org.apache.commons.httpclient

Classes and interfaces supporting the client side of the HTTP protocol.

The HttpClient component supports the client-side of RFC 1945 (HTTP/1.0) and RFC 2616 (HTTP/1.1), several related specifications (RFC 2109 (Cookies), RFC 2617 (HTTP Authentication), etc.), and provides a framework by which new request types (methods) or HTTP extensions can can be easily created or supported.

The basis for the abstraction is provided by three types:

{@link org.apache.commons.httpclient.HttpConnection}

represents a network connection to some HTTP host.

{@link org.apache.commons.httpclient.HttpMethod}

represents a request to be made over some {@link org.apache.commons.httpclient.HttpConnection} and contains the server's response.

{@link org.apache.commons.httpclient.HttpState}

contains the HTTP attributes that may persist from request to request, such as cookies and authentication credentials.

and several simple bean-style classes:

{@link org.apache.commons.httpclient.Cookie}

represents HTTP cookie.

{@link org.apache.commons.httpclient.Credentials}

an interface representing a set of authentication credentials.

{@link org.apache.commons.httpclient.Header}

represents an HTTP request or response header.

{@link org.apache.commons.httpclient.HeaderElement}

represents a single element of a multi-part header.

{@link org.apache.commons.httpclient.UsernamePasswordCredentials}

a username and password pair.

{@link org.apache.commons.httpclient.HttpClient} provides a simple "user-agent" implementation that will suffice for many applications, but whose use is not required.

HttpClient also provides several utilities that may be useful when extending the framework:

{@link org.apache.commons.httpclient.HttpMethodBase}

an abstract base implementation of HttpMethod, which may be extended to create new method types or to support additional protocol HTTP features.

{@link org.apache.commons.httpclient.HttpStatus}

an enumeration of HttpStatus codes.

{@link org.apache.commons.httpclient.ChunkedOutputStream}

an {@link java.io.OutputStream} wrapper supporting the "chunked" transfer encoding.

{@link org.apache.commons.httpclient.ChunkedInputStream}

an {@link java.io.InputStream} wrapper supporting the "chunked" transfer encoding.

{@link org.apache.commons.httpclient.util.URIUtil}

provides utilities for encoding and decoding URI's in the %HH format.

HttpClient Configuration with Java Properties

Transparently coalesces chunks of a HTTP stream that uses Transfer-Encoding chunked.

Note that this class NEVER closes the underlying stream, even when close gets called.

Implementation note: Choices abound.

HTTP "magic-cookie" represents a piece of state information that the HTTP agent and the target server can exchange to maintain a session.

Authentication credentials.

This is just a marker interface, the current implementation has no methods.

One element of an HTTP header's value.

Some HTTP headers (such as the set-cookie header) have values that can be decomposed into multiple elements.

An HTTP "user-agent", containing an HttpState HTTP state and one or more HttpConnection HTTP connections , to which HttpMethod HTTP methods can be applied.

The following options are set on the socket before getting the input/output streams in the HttpConnection.open() method:

Socket Method	Sockets Option	Configuration
java.net.Socket.setTcpNoDelay(boolean)	SO_NODELAY	HttpConnectionParams.setTcpNoDelay(boolean)
java.net.Socket.setSoTimeout(int)	SO_TIMEOUT	HttpConnectionParams.setSoTimeout(int)
java.net.Socket.setSendBufferSize(int)	SO_SNDBUF	HttpConnectionParams.setSendBufferSize(int)
java.net.Socket.setReceiveBufferSize(int)	SO_RCVBUF	HttpConnectionParams.setReceiveBufferSize(int)

author:
   Rod Waldhoff
author:
   Sean C.

HttpMethod interface represents a request to be sent via a HttpConnection HTTP connection and a corresponding response.

At minimum, subclasses will need to override:

• HttpMethodBase.getName to return the approriate name for this method

When a method requires additional request headers, subclasses will typically want to override:

• HttpMethodBase.addRequestHeaders addRequestHeaders(HttpState,HttpConnection) to write those headers

When a method expects specific response headers, subclasses may want to override:

• HttpMethodBase.processResponseHeaders processResponseHeaders(HttpState,HttpConnection) to handle those headers

Signals that an HTTP or HttpClient exception has occurred.

A container for HTTP attributes that may persist from request to request, such as Cookie cookies and authentication Credentials credentials .

HTTP version, as specified in RFC 2616.

HTTP uses a "<major>.<minor>" numbering scheme to indicate versions of the protocol.

A simple class encapsulating a name/value pair.

Signals that the target server failed to respond with a valid HTTP response.

 6.1 Status-Line
 The first line of a Response message is the Status-Line, consisting
 of the protocol version followed by a numeric status code and its
 associated textual phrase, with each element separated by SP
 characters.

A URI is always in an "escaped" form, since escaping or unescaping a completed URI might change its semantics.

Username and password Credentials .