Migrate NRE departures script to JavaScript (#56)

.gitignore

@@ -3,4 +3,7 @@ _site
 .jekyll-metadata
 vendor
 node_modules
+
+# wrangler
+.dev.vars
 .wrangler

README.md

@@ -17,7 +17,7 @@ The easiest way to run Jekyll is using Docker:
 
 ### Using Wrangler
 
-To test some of the dynamic aspects of the website (e.g. [Cloudflare Pages Functions](https://developers.cloudflare.com/pages/functions/)), it is necessary to use [Wrangler](https://developers.cloudflare.com/workers/wrangler/).
+To test some of the dynamic aspects of the website (e.g. [Cloudflare Pages Functions](https://developers.cloudflare.com/pages/functions/)), it is necessary to use [Wrangler](https://developers.cloudflare.com/workers/wrangler/). You may also need [a local `.dev.vars` file](https://developers.cloudflare.com/pages/functions/bindings/#interact-with-your-secrets-locally) containing secrets.
 
 To set up a local database:
 

_config.yml

@@ -14,6 +14,7 @@ include:
   - _redirects
 
 exclude:
+  - .wrangler
   - functions
   - functions-src
   - sql

functions/api/nreDepartures/v1/[[departures]].js

@@ -0,0 +1,121 @@
+import { USER_AGENT } from "../../../../functions-src/util";
+
+// TODO: allow these values to be customised through request params
+const NUM_SERVICES = 4;
+const TIME_OFFSET = 5;
+
+export async function onRequest(context) {  
+  if (context.request.method !== "GET") {
+    return new Response("Invalid request method", { status: 405 });
+  }
+
+  const crsLocation = context.params.departures[0];
+  if (!crsLocation.match(CRS_REGEX)) {
+    return new Response(`Invalid crsLocation: ${crsLocation}`, { status: 400 });
+  }
+  const crsFilter = context.params.departures[1];
+  if (crsFilter && !crsFilter.match(CRS_REGEX)) {
+    return new Response(`Invalid crsFilter: ${crsFilter}`, { status: 400 });
+  }
+
+  const params = { "timeOffset": TIME_OFFSET };
+  if (crsFilter) {
+    params["filterCrs"] = crsFilter;
+  }
+  const paramsString = new URLSearchParams(params).toString();
+  const response = await fetch(new Request(`https://api1.raildata.org.uk/1010-live-departure-board-dep/LDBWS/api/20220120/GetDepBoardWithDetails/${crsLocation}?${paramsString}`, {
+    headers: {
+      "user-agent": USER_AGENT,
+      "x-apikey": context.env.RAILDATA_LIVE_DEPARTURES_API_KEY,
+    },
+  }));
+  const nreDepartures = await response.json();
+
+  const data = {};
+  data["location"] = nreDepartures["locationName"];
+  if (crsFilter) {
+    data["filterLocation"] = nreDepartures["filterLocationName"];
+  }
+  const tsRe = nreDepartures["generatedAt"].match(/^(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2}):(\d{2}).\d*(\+\d{2}:\d{2})$/);
+  data["generatedAt"] = `${tsRe[1]}-${tsRe[2]}-${tsRe[3]}T${tsRe[4]}:${tsRe[5]}:${tsRe[6]}${tsRe[7]}`;
+  const services = []
+  if ("trainServices" in nreDepartures) {
+    nreDepartures["trainServices"].forEach((nreService) => {
+      const service = {};
+
+      // verify that the service still calls at the filter station (if applicable)
+      if (crsFilter) {
+        const allCallingPoints = []
+        nreService["subsequentCallingPoints"].forEach((callingPoints => {
+          console.log(callingPoints["callingPoint"]);
+          allCallingPoints.push(...callingPoints["callingPoint"]);
+        }))
+        const callingPoint = allCallingPoints.filter(cp => cp["crs"] === crsFilter)[0];
+        if (callingPoint["isCancelled"]) {
+          return;
+        }
+      }
+
+      // cancellations
+      service["cancelled"] = nreService["isCancelled"];
+      if ("cancelReason" in nreService) {
+        if (nreService["cancelReason"].includes(CANCEL_REASON_PREFIX)) {
+          service["cancelReason"] = `Due to ${nreService["cancelReason"].substring(CANCEL_REASON_PREFIX.length)}`;
+        } else {
+          service["cancelReason"] = nreService["cancelReason"];
+        }
+      }
+
+      // timings
+      service["etd"] = nreService["etd"];
+      service["std"] = nreService["std"];
+      service["timeForSort"] = service["std"];
+      if (service["etd"].includes(":")) {
+        service["timeForSort"] = service["etd"];
+      }
+
+      // other bits
+      service["destination"] = nreService["destination"][0]["locationName"]; // TODO: handle multiple destinations
+      service["length"] = nreService["length"].toString();
+      if (service["length"] === "0") {
+        service["length"] = "?";
+      }
+      service["operator"] = nreService["operator"];
+      service["operatorCode"] = nreService["operatorCode"];
+      service["platform"] = "?";
+      if ("platform" in nreService) {
+        service["platform"] = nreService["platform"];
+      }
+
+      services.push(service);
+    });
+  }
+
+  let servicesContainsEarlyMorning = false;
+  let servicesContainsLateNight = false;
+  services.forEach((service) => {
+    const serviceHour = service["timeForSort"].split(":")[0];
+    if (serviceHour in SERVICE_HOURS_EARLY_MORNING) {
+      servicesContainsEarlyMorning = true;
+    } else if (serviceHour in SERVICE_HOURS_LATE_NIGHT) {
+      servicesContainsLateNight = true;
+    }
+  });
+  if (servicesContainsLateNight && servicesContainsEarlyMorning) {
+    services.forEach((service, index) => {
+      const serviceHour = service["timeForSort"].split(":")[0];
+      const serviceMinute = service["timeForSort"].split(":")[1];
+      if (serviceHour in SERVICE_HOURS_EARLY_MORNING) {
+        this[index]["timeForSort"] = `${parseInt(serviceHour)+24}:${serviceMinute}`;
+      }
+    });
+  }
+
+  data["services"] = services.sort().splice(0, NUM_SERVICES);
+  return Response.json(data);
+}
+
+const CANCEL_REASON_PREFIX = "This train has been cancelled because of "
+const CRS_REGEX = /^[A-Z]{3}$/;
+const SERVICE_HOURS_EARLY_MORNING = ["00", "01", "02", "03"];
+const SERVICE_HOURS_LATE_NIGHT = ["20", "21", "22", "23"];