discourse/app/services/push_notification_pusher.rb

# frozen_string_literal: true

class PushNotificationPusher
  TOKEN_VALID_FOR_SECONDS ||= 5 * 60

  def self.push(user, payload)
    I18n.with_locale(user.effective_locale) do
      message = {
        title: I18n.t(
          "discourse_push_notifications.popup.#{Notification.types[payload[:notification_type]]}",
          site_title: SiteSetting.title,
          topic: payload[:topic_title],
          username: payload[:username]
        ),
        body: payload[:excerpt],
        badge: get_badge,
        icon: ActionController::Base.helpers.image_url("push-notifications/#{Notification.types[payload[:notification_type]]}.png"),
        tag: "#{Discourse.current_hostname}-#{payload[:topic_id]}",
        base_url: Discourse.base_url,
        url: payload[:post_url],
        hide_when_active: true
      }

      subscriptions(user).each do |subscription|
        subscription = JSON.parse(subscription.data)
        send_notification(user, subscription, message)
      end
    end
  end

  def self.subscriptions(user)
    user.push_subscriptions
  end

  def self.clear_subscriptions(user)
    user.push_subscriptions.clear
  end

  def self.subscribe(user, subscription, send_confirmation)
    data = subscription.to_json
    subscriptions = PushSubscription.where(user: user, data: data)
    subscriptions_count = subscriptions.count

    if subscriptions_count > 1
      subscriptions.destroy_all
      PushSubscription.create!(user: user, data: data)
    elsif subscriptions_count == 0
      PushSubscription.create!(user: user, data: data)
    end

    if send_confirmation == "true"
      message = {
        title: I18n.t("discourse_push_notifications.popup.confirm_title",
                      site_title: SiteSetting.title),
        body: I18n.t("discourse_push_notifications.popup.confirm_body"),
        icon: ActionController::Base.helpers.image_url("push-notifications/check.png"),
        badge: get_badge,
        tag: "#{Discourse.current_hostname}-subscription"
      }

      send_notification(user, subscription, message)
    end
  end

  def self.unsubscribe(user, subscription)
    PushSubscription.find_by(user: user, data: subscription.to_json)&.destroy!
  end

  protected

  def self.get_badge
    if (url = SiteSetting.site_push_notifications_icon_url).present?
      url
    else
      ActionController::Base.helpers.image_url("push-notifications/discourse.png")
    end
  end

  def self.send_notification(user, subscription, message)
    endpoint = subscription["endpoint"]
    p256dh = subscription.dig("keys", "p256dh")
    auth = subscription.dig("keys", "auth")

    if (endpoint.blank? || p256dh.blank? || auth.blank?)
      unsubscribe(user, subscription)
      return
    end

    begin
      Webpush.payload_send(
        endpoint: endpoint,
        message: message.to_json,
        p256dh: p256dh,
        auth: auth,
        vapid: {
          subject: Discourse.base_url,
          public_key: SiteSetting.vapid_public_key,
          private_key: SiteSetting.vapid_private_key,
          expiration: TOKEN_VALID_FOR_SECONDS
        }
      )
    rescue Webpush::ExpiredSubscription
      unsubscribe(user, subscription)
    rescue Webpush::ResponseError => e
      if e.response.message == "MismatchSenderId"
        unsubscribe(user, subscription)
      else
        Discourse.warn_exception(
          e,
          message: "Failed to send push notification",
          env: {
            user_id: user.id,
            endpoint: subscription["endpoint"],
            message: message.to_json
          }
        )
      end
    end
  end
end