Check if reverse proxy is correctly configured

options/locale/locale_en-US.ini

@@ -3320,6 +3320,7 @@ self_check.database_collation_case_insensitive = Database is using a collation %
 self_check.database_inconsistent_collation_columns = Database is using collation %s, but these columns are using mismatched collations. It might cause some unexpected problems.
 self_check.database_fix_mysql = For MySQL/MariaDB users, you could use the "gitea doctor convert" command to fix the collation problems, or you could also fix the problem by "ALTER ... COLLATE ..." SQLs manually.
 self_check.database_fix_mssql = For MSSQL users, you could only fix the problem by "ALTER ... COLLATE ..." SQLs manually at the moment.
+self_check.location_origin_mismatch = Current URL (%[1]s) doesn't match the URL seen by Gitea (%[2]s). If you are using a reverse proxy, please make sure the "Host" and "X-Forwarded-Proto" headers are set correctly.
 
 [action]
 create_repo = created repository <a href="%s">%s</a>

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

@@ -685,6 +685,7 @@ 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)

services/context/base.go

@@ -309,7 +309,8 @@ func NewBaseContext(resp http.ResponseWriter, req *http.Request) (b *Base, close
 		Locale:    middleware.Locale(resp, req),
 		Data:      middleware.GetContextData(req.Context()),
 	}
-	b.AppendContextValue(translation.ContextKey, b.Locale)
 	b.Req = b.Req.WithContext(b)
+	b.AppendContextValue(translation.ContextKey, b.Locale)
+	b.AppendContextValue(httplib.RequestContextKey, b.Req)
 	return b, b.cleanUp
 }

services/contexttest/context_tests.go

@@ -39,7 +39,7 @@ func mockRequest(t *testing.T, reqPath string) *http.Request {
 	}
 	requestURL, err := url.Parse(path)
 	assert.NoError(t, err)
-	req := &http.Request{Method: method, URL: requestURL, Form: maps.Clone(requestURL.Query()), Header: http.Header{}}
+	req := &http.Request{Method: method, Host: requestURL.Host, URL: requestURL, Form: maps.Clone(requestURL.Query()), Header: http.Header{}}
 	req = req.WithContext(middleware.WithContextData(req.Context()))
 	return req
 }

templates/admin/self_check.tmpl

@@ -1,21 +1,23 @@
-{{template "admin/layout_head" (dict "ctxData" . "pageClass" "admin config")}}
+{{template "admin/layout_head" (dict "ctxData" . "pageClass" "admin")}}
 
 <div class="admin-setting-content">
 	<h4 class="ui top attached header">
 		{{ctx.Locale.Tr "admin.self_check"}}
 	</h4>
 
 	{{if .StartupProblems}}
-	<div class="ui attached segment">
+	<div class="ui attached segment self-check-problem">
 		<div class="ui warning message">
 			<div>{{ctx.Locale.Tr "admin.self_check.startup_warnings"}}</div>
 			<ul class="tw-w-full">{{range .StartupProblems}}<li>{{.}}</li>{{end}}</ul>
 		</div>
 	</div>
 	{{end}}
 
+	<div class="ui attached segment tw-hidden self-check-problem self-check-by-frontend"></div>
+
 	{{if .DatabaseCheckHasProblems}}
-	<div class="ui attached segment">
+	<div class="ui attached segment self-check-problem">
 		{{if .DatabaseType.IsMySQL}}
 			<div class="tw-p-2">{{ctx.Locale.Tr "admin.self_check.database_fix_mysql"}}</div>
 		{{else if .DatabaseType.IsMSSQL}}
@@ -29,22 +31,22 @@
 		{{end}}
 		{{if .DatabaseCheckInconsistentCollationColumns}}
 			<div class="ui red message">
-				{{ctx.Locale.Tr "admin.self_check.database_inconsistent_collation_columns" .DatabaseCheckResult.DatabaseCollation}}
-				<ul class="tw-w-full">
-				{{range .DatabaseCheckInconsistentCollationColumns}}
-					<li>{{.}}</li>
-				{{end}}
-				</ul>
+				<details>
+					<summary>{{ctx.Locale.Tr "admin.self_check.database_inconsistent_collation_columns" .DatabaseCheckResult.DatabaseCollation}}</summary>
+					<ul class="tw-w-full">
+					{{range .DatabaseCheckInconsistentCollationColumns}}
+						<li>{{.}}</li>
+					{{end}}
+					</ul>
+				</details>
 			</div>
 		{{end}}
 	</div>
 	{{end}}
-
-	{{if and (not .StartupProblems) (not .DatabaseCheckHasProblems)}}
-	<div class="ui attached segment">
+	{{/* only shown when there is no visible "self-check-problem" */}}
+	<div class="ui attached segment tw-hidden self-check-no-problem">
 		{{ctx.Locale.Tr "admin.self_check.no_problem_found"}}
 	</div>
-	{{end}}
 </div>
 
 {{template "admin/layout_footer" .}}

web_src/js/bootstrap.js

@@ -16,20 +16,20 @@ function shouldIgnoreError(err) {
   return false;
 }
 
-export function showGlobalErrorMessage(msg) {
+export function showGlobalErrorMessage(msg, msgType = 'error') {
   const msgContainer = document.querySelector('.page-content') ?? document.body;
   const msgCompact = msg.replace(/\W/g, '').trim(); // compact the message to a data attribute to avoid too many duplicated messages
   let msgDiv = msgContainer.querySelector(`.js-global-error[data-global-error-msg-compact="${msgCompact}"]`);
   if (!msgDiv) {
     const el = document.createElement('div');
-    el.innerHTML = `<div class="ui container negative message center aligned js-global-error tw-mt-[15px] tw-whitespace-pre-line"></div>`;
+    el.innerHTML = `<div class="ui container js-global-error tw-my-4"><div class="ui ${msgType} message tw-text-center tw-whitespace-pre-line"></div></div>`;
     msgDiv = el.childNodes[0];
   }
   // merge duplicated messages into "the message (count)" format
   const msgCount = Number(msgDiv.getAttribute(`data-global-error-msg-count`)) + 1;
   msgDiv.setAttribute(`data-global-error-msg-compact`, msgCompact);
   msgDiv.setAttribute(`data-global-error-msg-count`, msgCount.toString());
-  msgDiv.textContent = msg + (msgCount > 1 ? ` (${msgCount})` : '');
+  msgDiv.querySelector('.ui.message').textContent = msg + (msgCount > 1 ? ` (${msgCount})` : '');
   msgContainer.prepend(msgDiv);
 }
 

web_src/js/features/admin/selfcheck.js

@@ -0,0 +1,31 @@
+import {toggleElem} from '../../utils/dom.js';
+import {POST} from '../../modules/fetch.js';
+
+const {appSubUrl} = window.config;
+
+export async function initAdminSelfCheck() {
+  const elCheckByFrontend = document.querySelector('.page-content.admin .self-check-by-frontend');
+  if (!elCheckByFrontend) return;
+
+  const elContent = document.querySelector('.page-content.admin .admin-setting-content');
+
+  // send frontend self-check request
+  const resp = await POST(`${appSubUrl}/admin/self_check`, {
+    data: new URLSearchParams({
+      location_origin: window.location.origin,
+      now: Date.now(), // TODO: check time difference between server and client
+    }),
+  });
+  const json = await resp.json();
+  toggleElem(elCheckByFrontend, Boolean(json.problems?.length));
+  for (const problem of json.problems ?? []) {
+    const elProblem = document.createElement('div');
+    elProblem.classList.add('ui', 'warning', 'message');
+    elProblem.textContent = problem;
+    elCheckByFrontend.append(elProblem);
+  }
+
+  // only show the "no problem" if there is no visible "self-check-problem"
+  const hasProblem = Boolean(elContent.querySelectorAll('.self-check-problem:not(.tw-hidden)').length);
+  toggleElem(elContent.querySelector('.self-check-no-problem'), !hasProblem);
+}

web_src/js/features/common-global.js

@@ -451,5 +451,5 @@ export function checkAppUrl() {
     return;
   }
   showGlobalErrorMessage(`Your ROOT_URL in app.ini is "${appUrl}", it's unlikely matching the site you are visiting.
-Mismatched ROOT_URL config causes wrong URL links for web UI/mail content/webhook notification/OAuth2 sign-in.`);
+Mismatched ROOT_URL config causes wrong URL links for web UI/mail content/webhook notification/OAuth2 sign-in.`, 'warning');
 }

web_src/js/index.js

@@ -87,6 +87,7 @@ import {initRepoDiffCommitBranchesAndTags} from './features/repo-diff-commit.js'
 import {initDirAuto} from './modules/dirauto.js';
 import {initRepositorySearch} from './features/repo-search.js';
 import {initColorPickers} from './features/colorpicker.js';
+import {initAdminSelfCheck} from './features/admin/selfcheck.js';
 
 // Init Gitea's Fomantic settings
 initGiteaFomantic();
@@ -132,6 +133,7 @@ onDomReady(() => {
   initAdminEmails();
   initAdminUserListSearchForm();
   initAdminConfigs();
+  initAdminSelfCheck();
 
   initDashboardRepoList();