 18:11:43 +0900
Subject: [PATCH] watchbot: Add support for smart git-over-http protocol

Watchbot does not support the smart git-over-http protocol, making
it unable to watch repositories hosted by Github and other services.

This commit adds support for the smart git-over-http protocol to
watchbot.
---
 watchbot.sh | 43 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 42 insertions(+), 1 deletion(-)

diff --git a/watchbot.sh b/watchbot.sh
index 8b5c476..a1317fe 100755
--- a/watchbot.sh
+++ b/watchbot.sh
@@ -37,7 +37,33 @@ watch_to_branch() {
 	return 0
 }
 
-fetch_head_remote() {
+fetch_head_smart_http() {
+	local watch="$1"
+
+	local repository
+	local branch
+	local url
+	local re
+	local data
+	local ref
+
+	repository=$(watch_to_repository "$watch")
+	branch=$(watch_to_branch "$watch")
+
+	re="00[0-9a-f]{2}\\K[0-9a-f]{40} refs/heads/$branch"
+	url="$repository/info/refs?service=git-upload-pack"
+
+	if ! data=$(curl --get --silent --location "$url" 2>/dev/null |
+			    grep -oP "$re" --binary-files=text); then
+		return 1
+	fi
+
+	ref="${data%% *}"
+	echo "$ref"
+	return 0
+}
+
+fetch_head_dumb_http() {
 	local watch="$1"
 
 	local repository
@@ -69,6 +95,21 @@ fetch_head_remote() {
 	return 0
 }
 
+fetch_head_remote() {
+	local watch="$1"
+
+	local head
+
+	if ! head=$(fetch_head_smart_http "$watch"); then
+		if ! head=$(fetch_head_dumb_http "$watch"); then
+			return 1
+		fi
+	fi
+
+	echo "$head"
+	return 0
+}
+
 fetch_head_local() {
 	local watch="$1"
 
-- 
2.47.3