webclientengine.h

使用yahoo图片搜索功能在手机上的以应用

/*
* ==============================================================================
*  Name		: WebClientEngine.h
*  Part of	 : WebClient
*  Interface   : 
*  Description : 
*  Version	 : 
*
*  Copyright (c) 2005-2006 Nokia Corporation.
*  This material, including documentation and any related 
*  computer programs, is protected by copyright controlled by 
*  Nokia Corporation.
* 
* Based on the CWebClientEngine class in the S60 SDK WebClient 
* example application.
* ==============================================================================
*/

#ifndef WEBCLIENTENGINE_H
#define WEBCLIENTENGINE_H

// INCLUDES
#include <coecntrl.h>
#include <http.h>
#include <http/mhttpauthenticationcallback.h>
#include <es_sock.h>

// CONSTANTS
const TInt KMaxHeaderNameLength	 = 32;
const TInt KMaxHeaderValueLength	= 128;
const TInt KMaxAuthTypeLength	   = 128;
const TInt KMaxDateTimeStringLength = 40;
const TInt KMaxStatusTextLength	 = 32;
const TInt KMaxUserNameLength	   = 128;
const TInt KMaxPasswordLength	   = 128;

// Used user agent for requests
_LIT8( KUserAgent, "WebClient 1.0" );

// This client accepts all content types.
// (change to e.g. "text/plain" for plain text only)
_LIT8( KAccept, "*/*" );

// Format for output of data/time values
_LIT( KDateFormat,"%D%M%Y%/0%1%/1%2%/2%3%/3 %:0%H%:1%T%:2%S.%C%:3" );

// Some texts for header output
_LIT( KColon, ": " );
_LIT( Krealm, "Realm: " );

class CWebClientEngine;

// CLASS DECLARATION

/**
* MWebClientObserver
* CWebClientEngine passes events and responses body data with this interface. 
* An instance of this class must be provided for construction of CWebClientEngine.
*/
class MWebClientObserver 
	{
	public:
		/**
		 * ClientOpenSessionFailedL( CWebClientEngine& anEngine )
		 * An error occurred opening the HTTP session. The calling code
		 * will leave after this method returns.
		 * @param anError: the error code
		 * Most common error; no access point configured, and session creation
		 * leaves with KErrNotFound.
		 */
		virtual void ClientOpenSessionFailedL( CWebClientEngine& anEngine, TInt anError ) = 0;
		/**
		 * ClientConnectingL()
		 * Called to notify that a connection was initiated
		 */
		virtual void ClientConnectingL( CWebClientEngine& anEngine ) = 0;
 
		/**
		* ClientHeaderReceivedL()
		* Called when HTTP header is received.
		* @param aHeaderData: Header field name and value
		*/
		virtual void ClientHeaderReceivedL( CWebClientEngine& anEngine, const TDesC& aHeaderData ) = 0;

		/**
		* ClientBodyReceivedL()
		* Called when a part of the HTTP body is received.
		* @param aBodyData:  Part of the body data received. (e.g. part of
		*					the received HTML page)
		*/
		virtual void ClientBodyReceivedL( CWebClientEngine& anEngine, const TDesC8& aBodyData ) = 0;

		/**
		 * ClientConnectionCanceledL()
		 * Called to notify that a connection attempt has been canceled
		 */
		virtual void ClientConnectionCanceledL( CWebClientEngine& anEngine ) = 0;
		
		/**
		 * ClientResponseCompleteL
		 * Called to notify that a transaction's response is complete.
		 * See TTransactionEvent::EResponseComplete
		 */
		virtual void ClientResponseCompleteL( CWebClientEngine& anEngine ) = 0;
		
		/**
		 * ClientTransactionSucceeded()
		 * Called to notify that a transaction completed successfully
		 * See TTransactionEvent::ESucceeded
		 */
		virtual void ClientTransactionSucceededL( CWebClientEngine& anEngine ) = 0;
		
		/** 
		 * ClientTransactionFailed()
		 * Catch-all for failure. 
		 * See TTransactionEvent::EFailed
		 */
		 virtual void ClientTransactionFailedL( CWebClientEngine& anEngine ) = 0;
		 
		/**
		 * ClientUnknownEventL()
		 * Called to notify that an unknown HTTP event has
		 * been received.
		 * @param aStatus: the iStatus field of the event
		 * See THTTPEvent::iStatus
		 */
		 virtual void ClientUnknownEventL( CWebClientEngine& anEngine , TInt aStatus ) = 0;
		
		/**
		 * ClientRunErrorL()
		 * Called when a error occurs in the handling of a transaction event.
		 * @param anError: the error code
		 */
		virtual void ClientRunErrorL( CWebClientEngine& anEngine , TInt anError) = 0;
		
		/**
		 * ClientGetCredentialsL()
		 * Called when authentication has been requested by the server.
		 * Return EFalse for no authentication or e.g. the user cancels
		 * an input dialog. Otherwise return the user name and password 
		 * as out parameters along with an ETrue result.
		 * @param aUri: the current URI
		 * @param aRealm: the realm associated with the request
		 * @param aUserName: the returned user name
		 * @param aPassword: the returned password
		 */
		virtual TBool ClientGetCredentialsL( CWebClientEngine& anEngine, const TUriC8& aUri, 
								const TDesC8& aRealm, 
								TDes& aUsername, 
								TDes& aPassword ) = 0;
		
	};

/**
* CWebClientEngine
* Provides simple interface to HTTP Client API.
*/
class CWebClientEngine : public CBase, 
						 public MHTTPTransactionCallback,
						 public MHTTPAuthenticationCallback
	{
	public:
		/**
		* NewL()
		* Create a CWebClientEngine object.
		* @param  iObserver: 
		* @return A pointer to the created instance of CWebClientEngine
		*/
		static CWebClientEngine* NewL( MWebClientObserver& aObserver );

		/**
		* NewLC()
		* Create a CWebClientEngine object.
		* @param  iObserver:
		* @return A pointer to the created instance of CWebClientEngine
		*/
		static CWebClientEngine* NewLC( MWebClientObserver& aObserver );

		/**
		* ~CWebClientEngine()
		* Destroy the object
		*/
		~CWebClientEngine();
		
		/**
		 * Opens the HTTP session. Automatically called when a session is initiated,
		 * or can be called separately.
		 */
		void OpenSessionL();

		/**
		* IssueHTTPGetL()
		* Starts a new HTTP GET transaction.
		* @param aUri: URI to get. (e.g. http://host.org")
		*/
		void IssueHTTPGetL( const TDesC8& aUri );

		/**
		* CancelTransactionL()
		* Closes currently running transaction and frees resources related to it.
		*/
		void CancelTransactionL();

		/**
		* IsRunning()
		* Checks if the transaction is running.
		* @return ETrue, if transaction is currently running.
		*/
		inline TBool IsRunning() { return iRunning; };

	private:
		/**
		* ConstructL()
		* Perform the second phase construction of a CWebClientEngine object.
		*/
		void ConstructL();

		/**
		* CWebClientEngine()
		* Perform the first phase of two phase construction.
		* @param iObserver: 
		*/
		CWebClientEngine( MWebClientObserver& iObserver );

		/**
		* SetHeaderL()
		* Sets header value of an HTTP request.
		* @param aHeaders:  Headers of the HTTP request
		* @param aHdrField: Enumerated HTTP header field, e.g. HTTP::EUserAgent
		* @param aHdrValue: New value for header field
		*/
		void SetHeaderL( RHTTPHeaders aHeaders, TInt aHdrField, 
						 const TDesC8& aHdrValue );

		/**
		* DumpRespHeadersL()
		* Called when HTTP header is received.
		* Displays HTTP header field names and values
		* @param aTransaction: The transaction that is processed.
		*/
		void DumpRespHeadersL( RHTTPTransaction& aTransantion );

		/**
		* HandleRunErrorL()
		* Called from MHFRunError() when *leave* occurs in handling of transaction event. 
		* @param aError:	   The leave code that occured.
		*/
		void HandleRunErrorL( TInt aError );

	/**
	* From MHTTPSessionEventCallback
	*/
	private:
		/**
		* MHFRunL()
		* Called by framework to notify about transaction events.
		* @param aTransaction: Transaction, where the event occured.
		* @param aEvent:	   Occured event.
		*/
		void MHFRunL( RHTTPTransaction aTransaction, const THTTPEvent& aEvent );

		/**
		* MHFRunError()
		* Called by framework when *leave* occurs in handling of transaction event. 
		* @param aError:	   The leave code that occured.
		* @param aTransaction: The transaction that was being processed when leave occured.
		* @param aEvent:	   The event that was being processed when leave occured.
		* @return KErrNone,	if the error was handled. Otherwise the value of aError, or
		*					  some other error value. Returning error value causes causes 
		*					  HTTP-CORE 6 panic.
		*/
		TInt MHFRunError( TInt aError, 
							RHTTPTransaction aTransaction, 
							const THTTPEvent& aEvent );

	/**
	* From MHTTPAuthenticationCallback (needed for HTTP authentication)
	*/
	private:
		/**
		* GetCredentialsL()
		* Called by framework when username and password for requested URI is 
		* needed.
		* @param aURI: The URI being requested (e.g. "http://host.org")
		* @param aRealm: The realm being requested (e.g. "[e-mail]")
		* @param aAuthenticationType: Authentication type. (e.g. "Basic")
		* @param aUsername: Given user name.
		* @param aPassword: Given password.
		* @return A pointer to the created document
		*/
		TBool GetCredentialsL(  const TUriC8& aUri, 
								RString aRealm, 
								RStringF aAuthenticationType, 
								RString& aUsername, 
								RString& aPassword );
								
	private: // Data
		RHTTPSession			iSession;
		RHTTPTransaction		iTransaction;
		RSocketServ 			iSocketServ;
		RConnection 			iConnection;
		
		MWebClientObserver&	 iObserver;	  // Used for passing body data and
												// events to UI.
		TBool					iSessionOpened; // ETrue, if session successfully opened
		TBool				   iRunning;	   // ETrue, if transaction running
	};

#endif // WEBCLIENTENGINE_H