From bd422066869b48ba4a920b04409fd398e5400f2d Mon Sep 17 00:00:00 2001
From: Linus Rath <139418639+rathlinus@users.noreply.github.com>
Date: Thu, 24 Sep 2026 18:36:31 +0200
Subject: [PATCH] fix: accept a pasted JMAP session URL as the server address
 #971

---
 src/lib/__tests__/server-discovery.test.ts | 15 +++++++++++++++
 src/lib/server-discovery.ts                | 11 ++++++-----
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/src/lib/__tests__/server-discovery.test.ts b/src/lib/__tests__/server-discovery.test.ts
index 1e4e2d06..72e78853 100644
--- a/src/lib/__tests__/server-discovery.test.ts
+++ b/src/lib/__tests__/server-discovery.test.ts
@@ -50,6 +50,21 @@ describe('normalizeServerUrl', () => {
     expect(normalizeServerUrl('mail.example.com/jmap')).toBe('https://mail.example.com');
   });
 
+  it('strips a pasted session URL with its query or fragment (#971)', () => {
+    expect(normalizeServerUrl('https://mail.example.com/jmap/session')).toBe('https://mail.example.com');
+    expect(normalizeServerUrl('mail.example.com/jmap/session/')).toBe('https://mail.example.com');
+    expect(normalizeServerUrl('https://mail.example.com/.well-known/jmap?x=1#top')).toBe(
+      'https://mail.example.com',
+    );
+    expect(normalizeServerUrl('https://mail.example.com/?x=1')).toBe('https://mail.example.com');
+  });
+
+  it('keeps a base path prefix in front of the session suffix', () => {
+    expect(normalizeServerUrl('https://example.com/mail/jmap/session')).toBe('https://example.com/mail');
+    expect(normalizeServerUrl('https://example.com/mail/.well-known/jmap')).toBe('https://example.com/mail');
+    expect(normalizeServerUrl('https://example.com/mail')).toBe('https://example.com/mail');
+  });
+
   it('keeps an explicit http scheme and port', () => {
     expect(normalizeServerUrl('http://localhost:8080')).toBe('http://localhost:8080');
   });
diff --git a/src/lib/server-discovery.ts b/src/lib/server-discovery.ts
index 2254f67e..e21da1a9 100644
--- a/src/lib/server-discovery.ts
+++ b/src/lib/server-discovery.ts
@@ -34,8 +34,8 @@ const EMAIL_RE = /^[^\s@]+@([^\s@]+\.[^\s@]+)$/;
 
 /**
  * Accept what people actually type — `mail.example.com`, `example.com/`,
- * `https://mail.example.com/.well-known/jmap` — and return the base URL the
- * JMAP client expects, or null if it can't be one.
+ * `https://mail.example.com/.well-known/jmap`, `…/jmap/session` — and return
+ * the base URL the JMAP client expects, or null if it can't be one.
  */
 export function normalizeServerUrl(input: string): string | null {
   let value = input.trim();
@@ -57,11 +57,12 @@ export function normalizeServerUrl(input: string): string | null {
   if (/^http:\/\//i.test(value) && !isLocalHost(value)) return null;
 
   // Someone pasting the endpoint they found in the webmail's settings gets the
-  // same result as someone typing the address they use in the browser.
+  // same result as someone typing the address they use in the browser. Only
+  // the session or API suffix goes, so a base path prefix survives (#971).
   value = value
+    .replace(/[?#].*$/, '')
     .replace(/\/+$/, '')
-    .replace(/\/\.well-known\/jmap$/i, '')
-    .replace(/\/jmap$/i, '')
+    .replace(/\/(?:jmap\/session|\.well-known\/jmap|jmap)$/i, '')
     .replace(/\/+$/, '');
 
   const host = value.slice(value.indexOf('://') + 3).split('/')[0];