Add PWA, service worker and Web Push

- Use new notification request/opt-in flow for push
- Implement unsubscribing
- Implement muting
- Implement emojis in title
- Add iOS specific PWA warning
- Don’t use websockets when web push is enabled
- Fix duplicate notifications
- Implement default web push setting
- Implement changing subscription type
- Implement web push subscription refresh
- Implement web push notification click

server/web_push.go

@@ -0,0 +1,132 @@
+package server
+
+import (
+	"database/sql"
+
+	_ "github.com/mattn/go-sqlite3" // SQLite driver
+)
+
+// Messages cache
+const (
+	createWebPushSubscriptionsTableQuery = `
+		BEGIN;
+		CREATE TABLE IF NOT EXISTS web_push_subscriptions (
+			id INTEGER PRIMARY KEY AUTOINCREMENT,
+			topic TEXT NOT NULL,
+			username TEXT,
+			endpoint TEXT NOT NULL,
+			key_auth TEXT NOT NULL,
+			key_p256dh TEXT NOT NULL,
+			updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
+		);
+		CREATE INDEX IF NOT EXISTS idx_topic ON web_push_subscriptions (topic);
+		CREATE INDEX IF NOT EXISTS idx_endpoint ON web_push_subscriptions (endpoint);
+		CREATE UNIQUE INDEX IF NOT EXISTS idx_topic_endpoint ON web_push_subscriptions (topic, endpoint);
+		COMMIT;
+	`
+	insertWebPushSubscriptionQuery = `
+		INSERT OR REPLACE INTO web_push_subscriptions (topic, username, endpoint, key_auth, key_p256dh)
+		VALUES (?, ?, ?, ?, ?);
+	`
+	deleteWebPushSubscriptionByEndpointQuery         = `DELETE FROM web_push_subscriptions WHERE endpoint = ?`
+	deleteWebPushSubscriptionByUsernameQuery         = `DELETE FROM web_push_subscriptions WHERE username = ?`
+	deleteWebPushSubscriptionByTopicAndEndpointQuery = `DELETE FROM web_push_subscriptions WHERE topic = ? AND endpoint = ?`
+
+	selectWebPushSubscriptionsForTopicQuery = `SELECT endpoint, key_auth, key_p256dh, username FROM web_push_subscriptions WHERE topic = ?`
+
+	selectWebPushSubscriptionsCountQuery = `SELECT COUNT(*) FROM web_push_subscriptions`
+)
+
+type webPushSubscriptionStore struct {
+	db *sql.DB
+}
+
+func newWebPushSubscriptionStore(filename string) (*webPushSubscriptionStore, error) {
+	db, err := sql.Open("sqlite3", filename)
+	if err != nil {
+		return nil, err
+	}
+	if err := setupSubscriptionDb(db); err != nil {
+		return nil, err
+	}
+	webPushSubscriptionStore := &webPushSubscriptionStore{
+		db: db,
+	}
+	return webPushSubscriptionStore, nil
+}
+
+func setupSubscriptionDb(db *sql.DB) error {
+	// If 'messages' table does not exist, this must be a new database
+	rowsMC, err := db.Query(selectWebPushSubscriptionsCountQuery)
+	if err != nil {
+		return setupNewSubscriptionDb(db)
+	}
+	rowsMC.Close()
+	return nil
+}
+
+func setupNewSubscriptionDb(db *sql.DB) error {
+	if _, err := db.Exec(createWebPushSubscriptionsTableQuery); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (c *webPushSubscriptionStore) AddSubscription(topic string, username string, subscription webPushSubscribePayload) error {
+	_, err := c.db.Exec(
+		insertWebPushSubscriptionQuery,
+		topic,
+		username,
+		subscription.BrowserSubscription.Endpoint,
+		subscription.BrowserSubscription.Keys.Auth,
+		subscription.BrowserSubscription.Keys.P256dh,
+	)
+	return err
+}
+
+func (c *webPushSubscriptionStore) RemoveSubscription(topic string, endpoint string) error {
+	_, err := c.db.Exec(
+		deleteWebPushSubscriptionByTopicAndEndpointQuery,
+		topic,
+		endpoint,
+	)
+	return err
+}
+
+func (c *webPushSubscriptionStore) GetSubscriptionsForTopic(topic string) (subscriptions []webPushSubscription, err error) {
+	rows, err := c.db.Query(selectWebPushSubscriptionsForTopicQuery, topic)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	data := []webPushSubscription{}
+	for rows.Next() {
+		i := webPushSubscription{}
+		err = rows.Scan(&i.BrowserSubscription.Endpoint, &i.BrowserSubscription.Keys.Auth, &i.BrowserSubscription.Keys.P256dh, &i.Username)
+		if err != nil {
+			return nil, err
+		}
+		data = append(data, i)
+	}
+	return data, nil
+}
+
+func (c *webPushSubscriptionStore) ExpireWebPushEndpoint(endpoint string) error {
+	_, err := c.db.Exec(
+		deleteWebPushSubscriptionByEndpointQuery,
+		endpoint,
+	)
+	return err
+}
+
+func (c *webPushSubscriptionStore) ExpireWebPushForUser(username string) error {
+	_, err := c.db.Exec(
+		deleteWebPushSubscriptionByUsernameQuery,
+		username,
+	)
+	return err
+}
+func (c *webPushSubscriptionStore) Close() error {
+	return c.db.Close()
+}