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在BREW中实现自己的GUI（8）－IWEB的封装

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BREWWeb.net 
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封装IWeb其实并不算是GUI的范畴，但是一并说了罢。在BREW中实现网络访问有两个选择：ISocket和IWeb，我是比较倾向于使用IWeb的，只要你不是要做一个长连接。因为服务端程序比较容易做，可以直接使用现成的WEB服务器，我们不再需要自己处理并发、缓存等网络服务必须要考虑的东西。

使用IWeb并非只能处理HTML的页面，事实上我们完全可以拿它来做文件下载、提交信息（如下载报告）之类的管理。也并非IWeb只能与IHtmlViewer合并使用，我们完全可以将一个IMenuCtl的信息打成二进制包使用IWeb下载并用IMenuCtl来展示，也就是说把它当成一个ISocket一样来使用。

首先我们需要定义一个回调，用WSNotify定义了回调的通知参数，包括状态、代码以及获取的内容等等。

typedef struct _IWebSocket IWebSocket;

//定义回调的参数
typedef struct
...{
    uint16  wStatus;
    int        wCode;
    byte    *pBuffer;
    uint32    bLength;
    uint32    cLength;

} WSNotify;

//定义回调格式
typedef void (*PFNWSOCKETNOTIFY)(
      void *            pvUser,
      WSNotify            aWSNotify
   );


再看看这个组件包括的成员变量有哪些吧，除了IWeb和IWebResp以外，还需要回调cbNotify、目标地址m_TargetURL、临时的内容缓冲区m_BodyBuffer等成员：

struct _IWebSocket
...{
    const AEEVTBL(IWebSocket) * pvt;

    uint32          m_nRefs;    
    IShell            *m_pIShell;
    IModule            *m_pIModule;

    AEECallback    cb; 

    PFNWSOCKETNOTIFY    cbNotify;
    void                *pUser;
    
    IWeb        *m_pIWeb;    
    IWebResp    *m_piWResp; 
    
    //保存下载文件内容的缓冲区
    byte        *m_BodyBuffer;    
    uint32        m_BodySize;    
    uint32        m_BodyAllocSize;

    char        *m_LocationURL;

    //目标URL
    char        *m_TargetURL;
    char        *m_Header;

    //当前状态
    uint8        m_State;

    //尝试次数
    uint8        tryCount;

    byte        buf[1024];
    byte        cBuffer[10240];
    int            cLen;

};


要实现的接口函数是：

AEEINTERFACE(IWebSocket)
...{
    DECLARE_IBASE(IWebSocket)    

    byte*        (*GetBuffer)            (IWebSocket * po,uint32 * outSize);
    void        (*SetNotifyFn)            (IWebSocket * po,PFNWSOCKETNOTIFY cb,void * pUser);
    void        (*SetHeader)            (IWebSocket * po,const char * header);
    void        (*SetURL)                (IWebSocket * po,const char * url);
    void        (*Stop)                    (IWebSocket * po);
    void        (*Resume)                (IWebSocket * po);
    void        (*Start)                (IWebSocket * po);    
    void        (*StartStream)            (IWebSocket * po);
    
};


OK，实现就类似于BREW中的那个 IWeb例子，做两个Start函数，一个是普通的下载（每下一个包回调一次），另一个是流式（建立一个小的缓冲区，这个小缓冲满了则回调一次）：

static void IWebSocket_Start(IWebSocket *pMe)
...{
    FREEIF(pMe->m_BodyBuffer);
    pMe->m_BodyBuffer = NULL;
    pMe->m_BodySize = 0;
    pMe->m_BodyAllocSize = 0;

    CALLBACK_Cancel(&pMe->cb);
    CALLBACK_Init(&pMe->cb, webDownloadData, pMe);
    
    if(!pMe->m_pIWeb)
        initWeb(pMe);

    IWEB_GetResponse(pMe->m_pIWeb,
                        (pMe->m_pIWeb, &pMe->m_piWResp, &pMe->cb, pMe->m_TargetURL, 
                        WEBOPT_HANDLERDATA, pMe, 
                        WEBOPT_HEADERHANDLER, webHeader, 
                        WEBOPT_STATUSHANDLER, webStatus, 
                        WEBOPT_END));
  
}
static void IWebSocket_StartStream(IWebSocket *pMe)
...{
    FREEIF(pMe->m_BodyBuffer);
    pMe->m_BodyBuffer = NULL;
    pMe->m_BodySize = 0;
    pMe->m_BodyAllocSize = 0;

    pMe->cLen=0;
    MEMSET(pMe->buf,0,sizeof(pMe->buf));
    MEMSET(pMe->cBuffer,0,sizeof(pMe->cBuffer));

    CALLBACK_Cancel(&pMe->cb);
    CALLBACK_Init(&pMe->cb, webDownloadStream, pMe);
    
    if(!pMe->m_pIWeb)
        initWeb(pMe);

    IWEB_GetResponse(pMe->m_pIWeb,
                        (pMe->m_pIWeb, &pMe->m_piWResp, &pMe->cb, pMe->m_TargetURL, 
                        WEBOPT_HANDLERDATA, pMe, 
                        WEBOPT_HEADERHANDLER, webHeader, 
                        WEBOPT_STATUSHANDLER, webStatus, 
                        WEBOPT_END));
  
}


两个下载的具体实现是：

//响应
static void webDownloadData(void * p)
...{
    IWebSocket *pMe = (IWebSocket *)p;
    
    WebRespInfo *pwri;
    int ByteCount;
           
    pwri = IWEBRESP_GetInfo(pMe->m_piWResp);

    if( !WEB_ERROR_SUCCEEDED(pwri->nCode) )
    ...{
        FREEIF(pMe->m_BodyBuffer);
        pMe->m_BodyBuffer = NULL;
        pMe->m_BodySize = 0;
        pMe->m_BodyAllocSize = 0;

        if( (pwri->nCode==302 || pwri->nCode==301) && pMe->m_LocationURL!=NULL )
        ...{
            pMe->tryCount=0;

            FREEIF(pMe->m_TargetURL);
            pMe->m_TargetURL=NULL;
            pMe->m_TargetURL=STRDUP(pMe->m_LocationURL);

            FREEIF(pMe->m_LocationURL);
            pMe->m_LocationURL=NULL;
            
            IWebSocket_Stop(pMe);
            ISHELL_SetTimer(pMe->m_pIShell,0,(PFNNOTIFY)IWebSocket_Start,(void*)pMe);
            return;
        }

        if(pMe->tryCount<MAX_TRY_COUNT)
        ...{
            IWebSocket_Stop(pMe);
            pMe->tryCount++;
            ISHELL_SetTimer(pMe->m_pIShell,3000,(PFNNOTIFY)IWebSocket_Start,(void*)pMe);
        }
        else
        ...{
            WSNotify wsn;
            wsn.wCode=pwri->nCode;
            wsn.wStatus=WS_STATUS_ERROR;
            wsn.pBuffer=NULL;
            wsn.bLength=0;
            wsn.cLength=0;
            pMe->cbNotify(pMe->pUser,wsn);
        }
        return;
    }
    ISHELL_CancelTimer(pMe->m_pIShell,(PFNNOTIFY)IWebSocket_Start,(void*)pMe);

    MEMSET(pMe->buf,0,sizeof(pMe->buf));       
    if ((ISource *)0 != pwri->pisMessage) 
    ...{
        ISource * pISource = pwri->pisMessage;
        ByteCount =    ISOURCE_Read(pISource, (char *)pMe->buf, sizeof(pMe->buf));
        
        switch(ByteCount)
        ...{
            case ISOURCE_END:    //表示读网络完成                        
                ...{
                    WSNotify wsn;

                    IWebSocket_Stop(pMe);
                    
                    wsn.wCode = 0;
                    wsn.wStatus = WS_STATUS_SUCCESS;
                    wsn.pBuffer=pMe->m_BodyBuffer;
                    wsn.bLength=pMe->m_BodySize;
                    wsn.cLength=pwri->lContentLength;

                    pMe->cbNotify(pMe->pUser,wsn);                
                    break;
                }
           case ISOURCE_ERROR:
                ...{
                    WSNotify wsn;
                    wsn.wCode=pwri->nCode;
                    wsn.wStatus=WS_STATUS_ERROR;
                    wsn.pBuffer=NULL;
                    wsn.bLength=0;
                    wsn.cLength=pwri->lContentLength;

                    pMe->cbNotify(pMe->pUser,wsn);
                }
                break;
           case ISOURCE_WAIT:               
                ISOURCE_Readable(pISource, &pMe->cb);
                break;
           default:               
               if (ByteCount)
               ...{
                    if (pMe->m_BodySize + ByteCount > pMe->m_BodyAllocSize)
                    ...{
                        const int NewSize = pMe->m_BodyAllocSize + ByteCount;
                        byte* NewBuf = (byte*)REALLOC(pMe->m_BodyBuffer, NewSize);
                       
                        if (NewBuf)
                        ...{
                            pMe->m_BodyBuffer = NewBuf;
                            pMe->m_BodyAllocSize = NewSize;
                        }
                        else
                            return;
                    }
                    if(pMe->m_BodySize + ByteCount <= pMe->m_BodyAllocSize)
                    ...{
                        MEMCPY(pMe->m_BodyBuffer + pMe->m_BodySize, pMe->buf, ByteCount);
                        pMe->m_BodySize += ByteCount;
                    }

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评论
3 楼 咖啡舞者 2009-05-05  
非常感谢这种分享精神.
2 楼 haorui215 2009-04-24  
[/size][size=zXlarge][align=center][/align]
1 楼 haorui215 2009-04-24  
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