databag/net/server/internal/api_status.go

/*
 * DataBag
 *
 * DataBag provides storage for decentralized identity based self-hosting apps. It is intended to support sharing of personal data and hosting group conversations. 
 *
 * API version: 0.0.1
 * Contact: roland.osborne@gmail.com
 * Generated by: Swagger Codegen (https://github.com/swagger-api/swagger-codegen.git)
 */
package databag

import (
  "log"
  "sync"
	"net/http"
  "github.com/gorilla/websocket"
  "databag/internal/store"
)

type accountRevision struct {
  ProfileRevision int64
  ContentRevision int64
  ViewRevision int64
  GroupRevision int64
  LabelRevision int64
  CardRevision int64
  DialogueRevision int64
  InsightRevision int64
}

var wsSync sync.Mutex;
var statusListener = make(map[uint][]chan<-accountRevision)
var upgrader = websocket.Upgrader{}

func Status(w http.ResponseWriter, r *http.Request) {

  // accept websocket connection
  conn, err := upgrader.Upgrade(w, r, nil)
  if err != nil {
      log.Print("Status: failed upgrade connection", err)
      return
  }
  defer conn.Close()

  log.Println("CONNECTED")
  // receive announce message

  // open channel for revisions
  c := make(chan accountRevision)
  AddStatusListener(0, c);

  for {
      messageType, message, err := conn.ReadMessage()
      if err != nil {
          log.Println("Error during message reading:", err)
          break
      }
      log.Printf("Received: %s", message)
      err = conn.WriteMessage(messageType, message)
      if err != nil {
          log.Println("Error during message writing:", err)
          break
      }
  }

  // close channel
  RemoveStatusListener(0, c);
  close(c);
}

func SetStatus(act uint) {

  // get revisions for the account
  var rev accountRevision;
  err := store.DB.Model(&Revision{}).Where("ID = ?", act).First(&rev).Error
  if err != nil {
    log.Println("SetStatus - failed to retrieve account revisions");
  }

  // lock access to statusListener
  wsSync.Lock()
  defer wsSync.Unlock();

  // check if we have any listeners
  chs, ok := statusListener[act]
  if ok {

    // notify all listeners
    for _, ch := range chs {
      ch <- rev
    }
  }
}

func AddStatusListener(act uint, ch chan<-accountRevision) {

  // lock access to statusListener
  wsSync.Lock()
  defer wsSync.Unlock();

  // check if account has listeners
  chs, ok := statusListener[act]
  if ok {
    chs = append(chs, ch);
  } else {
    statusListener[act] = []chan<-accountRevision{ch}
  }
}

func RemoveStatusListener(act uint, ch chan<-accountRevision) {

  // lock access to statusListener
  wsSync.Lock()
  defer wsSync.Unlock();

  // remove channel
  chs, ok := statusListener[act]
  if ok {
    for i, c := range chs {
      if ch == c {
        if len(chs) == 1 {
          delete(statusListener, act)
        } else {
          chs[i] = chs[len(chs)-1]
          statusListener[act] = chs[:len(chs)-1]
        }
      }
    }
  }
}