134 lines
2.8 KiB
Go
134 lines
2.8 KiB
Go
package main
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import (
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"encoding/json"
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"fmt"
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"log"
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"net/http"
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"os"
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"time"
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. "subscribe/backend-protobuf/go"
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"github.com/joho/godotenv"
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"github.com/julienschmidt/httprouter"
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"github.com/nats-io/go-nats"
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"github.com/golang/protobuf/proto"
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)
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type RawClient struct {
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UserId string `json:"userid"`
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ClientId string `json:"clientid"`
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}
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type JsonResponse struct {
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Code uint32 `json:"code"`
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Message string `json:"message"`
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}
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var listen string
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var natsHost string
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var nc *nats.Conn
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var connections map[RawClient]chan []byte
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func main() {
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// Load .env
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err := godotenv.Load()
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if err != nil {
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log.Fatal("Error loading .env file")
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}
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listen = os.Getenv("LISTEN")
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natsHost = os.Getenv("NATS")
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connections = make(map[RawClient]chan []byte)
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// Routes
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router := httprouter.New()
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router.GET("/subscribe", Subscribe)
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// NATS
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nc, err = nats.Connect(natsHost)
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if err != nil {
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log.Fatal(err)
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}
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nc.Subscribe("res", ResponseHandler)
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// Start server
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log.Printf("starting server on %s", listen)
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log.Fatal(http.ListenAndServe(listen, router))
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}
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func Subscribe(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
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flusher, ok := w.(http.Flusher)
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if !ok {
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http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
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return
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}
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ua := r.Header.Get("X-User-Claim")
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if ua == "" {
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http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
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return
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}
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var client RawClient
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err := json.Unmarshal([]byte(ua), &client)
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if err != nil {
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http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
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return
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}
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w.Header().Set("Content-Type", "text/event-stream")
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w.Header().Set("Cache-Control", "no-cache")
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w.Header().Set("Connection", "keep-alive")
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recv := make(chan []byte)
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connections[client] = recv;
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// Refresh connection periodically
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resClosed := w.(http.CloseNotifier).CloseNotify()
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ticker := time.NewTicker(25 * time.Second)
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for {
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select {
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case msg := <- recv:
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fmt.Fprintf(w, "data: %s\n\n", msg)
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flusher.Flush()
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case <- ticker.C:
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w.Write([]byte(":\n\n"))
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case <- resClosed:
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ticker.Stop()
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delete(connections, client)
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return
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}
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}
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}
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func ResponseHandler(msg *nats.Msg) {
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response := Response {}
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if err := proto.Unmarshal(msg.Data, &response); err != nil { // Fail quietly
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log.Println(err)
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return
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}
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client := RawClient {
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UserId: response.Client.Key,
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ClientId: response.Client.Client,
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}
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connection, present := connections[client]
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if present {
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res := JsonResponse {
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Code: response.Code,
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Message: string(response.Message),
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}
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json_string, err := json.Marshal(res)
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if err != nil {
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log.Println(err)
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return
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}
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connection <- []byte(json_string)
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}
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}
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