feat(server): add vpn route to replace /openvpn

internal/server/vpn.go

@@ -0,0 +1,93 @@
+package server
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"strings"
+)
+
+func newVPNHandler(ctx context.Context, looper VPNLooper,
+	w warner) http.Handler {
+	return &vpnHandler{
+		ctx:    ctx,
+		looper: looper,
+		warner: w,
+	}
+}
+
+type vpnHandler struct {
+	ctx    context.Context //nolint:containedctx
+	looper VPNLooper
+	warner warner
+}
+
+func (h *vpnHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	r.RequestURI = strings.TrimPrefix(r.RequestURI, "/vpn")
+	switch r.RequestURI {
+	case "/status":
+		switch r.Method {
+		case http.MethodGet:
+			h.getStatus(w)
+		case http.MethodPut:
+			h.setStatus(w, r)
+		default:
+			http.Error(w, "method "+r.Method+" not supported", http.StatusBadRequest)
+		}
+	case "/settings":
+		switch r.Method {
+		case http.MethodGet:
+			h.getSettings(w)
+		default:
+			http.Error(w, "method "+r.Method+" not supported", http.StatusBadRequest)
+		}
+	default:
+		http.Error(w, "route "+r.RequestURI+" not supported", http.StatusBadRequest)
+	}
+}
+
+func (h *vpnHandler) getStatus(w http.ResponseWriter) {
+	status := h.looper.GetStatus()
+	encoder := json.NewEncoder(w)
+	data := statusWrapper{Status: string(status)}
+	if err := encoder.Encode(data); err != nil {
+		h.warner.Warn(err.Error())
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+}
+
+func (h *vpnHandler) setStatus(w http.ResponseWriter, r *http.Request) {
+	decoder := json.NewDecoder(r.Body)
+	var data statusWrapper
+	if err := decoder.Decode(&data); err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	status, err := data.getStatus()
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	outcome, err := h.looper.ApplyStatus(h.ctx, status)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	encoder := json.NewEncoder(w)
+	if err := encoder.Encode(outcomeWrapper{Outcome: outcome}); err != nil {
+		h.warner.Warn(err.Error())
+		http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
+		return
+	}
+}
+
+func (h *vpnHandler) getSettings(w http.ResponseWriter) {
+	settings := h.looper.GetSettings()
+	encoder := json.NewEncoder(w)
+	if err := encoder.Encode(settings); err != nil {
+		h.warner.Warn(err.Error())
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+}