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| <body> |
| 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 |
| {@link org.apache.http.Header 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. |
| <br/> |
| An HTTP {@link org.apache.http.protocol.HttpProcessor 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 |
| {@link org.apache.http.HttpRequestInterceptor requests} or |
| {@link org.apache.http.HttpResponseInterceptor responses}, |
| on the client or server side: |
| |
| <table border="1" cellpadding="5"> |
| <tr><th></th> |
| <th>Client</th> |
| <th>Server</th> |
| </tr> |
| <tr><th>Request</th> |
| <td>prepares headers before a request is sent</td> |
| <td>interprets headers when a request is received</td> |
| </tr> |
| <tr><th>Response</th> |
| <td>interprets headers when a response is received</td> |
| <td>prepares headers before a response is sent</td> |
| </tr> |
| </table> |
| |
| <p> |
| {@link org.apache.http.protocol.HttpRequestExecutor HttpRequestExecutor} |
| is a processor for the client side, |
| {@link org.apache.http.protocol.HttpService HttpService} |
| for the server side. |
| On the client side, a {@link org.apache.http.protocol.HttpContext 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. |
| </p> |
| |
| <p> |
| <font size="+1"> |
| <i> |
| 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. |
| </i> |
| </font> |
| </p> |
| |
| <p> |
| <b>Note:</b> |
| 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 <a href="http://tomcat.apache.org/">Tomcat</a> or full-blown |
| JSEE container like <a href="http://geronimo.apache.org/">Geronimo</a>. |
| If you prefer to implement a server-side application based on our |
| {@link org.apache.http.protocol.HttpService 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. |
| </p> |
| |
| |
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