Merge branch 'feature/mobile-push'

# Conflicts:
#	internal/sandbar/api.go

internal/sandbar/server.go

@@ -1,6 +1,7 @@
 package sandbar
 
 import (
+	"crypto/ecdsa"
 	_ "embed"
 	"log"
 	"net/http"
@@ -28,6 +29,17 @@ type Options struct {
 	HitDays      int  // how long website analytics are kept (default 365)
 	TrustProxy   bool // take the client address from X-Forwarded-For, for use behind a reverse proxy
 
+	// Mobile companion (see push.go and mobile.go).
+	AppDir           string // folder with the companion PWA, served at /app/
+	AppOrigin        string // origin allowed to call the API from another site, such as https://sandbar-app.example.com
+	VapidSubject     string // contact sent to push services: a mailto: or https: address (default: URL, if https)
+	PushAllowPrivate bool   // allow push endpoints on private addresses and plain http, for development only
+
+	// Hammerhead link: when set, GET /api/v1/hammerhead/edges shows its edge and tunnel status.
+	HammerheadURL      string
+	HammerheadEmail    string
+	HammerheadPassword string
+
 	// Self-update (see update.go). Version is the running release, such as v0.2.0; anything else
 	// ("dev") never updates. Restart is called after a new binary is installed and should close
 	// what the process holds open before re-executing it.
@@ -57,6 +69,13 @@ type Server struct {
 
 	upd updateState
 
+	pushMu   sync.Mutex // the VAPID key pair, loaded or created on first use
+	vapid    *ecdsa.PrivateKey
+	vapidPub string
+
+	hhMu     sync.Mutex
+	hhClient *http.Client
+
 	anaMu     sync.Mutex // website analytics: the visitor salt and a per-address rate limit
 	anaSecret string
 	anaTry    map[string][]time.Time