Build TFI Live G2 deployable app

worker/nta-proxy.js

@@ -0,0 +1,161 @@
+const DEFAULT_TRIP_UPDATES_URL = 'https://api.nationaltransport.ie/gtfsr/v2/TripUpdates?format=json'
+const CACHE_SECONDS = 25
+
+export default {
+  async fetch(request, env, ctx) {
+    const url = new URL(request.url)
+
+    if (request.method === 'OPTIONS') {
+      return new Response(null, { headers: corsHeaders() })
+    }
+
+    try {
+      if (url.pathname === '/health') {
+        return json({ ok: true })
+      }
+
+      if (url.pathname === '/stops') {
+        return fetchStops(env)
+      }
+
+      if (url.pathname === '/departures') {
+        return fetchDepartures(url, env, ctx)
+      }
+
+      return json({ error: 'Not found' }, 404)
+    } catch (error) {
+      return json({ error: error instanceof Error ? error.message : 'Unknown error' }, 500)
+    }
+  },
+}
+
+async function fetchStops(env) {
+  if (!env.STOPS_URL) {
+    return json({ stops: [], error: 'STOPS_URL is not configured' }, 503)
+  }
+
+  const response = await fetch(env.STOPS_URL, {
+    headers: { Accept: 'application/json' },
+    cf: { cacheTtl: 3600, cacheEverything: true },
+  })
+  return withCors(response)
+}
+
+async function fetchDepartures(url, env, ctx) {
+  const stopId = url.searchParams.get('stopId') ?? ''
+  const stopCode = url.searchParams.get('stopCode') ?? ''
+  if (!stopId && !stopCode) {
+    return json({ departures: [], error: 'stopId or stopCode is required' }, 400)
+  }
+  if (!env.NTA_API_KEY) {
+    return json({ departures: [], error: 'NTA_API_KEY is not configured' }, 503)
+  }
+
+  const feed = await getTripUpdateFeed(env, ctx)
+  return json({
+    departures: parseTripUpdates(feed, stopId, stopCode),
+    updatedAt: Date.now(),
+  })
+}
+
+async function getTripUpdateFeed(env, ctx) {
+  const endpoint = env.NTA_TRIP_UPDATES_TARGET || DEFAULT_TRIP_UPDATES_URL
+  const cache = caches.default
+  const cacheKey = new Request(endpoint)
+  const cached = await cache.match(cacheKey)
+  if (cached) {
+    return cached.json()
+  }
+
+  const response = await fetch(endpoint, {
+    headers: {
+      Accept: 'application/json',
+      'Ocp-Apim-Subscription-Key': env.NTA_API_KEY,
+      'x-api-key': env.NTA_API_KEY,
+    },
+  })
+  if (!response.ok) {
+    throw new Error(`NTA returned ${response.status}`)
+  }
+
+  const payload = await response.json()
+  const cacheResponse = json(payload, 200, {
+    'Cache-Control': `public, max-age=${CACHE_SECONDS}`,
+  })
+  ctx.waitUntil(cache.put(cacheKey, cacheResponse.clone()))
+  return payload
+}
+
+function parseTripUpdates(payload, stopId, stopCode) {
+  const entities = Array.isArray(payload?.entity) ? payload.entity : []
+  const departures = []
+
+  for (const entity of entities) {
+    const tripUpdate = entity.tripUpdate || entity.trip_update || {}
+    const trip = tripUpdate.trip || {}
+    const route = trip.routeId || trip.route_id || 'Route'
+    const headsign = trip.tripHeadsign || trip.trip_headsign || 'Destination'
+    const updates = tripUpdate.stopTimeUpdate || tripUpdate.stop_time_update || []
+
+    for (const update of updates) {
+      const updateStopId = update.stopId || update.stop_id
+      if (updateStopId !== stopId && updateStopId !== stopCode) {
+        continue
+      }
+
+      const departure = update.departure || update.arrival || {}
+      const epoch = Number(departure.time)
+      if (!epoch) {
+        continue
+      }
+
+      const millis = epoch < 10_000_000_000 ? epoch * 1000 : epoch
+      if (millis < Date.now() - 120_000) {
+        continue
+      }
+      departures.push({
+        id: `${entity.id || route}-${millis}`,
+        route,
+        destination: headsign,
+        dueMinutes: Math.max(0, Math.round((millis - Date.now()) / 60_000)),
+        scheduledTime: new Date(millis).toLocaleTimeString('en-IE', {
+          hour: '2-digit',
+          minute: '2-digit',
+        }),
+        realtime: true,
+        status: update.scheduleRelationship || update.schedule_relationship || undefined,
+      })
+    }
+  }
+
+  return departures.sort((a, b) => a.dueMinutes - b.dueMinutes).slice(0, 40)
+}
+
+function json(body, status = 200, headers = {}) {
+  return new Response(JSON.stringify(body), {
+    status,
+    headers: {
+      'Content-Type': 'application/json; charset=utf-8',
+      ...corsHeaders(),
+      ...headers,
+    },
+  })
+}
+
+function withCors(response) {
+  const headers = new Headers(response.headers)
+  Object.entries(corsHeaders()).forEach(([key, value]) => headers.set(key, value))
+  return new Response(response.body, {
+    status: response.status,
+    statusText: response.statusText,
+    headers,
+  })
+}
+
+function corsHeaders() {
+  return {
+    'Access-Control-Allow-Origin': '*',
+    'Access-Control-Allow-Methods': 'GET, OPTIONS',
+    'Access-Control-Allow-Headers': 'Accept, Content-Type',
+  }
+}