contact messages: client proof flow, upload re-auth, trail ✉️

The contact bundle submits each solved challenge immediately and treats
{quota} frames as the grant that releases queued sends/uploads; an
upload answered 429 "pow" re-registers for a fresh challenge and
retries once it lands (Composer's reauthorize prop). The contact email
frame fills the dialog's mailto link only after a solve. Visit trails
render the ✉️ marker on the step where the panel was opened and the
proof solved.

frontend/src/Composer.vue

@@ -18,6 +18,9 @@ const props = defineProps({
   // kept — e.g. the contact panel's first-message name/email fields are
   // still empty.
   sendDisabled: { type: Boolean, default: false },
+  // Visitor side: an upload hit the end of the PoW quota (429 "pow") —
+  // re-prove and resolve, then the upload retries once.
+  reauthorize: { type: Function, default: null },
 })
 const emit = defineEmits(['send'])
 
@@ -86,7 +89,13 @@ async function uploadFiles(files) {
       const path = `/_${props.token ? 'contact' : 'api'}/files/${encodeURIComponent(file.name)}`
       const init = { method: 'PUT', body: file }
       if (props.token) init.headers = { 'x-contact-token': props.token }
-      const r = await (props.token ? fetch(path, init) : apiFetch(path, init))
+      const put = () => (props.token ? fetch(path, init) : apiFetch(path, init))
+      let r = await put()
+      if (!r.ok && r.status === 429 && props.reauthorize) {
+        // The PoW quota (shared with messages) ran out: re-prove, retry once.
+        const detail = await r.json().then((d) => d?.detail, () => null)
+        if (detail === 'pow' && (await props.reauthorize())) r = await put()
+      }
       if (!r.ok) {
         const detail = await r.json().then((d) => d?.detail, () => null)
         throw new Error(detail || `status ${r.status}`)

frontend/src/ContactOverlay.vue

@@ -12,6 +12,8 @@ import MessagesView from './MessagesView.vue'
 const props = defineProps({
   state: { type: Object, required: true },
   token: { type: String, required: true },
+  // Visitor-side PoW quota re-grant for the composer's upload retries.
+  reauthorize: { type: Function, default: null },
 })
 const emit = defineEmits(['send', 'close'])
 
@@ -45,7 +47,13 @@ onUnmounted(() => removeEventListener('keydown', onKey))
         <a v-if="!admin && state.email" class="mailto" :href="mailto">{{ state.email }}</a>
         <button type="button" class="close" title="close" @click="emit('close')">✕</button>
       </header>
-      <ContactPanel v-if="!admin" :state="state" :token="token" @send="(p) => emit('send', p)" />
+      <ContactPanel
+        v-if="!admin"
+        :state="state"
+        :token="token"
+        :reauthorize="reauthorize"
+        @send="(p) => emit('send', p)"
+      />
       <MessagesView v-else :state="state" />
     </section>
   </div>

frontend/src/ContactPanel.vue

@@ -11,6 +11,9 @@ import Composer from './Composer.vue'
 const props = defineProps({
   state: { type: Object, required: true },
   token: { type: String, required: true },
+  // Re-grant the PoW quota (an upload hit its end): resolves once the
+  // fresh proof is accepted, so the upload can retry.
+  reauthorize: { type: Function, default: null },
 })
 const emit = defineEmits(['send'])
 
@@ -81,7 +84,13 @@ function onSend(md) {
     <input v-model="intro.name" type="text" placeholder="Your name" maxlength="100">
     <input v-model="intro.email" type="email" placeholder="Your email (optional)" maxlength="200">
   </div>
-  <Composer :token="token" :send-disabled="introInvalid" autofocus @send="onSend" />
+  <Composer
+    :token="token"
+    :send-disabled="introInvalid"
+    :reauthorize="reauthorize"
+    autofocus
+    @send="onSend"
+  />
 </template>
 
 <style scoped>

frontend/src/TrailLink.vue

@@ -24,6 +24,9 @@ const title = computed(() => {
   if (hasError.value) {
     parts.push(`${props.step.status}`)
   }
+  if (props.step.contact) {
+    parts.push('contact panel opened, proof of work solved')
+  }
   return parts.filter(Boolean).join(' — ')
 })
 </script>
@@ -39,6 +42,7 @@ const title = computed(() => {
     <small v-if="count > 1" class="muted">{{ formatCount(count) }}×</small>
     <img v-if="favicon" class="favicon" :src="favicon" alt="" />
     <span>{{ step.slug }}</span>
+    <span v-if="step.contact" class="contact-mark">✉️</span>
     <span v-for="(f, fi) in flags" :key="fi" class="flag" v-html="f"></span>
   </a>
 </template>
@@ -51,6 +55,12 @@ const title = computed(() => {
   vertical-align: -0.1em;
 }
 
+/* The contact-panel marker (PoW solved on this step). */
+.contact-mark {
+  margin-left: 0.25em;
+  font-size: 0.85em;
+}
+
 /* Same flag chip as the visitor cells (VisitorCell.vue). */
 .flag {
   display: inline-flex;

frontend/src/analytics/format.js

@@ -656,6 +656,8 @@ export function formatVisitRows(visits, clients, pageTree, now = Date.now(), sit
           if (item.read) step.readSeconds = item.read
           if (item.status) step.status = item.status
           if (item.lang) step.lang = item.lang
+          // Contact panel opened here and its PoW solved (✉️ marker).
+          if (item.contact) step.contact = true
         }
         return step
       })
@@ -667,6 +669,7 @@ export function formatVisitRows(visits, clients, pageTree, now = Date.now(), sit
         if (step.lang && step.lang !== prev.langs[prev.langs.length - 1]) prev.langs.push(step.lang)
         if (step.readSeconds) prev.readSeconds = (prev.readSeconds || 0) + step.readSeconds
         if (step.status) prev.status = step.status
+        if (step.contact) prev.contact = true
       } else {
         step.langs = step.lang ? [step.lang] : []
         trail.push(step)

frontend/src/contact-main.js

@@ -50,7 +50,8 @@ function readContactStrings() {
   }
   state.label = assets['pagerite:contact-label'] || 'Contact us'
   state.subject = assets['pagerite:contact-subject'] || state.label
-  state.email = assets['pagerite:contact-email'] || ''
+  // state.email is NOT reset here: it arrives over the socket after the
+  // PoW is solved and stays valid for the session.
 }
 
 // The panel is main content, not a sidebar: while open it holds paskia's
@@ -83,52 +84,72 @@ function markSeen() {
 }
 
 // PoW (easypow, docs/messages.md): the server issues a fresh single-use
-// challenge with every registration/resync and after every accepted
-// message; one solution burns one message. The solver module is served
-// by the backend from the easypow package, so both sides always match.
+// challenge on registration/resync and whenever the quota runs out. The
+// solver runs in the background and the solution is submitted as soon as
+// it is ready; a validated proof grants a quota of messages and uploads
+// and reveals the site's contact email (never carried in the page's
+// asset config). The solver module is served by the backend from the
+// easypow package, so both sides always match.
 const SOLVER_URL = '/_contact/easypow.js' // backend-served; kept in a variable so Rollup leaves the import dynamic
 let bridge = null
 let token = ''
 let solverPromise = null
 let powSolution = null // Promise<string> solving the current challenge
 let powAborter = null
-let unsent = null // last message frame, retried once if its solution was rejected
+let unsent = null // last message frame, retried once when its send races the quota
+let quotaWaiters = [] // uploads waiting for a re-granted quota
 
-// The solution for the currently outstanding challenge; rides out a
-// challenge replacement (reconnect) by continuing with the new solve.
-async function currentSolution() {
-  for (;;) {
-    const p = powSolution
-    if (!p) return ''
-    try {
-      return await p
-    } catch {
-      if (p === powSolution) return '' // failed without a replacement
+// The solved solution goes out immediately, ahead of any send.
+async function submitProof() {
+  const p = powSolution
+  if (!p) return
+  try {
+    const pow = await p
+    if (pow && p === powSolution) bridge.send({ token, pow })
+  } catch { /* aborted: a newer solve is in flight */ }
+}
+
+function sendMessage(md, name = '', email = '') {
+  unsent = { md, name, email, retried: false }
+  bridge.send({ token, msg: md, ...(name && { name, email }) })
+}
+
+function onPow(msg) {
+  if (typeof msg.quota === 'number') {
+    // Proof accepted, quota granted: queued uploads and the racing send
+    // (rejected for a stale/empty quota) continue.
+    const waiters = quotaWaiters
+    quotaWaiters = []
+    for (const resolve of waiters) resolve(true)
+    if (unsent && !unsent.retried) {
+      const { md, name, email } = unsent
+      unsent.retried = true
+      bridge.send({ token, msg: md, ...(name && { name, email }) })
     }
+    return
   }
-}
-
-async function sendMessage(md, name = '', email = '') {
-  unsent = { md, name, email }
-  const pow = await currentSolution()
-  if (pow) bridge.send({ token, msg: md, pow, ...(name && { name, email }) })
-}
-
-async function onPow(msg) {
   powAborter?.abort() // superseded challenge: stop the stale solve
   const ac = (powAborter = new AbortController())
   solverPromise ??= import(/* @vite-ignore */ SOLVER_URL)
-  const { solve } = await solverPromise
-  powSolution = solve(msg.challenge, ac.signal)
-  powSolution.catch(() => {}) // aborts are expected
-  // A rejected send (stale or already burned solution) is retried once
-  // the fresh challenge is solved; a second rejection drops it.
-  if (msg.required && unsent) {
-    const { md, name, email } = unsent
-    unsent = null
-    const pow = await currentSolution()
-    if (pow) bridge.send({ token, msg: md, pow, ...(name && { name, email }) })
-  }
+  solverPromise.then(({ solve }) => {
+    powSolution = solve(msg.challenge, ac.signal)
+    powSolution.catch(() => {}) // aborts are expected
+    submitProof()
+  })
+}
+
+function onEmail(msg) {
+  state.email = msg.email || ''
+}
+
+// An upload hit the end of the PoW quota: re-register (the server pushes
+// a fresh challenge, solved and proven in the background) and resolve
+// once the new quota lands.
+function requestQuota() {
+  return new Promise((resolve) => {
+    quotaWaiters.push(resolve)
+    bridge.send({ token }) // re-registration: a fresh challenge follows
+  })
 }
 
 // Unread markers: the has-unread class (a periodic nudge animation, see
@@ -147,6 +168,7 @@ export function refreshBadges() {
 
 function onThread(thread) {
   state.thread = thread
+  unsent = null // the send landed (a thread push acknowledges it)
   const lastAdmin = [...thread.messages].reverse().find((m) => m.admin)
   if (lastAdmin) localStorage.setItem(LASTADMIN_KEY, lastAdmin.t)
   const viewing = state.open && state.mode === 'visitor'
@@ -163,6 +185,7 @@ export function open(br, { admin = false } = {}) {
     app = createApp(ContactOverlay, {
       state,
       token,
+      reauthorize: requestQuota,
       onSend: ({ md, name, email }) => sendMessage(md, name, email),
       onClose: () => {
         state.open = false
@@ -177,7 +200,7 @@ export function open(br, { admin = false } = {}) {
     // state back, and pagerite.js re-registers on every socket reconnect.
     // Registered on first open in either mode — the visitor thread is
     // also the admin's own (the trigger buttons open it for them).
-    bridge.register(token, onThread, onPow)
+    bridge.register(token, onThread, onPow, onEmail)
   }
   state.mode = admin ? 'admin' : 'visitor'
   readContactStrings()

frontend/src/pagerite.js

@@ -680,6 +680,7 @@ import { reconnectPolicy, socketSlot, watchConnecting } from "./reconnect";
       }
       if (msg?.type === "thread") contactListener(msg);
       else if (msg?.type === "pow") contactPowListener?.(msg);
+      else if (msg?.type === "contact-email") contactEmailListener?.(msg);
       else if (msg?.type === "contact-error") console.warn("contact:", msg.detail);
     };
     ws.onclose = () => {
@@ -945,11 +946,13 @@ import { reconnectPolicy, socketSlot, watchConnecting } from "./reconnect";
   let contactToken = "";
   let contactListener = null;
   let contactPowListener = null;
+  let contactEmailListener = null;
   const contactBridge = {
-    register(token, onThread, onPow) {
+    register(token, onThread, onPow, onEmail) {
       contactToken = token;
       contactListener = onThread;
       contactPowListener = onPow;
+      contactEmailListener = onEmail;
       contactBridge.send({ token });
     },
     send(msg) {