HTTP on Symbian OS

核心提示：between client and server: a client request and a server response. However, the transaction may be extended by filters that operate on it.Transactions execute a

between client and server: a client request and a server response. However, the transaction may be extended by filters that operate on it.

Transactions execute asychronously within the client's process. The client is notified when events are available for each outstanding transaction.

Both the request and response portion of a transaction are composed of a header and an optional body. The request portion of the transaction also specifies an HTTP Method that describes the type of operation that the client wishes to invoke at the origin server, together with a URI that specifies the resource held at the server on which the method is to be invoked. The response portion of a transaction contains an HTTP status code and message, which indicate the success of the method or the state of the resource following the method. The use of request and response bodies is determined by the HTTP method in use; e.g. in error conditions, some servers may just return a status code and message, providing no entity body.

The transaction class is provided by RHTTPTransaction.

Headers

The header portion of requests and responses may have zero or more fields, which are used to convey information between the HTTP client and server. The information might relate to the data conveyed in body of the message, to the actual connection between the client and server, or might be used to convey data describing the client or server themselves. Headers as transmitted to or received from the HTTP server will be in an encoded form, according to the HTTP protocol and encoding that are used. Since the HTTP API gives clients implementation independence from these choices, a generic form is used to represent header data in the API.

The headers class is provided by RHTTPHeaders.

Data suppliers

The body portion of requests and responses is represented in the API as a mix-in interface, allowing the real implementation of the classes that generate