Files
damus/damus/Nostr/RelayConnection.swift
2023-02-19 08:36:03 -08:00

157 lines
4.1 KiB
Swift

//
// NostrConnection.swift
// damus
//
// Created by William Casarin on 2022-04-02.
//
import Foundation
import Starscream
enum NostrConnectionEvent {
case ws_event(WebSocketEvent)
case nostr_event(NostrResponse)
}
final class RelayConnection: WebSocketDelegate {
private(set) var isConnected = false
private(set) var isConnecting = false
private(set) var isReconnecting = false
private(set) var last_connection_attempt: TimeInterval = 0
private lazy var socket = {
let req = URLRequest(url: url)
let socket = WebSocket(request: req, compressionHandler: .none)
socket.delegate = self
return socket
}()
private var handleEvent: (NostrConnectionEvent) -> ()
private let url: URL
init(url: URL, handleEvent: @escaping (NostrConnectionEvent) -> ()) {
self.url = url
self.handleEvent = handleEvent
}
func reconnect() {
if isConnected {
isReconnecting = true
disconnect()
} else {
// we're already disconnected, so just connect
connect(force: true)
}
}
func connect(force: Bool = false) {
if !force && (isConnected || isConnecting) {
return
}
isConnecting = true
last_connection_attempt = Date().timeIntervalSince1970
socket.connect()
}
func disconnect() {
socket.disconnect()
isConnected = false
isConnecting = false
}
func send(_ req: NostrRequest) {
guard let req = make_nostr_req(req) else {
print("failed to encode nostr req: \(req)")
return
}
socket.write(string: req)
}
// MARK: - WebSocketDelegate
func didReceive(event: WebSocketEvent, client: WebSocket) {
switch event {
case .connected:
self.isConnected = true
self.isConnecting = false
case .disconnected:
self.isConnecting = false
self.isConnected = false
if self.isReconnecting {
self.isReconnecting = false
self.connect()
}
case .cancelled, .error:
self.isConnecting = false
self.isConnected = false
case .text(let txt):
if txt.count > 2000 {
DispatchQueue.global(qos: .default).async {
if let ev = decode_nostr_event(txt: txt) {
DispatchQueue.main.async {
self.handleEvent(.nostr_event(ev))
}
return
}
}
} else {
if let ev = decode_nostr_event(txt: txt) {
handleEvent(.nostr_event(ev))
return
}
}
print("decode failed for \(txt)")
// TODO: trigger event error
default:
break
}
handleEvent(.ws_event(event))
}
}
func make_nostr_req(_ req: NostrRequest) -> String? {
switch req {
case .subscribe(let sub):
return make_nostr_subscription_req(sub.filters, sub_id: sub.sub_id)
case .unsubscribe(let sub_id):
return make_nostr_unsubscribe_req(sub_id)
case .event(let ev):
return make_nostr_push_event(ev: ev)
}
}
func make_nostr_push_event(ev: NostrEvent) -> String? {
guard let event = encode_json(ev) else {
return nil
}
let encoded = "[\"EVENT\",\(event)]"
print(encoded)
return encoded
}
func make_nostr_unsubscribe_req(_ sub_id: String) -> String? {
"[\"CLOSE\",\"\(sub_id)\"]"
}
func make_nostr_subscription_req(_ filters: [NostrFilter], sub_id: String) -> String? {
let encoder = JSONEncoder()
var req = "[\"REQ\",\"\(sub_id)\""
for filter in filters {
req += ","
guard let filter_json = try? encoder.encode(filter) else {
return nil
}
let filter_json_str = String(decoding: filter_json, as: UTF8.self)
req += filter_json_str
}
req += "]"
return req
}