Package org.apache.http.protocol

HTTP protocol execution framework. Apart from simply sending and receiving messages, there are a lot of things to consider when communicating with HTTP. Many details such as transport encodings or connection management are handled by setting up or interpreting headers in the messages. In order to relieve applications from the responsibility of implementing these nitty-gritty details of the protocol, HTTP components provides an execution framework that sets up some of the headers before sending a message, and interprets headers when a message has been received.
An HTTP processor typically keeps lists of so-called interceptors that will be executed before a message is sent and after it has been received. An application should initialize a processor, set up the lists with the required and desired processors, and then communicate through that processor. There are four kinds of interceptors, depending on whether they act on requests or responses, on the client or server side:

	Client	Server
Request	prepares headers before a request is sent	interprets headers when a request is received
Response	interprets headers when a response is received	prepares headers before a response is sent

HttpRequestExecutor is a processor for the client side, HttpService for the server side. On the client side, a context is used to tie together a request, the response to it, and other data that might be associated with the request execution. It is passed to the request executor whenever needed.

Information about required and recommended interceptors for the client side will be provided elsewhere. For the time being, please refer to the comments in the example applications or ask on one of the mailing lists.

Note: If you want to develop a server-side application, we recommend that you implement your application as a servlet running in a servlet engine like Tomcat or full-blown JSEE container like Geronimo. If you prefer to implement a server-side application based on our HttpService, we'll assume that you know what you're doing and that you don't need help in figuring out which interceptors need to be configured.

Interface Summary

Interface	Description
ExecutionContext	Context attribute names for protocol execution.
HttpContext	A context for executing a request.
HttpExpectationVerifier	Defines an interface to verify whether an incoming HTTP request meets the target server's expectations.
HttpProcessor	Performs interceptor processing of requests and responses.
HttpRequestHandler
HttpRequestHandlerResolver	Interface to be implemented by objects that can resolve HttpRequestHandler instances by request URI.
HttpRequestInterceptorList	Provides access to an ordered list of request interceptors.
HttpResponseInterceptorList	Provides access to an ordered list of response interceptors.

Class Summary

Class	Description
BasicHttpContext	Default implementation of the HttpContext.
BasicHttpProcessor	Keeps lists of interceptors for processing requests and responses.
DefaultedHttpContext	HttpContext implementation that delegates resolution of an attribute to the given default HttpContext instance if the attribute is not present in the local one.
HTTP	Constants and static helpers related to the HTTP protocol.
HttpDateGenerator	Generates a date in the format required by the HTTP protocol.
HttpRequestExecutor	Sends HTTP requests and receives the responses.
HttpRequestHandlerRegistry	Maintains a map of HTTP request handlers keyed by a request URI pattern.
HttpService	Minimalistic server-side implementation of an HTTP processor.
RequestConnControl	A request interceptor that suggests connection keep-alive to the server.
RequestContent	A request interceptor that decides about the transport encoding.
RequestDate	A request interceptor that adds a Date header.
RequestExpectContinue	A request interceptor that enables the expect-continue handshake.
RequestTargetHost	A request interceptor that sets the Host header for HTTP/1.1 requests.
RequestUserAgent	A request interceptor that adds a User-Agent header.
ResponseConnControl	A response interceptor that suggests connection keep-alive to the client.
ResponseContent	A response interceptor that sets up entity-related headers.
ResponseDate	A response interceptor that adds a Date header.
ResponseServer	A response interceptor that adds a Server header.
SyncBasicHttpContext	Thread-safe extension of the BasicHttpContext.
UriPatternMatcher	Maintains a map of objects keyed by a request URI pattern.