Socket connection 301 or 400 - c++

Question

i have a problem with sending GET to my domain. With 80 port, i receive 301 moved permanently, with 443 port, i receive 400 Bad Request. When i turn off redirect to https, all ok.
std::string HttpGet(std::string szHost, std::string szApi) {
std::string request;
std::string response;
int resp_leng;
char buffer[1024];
struct sockaddr_in serveraddr;
int sock;
WSADATA wsaData;
if (WSAStartup(MAKEWORD(2, 0), &wsaData) != 0) L::Print(XorStr("web_parser: WSAStartup() failed"));
struct hostent* host;
host = gethostbyname(szHost.c_str());
int port = 80;
request += "GET " + szApi + " HTTP/1.0\r\n";
request += "Host: " + szHost + "\r\n";
request += "User-Agent: WebParser [Build: 1.1] \r\n";
request += "\r\n";
if ((sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) L::Print(XorStr("web_parser: socket() failed"));
memset(&serveraddr, 0, sizeof(serveraddr));
serveraddr.sin_family = AF_INET;
serveraddr.sin_addr.s_addr = *((unsigned long*)host->h_addr);
serveraddr.sin_port = htons((unsigned short)port);
struct in_addr** addr_list;
addr_list = (struct in_addr**)host->h_addr_list;
response = "";
if (connect(sock, (struct sockaddr*)&serveraddr, sizeof(serveraddr)) < 0) L::Print(XorStr("web_зarser: connect() failed"));
if (send(sock, request.c_str(), request.length(), 0) != request.length()) L::Print(XorStr("web_parser: send() sent a different number of bytes than expected"));
resp_leng = 1024;
while (resp_leng > 0) {
resp_leng = recv(sock, (char*)&buffer, 1024, 0);
if (resp_leng > 0) response += std::string(buffer).substr(0, resp_leng);
}
closesocket(sock);
WSACleanup();
const char* buf = response.c_str(); // Get HTTP response from URL
const char* content = strstr(buf, "\r\n\r\n");
if (content != NULL) {
content += 4; // Offset by 4 bytes to start of content
}
else {
content = buf; // Didn't find end of header, write out everything
}
return content;
}
Thank you.

Answer 1

The result codes 400 and 301 are correct in this case as #Steffen Ullrich wrote in his comment.
When you try to connect to the port 80 and the server is configured to do redirect to https then the server indeed tries to redirect to https and it sends a response '301 Moved Permanently' with a header 'Location: https://....'. The standard response phrase is 'Moved Permanently' in this case. A few responses may cause redirect. These responses have codes 300 - 399 and they are called 'redirect' responses.
When you try to connect to the port 443 then the communication does not start with HTTP protocol but the SSL/TLS handshake must be be done before HTTP communication starts and HTTP communication must be sent through the SSL/TLS session when it is established. You got 400 Bad Request because your code does not try to do SSL/TLS handshake.
There are a few options how to support SSL/TLS in your application
Implement SSL/TLS layer from scratch just using the socket API. That is a very difficult task even for a experienced developer. Perhaps you can try learning experience but do not do that for a real application.
Use an existing SSL/TLS library for example windows built-in SSL stuff. See SSL api for winsock?. It is easier than the first option but still quite complex task.
Use a library that support HTTP and HTTPS. There are lot of libraries. For example Microsoft provides WinHTTP. It is a recommended way to implement an HTTP/HTTPS clients because it is not necessary to reinvent a wheel.