rfc_notes.txt

HTTP Protocol

Hypertext Transfer Protocol (HTTP) is an application-level protocol for distributed, collaborative, hypermedia information systems.

HTTP/1.1 Protocol - given in rfc2616

Open ended set of methods and headers
Messages are passed in a format similar to that used by Internet mail as defined by the Multipurpose Internet Mail Extensions (MIME)
Connection = transport layer virtual circuit established between 2 programs for communication
Message = Basic unit of HTTP Communication- structured sequence of octets - transmitted via connection
HTTP Request
HTTP Response
Resource = network data object/service - identified by URI(Uniform Resource Identifier) - available in multiple representations
Entity = info transferred as payload of request or response - 
	Entity header fields = has meta info
	Entity body = has content
Representation = Entity + response
Content negotiation = select appropriate representation when servicing a request

-Operation
 The HTTP protocol is a request/response protocol. A client sends a
   request to the server in the form of a request method, URI, and
   protocol version, followed by a MIME-like message containing request
   modifiers, client information, and possible body content over a
   connection with a server. The server responds with a status line,
   including the message's protocol version and a success or error code,
   followed by a MIME-like message containing server information, entity
   metainformation, and possible entity-body content. 

There are three common forms of intermediary:
1.A proxy is a forwarding agent, receiving
requests for a URI in its absolute form, rewriting all or part of the message, and forwarding the reformatted request
toward the server identified by the URI. 
2.A gateway is a receiving agent, acting as a layer above some other server(s)
and, if necessary, translating the requests to the underlying server’s protocol. 
3.A tunnel acts as a relay point between
two connections without changing the messages; tunnels are used when the communication needs to pass through an
intermediary (such as a firewall) even when the intermediary cannot understand the contents of the messages.