From 945c21ca437a6f2dc6db78119cf8043d45d18d2e Mon Sep 17 00:00:00 2001
From: MoonFruit <dkmoonfruit@gmail.com>
Date: Tue, 2 Apr 2024 11:06:53 +0800
Subject: [PATCH] Make remote rule sets support multiple URLs

---
 option/rule_set.go       |  6 +++---
 route/rule_set.go        |  3 +++
 route/rule_set_remote.go | 15 +++++++++++++--
 3 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/option/rule_set.go b/option/rule_set.go
index 8e367e69a5..7af7fae8d3 100644
--- a/option/rule_set.go
+++ b/option/rule_set.go
@@ -74,9 +74,9 @@ type LocalRuleSet struct {
 }
 
 type RemoteRuleSet struct {
-	URL            string   `json:"url"`
-	DownloadDetour string   `json:"download_detour,omitempty"`
-	UpdateInterval Duration `json:"update_interval,omitempty"`
+	URL            Listable[string] `json:"url"`
+	DownloadDetour string           `json:"download_detour,omitempty"`
+	UpdateInterval Duration         `json:"update_interval,omitempty"`
 }
 
 type _HeadlessRule struct {
diff --git a/route/rule_set.go b/route/rule_set.go
index f644fb406f..bf745866e3 100644
--- a/route/rule_set.go
+++ b/route/rule_set.go
@@ -20,6 +20,9 @@ func NewRuleSet(ctx context.Context, router adapter.Router, logger logger.Contex
 	case C.RuleSetTypeLocal:
 		return NewLocalRuleSet(router, options)
 	case C.RuleSetTypeRemote:
+		if len(options.RemoteOptions.URL) == 0 {
+			return nil, E.New("missing urls")
+		}
 		return NewRemoteRuleSet(ctx, router, logger, options), nil
 	default:
 		return nil, E.New("unknown rule set type: ", options.Type)
diff --git a/route/rule_set_remote.go b/route/rule_set_remote.go
index a14c6fe543..d0f25e1c76 100644
--- a/route/rule_set_remote.go
+++ b/route/rule_set_remote.go
@@ -184,7 +184,18 @@ func (s *RemoteRuleSet) loopUpdate() {
 }
 
 func (s *RemoteRuleSet) fetchOnce(ctx context.Context, startContext adapter.RuleSetStartContext) error {
-	s.logger.Debug("updating rule-set ", s.options.Tag, " from URL: ", s.options.RemoteOptions.URL)
+	var err error
+	for _, url := range s.options.RemoteOptions.URL {
+		err = s.fetchURL(ctx, url, startContext)
+		if err == nil {
+			return nil
+		}
+	}
+	return err
+}
+
+func (s *RemoteRuleSet) fetchURL(ctx context.Context, url string, startContext adapter.RuleSetStartContext) error {
+	s.logger.Debug("updating rule-set ", s.options.Tag, " from URL: ", url)
 	var httpClient *http.Client
 	if startContext != nil {
 		httpClient = startContext.HTTPClient(s.options.RemoteOptions.DownloadDetour, s.dialer)
@@ -199,7 +210,7 @@ func (s *RemoteRuleSet) fetchOnce(ctx context.Context, startContext adapter.Rule
 			},
 		}
 	}
-	request, err := http.NewRequest("GET", s.options.RemoteOptions.URL, nil)
+	request, err := http.NewRequest("GET", url, nil)
 	if err != nil {
 		return err
 	}