added minimal web interface

3 files changed, 129 insertions, 4 deletions

diff --git a/cmd/dolmetschctld/dolmetschctld.go b/cmd/dolmetschctld/dolmetschctld.go
index 4c31dbf..cc75319 100644
--- a/cmd/dolmetschctld/dolmetschctld.go
+++ b/cmd/dolmetschctld/dolmetschctld.go
@@ -40,6 +40,9 @@ func addLanguage(sm *StateMachine, name Language, original, interpreter mixer.Ch
 func main() {
 	log.Println("hello world.")
 
+	// *************************************
+	// * initialize core
+
 	m, err := mixer.NewMixer(mixer.Config{DevIn: "ESI MIDIMATE eX MIDI 2", DevOut: "ESI MIDIMATE eX MIDI 1"})
 	if err != nil {
 		log.Printf("Error opening the mixer: %v", err)
@@ -71,16 +74,44 @@ func main() {
 	sm.Start()
 	defer sm.Shutdown()
 
+	// *************************************
+	// * initialize control interfaces
+
 	var telnet *TelnetInterface
 	if telnet, err = NewTelnetInterface("127.0.0.1:1234", sm); err != nil {
-		log.Printf("creating telnet control interface failed: %v", err)
+		log.Printf("creating telnet interface failed: %v", err)
 		os.Exit(1)
 	}
 	log.Printf("telnet interface successfully initialized!")
 
-	if err = telnet.Run(); err != nil {
-		log.Printf("running telnet interface failed: %v", err)
+	var web *WebInterface
+	if web, err = NewWebInterface("127.0.0.1:8234", sm); err != nil {
+		log.Printf("creating web interface failed: %v", err)
+		os.Exit(1)
 	}
+	log.Printf("web interface successfully initialized!")
+
+	// *************************************
+	// * run control interfaces
+
+	stop := make(chan bool)
+
+	go func() {
+		log.Printf("starting telnet interface")
+		if err = telnet.Run(); err != nil {
+			log.Printf("running telnet interface failed: %v", err)
+		}
+		stop <- true
+	}()
+
+	go func() {
+		log.Printf("starting web interface")
+		if err = web.Run(); err != nil {
+			log.Printf("running web interface failed: %v", err)
+		}
+		stop <- true
+	}()
 
-	log.Printf("exiting.")
+	<-stop
+	log.Printf("at least one control interface has stopped - bringing down the whole process")
 }
diff --git a/cmd/dolmetschctld/statemachine.go b/cmd/dolmetschctld/statemachine.go
index b1e74c7..7082460 100644
--- a/cmd/dolmetschctld/statemachine.go
+++ b/cmd/dolmetschctld/statemachine.go
@@ -51,6 +51,11 @@ func (s State) String() string {
 	}
 }
 
+func (s State) MarshalText() (data []byte, err error) {
+	data = []byte(s.String())
+	return
+}
+
 type Language string
 
 func (l Language) String() string {
diff --git a/cmd/dolmetschctld/web.go b/cmd/dolmetschctld/web.go
new file mode 100644
index 0000000..ad42429
--- /dev/null
+++ b/cmd/dolmetschctld/web.go
@@ -0,0 +1,89 @@
+//
+//  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"
+	"net/http"
+	"time"
+)
+
+type WebInterface struct {
+	server *http.Server
+}
+
+type webHandler struct {
+	sm *StateMachine
+	H  func(*StateMachine, http.ResponseWriter, *http.Request)
+}
+
+func (self webHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	self.H(self.sm, w, r)
+}
+
+func webSendResponse(w http.ResponseWriter, status int, respdata interface{}) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	encoder := json.NewEncoder(w)
+	encoder.Encode(respdata)
+}
+
+type webError struct {
+	ResponseCode int    `json:"response-code"`
+	Error        string `json:"error"`
+}
+
+func webSendErrorResponse(w http.ResponseWriter, status int, error string) {
+	webSendResponse(w, status, webError{ResponseCode: status, Error: error})
+}
+
+type webState struct {
+	State State    `json:"state"`
+	Ratio float32  `json:"original-to-interpreter-ratio"`
+	Lang  Language `json:"language"`
+}
+
+func webGetStateHandler(sm *StateMachine, w http.ResponseWriter, r *http.Request) {
+	if r.Method != "GET" {
+		webSendErrorResponse(w, http.StatusMethodNotAllowed, "only GET method is allowed")
+		return
+	}
+
+	var result webState
+	result.State, result.Ratio, result.Lang = sm.GetState()
+	webSendResponse(w, http.StatusOK, result)
+}
+
+func (web *WebInterface) Run() error {
+	return web.server.ListenAndServe()
+}
+
+func NewWebInterface(addr string, sm *StateMachine) (web *WebInterface, err error) {
+	web = &WebInterface{}
+
+	http.Handle("/api/v1/state", webHandler{sm, webGetStateHandler})
+	// TODO: add other handler
+
+	web.server = &http.Server{Addr: addr, ReadTimeout: 2 * time.Hour, WriteTimeout: 2 * time.Hour}
+	return
+}