ot-browser/cmd/ot-browser/ot-browser.go

package main

import (
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"os"
	"strings"

	"gopkg.in/ini.v1"
)

type Config struct {
	wwwDir     string
	bindAddr   string
	mqttRemote string
}

var config Config
var mqtt MQTTReceiver
var devices map[string]Location

func (c *Config) SetDefaults() {
	c.wwwDir = ""
	c.bindAddr = "127.0.0.1:8090"
	c.mqttRemote = ""
}

func mqtt_recv(id string, loc Location) {
	devices[id] = loc
}

func parseProgramArguments() error {
	args := os.Args[1:]
	for i := 0; i < len(args); i++ {
		arg := args[i]
		if len(arg) == 0 {
			continue
		}
		if arg == "-h" || arg == "--help" {
			fmt.Printf("Usage: %s [OPTIONS]", os.Args[0])
			fmt.Println("  -h,--help                   Print this help message")
			fmt.Println("  -w,--www DIR                Set WWW content directory")
			fmt.Println("  -c,--config FILE            Read configuration from the ini FILE")
			fmt.Println("  -b,--bind ADDR              Bind webserver to ADDR")
			os.Exit(0)
		} else if arg == "-w" || arg == "--www" {
			i++
			config.wwwDir = args[i]
		} else if arg == "-c" || arg == "--config" {
			i++
			if err := config.ReadFile(args[i]); err != nil {
				return err
			}
		} else if arg == "-b" || arg == "--bind" {
			i++
			config.bindAddr = args[i]
		} else {
			return fmt.Errorf("Invalid argument: %s\n", arg)
		}
	}
	return nil
}

func main() {
	fmt.Println("ot-browser")
	devices = make(map[string]Location, 0)
	config.SetDefaults()
	parseProgramArguments()

	// Connect mqtt
	if config.mqttRemote == "" {
		fmt.Fprintf(os.Stderr, "No mqtt remote set\n")
		os.Exit(1)
	}
	mqtt.Received = mqtt_recv
	if err := mqtt.Connect(config.mqttRemote, "owntracks/#", "", "", "ot-browser"); err != nil {
		fmt.Fprintf(os.Stderr, "mqtt error: %s\n", err)
		os.Exit(1)
	}

	// Setup webserver
	fs := http.FileServer(http.Dir(config.wwwDir))
	http.Handle("/", http.StripPrefix("/", fs))
	http.HandleFunc("/devices", handlerDevices)
	http.HandleFunc("/devices.json", handlerDevices)
	http.HandleFunc("/locations", handlerLocations)
	http.HandleFunc("/devices/", handlerDeviceQuery)
	fmt.Println("Serving: http://" + config.bindAddr)
	log.Fatal(http.ListenAndServe(config.bindAddr, nil))
}

func (c *Config) ReadFile(filename string) error {
	cfg, err := ini.InsensitiveLoad(filename)
	if err != nil {
		return err
	}

	mqtt := cfg.Section("mqtt")
	if val := mqtt.Key("remote").String(); val != "" {
		c.mqttRemote = val
	}
	www := cfg.Section("www")
	if val := www.Key("remote").String(); val != "" {
		c.wwwDir = val
	}
	if val := mqtt.Key("bind").String(); val != "" {
		c.bindAddr = val
	}
	return nil
}

func handlerDevices(w http.ResponseWriter, r *http.Request) {
	devs := make([]string, 0)
	for dev := range devices {
		devs = append(devs, dev)
	}

	buf, err := json.Marshal(devs)
	if err != nil {
		w.WriteHeader(500)
		w.Write([]byte("Server error"))
		fmt.Fprintf(os.Stderr, "json marshal error: %s\n", err)
		return
	}
	w.Write(buf)
}

func handlerLocations(w http.ResponseWriter, r *http.Request) {
	locations := make([]GeoJSON, 0)
	for dev, loc := range devices {
		point := CreatePoint(loc.Lon, loc.Lat)
		point.Properties["name"] = dev
		point.Properties["id"] = dev
		point.Properties["time"] = fmt.Sprintf("%d", loc.Timestamp)
		point.Properties["altitude"] = fmt.Sprintf("%d", loc.Alt)
		point.Properties["accuracy"] = fmt.Sprintf("%d", loc.Acc)
		locations = append(locations, point)
	}

	buf, err := json.Marshal(locations)
	if err != nil {
		w.WriteHeader(500)
		w.Write([]byte("Server error"))
		fmt.Fprintf(os.Stderr, "json marshal error: %s\n", err)
		return
	}
	w.Write([]byte("{ \"features\": "))
	w.Write(buf)
	w.Write([]byte("}"))
}

func handlerDeviceQuery(w http.ResponseWriter, r *http.Request) {
	// extract device name from the path
	path := r.URL.Path
	device := ""
	if i := strings.Index(path, "devices/"); i > 0 {
		device = path[i+8:]
	} else {
		goto server_Error
	}

	if loc, ok := devices[device]; ok {
		buf, err := json.Marshal(loc)
		if err != nil {
			w.WriteHeader(500)
			w.Write([]byte("Server error"))
			fmt.Fprintf(os.Stderr, "json marshal error: %s\n", err)
			return
		}
		w.Write(buf)
	} else {
		w.WriteHeader(404)
		w.Write([]byte("device not found"))
	}
	return
server_Error:
	w.WriteHeader(500)
	w.Write([]byte("Server error"))
	return
}