socket重复调用send要怎么做？

[sunlamb]

第一次调用可以，第二次调用Receive不到东西
这个项目只能用socket，因为需要用到socket5代理
部分代码
Function SocketRead(ByVal url As String, ByVal con As Socket) As String
Dim ascii As Encoding = Encoding.ASCII
Dim request As String = url
Dim bytesSent As [Byte]() = ascii.GetBytes(request)
Dim bytesReceived(255) As [Byte]

Dim s As Socket = con
If s Is Nothing Then
Return "Connection failed"
End If
s.Send(bytesSent, bytesSent.Length, 0)
Dim bytes As Int32
Dim page As [String] = ""
Do
bytes = s.Receive(bytesReceived, bytesReceived.Length, 0)
page = page + Encoding.UTF8.GetString(bytesReceived, 0, bytes)
Loop While bytes > 0
Return page
End Function

[sunlamb]

有点急，请问是什么地方有问题

[ZengHD]

Function SocketRead(ByVal url As String, ByVal con As Socket) As String
        Dim ascii As Encoding = Encoding.ASCII
        Dim request As String = url
        Dim bytesSent As [Byte]() = ascii.GetBytes(request)
        Dim bytesReceived(255) As [Byte]

        Dim s As Socket = con
        If s Is Nothing Then
            Return "Connection failed"
        End If
        s.Send(bytesSent)
        Dim bytes As Int32
        Dim page As [String] = ""
        bytes = s.Receive(bytesReceived)
        page = Encoding.Unicode.UTF8.GetString(bytesReceived)

        While s.Available > 0
            System.Array.Clear(bytesReceived, 0, bytesReceived.Length)
            bytes = s.Receive(bytesReceived)
            page = page + Encoding.Unicode.UTF8.GetString(bytesReceived)
'根据VB6的经验，这样的情况是不是应该加上DoEvents()呢？？？
            Application.DoEvents();
        End While
        Return page
    End Function

[sunlamb]

多谢提醒
难道说这样的方法无法实现，一次Connect可多次使用 Send 和 Receive（下载网页）
是否只能考虑异步调用？

[sunlamb]

 
  Private Function Gettest(ByVal strIpAdd As String, ByVal iPort As Integer) As Socket

        Dim hostadd As IPAddress = Dns.Resolve(strIpAdd).AddressList(0)
        Dim EPhost As New IPEndPoint(hostadd, iPort)
        Dim s As New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)
        s.Connect(EPhost)
   Return s
    End Function

 Function SocketRead(ByVal request As String, ByVal s As Socket) As String
        Dim ascii As Encoding = Encoding.UTF8
        Dim bytesSent As [Byte]() = ascii.GetBytes(request)
        Dim bytes As Int32
        Dim page As [String] = ""
        Dim bytesReceived(255) As [Byte]

      
        s.Send(bytesSent)
       
        Do
            System.Array.Clear(bytesReceived, 0, bytesReceived.Length)
            bytes = s.Receive(bytesReceived)
            page = page + Encoding.UTF8.GetString(bytesReceived, 0, bytes)
            Application.DoEvents()

        Loop While s.Available > 0
       
        Return page
    End Function

 Function test()
        Dim regStr, constr, headget As String
        Dim head As [String]
        Dim chr As String = ControlChars.Cr + ControlChars.Lf
        Dim host As String = "www.verycd.com"
        Dim sb As Socket = Gettest("www.verycd.com", "80")

        headget = "GET {0} HTTP/1.1" + chr & _
                "Host: www.verycd.com" + chr & _
                "User-Agent:Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN; rv:1.8.1.16) Gecko/20080702 Firefox/2.0.0.16" + chr & _
                "Accept:application/x-shockwave-flash,text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5" + chr & _
                "Accept-Language:zh-cn,zh;q=0.5" + chr & _
                "Accept-Encoding:gzip,deflate" + chr & _
                "Accept-Charset:gb2312,utf-8;q=0.7,*;q=0.7" + chr & _
                "Keep-Alive: 300" + chr & _
                "Connection: keep-alive" + chr & _
                "Cookie: XXXXX" + chr & _
                 chr
        head = String.Format(headget, "www.verycd.com")
        constr = SocketRead(head, sb)
        TextBox1.Text = "setp1:" + constr + chr


        head = String.Format(headget, "www.verycd.com")
        constr = SocketRead(head, sb)
        TextBox1.Text += "setp2:" + constr + chr
    End Function

使用的时候，调用test()，麻烦帮我看看了，谢谢

[exceed_me]

很可能是第一次发送后没有接收，而第二次又发送过去，当然收不到

[sunlamb]

Receive不是接收吗？那请问该怎么做？
24楼那个是完整的代码

[ZengHD]

我测试好像可以啊，我在Button里调用两次test(),都获取到数据啊

[sunlamb]

test（）里面有两次SocketRead(head, sb)了
所以调用一次test（），setp1为第一次调用，setp2为第二次调用

[ZengHD]

只有一个setp2，没有setp1
奇怪

[ZengHD]

[Quote=引用 29 楼 ZengHD 的回复:]
只有一个setp2，没有setp1
奇怪
[/Quote]

错了，应该是这样

[code=HTML]setp1:HTTP/1.0 400 Bad Request
Server: squid/2.6.STABLE20
Date: Sun, 14 Sep 2008 06:58:28 GMT
Content-Type: text/html
Content-Length: 1367
Expires: Sun, 14 Sep 2008 06:58:28 GMT
X-Squid-Error: ERR_INVALID_URL 0
X-Cache: MISS from httpd-20.verycd.com
Via: 1.0 httpd-20.verycd.com:80 (squid/2.6.STABLE20)
Connection: close

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<HTML><HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=gb2312">
<TITLE>���������������ַ��URL���޷���ȡ</TITLE>
<STYLE type="text/css"><!--BODY{background-color:#ffffff;font-family:verdana,sans-serif}PRE{font-family:sans-serif}--></STYLE>
</HEAD><BODY>
<H1>����</H1>
<H2>�����������ַ��URL���޷���ȡ</H2>
<HR noshade size="1px">
<P>
�����Զ�ȡ������ַ��URL��ʱ��
<A HREF="www.verycd.com">www.verycd.com</A>
<P>
���������еĴ���
<UL>
<LI>
<STRONG>
Invalid URL
<BR>
��Ч����ַ
</STRONG>
</UL>

<P>
Some aspect of the requested URL is incorrect. Possible problems:
<BR>
������ַ��ijЩ�ط����

[sunlamb]

“setp2：”是第二次發送send的，这部分没有数据，在最下面一行
相关代码：
head = String.Format(headget, "www.verycd.com")
constr = SocketRead(head, sb)
TextBox1.Text = "setp1:" + constr + chr


head = String.Format(headget, "www.verycd.com")
constr = SocketRead(head, sb)
TextBox1.Text += "setp2:" + constr + chr

[ZengHD]

第一次之后sb.Close()再connect，倒是可以，但可能不是你要的

[sunlamb]

恩，因为第一次连接后需要登录，然后获取登录后的一些网站信息，所以不能close，或者需用到异步调用？

[yanlongwuhui]

[Quote=引用 18 楼 sunlamb 的回复:]
难道说这样的方法无法实现，一次Connect可多次使用 Send 和 Receive（下载网页）
[/Quote]
可以一次Connect可多次使用 Send 和 Receive

[ldming]

顶！路过！！

[sunlamb]

[Quote=引用 19 楼 yanlongwuhui 的回复:]
引用 18 楼 sunlamb 的回复:
难道说这样的方法无法实现，一次Connect可多次使用 Send 和 Receive（下载网页）

可以一次Connect可多次使用 Send 和 Receive
[/Quote]
那我第二次使用send的时候总是取不到数据，请问知道是哪里出錯吗？

[sunlamb]

是否是因为我每次send，Receive以后没有释放缓存或者没有抛弃第一个http协议包？如果需要，请问该怎么做？

[yanlongwuhui]

贴上你的实现代码吧

[yanlongwuhui]

你的通讯采用的是阻塞模式，而你请求的操作的返回信息虽然接收完了，但操作没有完成，结果导致阻塞。你可以试试其它能正确执行的命令，或是调整实现方式。
你命令返回信息如下：
setp1:HTTP/1.0 400 Bad Request
Server: squid/2.6.STABLE20
Date: Mon, 15 Sep 2008 01:42:23 GMT
Content-Type: text/html
Content-Length: 1367
Expires: Mon, 15 Sep 2008 01:42:23 GMT
X-Squid-Error: ERR_INVALID_URL 0
X-Cache: MISS from httpd-20.verycd.com
Via: 1.0 httpd-20.verycd.com:80 (squid/2.6.STABLE20)
Connection: close
......

[yanlongwuhui]

VB.Net中Socket异步编程的实例
http://www.lob.cn/sl/network/278.shtml