ASP实现断点续传分段采集函数源码
url="http://www.zhaoxi.net/20051117173156951.swf" '测试用的地址if url="" then die("URL不能为空.") '敢唬我，空url可不行'
t=instrrev(url,"/") '获得最后一个"/"的位置'
if t=0 or t=len(url) then die("得不到文件名.") '没有"/"或以"/"结尾'
filename=right(url,len(url)-t) '获得要保存的文件名'
if not left(url,7)="http://" then url="http://"&url '如果粗心把“http://”忘了，加上'
filename=server.mappath(filename)
set fso=server.createobject("Scripting.FileSystemObject") 'FSO，ASO，HTTP三个对象一个都不能少'
set aso=server.createobject("ADODB.Stream")
set http=server.createobject("Microsoft.XMLHTTP")
if fso.fileexists(filename) then '判断要下载的文件是否已经存在'
start=fso.getfile(filename).size '存在，以当前文件大小作为开始位置'
else
start=0 '不存在，一切从零开始'
fso.createtextfile(filename).close '新建文件'
end if
response.write "Connectting..."
response.flush '好戏刚刚开始'
current=start '当前位置即开始位置
do
http.open "GET",url,false '这里用同步方式调用HTTP，本来想用异步方式，一直没有成功
http.setrequestheader "Range","bytes="&start&"-"&cstr(start+20480) '断点续传的奥秘就在这里
http.setrequestheader "Content-Type:","application/octet-stream"
http.send '构造完数据包就开始发送'
for i=1 to 60 '循环等待'
if http.readystate=3 then showplan() '状态3表示开始接收数据，显示进度'
if http.readystate=4 then exit for '状态4表示数据接受完成'
sleep(1) ‘这里延时，着正方法不是很好。
next
if not http.readystate=4 then die("超时.") '1分钟还没下完20k？超时！'
if http.status>299 then die("出错: "&http.status&" "&http.statustext) '不是吧，又出错？'
if not http.status=206 then die("服务器不支持断点续传.") '服务器不支持断点续传'
aso.type=1 '数据流类型设为字节'
aso.open
aso.loadfromfile filename '打开文件'
aso.position=start '设置文件指针初始位置'
aso.write http.responsebody '写入数据'
aso.savetofile filename,2 '覆盖保存'
aso.close
range=http.getresponseheader("Content-Range") '获得http头中的"Content-Range"'
if range="" then die("得不到.") '没有它就不知道下载完了没有'
temp=mid(range,instr(range,"-")+1) 'Content-Range是类似123-456/789的样子'
current=clng(left(temp,instr(temp,"/")-1)) '123是开始位置，456是结束位置'
total=clng(mid(temp,instr(temp,"/")+1)) '789是文件总字节数'
if total-current=1 then exit do '结束位置比总大小少1就表示传输完成了'
start=start+20480 '否则再下载20k'
loop while true
response.write chr(13)&"共下载了 ("&total&")." '下载完了，显示总字节数'
function die(msg) '函数名来自Perl内置函数die'
response.write msg '交代遗言^_^'
response.end '去见马克思了'
end function
function showplan() '显示下载进度'
if i mod 3 = 0 then c="/" '简单的动态效果'
if i mod 3 = 1 then c="-"
if i mod 3 = 2 then c="\"
response.write chr(13)&"Download ("¤t&") "&c&chr(8)'13号ASCII码是回到行首，8号是退格'
response.flush
end function
sub sleep(delaytime)
dim t1,t2,t3,ct,lt
t1=hour(time)*3600
t2=minute(time)*60
t3=second(time)
//把当前时间的小时，分钟转换成秒，存到ct里
ct=t1+t2+t3
//循环等待
do
t1=hour(time)*3600
t2=minute(time)*60
t3=second(time)
lt=t1+t2+t3
loop while(lt-ct<delaytime)
end sub
%>
<%
Option Explicit
Dim fso,aso,http,fo
Dim strRemoteFileUrl,strLocalFile
Dim nStartPos,nCurPos,Range,nTotalBytes,nPackage
Dim Temp,i
Set Fso = Server.CreateObject("Scripting.FileSystemObject")
Set Aso = Server.CreateObject("Adodb.Stream")
Set Http = Server.CreateObject("Microsoft.XmlHttp")
nPackage = 10240
strRemoteFileUrl = "http://www.zhaoxi.net/file.rar"
strLocalFile = "f:\down.file"
If Fso.FileExists(strLocalFile) Then
nStartPos = Fso.GetFile(strLocalFile).Size
Else
nStartPos = 0
Set fo = Fso.CreateTextFile(strLocalFile)
fo.Close
End If
nCurPos = nStartPos
Do
Http.Open "GET",strRemoteFileUrl,True
Http.SetRequestHeader "Range","Bytes = " & nStartPos & "-" & CStr(nStartPos + nPackage)
Http.SetRequestHeader "Content-type:","Application/Octet-stream"
Http.Send
Do
Loop While Http.ReadyState <> 4
Aso.Type = 1
Aso.Open
Aso.LoadFromFile strLocalFile
Aso.Position = nStartPos
Aso.Write Http.ResponseBody
Aso.SaveToFile strLocalFile, 2
Aso.Close
Range = Http.GetResponseHeader("Content-range")
If Range = "" Then
Response.Write "获取Range值时出错"
Exit Do
End If
Temp = Mid(Range, InStr(Range, "-") + 1)
response.write Range
nCurPos = CLng(Left(Temp,InStr(Temp,"/") - 1))
nTotalBytes = CLng(Mid(Temp,InStr(Temp, "/") + 1))
If nTotalBytes - nCurPos = 1 Then Exit Do
nStartPos = nStartPos + nPackage
Response.Write nStartPos & "<br>"
Loop While True
Response.Write "下载成功"
%>
