Function main

example/http/client/sync-ssl/http_client_sync_ssl.cpp:34–139

Performs an HTTP GET and prints the response

// Performs an HTTP GET and prints the response
int main(int argc, char** argv)
{
    try
    {
        // Check command line arguments.
        if(argc != 4 && argc != 5)
        {
            std::cerr <<
                "Usage: http-client-sync-ssl <host> <port> <target> [<HTTP version: 1.0 or 1.1(default)>]\n" <<
                "Example:\n" <<
                "    http-client-sync-ssl www.example.com 443 /\n" <<
                "    http-client-sync-ssl www.example.com 443 / 1.0\n";
            return EXIT_FAILURE;
        }
        auto const host = argv[1];
        auto const port = argv[2];
        auto const target = argv[3];
        int version = argc == 5 && !std::strcmp("1.0", argv[4]) ? 10 : 11;

        // The io_context is required for all I/O
        net::io_context ioc;

        // The SSL context is required, and holds certificates
        ssl::context ctx(ssl::context::tlsv12_client);

        // This holds the root certificate used for verification
        load_root_certificates(ctx);

        // Verify the remote server's certificate
        ctx.set_verify_mode(ssl::verify_peer);

            // These objects perform our I/O
        tcp::resolver resolver(ioc);
        ssl::stream<beast::tcp_stream> stream(ioc, ctx);

        // Set SNI Hostname (many hosts need this to handshake successfully)
        if(! SSL_set_tlsext_host_name(stream.native_handle(), host))
        {
            throw beast::system_error(
                static_cast<int>(::ERR_get_error()),
                net::error::get_ssl_category());
        }

        // Set the expected hostname in the peer certificate for verification
        stream.set_verify_callback(ssl::host_name_verification(host));

        // Look up the domain name
        auto const results = resolver.resolve(host, port);

        // Make the connection on the IP address we get from a lookup
        beast::get_lowest_layer(stream).connect(results);

        // Perform the SSL handshake
        stream.handshake(ssl::stream_base::client);

        // Set up an HTTP GET request message
        http::request<http::string_body> req{http::verb::get, target, version};
        req.set(http::field::host, host);