400 bad request error when send a GET http request

Question

I'm trying to send a GET request to a webserver(example: www.coursera.org,...). But sServer returns a response header: HTTP/1.1 400 bad request

I used Winsock in C++ and establish a socket connect to server. Then, send a GET request to server.

int main(void) {

    get_Website("www.coursera.org");

    cout << website_HTML;

    cout << "\n\nPress ANY key to close.\n\n";
    cin.ignore(); cin.get();


    return 0;
}


void get_Website(string url) 
{

    WSADATA wsaData;
    SOCKET Socket;
    SOCKADDR_IN SockAddr;
    int lineCount = 0;
    int rowCount = 0;
    struct hostent* localHost;
    string srequete;
    char* localIP;


    srequete = "GET / HTTP/1.0\r\n";
    srequete += "Host: www.coursera.org\r\n";
    srequete += "Connection: close\r\n\r\n";

    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) {
        cout << "WSAStartup failed.\n";
        system("pause");
        //return 1;
    }

    Socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    localHost = gethostbyname(url.c_str());
    localIP = inet_ntoa(*(struct in_addr *)*localHost->h_addr_list);
    SockAddr.sin_port = htons(443);
    SockAddr.sin_family = AF_INET;
    SockAddr.sin_addr.s_addr = inet_addr(localIP);

    if (connect(Socket, (SOCKADDR*)(&SockAddr), sizeof(SockAddr)) != 0) {
        cout << "Could not connect";
        system("pause");
        //return 1;
    }
    send(Socket, srequete.c_str(), strlen(srequete.c_str()), 0);

    int nDataLength;
    while ((nDataLength = recv(Socket, buffer, 10000, 0)) > 0) {
        int i = 0;
        while (buffer[i] >= 32 || buffer[i] == '\n' || buffer[i] == '\r') {
            website_HTML += buffer[i];
            i += 1;
        }
    }

    closesocket(Socket);
    WSACleanup();

}

The problem seems to be GET request that is wrong?

Answer 1

They can't parse your request because you are trying to send it to https port (443) unencrypted. You can try to send it http port (80), but they will redirect you to https://coursera.org anyway.