Secret links: one mount, not two

plugins/tools/frontend/views/SecureSendCreate.vue

@@ -151,12 +151,19 @@ async function createLink() {
     // withBase for the path: a site served under /shopdb or /ops carries that
     // in front of every route, and leaving it off produced a 404 from IIS for a
     // secret that existed - with the sender shown a link that could never work.
-    const origin = (await getSiteBaseUrl()).replace(/\/+$/, '')
-    const path = withBase(`/s/${token}`)
+    // site_base_url is DOCUMENTED as scheme + host, but sites really do set the
+    // full base including the subpath - and appending the mount to one that
+    // already carries it produced /shopdb/shopdb/s/<token>. Tolerate both
+    // rather than trusting the description: add the mount only when it is not
+    // there already.
+    const configured = (await getSiteBaseUrl()).replace(/\/+$/, '')
+    const mount = withBase('/').replace(/\/+$/, '')
+    const needsMount = mount && !configured.endsWith(mount)
 
     // The key rides in the FRAGMENT. Browsers never send it, so it reaches the
     // recipient and nowhere else.
-    link.value = `${origin}${path}#${sealed.fragmentKey}`
+    link.value =
+      `${configured}${needsMount ? mount : ''}/s/${token}#${sealed.fragmentKey}`
     // Drop the plaintext as soon as it is sealed: no reason to keep it in memory
     // behind the link that replaced it.
     plaintext.value = ''