Implement server

go.mod

@@ -0,0 +1,13 @@
+module github.com/Luzifer/mapshare
+
+go 1.13
+
+require (
+	github.com/Luzifer/rconfig/v2 v2.2.1
+	github.com/gofrs/uuid v3.2.0+incompatible
+	github.com/gorilla/mux v1.7.3
+	github.com/gorilla/websocket v1.4.1
+	github.com/konsorten/go-windows-terminal-sequences v1.0.2 // indirect
+	github.com/sirupsen/logrus v1.4.2
+	golang.org/x/sys v0.0.0-20200106162015-b016eb3dc98e // indirect
+)

go.sum

@@ -0,0 +1,30 @@
+github.com/Luzifer/rconfig v2.2.0+incompatible h1:Kle3+rshPM7LxciOheaR4EfHUzibkDDGws04sefQ5m8=
+github.com/Luzifer/rconfig/v2 v2.2.1 h1:zcDdLQlnlzwcBJ8E0WFzOkQE1pCMn3EbX0dFYkeTczg=
+github.com/Luzifer/rconfig/v2 v2.2.1/go.mod h1:OKIX0/JRZrPJ/ZXXWklQEFXA6tBfWaljZbW37w+sqBw=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/gofrs/uuid v3.2.0+incompatible h1:y12jRkkFxsd7GpqdSZ+/KCs/fJbqpEXSGd4+jfEaewE=
+github.com/gofrs/uuid v3.2.0+incompatible/go.mod h1:b2aQJv3Z4Fp6yNu3cdSllBxTCLRxnplIgP/c0N/04lM=
+github.com/gorilla/mux v1.7.3 h1:gnP5JzjVOuiZD07fKKToCAOjS0yOpj/qPETTXCCS6hw=
+github.com/gorilla/mux v1.7.3/go.mod h1:1lud6UwP+6orDFRuTfBEV8e9/aOM/c4fVVCaMa2zaAs=
+github.com/gorilla/websocket v1.4.1 h1:q7AeDBpnBk8AogcD4DSag/Ukw/KV+YhzLj2bP5HvKCM=
+github.com/gorilla/websocket v1.4.1/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
+github.com/konsorten/go-windows-terminal-sequences v1.0.1 h1:mweAR1A6xJ3oS2pRaGiHgQ4OO8tzTaLawm8vnODuwDk=
+github.com/konsorten/go-windows-terminal-sequences v1.0.1/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
+github.com/konsorten/go-windows-terminal-sequences v1.0.2 h1:DB17ag19krx9CFsz4o3enTrPXyIXCl+2iCXH/aMAp9s=
+github.com/konsorten/go-windows-terminal-sequences v1.0.2/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/sirupsen/logrus v1.4.2 h1:SPIRibHv4MatM3XXNO2BJeFLZwZ2LvZgfQ5+UNI2im4=
+github.com/sirupsen/logrus v1.4.2/go.mod h1:tLMulIdttU9McNUspp0xgXVQah82FyeX6MwdIuYE2rE=
+github.com/spf13/pflag v1.0.3 h1:zPAT6CGy6wXeQ7NtTnaTerfKOsV6V6F8agHXFiazDkg=
+github.com/spf13/pflag v1.0.3/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnInEg4=
+github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
+golang.org/x/sys v0.0.0-20190422165155-953cdadca894 h1:Cz4ceDQGXuKRnVBDTS23GTn/pU5OE2C0WrNTOYK1Uuc=
+golang.org/x/sys v0.0.0-20190422165155-953cdadca894/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200106162015-b016eb3dc98e h1:LwyF2AFISC9nVbS6MgzsaQNSUsRXI49GS+YQ5KX/QH0=
+golang.org/x/sys v0.0.0-20200106162015-b016eb3dc98e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/validator.v2 v2.0.0-20180514200540-135c24b11c19 h1:WB265cn5OpO+hK3pikC9hpP1zI/KTwmyMFKloW9eOVc=
+gopkg.in/validator.v2 v2.0.0-20180514200540-135c24b11c19/go.mod h1:o4V0GXN9/CAmCsvJ0oXYZvrZOe7syiDZSN1GWGZTGzc=
+gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=

handler.go

@@ -0,0 +1,121 @@
+package main
+
+import (
+	"encoding/json"
+	"net/http"
+	"sync"
+	"time"
+
+	"github.com/gofrs/uuid"
+	"github.com/gorilla/mux"
+	"github.com/gorilla/websocket"
+	log "github.com/sirupsen/logrus"
+)
+
+type position struct {
+	Lat      float64   `json:"lat"`
+	Lon      float64   `json:"lon"`
+	Retained bool      `json:"retained"`
+	Time     time.Time `json:"time"`
+}
+
+var (
+	reqDistributors     = map[string]map[string]chan position{}
+	reqDistributorsLock = new(sync.RWMutex)
+	reqRetainer         = map[string]position{}
+	reqRetainerLock     = new(sync.RWMutex)
+
+	upgrader = websocket.Upgrader{
+		ReadBufferSize:  1024,
+		WriteBufferSize: 1024,
+	}
+)
+
+func handleRedirectRandom(w http.ResponseWriter, r *http.Request) {
+	http.Redirect(w, r, uuid.Must(uuid.NewV4()).String(), http.StatusFound)
+}
+
+func handleMapFrontend(w http.ResponseWriter, r *http.Request) {
+	http.ServeFile(w, r, "frontend/index.html")
+}
+
+func handleMapSocket(w http.ResponseWriter, r *http.Request) {
+	var (
+		vars    = mux.Vars(r)
+		mapID   = vars["mapID"]
+		sockID  = uuid.Must(uuid.NewV4()).String()
+		updates = make(chan position, 10)
+	)
+
+	// Register update channel
+	reqDistributorsLock.Lock()
+	if _, ok := reqDistributors[mapID]; !ok {
+		reqDistributors[mapID] = make(map[string]chan position)
+	}
+	reqDistributors[mapID][sockID] = updates
+	reqDistributorsLock.Unlock()
+
+	// In case a retained position is available queue it
+	reqRetainerLock.RLock()
+	if p, ok := reqRetainer[mapID]; ok {
+		updates <- p
+	}
+	reqRetainerLock.RUnlock()
+
+	// Queue deregistration
+	defer func() {
+		reqDistributorsLock.Lock()
+		defer reqDistributorsLock.Unlock()
+
+		delete(reqDistributors[mapID], sockID)
+		close(updates)
+	}()
+
+	// Open socket
+	conn, err := upgrader.Upgrade(w, r, nil)
+	if err != nil {
+		log.WithError(err).Debug("Unable to open websocket")
+		return
+	}
+	defer conn.Close()
+
+	// Send updates
+	for pos := range updates {
+		if err = conn.WriteJSON(pos); err != nil {
+			log.WithError(err).Debug("Unable to send position")
+			return
+		}
+	}
+}
+
+func handleMapSubmit(w http.ResponseWriter, r *http.Request) {
+	var (
+		pos   position
+		vars  = mux.Vars(r)
+		mapID = vars["mapID"]
+	)
+
+	if err := json.NewDecoder(r.Body).Decode(&pos); err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+
+	if pos.Retained {
+		reqRetainerLock.Lock()
+		reqRetainer[mapID] = pos
+		reqRetainerLock.Unlock()
+	}
+
+	reqDistributorsLock.RLock()
+	defer reqDistributorsLock.RUnlock()
+
+	distributors, ok := reqDistributors[mapID]
+	if !ok || len(distributors) == 0 {
+		// No subscribers at all
+		return
+	}
+
+	for _, c := range distributors {
+		c <- pos
+	}
+}

main.go

@@ -0,0 +1,55 @@
+package main
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+
+	"github.com/gorilla/mux"
+	log "github.com/sirupsen/logrus"
+
+	"github.com/Luzifer/rconfig/v2"
+)
+
+var (
+	cfg = struct {
+		Listen         string `flag:"listen" default:":3000" description:"Port/IP to listen on"`
+		LogLevel       string `flag:"log-level" default:"info" description:"Log level (debug, info, warn, error, fatal)"`
+		VersionAndExit bool   `flag:"version" default:"false" description:"Prints current version and exits"`
+	}{}
+
+	version = "dev"
+)
+
+func init() {
+	if err := rconfig.ParseAndValidate(&cfg); err != nil {
+		log.Fatalf("Unable to parse commandline options: %s", err)
+	}
+
+	if cfg.VersionAndExit {
+		fmt.Printf("mapshare %s\n", version)
+		os.Exit(0)
+	}
+
+	if l, err := log.ParseLevel(cfg.LogLevel); err != nil {
+		log.WithError(err).Fatal("Unable to parse log level")
+	} else {
+		log.SetLevel(l)
+	}
+}
+
+func main() {
+	r := mux.NewRouter()
+
+	r.HandleFunc("/", handleRedirectRandom).Methods(http.MethodGet)
+
+	r.PathPrefix("/asset/").Handler(
+		http.StripPrefix("/asset/", http.FileServer(http.Dir("frontend"))),
+	).Methods(http.MethodGet)
+
+	r.HandleFunc("/{mapID}", handleMapFrontend).Methods(http.MethodGet)
+	r.HandleFunc("/{mapID}", handleMapSubmit).Methods(http.MethodPut)
+	r.HandleFunc("/{mapID}/ws", handleMapSocket).Methods(http.MethodGet)
+
+	log.WithError(http.ListenAndServe(cfg.Listen, r)).Error("HTTP server caused an error")
+}