1 files changed, 118 insertions, 0 deletions
diff --git a/cmd/dolmetschctld/web_socket.go b/cmd/dolmetschctld/web_socket.go
new file mode 100644
index 0000000..2e90b70
--- /dev/null
+++ b/cmd/dolmetschctld/web_socket.go
@@ -0,0 +1,118 @@
+//
+//  dolmetschctl
+//
+//
+//  Copyright (C) 2019 Christian Pointner <equinox@spreadspace.org>
+//
+//  This file is part of dolmetschctl.
+//
+//  dolmetschctl is free software: you can redistribute it and/or modify
+//  it under the terms of the GNU General Public License as published by
+//  the Free Software Foundation, either version 3 of the License, or
+//  any later version.
+//
+//  dolmetschctl is distributed in the hope that it will be useful,
+//  but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//  GNU General Public License for more details.
+//
+//  You should have received a copy of the GNU General Public License
+//  along with dolmetschctl. If not, see <http://www.gnu.org/licenses/>.
+//
+
+package main
+
+import (
+	"encoding/json"
+	"io"
+	"io/ioutil"
+	"log"
+	"net/http"
+
+	"github.com/gorilla/websocket"
+)
+
+type webSocketRequest struct {
+	Command string   `json:"command"`
+	Args    []string `json:"arguments"`
+}
+
+type webSocketResponseBase struct {
+	ResponseCode int    `json:"response-code"`
+	Type         string `json:"type"`
+}
+
+type webSocketResponseError struct {
+	webSocketResponseBase
+	ErrorString string `json:"error"`
+}
+
+type webSocketResponseState struct {
+	webSocketResponseBase
+	webState
+}
+
+func sendWebSocketResponse(ws *websocket.Conn, rd interface{}) {
+	if err := ws.WriteJSON(rd); err != nil {
+		log.Println("Web(socket) client", ws.RemoteAddr(), "write error:", err)
+	}
+}
+
+func sendWebSocketErrorResponse(ws *websocket.Conn, code int, errStr string) {
+	rd := &webSocketResponseError{}
+	rd.ResponseCode = code
+	rd.Type = "error"
+	rd.ErrorString = errStr
+	sendWebSocketResponse(ws, rd)
+}
+
+func webSocketHandleCommand(ws *websocket.Conn, sm *StateMachine, req webSocketRequest) {
+	switch req.Command {
+	case "state":
+		var result webSocketResponseState
+		result.ResponseCode = http.StatusOK
+		result.Type = "state"
+		result.State, result.Ratio, result.Lang = sm.GetState()
+		sendWebSocketResponse(ws, result)
+	default:
+		sendWebSocketErrorResponse(ws, http.StatusBadRequest, "unkown command: '"+req.Command+"'")
+	}
+}
+
+func webSocketHandler(sm *StateMachine, w http.ResponseWriter, r *http.Request) {
+	ws, err := websocket.Upgrade(w, r, nil, 64*1024, 64*1024)
+	if _, ok := err.(websocket.HandshakeError); ok {
+		http.Error(w, "Not a websocket handshake", 400)
+		return
+	} else if err != nil {
+		log.Println("Web(socket) client", ws.RemoteAddr(), "error:", err)
+		return
+	}
+	log.Println("Web(socket) client", ws.RemoteAddr(), "connected")
+
+	for {
+		t, r, err := ws.NextReader()
+		if err != nil {
+			log.Println("Web(socket) Client", ws.RemoteAddr(), "disconnected:", err)
+			return
+		}
+
+		switch t {
+		case websocket.TextMessage:
+			var req webSocketRequest
+			if err := json.NewDecoder(r).Decode(&req); err != nil {
+				if err == io.EOF {
+					err = io.ErrUnexpectedEOF
+				}
+				log.Println("Web(socket) client", ws.RemoteAddr(), "request error:", err)
+				sendWebSocketErrorResponse(ws, http.StatusBadRequest, err.Error())
+				return
+			}
+
+			webSocketHandleCommand(ws, sm, req)
+		case websocket.BinaryMessage:
+			sendWebSocketErrorResponse(ws, http.StatusBadRequest, "binary messages are not allowed")
+			io.Copy(ioutil.Discard, r) // consume all the data
+		}
+	}
+}