C++ HTTP GET using socket

Question

I connected to the server with the following code

 web_socket = socket(AF_INET, SOCK_STREAM, 0);
 memset(&server_address, 0, sizeof(struct sockaddr_in));
 inet_pton(AF_inet, "166.111.1.1", &server_address.sin_addr);
 server_address.sin_family = AF_INET;
 server_address.sin_port = htons(8080);
 indicator = connect(web_socket, (struct sockaddr *) &server_address, sizeof(server_address));

The execution of the above code results in indicator being 0, which means connection to the server is successful, but when I tried to write

 string request = "GET http://166.111.1.1:8080/sensor?value=10.3";
 indicator = write(web_socket, request.c_str(), request.length());

I cannot see anything under

 http://166.111.1.1:8080/sensor?value=10.3

or

 http://166.111.1.1:8080/sensor

though the indicator equals to the request length.

Is there anything wrong with the code above? I am testing on Ubuntu 12.04 using QT Creator, GCC

Answer 1

HTTP request (and reply) headers are terminated with the sequence \r\n\r\n; individual lines within the header are separated with a single \r\n. So what you need is:

string request("GET http://166.111.1.1:8080/sensor?value=10.3\r\n\r\n");

You don't actually need the protocol and IP address in there -- you're already connected -- so this can be reduced to:

string request("GET /sensor?value=10.3\r\n\r\n");

The short version is in fact better (and more normative), because it risks fewer complications with the server.