asp中常用的字符串安全处理函数集合(过滤特殊字符等)

'=====================================
'转换内容，防止意外
'=====================================
function content_encode(byval t0)
if isnull(t0) or len(t0)=0 then
content_encode=""
else
content_encode=replace(t0,"<","<")
content_encode=replace(content_encode,">",">")
end if
end function

'=====================================
'反转换内容
'=====================================
function content_decode(byval t0)
if isnull(t0) or len(t0)=0 then
content_decode=""
else
content_decode=replace(t0,"<","<")
content_decode=replace(content_decode,">",">")
end if
end function

'=====================================
'过滤字符
'=====================================
function filtertext(byval t0,byval t1)
if len(t0)=0 or isnull(t0) or isarray(t0) then filtertext="":exit function
t0=trim(t0)
select case t1
case "1"
t0=replace(t0,chr(32)," ")
t0=replace(t0,chr(13),"")
t0=replace(t0,chr(10)&chr(10),"<br>")
t0=replace(t0,chr(10),"<br>")
case "2"
t0=replace(t0,chr(8),"")'回格
t0=replace(t0,chr(9),"")'tab(水平制表符)
t0=replace(t0,chr(10),"")'换行
t0=replace(t0,chr(11),"")'tab(垂直制表符)
t0=replace(t0,chr(12),"")'换页
t0=replace(t0,chr(13),"")'回车 chr(13)&chr(10) 回车和换行的组合
t0=replace(t0,chr(22),"")
t0=replace(t0,chr(32),"")'空格 space
t0=replace(t0,chr(33),"")'!
t0=replace(t0,chr(34),"")'"
t0=replace(t0,chr(35),"")'#
t0=replace(t0,chr(36),"")'$
t0=replace(t0,chr(37),"")'%
t0=replace(t0,chr(38),"")'&
t0=replace(t0,chr(39),"")''
t0=replace(t0,chr(40),"")'(
t0=replace(t0,chr(41),"")')
t0=replace(t0,chr(42),"")'*
t0=replace(t0,chr(43),"")'+
t0=replace(t0,chr(44),"")',
t0=replace(t0,chr(45),"")'-
t0=replace(t0,chr(46),"")'.
t0=replace(t0,chr(47),"")'/
t0=replace(t0,chr(58),"")':
t0=replace(t0,chr(59),"")';
t0=replace(t0,chr(60),"")'<
t0=replace(t0,chr(61),"")'=
t0=replace(t0,chr(62),"")'>
t0=replace(t0,chr(63),"")'?
t0=replace(t0,chr(64),"")'@
t0=replace(t0,chr(91),"")'\
t0=replace(t0,chr(92),"")'\
t0=replace(t0,chr(93),"")']
t0=replace(t0,chr(94),"")'^
t0=replace(t0,chr(95),"")'_
t0=replace(t0,chr(96),"")'`
t0=replace(t0,chr(123),"")'{
t0=replace(t0,chr(124),"")'|
t0=replace(t0,chr(125),"")'}
t0=replace(t0,chr(126),"")'~
case else
t0=replace(t0, "&", "&")
t0=replace(t0, "'", "'")
t0=replace(t0, """", """)
t0=replace(t0, "<", "<")
t0=replace(t0, ">", ">")
end select
if instr(lcase(t0),"expression")>0 then
t0=replace(t0,"expression","e­xpression", 1, -1, 0)
end if
filtertext=t0
end function

'=====================================
'过滤常见字符及html
'=====================================
function filterhtml(byval t0)
if len(t0)=0 or isnull(t0) or isarray(t0) then filterhtml="":exit function
if len(sdcms_badhtml)>0 then t0=replacetext(t0,"<(\/|)("&sdcms_badhtml&")", "<$1$2")
if len(sdcms_badevent)>0 then t0=replacetext(t0,"<(.[^>]*)("&sdcms_badevent&")", "<$1$2")
t0=filtertext(t0,0)
filterhtml=t0
end function

function gottopic(byval t0,byval t1)
if len(t0)=0 or isnull(t0) then
gottopic=""
exit function
end if
dim l,t,c, i
t0=replace(replace(replace(replace(t0," "," "),""",chr(34)),">",">"),"<","<")
l=len(t0)
t=0
for i=1 to l
c=abs(asc(mid(t0,i,1)))
if c>255 then t=t+2 else t=t+1
if t>=t1 then
gottopic=left(t0,i)&"…"
exit for
else
gottopic=t0
end if
next
gottopic=replace(replace(replace(replace(gottopic," "," "),chr(34),"""),">",">"),"<","<")
end function

function urldecode(byval t0)
dim t1,t2,t3,i,t4,t5,t6
t1=""
t2=false
t3=""
for i=1 to len(t0)
t4=mid(t0,i,1)
if t4="+" then
t1=t1&" "
elseif t4="%" then
t5=mid(t0,i+1,2)
t6=cint("&h" & t5)
if t2 then
t2=false
t1=t1&chr(cint("&h"&t3&t5))
else
if abs(t6)<=127 then
t1=t1&chr(t6)
else
t2=true
t3=t5
end if
end if
i=i+2
else
t1=t1&t4
end if
next
urldecode=t1
end function

function cutstr(byval t0,byval t1)
dim l,t,c,i
if isnull(t0) then cutstr="":exit function
l=len(t0)
t1=int(t1)
t=0
for i=1 to l
c=asc(mid(t0,i,1))
if c<0 or c>255 then t=t+2 else t=t+1
if t>=t1 then
cutstr=left(t0,i)&"..."
exit for
else
cutstr=t0
end if
next
end function

function closehtml(byval t0)
dim t1,i,t2,t3,regs,matches,j,match
set regs=new regexp
regs.ignorecase=true
regs.global=true
t1=array("p","div","span","table","ul","font","b","u","i","h1","h2","h3","h4","h5","h6")
for i=0 to ubound(t1)
t2=0
t3=0
regs.pattern="\<"&t1(i)&"( [^\<\>]+|)\>"
set matches=regs.execute(t0)
for each match in matches
t2=t2+1
next
regs.pattern="\</"&t1(i)&"\>"
set matches=regs.execute(t0)
for each match in matches
t3=t3+1
next
for j=1 to t2-t3
t0=t0+"</"&t1(i)&">"
next
next
closehtml=t0
end function