fix: preserve POST across redirects in Stalwart JMAP passthrough #627

app/api/account/stalwart/jmap/route.ts

@@ -1,6 +1,7 @@
 import { NextRequest, NextResponse } from 'next/server';
 import { logger } from '@/lib/logger';
 import { getStalwartCredentials } from '@/lib/stalwart/credentials';
+import { JmapRedirectError, fetchJmapSession, postJmap, rebaseApiUrl } from '@/lib/stalwart/jmap-api';
 
 /**
  * POST /api/account/stalwart/jmap
@@ -23,14 +24,26 @@ export async function POST(request: NextRequest) {
 
     const body = await request.text();
 
-    const response = await fetch(`${creds.serverUrl}/jmap/`, {
-      method: 'POST',
-      headers: {
-        'Authorization': creds.authHeader,
-        'Content-Type': 'application/json',
-      },
-      body,
-    });
+    const directUrl = `${creds.serverUrl}/jmap/`;
+    let response = await postJmap(directUrl, creds.authHeader, body);
+
+    if (response.status === 404) {
+      // `${serverUrl}/jmap/` is not the API endpoint on this deployment
+      // (path prefix, non-Stalwart URL layout). Resolve the session's
+      // advertised apiUrl on the same host and retry once.
+      const session = await fetchJmapSession(creds.serverUrl, creds.authHeader);
+      const apiUrl = rebaseApiUrl(session, creds.serverUrl);
+      if (apiUrl && apiUrl !== directUrl) {
+        response = await postJmap(apiUrl, creds.authHeader, body);
+      }
+    }
+
+    if (!response.ok) {
+      logger.warn('Stalwart JMAP passthrough upstream error', {
+        status: response.status,
+        serverUrl: creds.serverUrl,
+      });
+    }
 
     const responseText = await response.text();
     return new NextResponse(responseText, {
@@ -38,6 +51,10 @@ export async function POST(request: NextRequest) {
       headers: { 'Content-Type': response.headers.get('Content-Type') || 'application/json' },
     });
   } catch (error) {
+    if (error instanceof JmapRedirectError) {
+      logger.error('Stalwart JMAP passthrough redirect error', { error: error.message });
+      return NextResponse.json({ error: error.message }, { status: 502 });
+    }
     logger.error('Stalwart JMAP passthrough error', {
       error: error instanceof Error ? error.message : 'Unknown',
     });

app/api/calendar-agenda/route.ts

@@ -1,6 +1,7 @@
 import { NextRequest, NextResponse } from 'next/server';
 import { logger } from '@/lib/logger';
 import { getStalwartCredentials } from '@/lib/stalwart/credentials';
+import { fetchJmapSession, postJmap, rebaseApiUrl } from '@/lib/stalwart/jmap-api';
 import { normalizeCalendarEventLike } from '@/lib/calendar-event-normalization';
 import { expandRecurringEvents } from '@/lib/recurrence-expansion';
 import { parseISO } from 'date-fns';
@@ -32,12 +33,6 @@ const EVENT_PROPERTIES = [
   'recurrenceOverrides', 'excludedRecurrenceRule',
 ] as const;
 
-interface JmapSession {
-  apiUrl?: string;
-  primaryAccounts?: Record<string, string>;
-  capabilities?: Record<string, unknown>;
-}
-
 interface AgendaEvent {
   id: string;
   uid: string | null;
@@ -141,9 +136,9 @@ export async function POST(request: NextRequest) {
       using.push('urn:ietf:params:jmap:principals:owner');
     }
 
-    // Send method calls to the same-origin JMAP endpoint the app's passthrough
-    // uses — never to session.apiUrl's (possibly unreachable) public host.
-    const apiUrl = `${creds.serverUrl}/jmap/`;
+    // Send method calls to the session's apiUrl rebased onto serverUrl's host
+    // — never to session.apiUrl's (possibly unreachable) public host.
+    const apiUrl = rebaseApiUrl(session, creds.serverUrl) ?? `${creds.serverUrl}/jmap/`;
 
     const now = new Date();
     const horizon = new Date(now.getTime() + days * 24 * 60 * 60 * 1000);
@@ -273,45 +268,12 @@ function clampInt(value: unknown, min: number, max: number, fallback: number): n
   return Math.min(max, Math.max(min, Math.round(n)));
 }
 
-/**
- * Fetch the JMAP session from the same host as `serverUrl`. Tries Stalwart's
- * canonical /jmap/session first (no redirect), then /.well-known/jmap as a
- * fallback for other servers. Returns null if neither yields a usable session.
- */
-async function fetchJmapSession(
-  serverUrl: string,
-  authHeader: string,
-): Promise<JmapSession | null> {
-  const candidates = [`${serverUrl}/jmap/session`, `${serverUrl}/.well-known/jmap`];
-  for (const url of candidates) {
-    try {
-      const res = await fetch(url, {
-        method: 'GET',
-        headers: { Authorization: authHeader },
-        redirect: 'follow',
-      });
-      if (!res.ok) continue;
-      const session = (await res.json()) as JmapSession;
-      if (session && typeof session === 'object' && session.primaryAccounts) {
-        return session;
-      }
-    } catch {
-      // Try the next candidate (e.g. canonical path 404s on a non-Stalwart server).
-    }
-  }
-  return null;
-}
-
 async function jmapPost(
   apiUrl: string,
   authHeader: string,
   payload: unknown,
 ): Promise<unknown> {
-  const res = await fetch(apiUrl, {
-    method: 'POST',
-    headers: { Authorization: authHeader, 'Content-Type': 'application/json' },
-    body: JSON.stringify(payload),
-  });
+  const res = await postJmap(apiUrl, authHeader, JSON.stringify(payload));
   if (!res.ok) {
     throw new Error(`JMAP request failed (${res.status})`);
   }