Winsock 2正在从URL读取文本

Winsock 2 Reading text from a URL

本文关键字：URL 读取 取文本 Winsock      更新时间：2023-10-16

例如，这就是我想要做的：

    if (http->Connect("http://pastebin.com/raw/9uL16CyN"))
    {
        YString data = "";
        if (http->ReceiveData(data))
        {
            std::cout << "Networked data: " << std::endl;
            std::cout << data << std::endl;
        }
        else
            std::cout << "Failed to connect to internet.n";
    }

我试图从中读取的页面是原始ASCII文本(http://pastebin.com/raw/9uL16CyN)

我希望这能很容易地工作，但显然不是，我一直收到WSA错误：WSAHOST_not_FOUND（11001）

我的连接功能：

bool Http::Connect(YString addr)
{
    _socket = Network::CreateConnectSocket(addr, 53); // 53 is the port
    return _socket != INVALID_SOCKET;
}

CreateConnectSocket函数：

int iResult;
SOCKET ConnectSocket = INVALID_SOCKET;
// holds address info for socket to connect to
struct addrinfo *result = NULL,
    *ptr = NULL,
    hints;
ZeroMemory(&hints, sizeof(hints));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;  //TCP connection!!!
                                  //resolve server address and port
iResult = getaddrinfo(addr.c_str(), std::to_string(port).c_str(), &hints, &result);
if (iResult != 0)
{
    printf("Network::CreateSocket failed with %s as addr, and %i as port.nError code: %i.n", (char*)addr.c_str(), port, iResult);
    return INVALID_SOCKET;
}
for (ptr = result; ptr != NULL; ptr = ptr->ai_next) {
    // Create a SOCKET for connecting to server
    ConnectSocket = socket(ptr->ai_family, ptr->ai_socktype, ptr->ai_protocol);
    if (ConnectSocket == INVALID_SOCKET) {
        printf("Network::CreateSocket failed with error: %ldn", WSAGetLastError());
        return INVALID_SOCKET;
    }
    // Connect to server.
    iResult = connect(ConnectSocket, ptr->ai_addr, (int)ptr->ai_addrlen);
    if (iResult == SOCKET_ERROR)
    {
        closesocket(ConnectSocket);
        ConnectSocket = INVALID_SOCKET;
        printf("Network::CreateSocket failed the server is down... did not connect.n");
    }
}
freeaddrinfo(result);
if (ConnectSocket == INVALID_SOCKET)
{
    printf("Network::CreateSocket failed.n");
    return INVALID_SOCKET;
}
u_long iMode = 1;
iResult = ioctlsocket(ConnectSocket, FIONBIO, &iMode);
if (iResult == SOCKET_ERROR)
{
    printf("Network::CreateSocket ioctlsocket failed with error: %dn", WSAGetLastError());
    closesocket(ConnectSocket);
    return INVALID_SOCKET;
}
char value = 1;
setsockopt(ConnectSocket, IPPROTO_TCP, TCP_NODELAY, &value, sizeof(value));
return ConnectSocket;

大部分来自现有来源。

您对Connect()的调用是错误的。不能将完整URL传递给getaddrinfo()。您只需要自己传递域名和端口号。顺便说一句，HTTP端口是80，而不是53。

此外，您不会向服务器发送HTTP GET请求，要求其向您发送文本文档。在您首先发送请求之前，HTTP服务器不会发送响应。

你需要更像这样的东西：

bool Http::Connect(YString addr, int port)
{
    _socket = Network::CreateConnectSocket(addr, port);
    return _socket != INVALID_SOCKET;
}

if (http->Connect("pastebin.com", 80))
{
    YString data = "GET /raw/9uL16CyN HTTP/1.1rn"
                   "Host: pastebin.comrn"
                   "Connection: closern"
                   "rn";
    if (http->SendData(data))
    {
        YString data = "";
        if (http->ReceiveData(data))
        {
            std::cout << "Networked data: " << std::endl;
            std::cout << data << std::endl;
        }
        else
            std::cout << "Failed to receive data from internet.n";
    }
    else
        std::cout << "Failed to send request to Pastebin.n";
}
else
    std::cout << "Failed to connect to Pastebin.n";

话虽如此，您需要考虑到服务器将用标头来构建响应数据，例如：

GET /raw/9uL16CyN HTTP/1.1
Host: pastebin.com

HTTP/1.1 200 OK
Date: Wed, 23 Dec 2015 00:00:01 GMT
Content-Type: text/plain; charset=utf-8
Transfer-Encoding: chunked
Connection: keep-alive
Set-Cookie: __cfduid=db6ba4b037d673b67757500aca4e2227b1450828801; expires=Thu, 22-Dec-16 00:00:01 GMT; path=/; domain=.pastebin.com; HttpOnly
X-Powered-By: PHP/5.5.5
Cache-Control: public, max-age=1801
Vary: Accept-Encoding
CF-Cache-Status: HIT
Expires: Wed, 23 Dec 2015 00:30:02 GMT
Server: cloudflare-nginx
CF-RAY: 258fc8a8168a2276-LAX
2a
Text, text, text, text! Some more text! :D
0

因此，假设ReceiveData()只是返回它接收到的任何内容，那么在您可以单独使用文本文件的内容之前，您必须去掉这些标头，并撤消chunked编码。请阅读RFC2616（或其后续RFC7230-7235），其中详细概述了HTTP协议。

话虽如此，您应该停止尝试手动实现HTTP（它比您意识到的更复杂），而是使用预先存在的库，就像libcurl，甚至Microsoft自己的WinInet或WinHTTP API一样。让他们为你做繁重的工作。

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