We build too many walls and not enough bridges

internal/api/api.go

@@ -0,0 +1,94 @@
+// Copyright (c) 2020 Proton Technologies AG
+//
+// This file is part of ProtonMail Bridge.
+//
+// ProtonMail Bridge 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
+// (at your option) any later version.
+//
+// ProtonMail Bridge 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 ProtonMail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+// Package api provides HTTP API of the Bridge.
+//
+// API endpoints:
+//  * /focus, see focusHandler
+package api
+
+import (
+	"crypto/tls"
+	"fmt"
+	"net/http"
+
+	"github.com/ProtonMail/proton-bridge/internal/bridge"
+	"github.com/ProtonMail/proton-bridge/internal/events"
+	"github.com/ProtonMail/proton-bridge/internal/preferences"
+	"github.com/ProtonMail/proton-bridge/pkg/config"
+	"github.com/ProtonMail/proton-bridge/pkg/listener"
+	"github.com/ProtonMail/proton-bridge/pkg/ports"
+)
+
+var (
+	log = config.GetLogEntry("api") //nolint[gochecknoglobals]
+)
+
+type apiServer struct {
+	host          string
+	pref          *config.Preferences
+	tls           *tls.Config
+	certPath      string
+	keyPath       string
+	eventListener listener.Listener
+}
+
+// NewAPIServer returns prepared API server struct.
+func NewAPIServer(pref *config.Preferences, tls *tls.Config, certPath, keyPath string, eventListener listener.Listener) *apiServer { //nolint[golint]
+	return &apiServer{
+		host:          bridge.Host,
+		pref:          pref,
+		tls:           tls,
+		certPath:      certPath,
+		keyPath:       keyPath,
+		eventListener: eventListener,
+	}
+}
+
+// Starts the server.
+func (api *apiServer) ListenAndServe() {
+	mux := http.NewServeMux()
+	mux.HandleFunc("/focus", wrapper(api, focusHandler))
+
+	addr := api.getAddress()
+	server := &http.Server{
+		Addr:         addr,
+		Handler:      mux,
+		TLSConfig:    api.tls,
+		TLSNextProto: make(map[string]func(*http.Server, *tls.Conn, http.Handler)),
+	}
+
+	log.Info("API listening at ", addr)
+	if err := server.ListenAndServeTLS(api.certPath, api.keyPath); err != nil {
+		api.eventListener.Emit(events.ErrorEvent, "API failed: "+err.Error())
+		log.Error("API failed: ", err)
+	}
+	defer server.Close() //nolint[errcheck]
+}
+
+func (api *apiServer) getAddress() string {
+	port := api.pref.GetInt(preferences.APIPortKey)
+	newPort := ports.FindFreePortFrom(port)
+	if newPort != port {
+		api.pref.SetInt(preferences.APIPortKey, newPort)
+	}
+	return getAPIAddress(api.host, newPort)
+}
+
+func getAPIAddress(host string, port int) string {
+	return fmt.Sprintf("%s:%d", host, port)
+}

internal/api/ctx.go

@@ -0,0 +1,51 @@
+// Copyright (c) 2020 Proton Technologies AG
+//
+// This file is part of ProtonMail Bridge.
+//
+// ProtonMail Bridge 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
+// (at your option) any later version.
+//
+// ProtonMail Bridge 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 ProtonMail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+package api
+
+import (
+	"net/http"
+
+	"github.com/ProtonMail/proton-bridge/pkg/listener"
+)
+
+// httpHandler with Go's Response and Request.
+type httpHandler func(http.ResponseWriter, *http.Request)
+
+// handler with our context.
+type handler func(handlerContext) error
+
+type handlerContext struct {
+	req           *http.Request
+	resp          http.ResponseWriter
+	eventListener listener.Listener
+}
+
+func wrapper(api *apiServer, callback handler) httpHandler {
+	return func(w http.ResponseWriter, req *http.Request) {
+		ctx := handlerContext{
+			req:           req,
+			resp:          w,
+			eventListener: api.eventListener,
+		}
+		err := callback(ctx)
+		if err != nil {
+			log.Error("API callback of ", req.URL, " failed: ", err)
+			http.Error(w, err.Error(), 500)
+		}
+	}
+}

internal/api/focus.go

@@ -0,0 +1,55 @@
+// Copyright (c) 2020 Proton Technologies AG
+//
+// This file is part of ProtonMail Bridge.
+//
+// ProtonMail Bridge 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
+// (at your option) any later version.
+//
+// ProtonMail Bridge 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 ProtonMail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+package api
+
+import (
+	"crypto/tls"
+	"fmt"
+	"net/http"
+
+	"github.com/ProtonMail/proton-bridge/internal/bridge"
+	"github.com/ProtonMail/proton-bridge/internal/events"
+)
+
+// focusHandler should be called from other instances (attempt to start bridge
+// for the second time) to get focus in the currently running instance.
+func focusHandler(ctx handlerContext) error {
+	log.Info("Focus from other instance")
+	ctx.eventListener.Emit(events.SecondInstanceEvent, "")
+	fmt.Fprintf(ctx.resp, "OK")
+	return nil
+}
+
+// CheckOtherInstanceAndFocus is helper for new instances to check if there is
+// already a running instance and get it's focus.
+func CheckOtherInstanceAndFocus(port int, tls *tls.Config) error {
+	transport := &http.Transport{TLSClientConfig: tls}
+	client := &http.Client{Transport: transport}
+
+	addr := getAPIAddress(bridge.Host, port)
+	resp, err := client.Get("https://" + addr + "/focus")
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close() //nolint[errcheck]
+
+	if resp.StatusCode != 200 {
+		log.Error("Focus error: ", resp.StatusCode)
+	}
+	return nil
+}