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Replace kiosk SignalR with polling — Azure App Service blocks anonymous hub handshakes

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SignalR WebSocket and SSE both receive immediate 'Handshake was canceled' from the
server-side hub context. The 15-second delay between negotiate and SSE connect
reveals the handshake timer has expired before the transport opens — caused by Azure
App Service's ingress proxy resetting anonymous long-lived connections.

Replacement: /Kiosk/PollSession (anonymous GET, no-cache) queried every 3 seconds.
Returns the most recent Active InPerson session created in the last 60 seconds.
The kiosk navigates when hasSession=true. Status dot: gray->green on first success,
yellow on network error, blue when navigating. Removed signalr.min.js from kiosk layout.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
This commit is contained in:
Scott Pouliot
2026-05-13 20:37:28 -04:00
parent 2acf54e1a9
commit 377bb1ce38
3 changed files with 50 additions and 42 deletions
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src/PowderCoating.Web/wwwroot/js/kiosk-welcome.js
+19 -40
View File
@@ -1,10 +1,12 @@
"use strict";
// Polls /Kiosk/PollSession every 3 seconds and navigates when staff triggers an intake.
// SignalR was replaced with polling because Azure App Service's ingress proxy cancels
// anonymous WebSocket and SSE handshakes before the SignalR protocol exchange completes.
(function () {
const el = document.getElementById("kiosk-welcome-root");
if (!el) return;
const companyId = el.dataset.companyId;
const dot = document.getElementById("kiosk-conn-dot");
const label = document.getElementById("kiosk-conn-label");
@@ -13,51 +15,28 @@
if (label) label.textContent = text;
}
if (!companyId) {
setStatus("#ef4444", "Not configured (no company ID)");
console.error("KioskHub: data-company-id is empty — kiosk activation may be invalid.");
return;
}
setStatus("#94a3b8", "Connecting…");
// Skip WebSocket — anonymous WebSocket upgrades are blocked by the Azure App Service
// ingress proxy before the SignalR handshake completes. Server-Sent Events and
// long polling work fine for the low-frequency "StartIntake" push this hub needs.
const connection = new signalR.HubConnectionBuilder()
.withUrl(`/hubs/kiosk?companyId=${companyId}`, {
transport: signalR.HttpTransportType.ServerSentEvents | signalR.HttpTransportType.LongPolling
})
.withAutomaticReconnect([2000, 5000, 10000, 30000])
.configureLogging(signalR.LogLevel.Information)
.build();
let active = true;
connection.on("StartIntake", function (sessionToken) {
setStatus("#2563eb", "Starting…");
window.location.href = `/Kiosk/Intake/${sessionToken}/Contact`;
});
async function startConnection() {
async function poll() {
if (!active) return;
try {
await connection.start();
const res = await fetch("/Kiosk/PollSession", { cache: "no-store" });
if (!res.ok) throw new Error("HTTP " + res.status);
const data = await res.json();
setStatus("#16a34a", "Ready");
console.info("KioskHub connected, group kiosk-" + companyId);
} catch (err) {
setStatus("#ef4444", "Connection failed — retrying…");
console.warn("KioskHub connect failed, retrying in 10s…", err);
setTimeout(startConnection, 10000);
if (data.hasSession && data.sessionToken) {
active = false;
setStatus("#2563eb", "Starting…");
window.location.href = `/Kiosk/Intake/${data.sessionToken}/Contact`;
return;
}
} catch {
setStatus("#f59e0b", "Connection issue — retrying…");
}
if (active) setTimeout(poll, 3000);
}
startConnection();
connection.onreconnecting(() => setStatus("#f59e0b", "Reconnecting…"));
connection.onreconnected(() => {
setStatus("#16a34a", "Ready");
console.info("KioskHub reconnected");
});
connection.onclose(() => {
setStatus("#ef4444", "Disconnected — retrying…");
setTimeout(startConnection, 10000);
});
setTimeout(poll, 500); // first poll quickly; subsequent every 3s
})();