Http 1.1

Contents:

• Keep Alive
• Pipelining
• Caching

Keep Alive

Don't close the TCP connection after a request/response cycle is complete

Under HTTP 1.0, there is no official           specification for how keepalive operates.

Connection: keep-alive

On every req/resp

In Http1.1 the default behavior is to keep the connection alive

Pipelining

• Possible since HTTP1.1 
• Relies on the connection to be kept alive
• In essence you send multiple requests without waiting for response. After that you get the resps in the same order of the requests.

Caching (Http 1.0)

• Expires header
• If-modified-since to check if the content is changed
• 304 it isn't changed or 200 with new resource
• Pragma: no-cache to tell the client to not cache 

Caching (Http 1.1)

• entity tag
  
• If-Unmodified-Since
  
• ​If-Match