用vc6提供的方法，哪种方法能够很稳定地读取网页内容（能够兼容死链接而不过于超时）？

如果是只是要取得当前访问的网页内容：
通过CHtmlView类的派生类，在它的OnDocumentComplete函数中添加：
HRESULT hr;
IDispatch *pDispathDoc = NULL;
CComPtr<IHTMLDocument2> pHTMLDoc;
CComPtr<IHTMLElement> pHTMLBody;
BSTR bstrInnerHTML;
pDispathDoc = GetHtmlDocument();
if(pDispathDoc == NULL)
return;
hr = pDispathDoc->QueryInterface(__uuidof(IHTMLDocument2), (void**)&pHTMLDoc);
if(FAILED(hr))
return;
hr = pHTMLDoc->get_body(&pHTMLBody);
pHTMLBody->get_innerHTML(&bstrInnerHTML);
CString sInnerHTML =CString( bstrInnerHTML);那么sInnerHTML 里的内容就是你浏览器窗口里的html源代码了，你自己再将它另存为即可。
想要下载东西才用其它方法

CInternetSession 类系列,还是很稳定的
如果需要更精细的控制,使用SOCKET 应该更好
我在使用中,多数情况下,偏好SOCKET,应为更灵活,但是代码麻烦一些
普通情况下,就使用CInternetSession 类系列,简单性能上,我的比较还是 SOCKET 要好一些

读取网页的程序通常应该有这样一些概念
1、多线程：每一个读取，应该是在一个单独的线程里工作
2、socket概念：一般使用同步阻塞模式，connect是否成功，很快就会返回，由此判定服务器相应服务是否可用，webserver通常80端口，程序中要做的是如果连接不成功，重复试几次的问题
3、HTTP协议，要自己写SOCKET网页下载程序，需要熟悉HTTP协议，详细了解浏览器与WEB SERVER是这样建立通信、传送数据的， HTTP应该说是比较简单的。通常连接成功以后，需要判断状态码，看是否请求被服务器理解并正常完成
使用socket底层编码，不会有“最长的有读死链接而导致3-4个小时线程才结束的情况”，因为一些都是可以控制的。我在使用中，就是用CInternetSession封装类，也从未发生你说的情况，不过阻塞十分钟左右的情况是有的，所以对于效率上有要求的还是不要使用简单的类或者组件，自己研究研究...

HRESULT hr;
IDispatch *pDispathDoc = NULL;
CComPtr<IHTMLDocument2> pHTMLDoc;
CComPtr<IHTMLElement> pHTMLBody;
BSTR bstrInnerHTML;
pDispathDoc = GetHtmlDocument();
if(pDispathDoc == NULL)
return;
hr = pDispathDoc->QueryInterface(__uuidof(IHTMLDocument2), (void**)&pHTMLDoc);
if(FAILED(hr))
return;
hr = pHTMLDoc->get_body(&pHTMLBody);
pHTMLBody->get_innerHTML(&bstrInnerHTML);
CString sInnerHTML =CString( bstrInnerHTML

我也是使用CInternetSession.OpenUrl 和CHttpFile来读取网页，对有极少数的网页会造成阻塞，CPU占有率竟达到了90%几，造成系统死机。不知道有什么方法能解决？楼主找到解决方法，通知我一声。

CInternetSession是可以
不过好像弄个线程类好像更好！

用阻塞socket设置timeout也不一定每次都能成功,我试了,也会很久不动,不知道什么原因不会返回

这个是最有效得办法了
http://www.zeali.net/entry/13

用非阻塞实现连接超时和接收发送超时
/*
* on Unix:
*    cc -c connector.c
*    cc -o connector connector.o
*
* on Windows NT:
*    open connector.c in Visual Studio
*    press 'F7' to link -- a project to be created
*    add wsock32.lib to the link section under project setting
*    press 'F7' again
*
* running:
*    type 'connector' for usage
*/#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <errno.h>
#include <fcntl.h>
#ifdef WIN32
#include <winsock2.h>
#else
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#endif#ifndef INADDR_NONE
#define INADDR_NONE     0xffffffff
#endif
#define MAX_STRING_LEN  1024
#define BUFSIZE  2048#ifndef WIN32
#define SOCKET int
#else
#define errno WSAGetLastError()
#define close(a) closesocket(a)
#define write(a, b, c) send(a, b, c, 0)
#define read(a, b, c) recv(a, b, c, 0)
#endifchar buf[BUFSIZE];static char i_host[MAX_STRING_LEN];  /* site name */
static char i_port[MAX_STRING_LEN];  /* port number */void err_doit(int errnoflag, const char *fmt, va_list ap);
void err_quit(const char *fmt, ...);
int tcp_connect(const char *host, const unsigned short port);
void print_usage();//xnet_select x defines
#define READ_STATUS  0
#define WRITE_STATUS 1
#define EXCPT_STATUS 2/*
s    - SOCKET
sec  - timeout seconds
usec - timeout microseconds
x    - select status
*/
SOCKET xnet_select(SOCKET s, int sec, int usec, short x)
{
int st = errno;
struct timeval to;
fd_set fs;
to.tv_sec = sec;
to.tv_usec = usec;
FD_ZERO(&fs);
FD_SET(s, &fs);
switch(x){
  case READ_STATUS:
  st = select(s+1, &fs, 0, 0, &to);
  break;
  case WRITE_STATUS:
  st = select(s+1, 0, &fs, 0, &to);
  break;
  case EXCPT_STATUS:
  st = select(s+1, 0, 0, &fs, &to);
  break;
}
return(st);
}int tcp_connect(const char *host, const unsigned short port)
{
    unsigned long non_blocking = 1;
    unsigned long blocking = 0;
    int ret = 0;
    char * transport = "tcp";
    struct hostent      *phe;   /* pointer to host information entry    */
    struct protoent *ppe;       /* pointer to protocol information entry*/
    struct sockaddr_in sin;     /* an Internet endpoint address  */
    SOCKET s;                    /* socket descriptor and socket type    */
    int error;#ifdef WIN32
    {
        WORD wVersionRequested;
        WSADATA wsaData;
        int err;

        wVersionRequested = MAKEWORD( 2, 0 );

        err = WSAStartup( wVersionRequested, &wsaData );
        if ( err != 0 ) {
            /* Tell the user that we couldn't find a usable */
            /* WinSock DLL.                               */
            printf("can't initialize socket library\n");
            exit(0);
        }
    }
#endif

    memset(&sin, 0, sizeof(sin));
    sin.sin_family = AF_INET;

    if ((sin.sin_port = htons(port)) == 0)
        err_quit("invalid port \"%d\"\n", port);

    /* Map host name to IP address, allowing for dotted decimal */
    if ( phe = gethostbyname(host) )
        memcpy(&sin.sin_addr, phe->h_addr, phe->h_length);
    else if ( (sin.sin_addr.s_addr = inet_addr(host)) == INADDR_NONE )
        err_quit("can't get \"%s\" host entry\n", host);

    /* Map transport protocol name to protocol number */
    if ( (ppe = getprotobyname(transport)) == 0)
        err_quit("can't get \"%s\" protocol entry\n", transport);

    /* Allocate a socket */
    s = socket(PF_INET, SOCK_STREAM, ppe->p_proto);
    if (s < 0)
        err_quit("can't create socket: %s\n", strerror(errno));

    /* Connect the socket with timeout */
#ifdef WIN32
    ioctlsocket(s,FIONBIO,&non_blocking);
#else
    ioctl(s,FIONBIO,&non_blocking);
#endif
    //fcntl(s,F_SETFL, O_NONBLOCK);
    if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) == -1){
        struct timeval tv;
        fd_set writefds;
        // 设置连接超时时间
        tv.tv_sec = 10; // 秒数
        tv.tv_usec = 0; // 毫秒
        FD_ZERO(&writefds);
        FD_SET(s, &writefds);
        if(select(s+1,NULL,&writefds,NULL,&tv) != 0){
            if(FD_ISSET(s,&writefds)){
                int len=sizeof(error);
                //下面的一句一定要，主要针对防火墙
                if(getsockopt(s, SOL_SOCKET, SO_ERROR,  (char *)&error, &len) < 0)
                    goto error_ret;
                if(error != 0)
                    goto error_ret;
            }
            else
                goto error_ret; //timeout or error happen
        }
        else goto error_ret; ; #ifdef WIN32
        ioctlsocket(s,FIONBIO,&blocking);
#else
        ioctl(s,FIONBIO,&blocking);
#endif    }
    else{
error_ret:
        close(s);
        err_quit("can't connect to %s:%d\n", host, port);
    }
    return s;
}void err_doit(int errnoflag, const char *fmt, va_list ap)
{
    int errno_save;
    char buf[MAX_STRING_LEN];    errno_save = errno;
    vsprintf(buf, fmt, ap);
    if (errnoflag)
        sprintf(buf + strlen(buf), ": %s", strerror(errno_save));
    strcat(buf, "\n");
    fflush(stdout);
    fputs(buf, stderr);
    fflush(NULL);
    return;
}

/* Print a message and terminate. */
void err_quit(const char *fmt, ...)
{
    va_list ap;
    va_start(ap, fmt);
    err_doit(0, fmt, ap);
    va_end(ap);
    exit(1);
}#ifdef WIN32
char *optarg;char getopt(int c, char *v[], char *opts)
{
    static int now = 1;
    char *p;    if (now >= c) return EOF;    if (v[now][0] == '-' && (p = strchr(opts, v[now][1]))) {
        optarg = v[now+1];
        now +=2;
        return *p;
    }    return EOF;
}#else
extern char *optarg;
#endif#define required(a) if (!a) { return -1; }int init(int argc, char *argv[])
{
    char c;
    //int i,optlen;
    //int slashcnt;    i_host[0]  =  '\0';
    i_port[0]  =  '\0';    while ((c = getopt(argc, argv, "h:p:?")) != EOF) {
        if (c == '?')
            return -1;
        switch (c) {
        case 'h':
            required(optarg);
            strcpy(i_host, optarg);
            break;
        case 'p':
            required(optarg);
            strcpy(i_port, optarg);
            break;
        default:
            return -1;
        }
    }    /*
     * there is no default value for hostname, port number,
     * password or uri
     */
    if (i_host[0] == '\0' || i_port[0] == '\0')
        return -1;    return 1;
}void print_usage()
{
    char *usage[] =
    {
        "Usage:",
        "    -h    host name",
        "    -p    port",
        "example:",
        "    -h 127.0.0.1 -p 4001",
    };
    int i;    for (i = 0; i < sizeof(usage) / sizeof(char*); i++)
        printf("%s\n", usage[i]);

    return;
}int main(int argc, char *argv[])
{
    SOCKET fd;
    int n;    /* parse command line etc ... */
    if (init(argc, argv) < 0) {
        print_usage();
        exit(1);
    }    buf[0] = '\0';    /* pack the info into the buffer */
    strcpy(buf, "HelloWorld");    /* make connection to the server */
    fd = tcp_connect(i_host, (unsigned short)atoi(i_port));    if(xnet_select(fd, 0, 500, WRITE_STATUS)>0){
        /* send off the message */
        write(fd, buf, strlen(buf));
    }
    else{
        err_quit("Socket I/O Write Timeout %s:%s\n", i_host, i_port);
    }    if(xnet_select(fd, 3, 0, READ_STATUS)>0){
        /* display the server response */
        printf("Server response:\n");
        n = read(fd, buf, BUFSIZE);
        buf[n] = '\0';
        printf("%s\n", buf);
    }
    else{
        err_quit("Socket I/O Read Timeout %s:%s\n", i_host, i_port);
    }
    close(fd);#ifdef WIN32
    WSACleanup();
#endif    return 0;
}

调试易

用vc6提供的方法，哪种方法能够很稳定地读取网页内容（能够兼容死链接而不过于超时）？

解决方案 »