.gitignore

@@ -1 +1 @@
-node_modules
+omnibus

config.go

@@ -0,0 +1,32 @@
+package main
+
+
+// network port to listen on
+var serverPort = 8080
+
+
+// which cardinal direction (n,e,s,w) is the display facing? (not the person looking at it)
+var screenDir = "w"
+
+
+// which routes do you want to show on the screen? add as many or as few as you'd like.
+var routes = []Route{
+	Route{
+		Id: 15280,
+		Name: "46 WB",
+		Dir: "n",
+	},
+	Route{
+		Id: 15412,
+		Name: "46 EB",
+		Dir: "s",
+	},
+	Route{
+		Id: 51430,
+		Name: "Blue line",
+	},
+	Route{
+		Id: 51415,
+		Name: "Blue line",
+	},
+}

config.js

@@ -1,33 +0,0 @@
-// ignore this line
-module.exports = {}
-
-module.exports.port = 8080
-
-// which cardinal direction (n,e,s,w) is the display facing? (not the person looking at it)
-module.exports.screenDir = 'w'
-
-// which routes do you want to show on the screen? add as many or as few as you'd like.
-module.exports.routes = [
-	// id     stop ID shown on sign or google maps
-	// name   friendly readable name (optional)
-	// dir    cardinal direction the bus or train is going (optional, will use value from API)
-	// ~~route  filter by route name (optional)~~ not yet implemented
-	{
-		id: '15280',
-		name: '46 WB',
-		dir: 'n',
-	},
-	{
-		id: '15412',
-		name: '46 EB',
-		dir: 's',
-	},
-	{
-		id: '51430',
-		name: 'Blue line',
-	},
-	{
-		id: '51415',
-		name: 'Blue line',
-	},
-]

go.mod

@@ -0,0 +1,3 @@
+module git.cyberia.club/reese/omnibus
+
+go 1.19

main.go

@@ -0,0 +1,142 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+	"math"
+	"net/http"
+	"time"
+)
+
+
+type Route struct {
+	Id      uint   // stop ID shown on sign or google maps
+	Name    string // friendly readable name (optional)
+	Dir     string // cardinal direction the bus or train is going (optional, will use value from API)
+	// Route   string // filter by route name (optional) /!\ not yet implemented /!\
+}
+
+type Eta struct {
+	Name    string  `json:"name"`
+	Dir     string  `json:"dir"`
+	Class   string  `json:"class"`
+	Delta   string  `json:"delta"`
+}
+var NilEta = Eta{}
+
+type StrSlice []string
+func (slice StrSlice) indexOf(value string) int {
+    for p, v := range slice {
+        if (v == value) {
+            return p
+        }
+    }
+    return -1
+}
+
+
+var cardinals = StrSlice{"n","e","s","w"}
+var bounds = StrSlice{"NB","EB","SB","WB"}
+var arrows = StrSlice{"↑","->","↓","<-"}
+func arrow(dir string) string {
+	var format *StrSlice
+	if len(dir) < 2 {
+		format = &cardinals
+	} else {
+		format = &bounds
+	}
+	going := (format.indexOf(dir) + cardinals.indexOf(screenDir)) % 4
+	return arrows[going]
+}
+
+
+func (r Route) getETA() Eta {
+	d := fetchRouteData(r.Id)
+	e := Eta{}
+	if len(d.Departures) == 0 {
+		return e
+	}
+	next := d.Departures[0]
+
+	// route name
+	if r.Name == "" {
+		e.Name = next.RouteShortName
+	} else {
+		e.Name = r.Name
+	}
+
+	// direction arrow
+	if r.Dir == "" {
+		e.Dir = arrow(next.DirectionText)
+	} else {
+		e.Dir = arrow(r.Dir)
+	}
+
+	// time delta
+	t := time.Unix(next.DepartureTime, 0)
+	dur := time.Until(t)
+	if dur.Minutes() <= 1 {
+		e.Delta = "Due"
+	} else if dur.Hours() < 60 {
+		e.Delta = fmt.Sprintf("%.0f minutes", dur.Minutes())
+	} else {
+		e.Delta = fmt.Sprintf("%.0fh %.0fm", dur.Hours(), dur.Minutes() - (math.Floor(dur.Hours())*60))
+	}
+
+
+	// css class name
+	if dur.Minutes() <= 1 {
+		e.Class = "now"
+	} else if dur.Minutes() <= 3 {
+		e.Class = "soon"
+	}
+
+	return e
+}
+
+
+func main(){
+	http.Handle("/", http.FileServer(http.Dir("./static")))
+	http.HandleFunc("/etas", api)
+	fmt.Printf("Starting server on port %d\n", serverPort)
+	if err := http.ListenAndServe(fmt.Sprintf(":%d", serverPort), nil); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func api(response http.ResponseWriter, request *http.Request){
+	var etas []Eta
+
+	for _, route := range routes {
+		eta := route.getETA()
+		if eta != NilEta {
+			etas = append(etas, eta)
+		}
+	}
+
+	data, err := json.Marshal(etas)
+	if err != nil {
+		fmt.Fprint(response, "[]")
+	} else {
+		fmt.Fprint(response, string(data))
+	}
+}
+
+// TODO: cache the ETA list
+
+// let etaCache = {
+// 	value: null,
+// 	createdAt: 0,
+// }
+// let getETAsFromCache = async (maxAge) => {
+// 	if (Date.now() / 1000 - etaCache.createdAt >= maxAge) {
+// 		etaCache.value = []
+// 		for (let r of conf.routes) {
+// 			let e = await getETA(r)
+// 			if (e !== null) etaCache.value.push(e)
+// 		}
+// 		etaCache.createdAt = Date.now() / 1000
+// 	}
+// 	return etaCache.value
+// }

main.js

@@ -1,88 +0,0 @@
-const express = require('express')
-const app = express()
-
-const fetch = require('node-fetch')
-const conf = require('./config.js')
-
-const cardinals = ['n', 'e', 's', 'w']
-const bounds = ['NB', 'EB', 'SB', 'WB']
-const arrows = ['↑', '->', '↓', '<-']
-let arrow = (dir) => {
-	let fmt
-	if (dir.length < 2) {
-		fmt = cardinals
-	} else {
-		fmt = bounds
-	}
-	let going = (fmt.indexOf(dir) + cardinals.indexOf(conf.screenDir)) % 4
-	return arrows[going]
-}
-
-let getETA = async (route) => {
-	let response = await fetch(
-		`https://svc.metrotransit.org/nextripv2/${route.id}`
-	)
-	let data = await response.json()
-
-	if (data.departures.length === 0) {
-		return null
-	}
-
-	let d = data.departures[0]
-
-	let eta = {}
-	eta.name = route.hasOwnProperty('name') ? route.name : d.route_short_name
-	eta.dir = arrow(route.hasOwnProperty('dir') ? route.dir : d.direction_text)
-	// eta.delta = d.departure_text.toLowerCase()
-
-	let dt = (d.departure_time - Date.now() / 1000) / 60
-	if (dt < 1) {
-		eta.delta = 'Due'
-	} else if (dt < 60) {
-		eta.delta = `${Math.ceil(dt)} minutes`
-	} else {
-		eta.delta = `${Math.floor(dt / 60)}h ${
-			Math.ceil(dt) - Math.floor(dt / 60) * 60
-		}m`
-	}
-
-	if (dt <= 1) {
-		eta.class = 'now'
-	} else if (dt <= 3) {
-		eta.class = 'soon'
-	} else {
-		eta.class = ''
-	}
-
-	return eta
-	// return {name: '46', dir: '<-', class: 'soon', delta: '2 min'}
-}
-
-let etaCache = {
-	value: null,
-	createdAt: 0,
-}
-let getETAsFromCache = async (maxAge) => {
-	if (Date.now() / 1000 - etaCache.createdAt >= maxAge) {
-		etaCache.value = []
-		for (let r of conf.routes) {
-			let e = await getETA(r)
-			if (e !== null) etaCache.value.push(e)
-		}
-		etaCache.createdAt = Date.now() / 1000
-	}
-	return etaCache.value
-}
-
-// Static assets (CSS, images)
-app.use('/', express.static('static'))
-
-// API for ETA data
-app.get('/etas', async (req, res) => {
-	let etas = await getETAsFromCache(29) // cache lives for 29 seconds
-	res.json(etas)
-})
-
-app.listen(conf.port, () => {
-	console.log(`Backend server started on port ${conf.port}.`)
-})

nextrip.go

@@ -0,0 +1,60 @@
+package main
+
+import (
+	"encoding/json"
+	"io"
+	"fmt"
+	"net/http"
+)
+
+// type Stop struct {
+// 	stop_id     uint
+// 	latitude    float32
+// 	longitude   float32
+// 	description string
+// }
+// type Alert struct {
+// 	alert_text  string
+// 	stop_closed bool
+// }
+type Departure struct {
+	// actual                  bool
+	// trip_id                 string
+	// stop_id                 uint
+	DepartureText      string  `json:"departure_text"`
+	DepartureTime      int64   `json:"departure_time"`
+	// description             string
+	// route_id                uint
+	RouteShortName     string  `json:"route_short_name"`
+	// direction_id            uint8
+	DirectionText      string  `json:"direction_text"`
+	// schedule_relationship   string
+}
+type RouteData struct {
+	// alerts            []Alert
+	Departures        []Departure  `json:"departures"`
+	// stops             []Stop
+}
+
+func fetchRouteData(id uint) RouteData {
+	resp, err := http.Get(fmt.Sprintf("https://svc.metrotransit.org/nextripv2/%d", id))
+	if err != nil {
+		fmt.Printf("Unable to reach NexTrip API:\n%s", err)
+		return RouteData{}
+	}
+	defer resp.Body.Close()
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		fmt.Printf("Error when reading NexTrip API response:\n%s", err)
+		return RouteData{}
+	}
+
+	var data RouteData
+	err = json.Unmarshal(body, &data)
+	if err != nil {
+		fmt.Printf("Error when parsing NexTrip API data:\n%s", err)
+		return RouteData{}
+	}
+
+	return data
+}

package.json

@@ -1,31 +0,0 @@
-{
-  "name": "omnibus",
-  "version": "1.0.0",
-  "description": "show schedule for Metro Transit (Twin Cities) routes",
-  "main": "main.js",
-  "scripts": {
-    "test": "echo \"Error: no test specified\" && exit 1",
-    "start": "node main.js",
-    "dev": "nodemon main.js"
-  },
-  "repository": {
-    "type": "git",
-    "url": "https://git.cyberia.club/reese/omnibus"
-  },
-  "author": "reese sapphire <reese@ovine.xyz>",
-  "license": "MIT",
-  "prettier": {
-    "printWidth": 80,
-    "semi": false,
-    "singleQuote": true,
-    "jsxSingleQuote": true,
-    "quoteProps": "consistent"
-  },
-  "dependencies": {
-    "express": "^4.18.1",
-    "node-fetch": "^2.6.7"
-  },
-  "devDependencies": {
-    "nodemon": "^2.0.19"
-  }
-}

readme.md

@@ -1,19 +1,21 @@
 ```
-                      __ __
+----------------------------------------------------
-.-----.--------.-----|__|  |--.--.--.-----.
+            /`                       '\
-|  _  |        |     |  |  _  |  |  |__ --|
+            \             __ __       /
-|_____|__|__|__|__|__|__|_____|_____|_____|
+    .-----.--------.-----|__|  |--.--.--.-----.
-
+    |  _  |        |     |  |  _  |  |  |__ --|
+    |_____|__|__|__|__|__|__|_____|_____|_____|
+====================================================
 ```
 
-lil node webserver that shows ETAs for Metro Transit stops
+lil go webserver that shows ETAs for Metro Transit stops
 
 ### usage
 
 1. download this repo.
-2. edit `config.js` with your desired values.
+2. edit `config.go` with your desired values.
-3. make sure you have nodejs installed, then download dependencies with `npm ci`.
+3. build it with `go build`.
-4. run it with `node main.js`. you can view the page at http://localhost:8080.
+4. run the `omnibus` binary. you can view the page at http://localhost:8080.
 
 ### ok but why?
 

static/index.html

@@ -9,6 +9,7 @@
 		let getETAs = async () => {
 			let response = await fetch('/etas')
 			let data = await response.json()
+			console.dir(data)
 
 			let tbody = document.getElementById('etas')
 			tbody.innerHTML = ''