Refactor Mihomo proxy to support WebSocket upgrades and enhance alias forwarding

- Introduced a new function `newAliasForward` to handle alias remapping for users, improving the flexibility of the proxy.
- Updated `NewMihomoForward` to differentiate between HTTP and WebSocket requests, ensuring proper handling of both types.
- Enhanced comments for clarity on the proxy behavior and request handling, improving maintainability.

internal/proxy/forward.go

@@ -17,6 +17,18 @@ func NewAliasForward(
 	stripPrefix, pathPrefix, auth string,
 	rt http.RoundTripper,
 	errHandler func(http.ResponseWriter, *http.Request, error),
+) http.Handler {
+	return newAliasForward(target, stripPrefix, pathPrefix, auth, rt, errHandler, true)
+}
+
+// newAliasForward is the shared HTTP forwarder. remapUsers maps top-level "users" → "stats/users"
+// for Telemt; Mihomo must pass false so /users is not rewritten.
+func newAliasForward(
+	target *url.URL,
+	stripPrefix, pathPrefix, auth string,
+	rt http.RoundTripper,
+	errHandler func(http.ResponseWriter, *http.Request, error),
+	remapUsers bool,
 ) http.Handler {
 	if errHandler == nil {
 		errHandler = defaultForwardErrorHandler
@@ -35,7 +47,7 @@ func NewAliasForward(
 		}
 		rest := strings.TrimPrefix(p, stripPrefix)
 		rest = strings.TrimPrefix(rest, "/")
-		if (r.Method == http.MethodGet || r.Method == http.MethodHead) && rest == "users" {
+		if remapUsers && (r.Method == http.MethodGet || r.Method == http.MethodHead) && rest == "users" {
 			rest = "stats/users"
 		}
 

internal/proxy/mihomo.go

@@ -8,15 +8,42 @@ import (
 	"strings"
 )
 
-// NewMihomoForward proxies /api/{alias}/mihomo/... to Mihomo external-controller (REST + WebSocket).
-// Используется Rewrite (Go 1.20+): очищается RequestURI и задаётся абсолютный URL — иначе строгий upstream
-// и WebSocket upgrade могут отвечать 400 (см. аналогично Telemt в forward.go).
+// NewMihomoForward proxies /api/{alias}/mihomo/... to Mihomo external-controller.
+//
+// REST и обычные GET/POST идут тем же путём, что и NewAliasForward (http.NewRequest + RoundTrip):
+// httputil.ReverseProxy в таком режиме часто даёт 400 на строгих upstream (в т.ч. Mihomo), хотя curl к ним работает.
+// Только WebSocket (traffic, memory, …) остаётся на ReverseProxy + Rewrite.
 func NewMihomoForward(
 	target *url.URL,
 	stripPrefix string,
 	auth string,
 	rt http.RoundTripper,
 	errHandler func(http.ResponseWriter, *http.Request, error),
+) http.Handler {
+	httpH := newAliasForward(target, stripPrefix, "", auth, rt, errHandler, false)
+	wsH := newMihomoWebSocketReverseProxy(target, stripPrefix, auth, rt, errHandler)
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if isWebSocketUpgrade(r) {
+			wsH.ServeHTTP(w, r)
+			return
+		}
+		httpH.ServeHTTP(w, r)
+	})
+}
+
+func isWebSocketUpgrade(r *http.Request) bool {
+	if r == nil {
+		return false
+	}
+	return strings.EqualFold(r.Header.Get("Upgrade"), "websocket")
+}
+
+func newMihomoWebSocketReverseProxy(
+	target *url.URL,
+	stripPrefix string,
+	auth string,
+	rt http.RoundTripper,
+	errHandler func(http.ResponseWriter, *http.Request, error),
 ) http.Handler {
 	if errHandler == nil {
 		errHandler = defaultForwardErrorHandler
@@ -26,7 +53,6 @@ func NewMihomoForward(
 	}
 	rp := &httputil.ReverseProxy{
 		Rewrite: func(pr *httputil.ProxyRequest) {
-			// Нормализуем Out, не In (контракт httputil.ProxyRequest: In не трогать).
 			NormalizeRequestURLPath(pr.Out)
 			p := pr.Out.URL.Path
 			if !strings.HasPrefix(p, stripPrefix) {
@@ -38,8 +64,6 @@ func NewMihomoForward(
 			du.RawQuery = pr.Out.URL.RawQuery
 			out := pr.Out
 			out.URL = &du
-			// Как в NewAliasForward: не оставлять Host клиента ни в поле, ни в Header —
-			// иначе строгий upstream (в т.ч. Mihomo) часто отвечает 400.
 			out.Header.Del("Host")
 			out.Host = du.Host
 			out.RequestURI = ""
@@ -51,8 +75,8 @@ func NewMihomoForward(
 				out.Header.Set("Authorization", auth)
 			}
 		},
-		Transport:      rt,
-		FlushInterval:  -1,
+		Transport: rt,
+		FlushInterval: -1,
 		ErrorHandler: func(w http.ResponseWriter, r *http.Request, err error) {
 			errHandler(w, r, err)
 		},