From 08a03534af459da00d57e5ad66c08a86954cee90 Mon Sep 17 00:00:00 2001
From: Luke Wilde <luke@ladybird.org>
Date: Mon, 7 Jul 2025 16:03:37 +0100
Subject: [PATCH] Meta+RequestServer: Enable HTTP/3 for curl

This adds an overlay port for curl that adds the features required for
HTTP/3.

This is not quite compatible with the upstream vcpkg.json, because
enabling HTTP/2 makes it use the default SSL backend, which is
sectransp for macOS and schannel on Windows. These backends are not
compatible with ngtcp2. Additionally, we can not build curl with
multiple SSL backends when using ngtcp2.

I couldn't find a way to selectively disable/enable dependencies based
on what features are enabled, so I made HTTP/2 pick OpenSSL in our
overlay port. Upstream vcpkg will likely want to support wolfSSL and
GnuTLS backends for ngtcp2, so they'll be additional work to get this
into upstream.
---
 .../vcpkg/overlay-ports/curl/portfile.cmake   |  1 +
 .../CMake/vcpkg/overlay-ports/curl/vcpkg.json | 23 +++++++++++++++++--
 .../RequestServer/ConnectionFromClient.cpp    |  4 ++++
 Services/RequestServer/ConnectionFromClient.h |  1 +
 vcpkg.json                                    |  3 +++
 5 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/Meta/CMake/vcpkg/overlay-ports/curl/portfile.cmake b/Meta/CMake/vcpkg/overlay-ports/curl/portfile.cmake
index acace7742e9..145ccdc9234 100644
--- a/Meta/CMake/vcpkg/overlay-ports/curl/portfile.cmake
+++ b/Meta/CMake/vcpkg/overlay-ports/curl/portfile.cmake
@@ -14,6 +14,7 @@ vcpkg_from_github(
 vcpkg_check_features(OUT_FEATURE_OPTIONS FEATURE_OPTIONS
     FEATURES
         http2       USE_NGHTTP2
+        http3       USE_NGTCP2
         wolfssl     CURL_USE_WOLFSSL
         openssl     CURL_USE_OPENSSL
         mbedtls     CURL_USE_MBEDTLS
diff --git a/Meta/CMake/vcpkg/overlay-ports/curl/vcpkg.json b/Meta/CMake/vcpkg/overlay-ports/curl/vcpkg.json
index 5ba1727c370..0f463941cbc 100644
--- a/Meta/CMake/vcpkg/overlay-ports/curl/vcpkg.json
+++ b/Meta/CMake/vcpkg/overlay-ports/curl/vcpkg.json
@@ -65,12 +65,31 @@
           "name": "curl",
           "default-features": false,
           "features": [
-            "ssl"
+            "openssl"
           ]
         },
         "nghttp2"
       ]
     },
+    "http3": {
+      "description": "HTTP3 support",
+      "dependencies": [
+        {
+          "name": "curl",
+          "default-features": false,
+          "features": [
+            "openssl"
+          ]
+        },
+        "nghttp3",
+        {
+          "name": "ngtcp2",
+          "features": [
+            "openssl"
+          ]
+        }
+      ]
+    },
     "httpsrr": {
       "description": "enable support for HTTPS RR"
     },
@@ -125,7 +144,7 @@
       ]
     },
     "non-http": {
-      "description": "Enables protocols beyond HTTP/HTTPS/HTTP2"
+      "description": "Enables protocols beyond HTTP/HTTPS/HTTP2/HTTP3"
     },
     "openssl": {
       "description": "SSL support (OpenSSL)",
diff --git a/Services/RequestServer/ConnectionFromClient.cpp b/Services/RequestServer/ConnectionFromClient.cpp
index 838d8d3988b..730182af504 100644
--- a/Services/RequestServer/ConnectionFromClient.cpp
+++ b/Services/RequestServer/ConnectionFromClient.cpp
@@ -13,6 +13,7 @@
 #include <LibCore/EventLoop.h>
 #include <LibCore/Proxy.h>
 #include <LibCore/Socket.h>
+#include <LibCore/StandardPaths.h>
 #include <LibRequests/NetworkError.h>
 #include <LibRequests/RequestTimingInfo.h>
 #include <LibRequests/WebSocket.h>
@@ -315,6 +316,8 @@ ConnectionFromClient::ConnectionFromClient(NonnullOwnPtr<IPC::Transport> transpo
 {
     s_connections.set(client_id(), *this);
 
+    m_alt_svc_cache_path = ByteString::formatted("{}/Ladybird/alt-svc-cache.txt", Core::StandardPaths::user_data_directory());
+
     m_curl_multi = curl_multi_init();
 
     auto set_option = [this](auto option, auto value) {
@@ -488,6 +491,7 @@ void ConnectionFromClient::start_request(i32 request_id, ByteString method, URL:
             set_option(CURLOPT_PORT, url.port_or_default());
             set_option(CURLOPT_CONNECTTIMEOUT, s_connect_timeout_seconds);
             set_option(CURLOPT_PIPEWAIT, 1L);
+            set_option(CURLOPT_ALTSVC, m_alt_svc_cache_path.characters());
 
             bool did_set_body = false;
 
diff --git a/Services/RequestServer/ConnectionFromClient.h b/Services/RequestServer/ConnectionFromClient.h
index 87d2550d518..bd9a8cfd24a 100644
--- a/Services/RequestServer/ConnectionFromClient.h
+++ b/Services/RequestServer/ConnectionFromClient.h
@@ -70,6 +70,7 @@ private:
     HashMap<int, NonnullRefPtr<Core::Notifier>> m_read_notifiers;
     HashMap<int, NonnullRefPtr<Core::Notifier>> m_write_notifiers;
     NonnullRefPtr<Resolver> m_resolver;
+    ByteString m_alt_svc_cache_path;
 };
 
 // FIXME: Find a good home for this
diff --git a/vcpkg.json b/vcpkg.json
index c2e30ad6c5e..e47384033ed 100644
--- a/vcpkg.json
+++ b/vcpkg.json
@@ -14,9 +14,12 @@
     },
     {
       "name": "curl",
+      "default-features": false,
       "features": [
         "brotli",
+        "non-http",
         "http2",
+        "http3",
         "openssl",
         "websockets"
       ]