016_building-a-tcp-server-for-http/

HTTP Server

HTTP uses TCP.

To create a server that works with HTTP, we just create a TCP server.

To configure our code to handle request/response in an HTTP fashion which works with browsers, we need to adhere to HTTP standards.

HTTP/1.1 message

An HTTP message is made up of the following:

• a request/status line
• zero or more header fields
• an empty line indicating the end of the header section
• an optional message body.

Request line (request)

GET / HTTP/1.1

method SP request-target SP HTTP-version CRLF

Status line (response)

HTTP/1.1 302 Found

HTTP-version SP status-code SP reason-phrase CRLF

Writing a response

body := "CHECK OUT THE RESPONSE BODY PAYLOAD"
io.WriteString(conn, "HTTP/1.1 200 OK\r\n") 			// status line
fmt.Fprintf(conn, "Content-Length: %d\r\n", len(body)) 	// header
fmt.Fprint(conn, "Content-Type: text/plain\r\n") 		// header
io.WriteString(conn, "\r\n") 							// blank line; CRLF; carriage-return line-feed
io.WriteString(conn, body) 								// body, aka, payload

Useful for parsing the request-line & status-line

Parsing String

strings.Fields

func Fields(s string) []string