LibRequests: Fail websockets when RequestServer dies

Detach live websocket wrappers from a dead RequestServer connection,
notify them with error and close events, and defer the
on_request_server_died callback out of RequestClient::die().

Without this, a dead RequestServer could leave existing websocket
objects stuck forever and future websocket construction could keep
using a stale RequestClient with no terminal events.

Libraries/LibRequests/RequestClient.cpp

@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <LibCore/EventLoop.h>
 #include <LibCore/Promise.h>
 #include <LibCore/System.h>
 #include <LibRequests/Request.h>
@@ -28,8 +29,29 @@ void RequestClient::die()
     for (auto& [id, promise] : m_pending_cache_size_estimations)
         promise->reject(Error::from_string_literal("RequestServer process died"));
 
+    auto websockets = move(m_websockets);
+
     m_requests.clear();
     m_pending_cache_size_estimations.clear();
+    m_websockets.clear();
+
+    for (auto& [id, websocket] : websockets) {
+        auto ready_state = websocket->ready_state();
+        websocket->detach_from_client({});
+        websocket->set_ready_state(WebSocket::ReadyState::Closed);
+
+        auto error = ready_state == WebSocket::ReadyState::Connecting
+            ? WebSocket::Error::CouldNotEstablishConnection
+            : WebSocket::Error::ServerClosedSocket;
+        websocket->did_error({}, to_underlying(error));
+        websocket->did_close({}, to_underlying(::WebSocket::CloseStatusCode::AbnormalClosure), {}, false);
+    }
+
+    if (auto request_server_died_callback = move(on_request_server_died)) {
+        Core::deferred_invoke([request_server_died_callback = move(request_server_died_callback)]() mutable {
+            request_server_died_callback();
+        });
+    }
 }
 
 RefPtr<Request> RequestClient::start_request(ByteString const& method, URL::URL const& url, Optional<HTTP::HeaderList const&> request_headers, ReadonlyBytes request_body, HTTP::CacheMode cache_mode, HTTP::Cookie::IncludeCredentials include_credentials, Core::ProxyData const& proxy_data)

Libraries/LibRequests/WebSocket.cpp

@@ -37,6 +37,8 @@ void WebSocket::set_subprotocol_in_use(ByteString subprotocol)
 
 void WebSocket::send(ReadonlyBytes binary_or_text_message, bool is_text)
 {
+    if (!m_client)
+        return;
     m_client->async_websocket_send(m_websocket_id, is_text, binary_or_text_message);
 }
 
@@ -47,6 +49,8 @@ void WebSocket::send(StringView text_message)
 
 void WebSocket::close(u16 code, ByteString reason)
 {
+    if (!m_client)
+        return;
     m_client->async_websocket_close(m_websocket_id, code, move(reason));
 }
 
@@ -78,9 +82,14 @@ void WebSocket::did_request_certificates(Badge<RequestClient>)
 {
     if (on_certificate_requested) {
         auto result = on_certificate_requested();
-        if (!m_client->websocket_set_certificate(m_websocket_id, result.certificate, result.key))
+        if (!m_client || !m_client->websocket_set_certificate(m_websocket_id, result.certificate, result.key))
             dbgln("WebSocket: set_certificate failed");
     }
 }
 
+void WebSocket::detach_from_client(Badge<RequestClient>)
+{
+    m_client = nullptr;
+}
+
 }

Libraries/LibRequests/WebSocket.h

@@ -70,6 +70,7 @@ public:
     void did_error(Badge<RequestClient>, i32);
     void did_close(Badge<RequestClient>, u16, ByteString, bool);
     void did_request_certificates(Badge<RequestClient>);
+    void detach_from_client(Badge<RequestClient>);
 
 private:
     WebSocket(RequestClient&, u64 websocket_id);