Check if reverse proxy is correctly configured (#30890) (#30935)

Backport #30890 by wxiaoguang

Follow #27011
Follow #30885

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

routers/web/admin/admin.go

@@ -9,12 +9,14 @@ import (
 	"net/http"
 	"runtime"
 	"sort"
+	"strings"
 	"time"
 
 	activities_model "code.gitea.io/gitea/models/activities"
 	"code.gitea.io/gitea/models/db"
 	"code.gitea.io/gitea/modules/base"
 	"code.gitea.io/gitea/modules/graceful"
+	"code.gitea.io/gitea/modules/httplib"
 	"code.gitea.io/gitea/modules/json"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
@@ -223,6 +225,16 @@ func SelfCheck(ctx *context.Context) {
 	ctx.HTML(http.StatusOK, tplSelfCheck)
 }
 
+func SelfCheckPost(ctx *context.Context) {
+	var problems []string
+	frontendAppURL := ctx.FormString("location_origin") + setting.AppSubURL + "/"
+	ctxAppURL := httplib.GuessCurrentAppURL(ctx)
+	if !strings.HasPrefix(ctxAppURL, frontendAppURL) {
+		problems = append(problems, ctx.Locale.TrString("admin.self_check.location_origin_mismatch", frontendAppURL, ctxAppURL))
+	}
+	ctx.JSON(http.StatusOK, map[string]any{"problems": problems})
+}
+
 func CronTasks(ctx *context.Context) {
 	ctx.Data["Title"] = ctx.Tr("admin.monitor.cron")
 	ctx.Data["PageIsAdminMonitorCron"] = true

routers/web/admin/admin_test.go

@@ -4,8 +4,14 @@
 package admin
 
 import (
+	"net/http"
 	"testing"
 
+	"code.gitea.io/gitea/modules/json"
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/test"
+	"code.gitea.io/gitea/services/contexttest"
+
 	"github.com/stretchr/testify/assert"
 )
 
@@ -66,3 +72,21 @@ func TestShadowPassword(t *testing.T) {
 		assert.EqualValues(t, k.Result, shadowPassword(k.Provider, k.CfgItem))
 	}
 }
+
+func TestSelfCheckPost(t *testing.T) {
+	defer test.MockVariableValue(&setting.AppURL, "http://config/sub/")()
+	defer test.MockVariableValue(&setting.AppSubURL, "/sub")()
+
+	ctx, resp := contexttest.MockContext(t, "GET http://host/sub/admin/self_check?location_origin=http://frontend")
+	SelfCheckPost(ctx)
+	assert.EqualValues(t, http.StatusOK, resp.Code)
+
+	data := struct {
+		Problems []string `json:"problems"`
+	}{}
+	err := json.Unmarshal(resp.Body.Bytes(), &data)
+	assert.NoError(t, err)
+	assert.Equal(t, []string{
+		ctx.Locale.TrString("admin.self_check.location_origin_mismatch", "http://frontend/sub/", "http://host/sub/"),
+	}, data.Problems)
+}

routers/web/web.go

@@ -686,6 +686,7 @@ func registerRoutes(m *web.Route) {
 		m.Post("", web.Bind(forms.AdminDashboardForm{}), admin.DashboardPost)
 
 		m.Get("/self_check", admin.SelfCheck)
+		m.Post("/self_check", admin.SelfCheckPost)
 
 		m.Group("/config", func() {
 			m.Get("", admin.Config)