Let web and API routes have different auth methods group (#19168)

* remove the global methods but create dynamiclly

* Fix lint

* Fix windows lint

* Fix windows lint

* some improvements

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

routers/web/auth.go

@@ -0,0 +1,12 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+//go:build !windows
+// +build !windows
+
+package web
+
+import auth_service "code.gitea.io/gitea/services/auth"
+
+func specialAdd(group *auth_service.Group) {}

routers/web/auth_windows.go

@@ -0,0 +1,20 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package web
+
+import (
+	"code.gitea.io/gitea/models/auth"
+	auth_service "code.gitea.io/gitea/services/auth"
+)
+
+// specialAdd registers the SSPI auth method as the last method in the list.
+// The SSPI plugin is expected to be executed last, as it returns 401 status code if negotiation
+// fails (or if negotiation should continue), which would prevent other authentication methods
+// to execute at all.
+func specialAdd(group *auth_service.Group) {
+	if auth.IsSSPIEnabled() {
+		group.Add(&auth_service.SSPI{})
+	}
+}

routers/web/web.go

@@ -73,6 +73,26 @@ func CorsHandler() func(next http.Handler) http.Handler {
 	}
 }
 
+// The OAuth2 plugin is expected to be executed first, as it must ignore the user id stored
+// in the session (if there is a user id stored in session other plugins might return the user
+// object for that id).
+//
+// The Session plugin is expected to be executed second, in order to skip authentication
+// for users that have already signed in.
+func buildAuthGroup() *auth_service.Group {
+	group := auth_service.NewGroup(
+		&auth_service.OAuth2{}, // FIXME: this should be removed and only applied in download and oauth realted routers
+		&auth_service.Basic{},  // FIXME: this should be removed and only applied in download and git/lfs routers
+		auth_service.SharedSession,
+	)
+	if setting.Service.EnableReverseProxyAuth {
+		group.Add(&auth_service.ReverseProxy{})
+	}
+	specialAdd(group)
+
+	return group
+}
+
 // Routes returns all web routes
 func Routes(sessioner func(http.Handler) http.Handler) *web.Route {
 	routes := web.NewRoute()
@@ -160,8 +180,13 @@ func Routes(sessioner func(http.Handler) http.Handler) *web.Route {
 	// Removed: toolbox.Toolboxer middleware will provide debug information which seems unnecessary
 	common = append(common, context.Contexter())
 
+	group := buildAuthGroup()
+	if err := group.Init(); err != nil {
+		log.Error("Could not initialize '%s' auth method, error: %s", group.Name(), err)
+	}
+
 	// Get user from session if logged in.
-	common = append(common, context.Auth(auth_service.NewGroup(auth_service.Methods()...)))
+	common = append(common, context.Auth(group))
 
 	// GetHead allows a HEAD request redirect to GET if HEAD method is not defined for that route
 	common = append(common, middleware.GetHead)