Refactor "route" related code, fix Safari cookie bug (#24330)

Fix #24176

Clean some misuses of route package, clean some legacy FIXMEs

---------

Co-authored-by: Giteabot <teabot@gitea.io>

5 files changed, 75 insertions, 44 deletions

diff --git a/modules/context/api.go b/modules/context/api.go
index d405c9972b..ae245ec1cb 100644
--- a/modules/context/api.go
+++ b/modules/context/api.go
@@ -343,6 +343,7 @@ func RepoRefForAPI(next http.Handler) http.Handler {
 			}
 			ctx.Repo.Commit = commit
 			ctx.Repo.TreePath = ctx.Params("*")
+			next.ServeHTTP(w, req)
 			return
 		}
 
diff --git a/modules/context/context.go b/modules/context/context.go
index f262c7cce7..702da8a965 100644
--- a/modules/context/context.go
+++ b/modules/context/context.go
@@ -446,6 +446,17 @@ func (ctx *Context) JSON(status int, content interface{}) {
 	}
 }
 
+func removeSessionCookieHeader(w http.ResponseWriter) {
+	cookies := w.Header()["Set-Cookie"]
+	w.Header().Del("Set-Cookie")
+	for _, cookie := range cookies {
+		if strings.HasPrefix(cookie, setting.SessionConfig.CookieName+"=") {
+			continue
+		}
+		w.Header().Add("Set-Cookie", cookie)
+	}
+}
+
 // Redirect redirects the request
 func (ctx *Context) Redirect(location string, status ...int) {
 	code := http.StatusSeeOther
@@ -453,6 +464,15 @@ func (ctx *Context) Redirect(location string, status ...int) {
 		code = status[0]
 	}
 
+	if strings.Contains(location, "://") || strings.HasPrefix(location, "//") {
+		// Some browsers (Safari) have buggy behavior for Cookie + Cache + External Redirection, eg: /my-path => https://other/path
+		// 1. the first request to "/my-path" contains cookie
+		// 2. some time later, the request to "/my-path" doesn't contain cookie (caused by Prevent web tracking)
+		// 3. Gitea's Sessioner doesn't see the session cookie, so it generates a new session id, and returns it to browser
+		// 4. then the browser accepts the empty session, then the user is logged out
+		// So in this case, we should remove the session cookie from the response header
+		removeSessionCookieHeader(ctx.Resp)
+	}
 	http.Redirect(ctx.Resp, ctx.Req, location, code)
 }
 
diff --git a/modules/context/context_test.go b/modules/context/context_test.go
new file mode 100644
index 0000000000..e1460c1fd7
--- /dev/null
+++ b/modules/context/context_test.go
@@ -0,0 +1,40 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package context
+
+import (
+	"net/http"
+	"testing"
+
+	"code.gitea.io/gitea/modules/setting"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type mockResponseWriter struct {
+	header http.Header
+}
+
+func (m *mockResponseWriter) Header() http.Header {
+	return m.header
+}
+
+func (m *mockResponseWriter) Write(bytes []byte) (int, error) {
+	panic("implement me")
+}
+
+func (m *mockResponseWriter) WriteHeader(statusCode int) {
+	panic("implement me")
+}
+
+func TestRemoveSessionCookieHeader(t *testing.T) {
+	w := &mockResponseWriter{}
+	w.header = http.Header{}
+	w.header.Add("Set-Cookie", (&http.Cookie{Name: setting.SessionConfig.CookieName, Value: "foo"}).String())
+	w.header.Add("Set-Cookie", (&http.Cookie{Name: "other", Value: "bar"}).String())
+	assert.Len(t, w.Header().Values("Set-Cookie"), 2)
+	removeSessionCookieHeader(w)
+	assert.Len(t, w.Header().Values("Set-Cookie"), 1)
+	assert.Contains(t, "other=bar", w.Header().Get("Set-Cookie"))
+}
diff --git a/modules/web/handler.go b/modules/web/handler.go
index 8a44673f12..bfb83820c8 100644
--- a/modules/web/handler.go
+++ b/modules/web/handler.go
@@ -8,7 +8,6 @@ import (
 	"fmt"
 	"net/http"
 	"reflect"
-	"strings"
 
 	"code.gitea.io/gitea/modules/context"
 	"code.gitea.io/gitea/modules/web/routing"
@@ -131,16 +130,22 @@ func hasResponseBeenWritten(argsIn []reflect.Value) bool {
 // toHandlerProvider converts a handler to a handler provider
 // A handler provider is a function that takes a "next" http.Handler, it can be used as a middleware
 func toHandlerProvider(handler any) func(next http.Handler) http.Handler {
-	if hp, ok := handler.(func(next http.Handler) http.Handler); ok {
-		return hp
-	}
-
 	funcInfo := routing.GetFuncInfo(handler)
 	fn := reflect.ValueOf(handler)
 	if fn.Type().Kind() != reflect.Func {
 		panic(fmt.Sprintf("handler must be a function, but got %s", fn.Type()))
 	}
 
+	if hp, ok := handler.(func(next http.Handler) http.Handler); ok {
+		return func(next http.Handler) http.Handler {
+			h := hp(next) // this handle could be dynamically generated, so we can't use it for debug info
+			return http.HandlerFunc(func(resp http.ResponseWriter, req *http.Request) {
+				routing.UpdateFuncInfo(req.Context(), funcInfo)
+				h.ServeHTTP(resp, req)
+			})
+		}
+	}
+
 	provider := func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(respOrig http.ResponseWriter, req *http.Request) {
 			// wrap the response writer to check whether the response has been written
@@ -175,26 +180,3 @@ func toHandlerProvider(handler any) func(next http.Handler) http.Handler {
 	provider(nil).ServeHTTP(nil, nil) // do a pre-check to make sure all arguments and return values are supported
 	return provider
 }
-
-// MiddlewareWithPrefix wraps a handler function at a prefix, and make it as a middleware
-// TODO: this design is incorrect, the asset handler should not be a middleware
-func MiddlewareWithPrefix(pathPrefix string, middleware func(handler http.Handler) http.Handler, handlerFunc http.HandlerFunc) func(next http.Handler) http.Handler {
-	funcInfo := routing.GetFuncInfo(handlerFunc)
-	handler := http.HandlerFunc(func(resp http.ResponseWriter, req *http.Request) {
-		routing.UpdateFuncInfo(req.Context(), funcInfo)
-		handlerFunc(resp, req)
-	})
-	return func(next http.Handler) http.Handler {
-		return http.HandlerFunc(func(resp http.ResponseWriter, req *http.Request) {
-			if !strings.HasPrefix(req.URL.Path, pathPrefix) {
-				next.ServeHTTP(resp, req)
-				return
-			}
-			if middleware != nil {
-				middleware(handler).ServeHTTP(resp, req)
-			} else {
-				handler.ServeHTTP(resp, req)
-			}
-		})
-	}
-}
diff --git a/modules/web/route.go b/modules/web/route.go
index fe35880849..6fd60f4ca7 100644
--- a/modules/web/route.go
+++ b/modules/web/route.go
@@ -44,23 +44,13 @@ type Route struct {
 // NewRoute creates a new route
 func NewRoute() *Route {
 	r := chi.NewRouter()
-	return &Route{
-		R:              r,
-		curGroupPrefix: "",
-		curMiddlewares: []interface{}{},
-	}
+	return &Route{R: r}
 }
 
 // Use supports two middlewares
 func (r *Route) Use(middlewares ...interface{}) {
-	if r.curGroupPrefix != "" {
-		// FIXME: this behavior is incorrect, should use "With" instead
-		r.curMiddlewares = append(r.curMiddlewares, middlewares...)
-	} else {
-		// FIXME: another misuse, the "Use" with empty middlewares is called after "Mount"
-		for _, m := range middlewares {
-			r.R.Use(toHandlerProvider(m))
-		}
+	for _, m := range middlewares {
+		r.R.Use(toHandlerProvider(m))
 	}
 }
 
@@ -116,9 +106,7 @@ func (r *Route) Methods(method, pattern string, h []any) {
 
 // Mount attaches another Route along ./pattern/*
 func (r *Route) Mount(pattern string, subR *Route) {
-	middlewares := make([]interface{}, len(r.curMiddlewares))
-	copy(middlewares, r.curMiddlewares)
-	subR.Use(middlewares...)
+	subR.Use(r.curMiddlewares...)
 	r.R.Mount(r.getPattern(pattern), subR.R)
 }