#889: add http tunnel mode for HTTP handler

cmd/gost/route.go

@@ -665,6 +665,7 @@ func (r *route) GenRouters() ([]router, error) {
 			gost.TCPModeHandlerOption(node.GetBool("tcp")),
 			gost.IPRoutesHandlerOption(tunRoutes...),
 			gost.ProxyAgentHandlerOption(node.Get("proxyAgent")),
+			gost.HTTPTunnelHandlerOption(node.GetBool("httpTunnel")),
 		)
 
 		rt := router{

handler.go

@@ -43,6 +43,7 @@ type HandlerOptions struct {
 	TCPMode       bool
 	IPRoutes      []IPRoute
 	ProxyAgent    string
+	HTTPTunnel    bool
 }
 
 // HandlerOption allows a common way to set handler options.
@@ -219,6 +220,13 @@ func ProxyAgentHandlerOption(agent string) HandlerOption {
 	}
 }
 
+// HTTPTunnelHandlerOption sets the Tunnel mode for HTTP client used in HTTP handler.
+func HTTPTunnelHandlerOption(tunnelMode bool) HandlerOption {
+	return func(opts *HandlerOptions) {
+		opts.HTTPTunnel = tunnelMode
+	}
+}
+
 type autoHandler struct {
 	options *HandlerOptions
 }

http.go

@@ -257,7 +257,9 @@ func (h *httpHandler) handleRequest(conn net.Conn, req *http.Request) {
 
 		// forward http request
 		lastNode := route.LastNode()
-		if req.Method != http.MethodConnect && lastNode.Protocol == "http" {
+		if req.Method != http.MethodConnect &&
+			lastNode.Protocol == "http" &&
+			!h.options.HTTPTunnel {
 			err = h.forwardRequest(conn, req, route)
 			if err == nil {
 				return