.gitignore

@@ -1,4 +1,3 @@
 node_modules
 dist
 .cache
-cache

script/show-courses

@@ -1,89 +0,0 @@
-#!/usr/bin/env node
-
-const courses = require('../src/tam/courses');
-const network = require('../src/tam/network.json');
-const {displayTime} = require('../src/util');
-const process = require('process');
-const path = require('path');
-
-/**
- * Convert stop ID to human-readable stop name.
- *
- * If the stop ID is not known, the ID will be kept as-is.
- */
-const getStopName = stopId =>
-{
-    if (stopId in network.stops)
-    {
-        return network.stops[stopId].properties.name;
-    }
-
-    return stopId;
-};
-
-/** Create a string representing a course for printing. */
-const courseToString = course =>
-{
-    let result = `Course #${course.id}
-Line ${course.line} - Direction ${course.direction} - Bound for ${getStopName(course.finalStopId)}
-
-Next stops:
-`;
-
-    for (let [stopId, time] of course.passings)
-    {
-        result += `${displayTime(new Date(time))} - ${getStopName(stopId)}\n`;
-    }
-
-    return result;
-};
-
-/** Show user help. */
-const doHelp = () =>
-{
-    const name = "./" + path.relative(process.cwd(), process.argv[1]);
-    process.stdout.write(`Usage: ${name} TYPE [COURSE]
-Show TaM courses data.
-
-Set TYPE to 'realtime' to fetch real-time data (limited time scope) or to
-'theoretical' to fetch planned courses for the day.
-
-Set COURSE to a valid course ID to limit the output to a given course.
-`);
-};
-
-/** Print realtime information for a course or all courses. */
-const doPrint = async (kind, courseId) =>
-{
-    const results = await courses.fetch(kind);
-
-    if (courseId)
-    {
-        if (courseId in results)
-        {
-            console.log(courseToString(results[courseId]));
-        }
-        else
-        {
-            console.log('Unknown course');
-        }
-    }
-    else
-    {
-        for (let course of Object.values(results))
-        {
-            console.log(courseToString(course));
-            console.log("======\n");
-        }
-    }
-};
-
-const argv = process.argv.slice(2);
-
-if (argv.length === 0)
-{
-    doHelp();
-    process.exit(1);
-}
-
-doPrint(argv[0], argv[1]);

src/back/index.js

@@ -1,12 +1,12 @@
 const express = require("express");
-const courses = require("../tam/courses");
+const realtime = require("../tam/realtime");
 
 const app = express();
 const port = 4321;
 
 app.get("/courses", async(req, res) => {
     res.header("Access-Control-Allow-Origin", "*");
-    return res.json(await courses.fetch("realtime"));
+    return res.json(await realtime.fetch());
 });
 
 app.listen(port, () => console.info(`App listening on port ${port}`));

src/front/index.js

@@ -84,26 +84,6 @@ setInterval(() => {
 }, 1000);
 
 // Create the network and courses map
-map.create(/* map = */ "map", coursesSimulation, courses => {
+map.create(/* map = */ "map", coursesSimulation, course => {
-    if (courses.length === 0) {
+    courseId = course;
-        // If no course were clicked, show nothing
-        courseId = null;
-    } else {
-        // If several courses were clicked, show the one departing the soonest,
-        // or the first moving one
-        courses.sort((id1, id2) => {
-            const course1 = coursesSimulation.courses[id1];
-            const course2 = coursesSimulation.courses[id2];
-
-            if (course1.state === "moving") {
-                return -1;
-            } else if (course2.state === "moving") {
-                return 1;
-            } else {
-                return course1.departureTime - course2.departureTime;
-            }
-        });
-
-        courseId = courses[0];
-    }
 });

src/front/map/index.js

@@ -120,7 +120,6 @@ const create = (target, coursesSimulation, onClick) => {
     map.on("singleclick", ev => {
         const mousePixel = map.getPixelFromCoordinate(ev.coordinate);
         const maxDistance = sizes.courseSize + sizes.courseInnerBorder;
-        const clicked = [];
 
         for (const course of Object.values(coursesSimulation.courses)) {
             const coursePixel = map.getPixelFromCoordinate(course.position);
@@ -129,11 +128,9 @@ const create = (target, coursesSimulation, onClick) => {
             const distance = dx * dx + dy * dy;
 
             if (distance <= maxDistance * maxDistance) {
-                clicked.push(course.id);
+                onClick(course.id);
             }
         }
-
-        onClick(clicked);
     });
 
     return map;

src/tam/courses.js

@@ -1,123 +0,0 @@
-const path = require("path");
-const fs = require("fs").promises;
-const tam = require("./sources/tam");
-const network = require("./network.json");
-
-/**
- * Information about the course of a vehicle.
- * @typedef {Object} Course
- * @property {string} id Unique identifier for this course.
- * @property {string} line Transport line number.
- * @property {string} finalStop Final stop to which the course is headed.
- * @property {Array.<Array>} passings Next stations to which
- * the vehicle will stop, associated to the passing timestamp, ordered by
- * increasing passing timestamp.
- */
-
-/** Parse time information relative to the current date. */
-const parseTime = (time, reference) =>
-{
-    const [hours, minutes, seconds] = time.split(':').map(x => parseInt(x, 10));
-    const result = new Date(reference);
-
-    result.setHours(hours);
-    result.setMinutes(minutes);
-    result.setSeconds(seconds);
-
-    if (reference > result.getTime()) {
-        // Timestamps in the past refer to the next day
-        result.setDate(result.getDate() + 1);
-    }
-
-    return result;
-};
-
-/**
- * Fetch information about courses in the TaM network.
- *
- * @param {string} kind Pass 'realtime' to get real-time information,
- * or 'theoretical' to get planned courses for the day.
- * @returns {Object.<string,Course>} Mapping from active course IDs to
- * information about each course.
- */
-const fetch = async (kind = 'realtime') => {
-    const courses = {};
-    const passings = (
-        kind === 'realtime'
-        ? tam.fetchRealtime()
-        : tam.fetchTheoretical()
-    );
-    const timing = (await passings.next()).value;
-
-    // Aggregate passings relative to the same course
-    for await (const passing of passings) {
-        const {
-            course: id,
-            routeShortName: line,
-            stopId,
-            destArCode: finalStopId,
-        } = passing;
-
-        const direction = (
-            'direction' in passing
-            ? passing.direction
-            : passing.directionId
-        );
-
-        const departureTime = (
-            'delaySec' in passing
-            ? timing.lastUpdate + parseInt(passing.delaySec, 10) * 1000
-            : parseTime(passing.departureTime, timing.lastUpdate)
-        );
-
-        if (!(id in courses)) {
-            courses[id] = {
-                id,
-                line,
-                direction,
-                finalStopId,
-                passings: {},
-            };
-        }
-
-        if (!(stopId in courses[id].passings) ||
-            courses[id].passings[stopId] < departureTime) {
-            // Only consider passings with an increased passing time
-            // or for stops not seen before
-            courses[id].passings[stopId] = departureTime;
-        }
-    }
-
-    // Filter courses to only keep those referring to known data
-    for (const courseId of Object.keys(courses)) {
-        const course = courses[courseId];
-
-        if (!(course.line in network.lines)) {
-            delete courses[courseId];
-        } else {
-            for (const stopId of Object.keys(course.passings)) {
-                if (!(stopId in network.stops)) {
-                    delete courses[courseId];
-                    break;
-                }
-            }
-        }
-    }
-
-    // Order next passings by increasing passing time
-    for (const course of Object.values(courses)) {
-        course.passings = (
-            Object.entries(course.passings).sort(
-                ([, time1], [, time2]) => time1 - time2
-            )
-        );
-
-        if (course.finalStopId === undefined) {
-            course.finalStopId = course.passings[course.passings.length - 1][0];
-        }
-    }
-
-    return courses;
-};
-
-exports.fetch = fetch;

src/tam/network.js

@@ -4,7 +4,8 @@
  * Extract static information about the TaM network from OpenStreetMap (OSM):
  * tram and bus lines, stops and routes.
  *
- * Functions in this file also report inconsistencies in OSM data.
+ * Functions in this file also report and offer to correct errors that may
+ * occur in OSM data.
  *
  * Because of the static nature of this data, it is cached in a
  * version-controlled file `network.json` next to this file. To update it, use
@@ -23,6 +24,7 @@ const osm = require("./sources/osm");
  * segments and lines.
  */
 const fetch = async lineRefs => {
+
     // Retrieve routes, ways and stops from OpenStreetMap
     const rawData = await osm.runQuery(`[out:json];
 

src/tam/realtime.js

@@ -0,0 +1,100 @@
+const tam = require("./sources/tam");
+const network = require("./network.json");
+
+// Time at which the course data needs to be updated next
+let nextUpdate = null;
+
+// Current information about courses
+let currentCourses = null;
+
+/**
+ * Information about the course of a vehicle.
+ * @typedef {Object} Course
+ * @property {string} id Unique identifier for this course.
+ * @property {string} line Transport line number.
+ * @property {string} finalStop Final stop to which the course is headed.
+ * @property {Array.<Array>} nextPassings Next stations to which
+ * the vehicle will stop, associated to the passing timestamp, ordered by
+ * increasing passing timestamp.
+ */
+
+/**
+ * Fetch real-time information about active courses in the TaM network.
+ *
+ * New data will only be fetched from the TaM server once every minute,
+ * otherwise pulling from the in-memory cache.
+ * @returns {Object.<string,Course>} Mapping from active course IDs to
+ * information about each course.
+ */
+const fetch = async() => {
+    if (nextUpdate === null || Date.now() >= nextUpdate) {
+        const courses = {};
+        const passings = tam.fetchRealtime();
+        const timing = (await passings.next()).value;
+
+        nextUpdate = timing.nextUpdate;
+
+        // Aggregate passings relative to the same course
+        for await (const passing of passings) {
+            const {
+                course: id,
+                routeShortName: line,
+                stopId,
+                destArCode: finalStop
+            } = passing;
+
+            const arrivalTime = (
+                timing.lastUpdate +
+                parseInt(passing.delaySec, 10) * 1000
+            );
+
+            if (!(id in courses)) {
+                courses[id] = {
+                    id,
+                    line,
+                    finalStop,
+
+                    // Initially accumulate passings in an object
+                    // to prevent duplicates
+                    nextPassings: { [stopId]: arrivalTime }
+                };
+            } else if (!(stopId in courses[id].nextPassings) ||
+                        courses[id].nextPassings[stopId] < arrivalTime) {
+                // Only consider passings with an increased passing time
+                // or for stops not seen before
+                courses[id].nextPassings[stopId] = arrivalTime;
+            }
+        }
+
+        // Filter courses to only keep those referring to known data
+        for (const courseId of Object.keys(courses)) {
+            const course = courses[courseId];
+
+            if (!(course.line in network.lines)) {
+                delete courses[courseId];
+            } else {
+                for (const stopId of Object.keys(course.nextPassings)) {
+                    if (!(stopId in network.stops)) {
+                        delete courses[courseId];
+                        break;
+                    }
+                }
+            }
+        }
+
+        // Order next passings by increasing passing time
+        for (const courseId of Object.keys(courses)) {
+            courses[courseId].nextPassings = (
+                Object.entries(courses[courseId].nextPassings).sort(
+                    ([, time1], [, time2]) => time1 - time2
+                )
+            );
+        }
+
+        currentCourses = courses;
+    }
+
+    return currentCourses;
+};
+
+exports.fetch = fetch;

src/tam/simulation.js

@@ -59,9 +59,8 @@ class Course {
 
     updateData(data) {
         this.line = data.line;
-        this.direction = data.direction;
+        this.finalStop = data.finalStop;
-        this.finalStop = data.finalStopId;
+        this.nextPassings = data.nextPassings;
-        this.nextPassings = data.passings;
 
         const now = Date.now();
 

src/tam/sources/tam.js

@@ -1,7 +1,5 @@
 const csv = require("csv-parse");
 const axios = require("axios");
-const path = require("path");
-const fs = require("fs").promises;
 const { snakeToCamelCase, unzipFile } = require("../../util");
 
 /**
@@ -19,65 +17,15 @@ const { snakeToCamelCase, unzipFile } = require("../../util");
  * @property {string} directionId Route identifier inside the line.
  * @property {string} departureTime Theoretical time at which the
  * vehicle will depart the stop (HH:MM:SS format).
- * @property {string} isTheorical (sic) True if this is only the planned
+ * @property {string} isTheorical (sic) Whether the arrival time is only
- * passing time, false if this is real-time information.
+ * a theoretical information.
  * @property {string} delaySec Number of seconds before the vehicle arrives
- * at the station (only if isTheorical is false).
+ * at the station.
  * @property {string} destArCode Unique network identifier for the final
- * stop of this trip (only if isTheorical is false).
+ * stop of this trip.
  */
 
-/**
- * Wrap a passing-fetching function to use a filesystem-based cache.
- *
- * @param {function} func Fetching function to wrap.
- * @param {string} cachePath Path to the file to use as a cache (will be
- * overwritten, may be non-existing).
- * @return {function} Wrapped function.
- */
-const makeCached = (func, cachePath) => {
-    return async function *() {
-        try {
-            const cacheRaw = await fs.readFile(cachePath, {encoding: "utf8"});
-            const cache = JSON.parse(cacheRaw);
-
-            if (Date.now() < cache.timing.nextUpdate) {
-                yield cache.timing;
-
-                for (const passing of cache.passings) {
-                    yield passing;
-                }
-
-                return;
-            }
-        } catch (err) {
-            // Ignore missing cache file
-            if (err.code !== 'ENOENT') {
-                throw err;
-            }
-        }
-
-        const passings = func();
-        const newCache = {
-            timing: (await passings.next()).value,
-            passings: [],
-        };
-
-        yield newCache.timing;
-
-        for await (const passing of passings) {
-            newCache.passings.push(passing);
-            yield passing;
-        }
-
-        fs.writeFile(cachePath, JSON.stringify(newCache));
-    };
-};
-
-const cacheDir = path.join(__dirname, "..", "..", "..", "cache");
-
 const realtimeEndpoint = "http://data.montpellier3m.fr/node/10732/download";
-const realtimeCachePath = path.join(cacheDir, "realtime.json");
 
 /**
  * Fetch real time passings of vehicles across the network.
@@ -106,10 +54,9 @@ const fetchRealtime = async function *() {
     }
 };
 
-exports.fetchRealtime = makeCached(fetchRealtime, realtimeCachePath);
+exports.fetchRealtime = fetchRealtime;
 
 const theoreticalEndpoint = "http://data.montpellier3m.fr/node/10731/download";
-const theoreticalCachePath = path.join(cacheDir, "theoretical.json");
 
 /**
  * Fetch theoretical passings for the current day across the network.
@@ -154,4 +101,4 @@ const fetchTheoretical = async function *() {
     }
 };
 
-exports.fetchTheoretical = makeCached(fetchTheoretical, theoreticalCachePath);
+exports.fetchTheoretical = fetchTheoretical;

src/util.js

@@ -63,11 +63,3 @@ const unzipFile = (data, fileName) => new Promise((res, rej) => {
 });
 
 exports.unzipFile = unzipFile;
-
-const displayTime = date => [
-    date.getHours(),
-    date.getMinutes(),
-    date.getSeconds()
-].map(number => number.toString().padStart(2, "0")).join(":");
-
-exports.displayTime = displayTime;