我如何知道请求是否完全使用 TCP 套接字接收？

Question

我有一个多线程 HTTP TCP 服务器（用 Linux 编写），下面是处理客户端的函数：

    void tcp_server::connection_handler(client* cl) {
    // add client to the clients <vector>
    mx.lock();

    cl->set_id(static_cast<int>(clients.size()));
    clients.push_back(*cl);
    cout << "New client with id " << cl->get_id() << " has been added to the clients list" << endl << endl;

    mx.unlock();

    char read_buffer[1024];
    ssize_t message_size;
    string received_message;
    while (accept_connections) {
        memset(&read_buffer, 0, sizeof(read_buffer));
        received_message.clear();

        message_size = recv(cl->sock, read_buffer, sizeof(read_buffer) - 1, 0);

        if (message_size == 0) {
            // client disconnected
            cout << "Client with id " << cl->get_id() << " has been disconnected" << endl;
            close(cl->sock);

            //remove client from the clients <vector>
            mx.lock();

            int client_index = find_client_index(cl);
            clients.erase(clients.begin() + client_index);
            cout << "Client with id " << cl->get_id() << " has been removed from the clients list" << endl;

            mx.unlock();

            delete cl;

            break;
        }
        if (message_size == -1) {
            if (!accept_connections) {
                cerr << "Unable to receive message from client with id " << cl->get_id() << ". Server has been shut down. Stop receiving messages from this client" << endl;
            }
            else {
                cerr << "Error while receiving message from client with id " << cl->get_id() << endl;
            }
            cerr << strerror(errno) << endl;
        }
        else {
            //message was received succesfully

            cout << "[Server] Client's message has been received" << endl;
            cout << "[Server] Client's message: " << endl;
            cout << "----------------------------" << endl;
            cout << read_buffer << endl;
            cout << "----------------------------" << endl;

            for (unsigned int i = 0; i < message_size; i++) {
                received_message.push_back(read_buffer[i]);
            }

            string response_message = convert_client_message(received_message);

            if (send(cl->sock, response_message.c_str(), response_message.size(), 0) == -1) {
                cout << "[Server] Message sending to client with id " << cl->get_id() << " failed" << endl;
            }

            cout << "[Server] Server's response: " << endl;
            cout << "----------------------------" << endl;
            cout << response_message << endl;
            cout << "----------------------------" << endl << endl;

            cout << "[Server] Message has been sent to client" << endl << endl;
            cout << "============================" << endl << endl;
        }
    }
}

你怎么看出来的，有一个缓冲区，里面有客户端的消息，只有1024字节，当请求可以大于1024字节的时候。所以，问题是：我需要知道请求是否被完全接收。我正在考虑编写可能会告诉我是否收到完整请求的解析器，但我真的不知道如何检测完整请求。

Answer 1

I was thinking about writing parser that might tell me if a full request was received, but I don't really know how to detect full request.

在实现协议时，建议实际仔细查看协议的规范。

如果您阅读 HTTP 1.1 specification, you will realize that each HTTP message consists of headers and an optional body. The request is fully read once you have read the request headers and optional body. The headers end with an empty line \r\n sequence. Some HTTP methods, like POST, might have a body, in which case you'll find the length of the body in the Content-Length header, or you have to deal with the chunked transfer encoding。

请研究规范以获取更多详细信息。

我如何知道请求是否完全使用 TCP 套接字接收？

How do I know if the request was received completely using TCP sockets?

c++

sockets

tcp

tcpserver