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求救:winsock传送二进制文件丢包的问题

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求救:winsock传送二进制文件丢包的问题[已结贴,结贴人:jzmark]

发表于：2007-03-07 18:43:32 楼主

做一个局域网内的下载功能，现在会出现客户端收到的文件比源文件小的情况。哪位能帮我看看，谢谢。
服务器端发送程序：
sub sendfiletoclient（xfilename as string, ipaddy as string, whichwinsock as winsock)
on error goto errorhandler
dim buffer as string
dim buffersize as integer
dim filelength as long, superbuffer as long, timeout as long
dim i as integer
dim j as integer
buffersize = 2048
do while whichwinsock.state <> 7: doevents
if whichwinsock.state = sckerror then
writeerrlog "winsock error: " & vbcrlf & err.description: exit sub
end if
loop
startsending = false
whichwinsock.senddata "filesize= " & filelen（xfilename)
do while startsending <> true
doevents
loop
i = freefile 'find free file
open xfilename for binary access read as #i
filelength = lof（i)
do while not eof（i)
doevents
if filelength - loc（i) < buffersize then
let buffersize = filelength - loc（i)
if buffersize = 0 then goto done
end if
'buffer = space（buffersize)
redim abuf（0 to buffersize - 1)
get #i, , buffer
whichwinsock.senddata buffer)
superbuffer = superbuffer + len（buffer)
'等待客户端接受以后再发
do while （timeout < 10000)
doevents
timeout = timeout + 1
if timeout > 10000 then exit do
loop
'debug.print j
timeout = 0
loop
done:
close #i
whichwinsock.senddata "sendend "
do while （timeout < 10000)
doevents
timeout = timeout + 1
if timeout > 10000 then exit do
loop
startsending = false
writeerrlog "sent ' " & xfilename & " ' （ " & superbuffer & " bytes) to ip ' " & ipaddy & " ' time/date= " & format（now, "yyyy/mm/dd hh:mm:ss ")
exit sub
errorhandler:
writeerrlog "sent ' " & xfilename & " 'to ip ' " & ipaddy & " ' time/date= " & format（now, "yyyy/mm/dd hh:mm:ss ") & "出现错误： " & err.description
end sub

客户端接收

private sub winsock_dataarrival（byval bytestotal as long)
dim data as string
dim receivearr（) as byte
if winsock.state <> 7 then exit sub
call winsock.getdata（data, , bytestotal)
if left（data, 6) = "error: " then
blnerror = true
fcomplete = true
exit sub
end if
if left（data, 9) = "filesize= " then
filesize = right（data, len（data) - 9)
inr = 1
if filesize = 0 then
close #filenum
fcomplete = true
exit sub
end if
call client.senddata（ "begin ")
exit sub
end if
if data = "sendend " then
close #filenum
fcomplete = true
exit sub
end if

if filenum > 0 then
put #filenum, , data
'debug.print inr
inr = inr + 1
if lof（filenum) = filesize then
close #filenum
fcomplete = true
exit sub
end if
end if
end sub

发表于：2007-03-07 20:22:321楼得分:100

唉，这个代码，几乎没注释……

只说两点吧：
1. 如果发送的数据大于8k，会激发多次dataarrival事件，你的服务器端代码必须将接收的数据拼起来
2. 客户端分两次发送的数据，服务器端可能会并为一次接收，也就是说只激发一次dataarrival事件

代码根本不用这么烦的，给段参考吧：

发送方（我这里是客户端）
'先发送文件名和大小，dlg为通用对话框的名称，用到一些控件，你看前缀就知道是什么控件了
private sub cmdsend_click（)
dlg.filename = " "
dlg.filter = "所有文件 ¦*.* "
dlg.showopen
if dlg.filename <> " " then
wsclient.senddata "$start* " & dlg.filetitle & "* " & filelen（dlg.filename)
lblstate.caption = "准备传送文件，等待对方应答... "
end if
end sub

'对方响应后发送实际文件
private sub wsclient_dataarrival（byval bytestotal as long)
dim s as string
wsclient.getdata s, vbstring
if s = "no " then
lblstate.caption = "对方拒绝接收 "
else
wsclient.senddata filetobytes（dlg.filename)
lblstate.caption = "正在传送文件... "
end if
end sub

'文件转为字节数组
private function filetobytes（filename as string) as byte（)
dim byt（) as byte
open filename for binary as #1
redim byt（lof（1) - 1)
get #1, 1, byt
close #1
filetobytes = byt
end function

接收方，dlg为通用对话框的名称
private sub wsserver_dataarrival（byval bytestotal as long)
dim byt（) as byte
dim strfileinfo as string
static issendbytes as boolean
static info（) as string

on error goto ext

if issendbytes = false then
wsserver.getdata strfileinfo, vbstring
info = split（strfileinfo, "* ")
if info（0) <> "$start " then exit sub
if msgbox（ "对方向你发送文件“ " & info（1) & "”，大小为 " & info（2) & "字节，是否接收？ ", vbquestion + vbyesno) = vbno then
wsserver.senddata "no "
else
dlg.filename = info（1)
dlg.filter = "所有文件 ¦*.* "
dlg.showsave
wsserver.senddata "yes " '向对方发送开始传送文件标志
issendbytes = true
end if
else
lblstate.caption = "正在接收文件，已接收 " & bytestotal & "字节 "
if bytestotal > = info（2) then '如果接收到的数据大于等于文件大小，表示接收完毕
wsserver.getdata byt, vbbyte + vbarray
bytestofile byt, dlg.filename
issendbytes = false
lblstate.caption = "文件已接收完毕 "
end if
end if
exit sub
ext:
wsserver.senddata "no " '点击取消，将引发错误，则向对方发送不同意传送文件的标志。此处省略了判断错误号的操作
end sub

'字节数组转为文件
private sub bytestofile（byt（) as byte, filename as string)
if dir（filename) <> " " then kill filename
open filename for binary as #1
put #1, 1, byt
close #1
end sub

发表于：2007-03-07 22:41:162楼得分:0

搞清楚问题了，是因为发送和接受用的是字符串，不是byte数组，谢谢

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