switch to coroutine execution model

2025-04-30 21:43:06 -07:00
parent f65b1f1c14
commit cc99050964
160 changed files with 269127 additions and 227736 deletions
@@ -0,0 +1,228 @@
+#pragma once
+
+#include "WindowsPlatform.hh"
+
+#include <stdlib.h>
+
+#include <asio.hpp>
+#include <exception>
+#include <functional>
+#include <memory>
+#include <optional>
+#include <phosg/Hash.hh>
+#include <phosg/Time.hh>
+#include <string>
+
+#include "AsyncUtils.hh"
+#include "Server.hh"
+
+struct HTTPRequest {
+  enum class Method {
+    GET = 0,
+    POST,
+    DELETE,
+    HEAD,
+    PATCH,
+    PUT,
+    UPDATE,
+    OPTIONS,
+    CONNECT,
+    TRACE,
+  };
+  std::string http_version;
+  Method method;
+  std::string path;
+  std::string fragment;
+  std::unordered_multimap<std::string, std::string> headers; // Header names converted to all lowercase
+  std::unordered_multimap<std::string, std::string> query_params;
+  std::string data;
+
+  // Header name should be entirely lowercase for this function. Returns
+  // nullptr if the header doesn't exist; throws http_error(400) if multiple
+  // instances of it exist.
+  const std::string* get_header(const std::string& name) const;
+
+  const std::string* get_query_param(const std::string& name) const;
+};
+
+struct HTTPResponse {
+  std::string http_version;
+  int response_code = 200;
+  // Content-Length should NOT be specified in headers; it is automatically
+  // added in async_write() if data is not blank.
+  std::unordered_multimap<std::string, std::string> headers;
+  std::string data;
+};
+
+struct WebSocketMessage {
+  uint8_t header[2] = {0, 0};
+  uint8_t opcode = 0x01;
+  uint8_t mask_key[4] = {0, 0, 0, 0};
+  std::string data;
+};
+
+class HTTPError : public std::runtime_error {
+public:
+  HTTPError(int code, const std::string& what);
+  int code;
+};
+
+struct HTTPClient {
+  AsyncSocketReader r;
+  uint64_t last_communication_time = 0;
+  bool is_websocket = false;
+
+  HTTPClient(asio::ip::tcp::socket&& sock);
+
+  asio::awaitable<HTTPRequest> recv_http_request(size_t max_line_size, size_t max_body_size);
+  asio::awaitable<void> send_http_response(const HTTPResponse& resp);
+
+  asio::awaitable<WebSocketMessage> recv_websocket_message(size_t max_data_size);
+  asio::awaitable<void> send_websocket_message(const void* data, size_t size, uint8_t opcode = 0x01);
+  asio::awaitable<void> send_websocket_message(const std::string& data, uint8_t opcode = 0x01);
+};
+
+struct HTTPServerLimits {
+  size_t max_http_request_line_size = 0x1000; // 4KB
+  size_t max_http_data_size = 0x200000; // 2MB
+  size_t max_http_keepalive_idle_usecs = 300 * 1000 * 1000; // 5 minutes (0 = no limit)
+  size_t max_websocket_message_size = 0x200000; // 2MB
+  size_t max_websocket_idle_usecs = 300 * 1000 * 1000; // 5 minutes (0 = no limit)
+};
+
+extern const HTTPServerLimits DEFAULT_HTTP_LIMITS;
+
+template <typename ClientT = HTTPClient>
+class AsyncHTTPServer : public Server<ClientT, ServerSocket> {
+public:
+  explicit AsyncHTTPServer(
+      std::shared_ptr<asio::io_context> io_context,
+      const std::string& log_prefix = "[AsyncHTTPServer] ",
+      const HTTPServerLimits& limits = DEFAULT_HTTP_LIMITS)
+      : Server<ClientT, ServerSocket>(io_context, log_prefix), limits(limits) {}
+  AsyncHTTPServer(const AsyncHTTPServer&) = delete;
+  AsyncHTTPServer(AsyncHTTPServer&&) = delete;
+  AsyncHTTPServer& operator=(const AsyncHTTPServer&) = delete;
+  AsyncHTTPServer& operator=(AsyncHTTPServer&&) = delete;
+  virtual ~AsyncHTTPServer() = default;
+
+  void listen(const std::string& addr, int port) {
+    if (port == 0) {
+      throw std::runtime_error("Listening port cannot be zero");
+    }
+    asio::ip::address asio_addr = addr.empty() ? asio::ip::address_v4::any() : asio::ip::make_address(addr);
+    auto sock = std::make_shared<ServerSocket>();
+    sock->name = std::format("http:{}:{}", addr, port);
+    sock->endpoint = asio::ip::tcp::endpoint(asio_addr, port);
+    this->add_socket(std::move(sock));
+  }
+
+protected:
+  HTTPServerLimits limits;
+
+  // Attempts to switch the client to WebSockets. Returns true if this is done
+  // successfully (and the caller should then receive/send WebSocket messages),
+  // or false if this failed (and the caller should send an HTTP response).
+  asio::awaitable<bool> enable_websockets(std::shared_ptr<ClientT> c, const HTTPRequest& req) {
+    if (req.method != HTTPRequest::Method::GET) {
+      co_return false;
+    }
+
+    auto connection_header = req.get_header("connection");
+    if (!connection_header || phosg::tolower(*connection_header) != "upgrade") {
+      co_return false;
+    }
+    auto upgrade_header = req.get_header("upgrade");
+    if (!upgrade_header || phosg::tolower(*upgrade_header) != "websocket") {
+      co_return false;
+    }
+    auto sec_websocket_key_header = req.get_header("sec-websocket-key");
+    if (!sec_websocket_key_header) {
+      co_return false;
+    }
+
+    std::string sec_websocket_accept_data = *sec_websocket_key_header + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
+    std::string sec_websocket_accept = phosg::base64_encode(phosg::SHA1(sec_websocket_accept_data).bin());
+
+    HTTPResponse resp;
+    resp.http_version = req.http_version;
+    resp.response_code = 101;
+    resp.headers.emplace("Upgrade", "websocket");
+    resp.headers.emplace("Connection", "upgrade");
+    resp.headers.emplace("Sec-WebSocket-Accept", std::move(sec_websocket_accept));
+    co_await c->send_http_response(resp);
+
+    c->is_websocket = true;
+    co_return true;
+  }
+
+  [[nodiscard]] virtual std::shared_ptr<ClientT> create_client(
+      std::shared_ptr<ServerSocket>, asio::ip::tcp::socket&& client_sock) {
+    return std::make_shared<HTTPClient>(std::move(client_sock));
+  }
+
+  // handle_request must do one of the following three things:
+  // 1. Return an HTTP response.
+  // 2. Call enable_websockets, and if it returns true, return nullptr. After
+  //    this point, handle_request will not be called again for this client;
+  //    handle_websocket_message will be called instead when any WebSocket
+  //    messages are received. If enable_websockets returns false,
+  //    handle_request must still return an HTTP response.
+  // 3. Throw an exception. In this case, the client receives an HTTP 500
+  //    response.
+  virtual asio::awaitable<std::unique_ptr<HTTPResponse>> handle_request(std::shared_ptr<ClientT> c, HTTPRequest&& req) = 0;
+  virtual asio::awaitable<void> handle_websocket_message(std::shared_ptr<ClientT>, WebSocketMessage&&) {
+    co_return;
+  }
+
+  virtual asio::awaitable<void> handle_client(std::shared_ptr<ClientT> c) {
+    asio::steady_timer idle_timer(*this->io_context);
+    while (c->r.get_socket().is_open()) {
+      if (c->is_websocket) {
+        WebSocketMessage msg = co_await c->recv_websocket_message(this->limits.max_websocket_message_size);
+        idle_timer.cancel();
+        try {
+          co_await this->handle_websocket_message(c, std::move(msg));
+        } catch (const std::exception& e) {
+          c->r.close();
+        }
+
+      } else {
+        HTTPRequest req = co_await c->recv_http_request(
+            this->limits.max_http_request_line_size, this->limits.max_http_data_size);
+        idle_timer.cancel();
+        std::unique_ptr<HTTPResponse> resp;
+        try {
+          resp = co_await this->handle_request(c, std::move(req));
+        } catch (const std::exception& e) {
+          resp = std::make_unique<HTTPResponse>();
+          resp->http_version = req.http_version;
+          resp->response_code = 500;
+          resp->headers.emplace("Content-Type", "text/plain");
+          resp->data = "Internal server error:\n";
+          resp->data += e.what();
+        }
+        if (resp) {
+          co_await c->send_http_response(*resp);
+        }
+        auto* conn_header = req.get_header("connection");
+        if (!conn_header || (*conn_header != "keep-alive")) {
+          c->r.close();
+        }
+      }
+
+      size_t idle_usecs_limit = c->is_websocket
+          ? this->limits.max_websocket_idle_usecs
+          : this->limits.max_http_keepalive_idle_usecs;
+      if (idle_usecs_limit && c->r.get_socket().is_open()) {
+        idle_timer.expires_after(std::chrono::microseconds(idle_usecs_limit));
+        idle_timer.async_wait([c](std::error_code ec) {
+          if (!ec) {
+            c->r.close();
+          }
+        });
+      }
+    }
+    idle_timer.cancel();
+  }
+};