read FeedMessages instead of FeedEntitys 💥

see also #1

index.js

@@ -1,8 +1,11 @@
 'use strict'
 
+const {FeedHeader} = require('gtfs-rt-bindings')
 const {Writable} = require('stream')
 const createEntitiesStore = require('./lib/entities-store')
 
+const {DIFFERENTIAL} = FeedHeader.Incrementality
+
 const tripSignature = (u) => {
 	if (u.trip.trip_id) return u.trip.trip_id
 	if (u.trip.route_id && u.vehicle.id) {
@@ -32,24 +35,37 @@ const gtfsRtAsDump = (opt = {}) => {
 
 	const entitiesStore = createEntitiesStore(ttl, timestamp)
 
-	const write = (entity) => {
-		// If the entity is not being deleted, exactly one of 'trip_update', 'vehicle' and 'alert' fields should be populated.
-		// https://developers.google.com/transit/gtfs-realtime/reference#message-feedentity
-		let sig = null
-		if (entity.trip_update) {
-			sig = tripUpdateSignature(entity.trip_update)
-		} else if (entity.vehicle) {
-			sig = vehiclePositionSignature(entity.vehicle)
+	const write = (msg) => {
+		if (msg.header.gtfs_realtime_version !== '2.0') {
+			const err = new Error('FeedMessage GTFS-RT 2.0')
+			err.feedMessage = msg
+			throw err
+		}
+		if (msg.header.incrementality !== DIFFERENTIAL) {
+			const err = new Error('FeedMessage must be DIFFERENTIAL')
+			err.feedMessage = msg
+			throw err
 		}
-		// todo: alert
 
-		if (sig !== null) {
-			entitiesStore.put(sig, entity)
-			return;
+		for (const entity of msg.entity) {
+			// If the entity is not being deleted, exactly one of 'trip_update', 'vehicle' and 'alert' fields should be populated.
+			// https://developers.google.com/transit/gtfs-realtime/reference#message-feedentity
+			let sig = null
+			if (entity.trip_update) {
+				sig = tripUpdateSignature(entity.trip_update)
+			} else if (entity.vehicle) {
+				sig = vehiclePositionSignature(entity.vehicle)
+			}
+			// todo: alert, see #1
+
+			if (sig !== null) {
+				entitiesStore.put(sig, entity)
+				continue
+			}
+			const err = new Error('invalid/unsupported kind of FeedEntity')
+			err.feedEntity = entity
+			throw err
 		}
-		const err = new Error('invalid/unsupported kind of FeedEntity')
-		err.feedEntity = entity
-		throw err
 	}
 
 	let feedMessage = null
@@ -59,12 +75,12 @@ const gtfsRtAsDump = (opt = {}) => {
 
 	const out = new Writable({
 		objectMode: true,
-		write: (entity, _, cb) => {
-			write(entity)
+		write: (feedMsg, _, cb) => {
+			write(feedMsg)
 			cb(null)
 		},
 		writev: (chunks, cb) => {
-			for (const {chunk: entity} of chunks) write(entity)
+			for (const {chunk: feedMsg} of chunks) write(feedMsg)
 			cb(null)
 		},
 		final: (cb) => {

readme.md

@@ -28,15 +28,15 @@ const toFull = toFullDataset({
 })
 toFull.on('error')
 
-differentialFeedEntities.pipe(toFull)
+differentialFeedMessages.pipe(toFull)
 setInterval(() => {
 	console.log(toFull.asFeedMessage())
 }, 5000)
 ```
 
-`toFull` will be a [writable stream](https://nodejs.org/api/stream.html#stream_class_stream_writable) in [object mode](https://nodejs.org/api/stream.html#stream_object_mode) that expects JS objects in the [`FeedEntity`](https://developers.google.com/transit/gtfs-realtime/reference/#message-feedentity) structure/format.
+`toFull` will be a [writable stream](https://nodejs.org/api/stream.html#stream_class_stream_writable) in [object mode](https://nodejs.org/api/stream.html#stream_object_mode) that expects JS objects in the [`FeedMessage`](https://developers.google.com/transit/gtfs-realtime/reference/#message-feedmessage) structure/format.
 
-`toFull.asFeedMessage()` returns a [protocol-buffer-encoded](https://developers.google.com/protocol-buffers/docs/overview) [`FeedMessage`](https://developers.google.com/transit/gtfs-realtime/reference/#message-feedmessage) with all relevant `FeedEntity` that have been written into `toFull` so far.
+`toFull.asFeedMessage()` returns a [protocol-buffer-encoded](https://developers.google.com/protocol-buffers/docs/overview) [`FeedMessage`](https://developers.google.com/transit/gtfs-realtime/reference/#message-feedmessage) with all relevant `FeedEntity`s that have been written into `toFull` so far.
 
 
 ## Contributing

test/data.ndjson

@@ -1,4 +1,3 @@
-{"id":"1","vehicle":{"trip":{"trip_id":"1|64512|1|86|12032020","route_id":"n18"},"vehicle":{"id":null,"label":"U Mohrenstr."},"position":{"latitude":52.5,"longitude":13.3},"stop_id":"900000005205","current_status":2}}
-{"id":"2","vehicle":{"trip":{"trip_id":"1|64466|1|86|12032020","route_id":"n6"},"vehicle":{"id":null,"label":"U Alt-Mariendorf"},"position":{"latitude":52.1,"longitude":13.1},"stop_id":"900000012106","current_status":1}}
-{"id":"3","trip_update":{"trip":{"trip_id":"1|25445|2|86|12032020","route_id":"n3"},"vehicle":{"id":"40813","label":"U Wittenbergplatz"},"stop_time_update":[{"stop_id":"900000050301","arrival":{"time":null,"delay":null},"departure":{"time":1584060600,"delay":0},"schedule_relationship":0},{"stop_id":"900000023354","arrival":{"time":1584062400,"delay":-60},"departure":{"time":1584062400,"delay":-60},"schedule_relationship":0},{"stop_id":"900000023203","arrival":{"time":1584062460,"delay":-60},"departure":{"time":1584062460,"delay":-60},"schedule_relationship":0},{"stop_id":"900000023204","arrival":{"time":1584062580,"delay":-60},"departure":{"time":1584062580,"delay":-60},"schedule_relationship":0},{"stop_id":"900000056101","arrival":{"time":1584062640,"delay":-60},"departure":{"time":null,"delay":null},"schedule_relationship":0}]}}
-{"id":"4","vehicle":{"trip":{"trip_id":"1|64512|1|86|12032020","route_id":"n18"},"vehicle":{"id":null,"label":"U Mohrenstr."},"position":{"latitude":52.6,"longitude":13.4},"stop_id":"900000005205","current_status":2}}
+{"header":{"gtfs_realtime_version":"2.0","incrementality":1,"timestamp":1},"entity":[{"id":"1","vehicle":{"trip":{"trip_id":"1|64512|1|86|12032020","route_id":"n18"},"vehicle":{"id":null,"label":"U Mohrenstr."},"position":{"latitude":52.5,"longitude":13.3},"stop_id":"900000005205","current_status":2}},{"id":"2","trip_update":{"trip":{"trip_id":"1|25445|2|86|12032020","route_id":"n3"},"vehicle":{"id":"40813","label":"U Wittenbergplatz"},"stop_time_update":[{"stop_id":"900000050301","arrival":{"time":null,"delay":null},"departure":{"time":1584060600,"delay":0},"schedule_relationship":0},{"stop_id":"900000023354","arrival":{"time":1584062400,"delay":-60},"departure":{"time":1584062400,"delay":-60},"schedule_relationship":0},{"stop_id":"900000023203","arrival":{"time":1584062460,"delay":-60},"departure":{"time":1584062460,"delay":-60},"schedule_relationship":0},{"stop_id":"900000023204","arrival":{"time":1584062580,"delay":-60},"departure":{"time":1584062580,"delay":-60},"schedule_relationship":0},{"stop_id":"900000056101","arrival":{"time":1584062640,"delay":-60},"departure":{"time":null,"delay":null},"schedule_relationship":0}]}}]}
+{"header":{"gtfs_realtime_version":"2.0","incrementality":1,"timestamp":2},"entity":[{"id":"3","vehicle":{"trip":{"trip_id":"1|64466|1|86|12032020","route_id":"n6"},"vehicle":{"id":null,"label":"U Alt-Mariendorf"},"position":{"latitude":52.1,"longitude":13.1},"stop_id":"900000012106","current_status":1}}]}
+{"header":{"gtfs_realtime_version":"2.0","incrementality":1,"timestamp":3},"entity":[{"id":"4","vehicle":{"trip":{"trip_id":"1|64512|1|86|12032020","route_id":"n18"},"vehicle":{"id":null,"label":"U Mohrenstr."},"position":{"latitude":52.6,"longitude":13.4},"stop_id":"900000005205","current_status":2}}]}

test/index.js

@@ -95,17 +95,17 @@ pump(
 
 		bufEqual(full.asFeedMessage(), Buffer.from(
 			`\
-0a090a03322e301001180112520a0132224d0a1b0a15317c36343436367c317c38367\
-c31323033323032302a026e36421212105520416c742d4d617269656e646f7266120a\
-0d66665042159a9951413a0c39303030303030313231303620011289020a01331a830\
-20a1b0a15317c32353434357c327c38367c31323033323032302a026e331a1a0a0534\
-303831331211552057697474656e62657267706c61747a121c220c393030303030303\
-53033303112001a08080010b8b1abf3052800122c220c393030303030303233333534\
-120c08c4ffffff0f10c0bfabf3051a0c08c4ffffff0f10c0bfabf3052800122c220c3\
-93030303030303233323033120c08c4ffffff0f10fcbfabf3051a0c08c4ffffff0f10\
-fcbfabf3052800122c220c393030303030303233323034120c08c4ffffff0f10f4c0a\
-bf3051a0c08c4ffffff0f10f4c0abf30528001220220c393030303030303536313031\
-120c08c4ffffff0f10b0c1abf3051a002800124f0a0134224a0a1c0a15317c3634353\
+0a090a03322e30100118011289020a01321a83020a1b0a15317c32353434357c327c3\
+8367c31323033323032302a026e331a1a0a0534303831331211552057697474656e62\
+657267706c61747a121c220c39303030303030353033303112001a08080010b8b1abf\
+3052800122c220c393030303030303233333534120c08c4ffffff0f10c0bfabf3051a\
+0c08c4ffffff0f10c0bfabf3052800122c220c393030303030303233323033120c08c\
+4ffffff0f10fcbfabf3051a0c08c4ffffff0f10fcbfabf3052800122c220c39303030\
+3030303233323034120c08c4ffffff0f10f4c0abf3051a0c08c4ffffff0f10f4c0abf\
+30528001220220c393030303030303536313031120c08c4ffffff0f10b0c1abf3051a\
+00280012520a0133224d0a1b0a15317c36343436367c317c38367c313230333230323\
+02a026e36421212105520416c742d4d617269656e646f7266120a0d66665042159a99\
+51413a0c3930303030303031323130362001124f0a0134224a0a1c0a15317c3634353\
 1327c317c38367c31323033323032302a036e3138420e120c55204d6f6872656e7374\
 722e120a0d6666524215666656413a0c3930303030303030353230352002`,
 			'hex'