缓存类图片显示技术

<%
'盗链判断
Dim server_v1,server_v2
server_v1=Cstr(Request.ServerVariables("HTTP_REFERER"))
server_v2=Cstr(Request.ServerVariables("SERVER_NAME"))
If Mid(server_v1,8,len(server_v2))<>server_v2 Then
Response.Write "非法的盗链"
Response.End
End If

Dim url, body, myCache

url = Request.QueryString("url")

Set myCache = new cache
myCache.name = "picindex"&url
If myCache.valid Then
body = myCache.value
Else
body = GetWebData(url)
myCache.add body,dateadd("d",1,now)
End If

If Err.Number = 0 Then
Response.CharSet = "UTF-8"
Response.ContentType = "application/octet-stream"
Response.BinaryWrite body
Response.Flush
Else
Wscript.Echo Err.Description
End if

'取得数据
Public Function GetWebData(ByVal strUrl)
Dim curlpath
curlpath = Mid(strUrl,1,Instr(8,strUrl,"/"))
Dim Retrieval
Set Retrieval = Server.CreateObject("Microsoft.XMLHTTP")
With Retrieval
.Open "Get", strUrl, False,"",""
.setRequestHeader "Referer", curlpath
.Send
GetWebData =.ResponseBody
End With
Set Retrieval = Nothing
End Function

'cache类

class Cache
private obj 'cache内容
private expireTime '过期时间
private expireTimeName '过期时间application名
private cacheName 'cache内容application名
private path 'url

private sub class_initialize()
path=request.servervariables("url")
path=left(path,instrRev(path,"/"))
end sub

private sub class_terminate()
end sub

public property get blEmpty
'是否为空
if isempty(obj) then
blEmpty=true
else
blEmpty=false
end if
end property

public property get valid
'是否可用(过期)
if isempty(obj) or not isDate(expireTime) then
valid=false
elseif CDate(expireTime)<now then
valid=false
else
valid=true
end if
end property

public property let name(str)
'设置cache名
cacheName=str & path
obj=application(cacheName)
expireTimeName=str & "expires" & path
expireTime=application(expireTimeName)
end property

public property let expires(tm)
'重设置过期时间
expireTime=tm
application.lock
application(expireTimeName)=expireTime
application.unlock
end property

public sub add(var,expire)
'赋值
if isempty(var) or not isDate(expire) then
exit sub
end if
obj=var
expireTime=expire
application.lock
application(cacheName)=obj
application(expireTimeName)=expireTime
application.unlock
end sub

public property get value
'取值
if isempty(obj) or not isDate(expireTime) then
value=null
elseif CDate(expireTime)<now then
value=null
else
value=obj
end if
end property

public sub makeEmpty()
'释放application
application.lock
application(cacheName)=empty
application(expireTimeName)=empty
application.unlock
obj=empty
expireTime=empty
end sub

public function equal(var2)
'比较
if typename(obj)<>typename(var2) then
equal=false
elseif typename(obj)="Object" then
if obj is var2 then
equal=true
else
equal=false
end if
elseif typename(obj)="Variant()" then
if join(obj,"^")=join(var2,"^") then
equal=true
else
equal=false
end if
else
if obj=var2 then
equal=true
else
equal=false
end if
end if
end function
end class
%>