Search code examples
rubyhttpclientpersistentrecv

Ruby: Persistent HTTP client not receiving response on second request

I am trying to create an HTTP client that uses persistent connections. My Code works when I send my first request and get my first response. However, when I send a second request, I am unable to get a second response. I am not sure why? I got the same error when I was coding in C.

Here is the code

require 'socket'
include Socket::Constants
socket = Socket.new( AF_INET, SOCK_STREAM, 0 )
sockaddr = Socket.pack_sockaddr_in( 80, 'www.google.com' )
socket.connect( sockaddr )

# This Works
socket.write( "GET / HTTP/1.0\r\n\r\n" )
results = socket.read

# This Works
socket.write( "GET / HTTP/1.0\r\n\r\n" )
# THIS DOESN'T WORK
results = socket.read

I do not want to use built libraries like Net::HTTP. What do I need to do to make this work?

Solution

  • You cannot make 2 HTTP requests on the same connection, unless you've told the server that you're expecting to do so. This is how HTTP persistent connection works. At a minimum, you have to make sure to add this to your request header:

    Connection: keep-alive

    Servers have differing support for persistent connections, although it's become common for servers to support basic persistent connections. Here's an SO question that asks What exactly does a “persistent connection” mean?

    Start there, and you'll find what you need to know to make persistent connections work correctly. You may have to check the HTTP response headers for an indication that the server will honor your request, or you may have to check that the server didn't simply close the connection when it was finished writing the first response. On your final request through a persistent connection, you should also specify the header:

    Connection: close

    Also check out these resources: