fix(settings): use Utils.api for SMTP settings to fix HTTP 415 (Fixes #240)

Settings Email save/test/load now send Content-Type application/json required by panel API middleware. Adds regression tests for POST without Content-Type.

CHANGELOG.md

@@ -8,6 +8,7 @@
 ## [3.3.109] — 2026-07-05
 
 ### Fixed
+- **Email/SMTP settings (Fixes #240):** Settings → Email “Test connection” no longer returns HTTP 415 — SMTP save/test/load now use `Utils.api()` so requests include `Content-Type: application/json` required by panel API middleware.
 - **Panel tabs redirect to dashboard (401):** RustDesk client API routes (`GET /api/devices`, `/api/strategies`) no longer shadow panel session routes — browser requests without Bearer token fall through to panel handlers; `users.js` uses `/api/panel/strategies`; `Utils.api` no longer redirects logged-in users to `/login` (which bounced to dashboard) on incidental 401.
 - **Devices/Users 429 rate limit:** extended panel poll whitelist (`/api/folders`, `/api/tags`, `/api/device-groups`, `/api/bd/notifications`, `/api/panel/*`); dedicated limiter for `POST /api/desktop/layout`; staggered Devices page API loads; desktop widget layout saves gated when desktop mode is inactive.
 

web-nodejs/public/js/settings.js

@@ -4935,13 +4935,7 @@
                 if (!confirmed) return;
             }
             try {
-                const res = await fetch('/api/settings/email/smtp', {
-                    method: 'PUT',
-                    headers: { 'Content-Type': 'application/json', 'X-CSRF-Token': window.BetterDesk?.csrfToken || '' },
-                    body: JSON.stringify(body),
-                });
-                const data = await res.json();
-                if (!res.ok) throw new Error(data.error || 'Save failed');
+                await Utils.api('/api/settings/email/smtp', { method: 'PUT', body });
                 Notifications.success(_('settings.email.smtp_saved'));
                 document.getElementById('email-smtp-pass').value = '';
                 await loadEmailSmtpConfig();
@@ -4952,11 +4946,7 @@
 
         testBtn.addEventListener('click', async () => {
             try {
-                const res = await fetch('/api/settings/email/smtp/test', {
-                    method: 'POST',
-                    headers: { 'X-CSRF-Token': window.BetterDesk?.csrfToken || '' },
-                });
-                const data = await res.json();
+                const data = await Utils.api('/api/settings/email/smtp/test', { method: 'POST', body: {} });
                 if (data.success) {
                     Notifications.success(_('settings.email.smtp_test_success'));
                 } else {
@@ -4970,8 +4960,7 @@
 
     async function loadEmailSmtpConfig() {
         try {
-            const res = await fetch('/api/settings/email/smtp');
-            const config = await res.json();
+            const config = await Utils.api('/api/settings/email/smtp');
             if (!config.configured) {
                 _smtpWasConfigured = false;
                 return;

web-nodejs/tests/smtpSettings.test.js

@@ -91,3 +91,52 @@ describe('SMTP settings handlers', () => {
         expect(res.body.success).toBe(true);
     });
 });
+
+/** Same logic as routes/index.js requireJsonContentType */
+function requireJsonContentType(req, res, next) {
+    if (['GET', 'DELETE', 'OPTIONS', 'HEAD'].includes(req.method)) {
+        return next();
+    }
+    if (!req.path.startsWith('/api/')) {
+        return next();
+    }
+    if (req.path.includes('/upload') || req.path.includes('/import')) {
+        return next();
+    }
+    if (!req.is('application/json')) {
+        return res.status(415).json({
+            success: false,
+            error: 'Content-Type must be application/json',
+        });
+    }
+    next();
+}
+
+describe('SMTP test route JSON Content-Type enforcement', () => {
+    let app;
+
+    beforeEach(() => {
+        jest.clearAllMocks();
+        app = createTestApp();
+        withAuth(app, { id: 1, username: 'admin', role: 'server_admin' });
+        app.use(requireJsonContentType);
+        app.post('/api/settings/email/smtp/test', testSmtpSettings);
+    });
+
+    it('returns 415 when POST has no Content-Type header', async () => {
+        const res = await request(app).post('/api/settings/email/smtp/test');
+        expect(res.status).toBe(415);
+        expect(res.body.error).toBe('Content-Type must be application/json');
+        expect(emailService.testConnection).not.toHaveBeenCalled();
+    });
+
+    it('allows POST with application/json Content-Type', async () => {
+        const res = await request(app)
+            .post('/api/settings/email/smtp/test')
+            .set('Content-Type', 'application/json')
+            .send({});
+        expect(res.status).toBe(200);
+        expect(res.body.success).toBe(true);
+        expect(emailService.testConnection).toHaveBeenCalled();
+    });
+});