ipn/localapi: move EditPrefs to localapi

Follow-up/revision to recent 53cfff109b which
added EditPrefs.

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

ipn/backend.go

@@ -158,8 +158,6 @@ type Backend interface {
 	// WantRunning. This may cause the wireguard engine to
 	// reconfigure or stop.
 	SetPrefs(*Prefs)
-	// EditPrefs is like SetPrefs but only sets the specified fields.
-	EditPrefs(*MaskedPrefs)
 	// RequestEngineStatus polls for an update from the wireguard
 	// engine. Only needed if you want to display byte
 	// counts. Connection events are emitted automatically without

ipn/fake_test.go

@@ -96,13 +96,6 @@ func (b *FakeBackend) SetPrefs(new *Prefs) {
 	}
 }
 
-func (b *FakeBackend) EditPrefs(mp *MaskedPrefs) {
-	// This fake implementation only cares about this one pref.
-	if mp.WantRunningSet {
-		b.SetPrefs(&mp.Prefs)
-	}
-}
-
 func (b *FakeBackend) RequestEngineStatus() {
 	if b.notify != nil {
 		b.notify(Notify{Engine: &EngineStatus{}})

ipn/ipnlocal/local.go

@@ -1302,17 +1302,18 @@ func (b *LocalBackend) SetCurrentUserID(uid string) {
 	b.mu.Unlock()
 }
 
-func (b *LocalBackend) EditPrefs(mp *ipn.MaskedPrefs) {
+func (b *LocalBackend) EditPrefs(mp *ipn.MaskedPrefs) (*ipn.Prefs, error) {
 	b.mu.Lock()
 	p0 := b.prefs.Clone()
 	p1 := b.prefs.Clone()
 	p1.ApplyEdits(mp)
 	if p1.Equals(p0) {
 		b.mu.Unlock()
-		return
+		return p1, nil
 	}
 	b.logf("EditPrefs: %v", mp.Pretty())
 	b.setPrefsLockedOnEntry("EditPrefs", p1)
+	return p1, nil
 }
 
 // SetPrefs saves new user preferences and propagates them throughout

ipn/localapi/localapi.go

@@ -23,6 +23,7 @@ import (
 	"time"
 
 	"inet.af/netaddr"
+	"tailscale.com/ipn"
 	"tailscale.com/ipn/ipnlocal"
 	"tailscale.com/ipn/ipnstate"
 	"tailscale.com/tailcfg"
@@ -224,10 +225,26 @@ func (h *Handler) servePrefs(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "prefs access denied", http.StatusForbidden)
 		return
 	}
+	var prefs *ipn.Prefs
+	if r.Method == "POST" {
+		mp := new(ipn.MaskedPrefs)
+		if err := json.NewDecoder(r.Body).Decode(mp); err != nil {
+			http.Error(w, err.Error(), 400)
+			return
+		}
+		var err error
+		prefs, err = h.b.EditPrefs(mp)
+		if err != nil {
+			http.Error(w, err.Error(), 400)
+			return
+		}
+	} else {
+		prefs = h.b.Prefs()
+	}
 	w.Header().Set("Content-Type", "application/json")
 	e := json.NewEncoder(w)
 	e.SetIndent("", "\t")
-	e.Encode(h.b.Prefs())
+	e.Encode(prefs)
 }
 
 func (h *Handler) serveFiles(w http.ResponseWriter, r *http.Request) {

ipn/message.go

@@ -80,7 +80,6 @@ type Command struct {
 	Login                 *tailcfg.Oauth2Token
 	Logout                *NoArgs
 	SetPrefs              *SetPrefsArgs
-	EditPrefs             *MaskedPrefs
 	RequestEngineStatus   *NoArgs
 	RequestStatus         *NoArgs
 	FakeExpireAfter       *FakeExpireAfterArgs
@@ -204,9 +203,6 @@ func (bs *BackendServer) GotCommand(ctx context.Context, cmd *Command) error {
 	} else if c := cmd.SetPrefs; c != nil {
 		bs.b.SetPrefs(c.New)
 		return nil
-	} else if c := cmd.EditPrefs; c != nil {
-		bs.b.EditPrefs(c)
-		return nil
 	} else if c := cmd.FakeExpireAfter; c != nil {
 		bs.b.FakeExpireAfter(c.Duration)
 		return nil
@@ -307,10 +303,6 @@ func (bc *BackendClient) SetPrefs(new *Prefs) {
 	bc.send(Command{SetPrefs: &SetPrefsArgs{New: new}})
 }
 
-func (bc *BackendClient) EditPrefs(mp *MaskedPrefs) {
-	bc.send(Command{EditPrefs: mp})
-}
-
 func (bc *BackendClient) RequestEngineStatus() {
 	bc.send(Command{RequestEngineStatus: &NoArgs{}})
 }