我有一个 Web 服务加载驱动程序，它是一个 Windows 脚本文件 (WSF)，其中包括一些 VBScript 和 JavaScript 文件。我的 Web 服务要求传入的消息是 base64 编码的。我目前有一个 VBScript 函数可以执行此操作，但效率非常低（内存密集型，主要是由于 VBScripts 糟糕的字符串连接）
[在旁边; 是的，我看过Jeff 的最新博文。连接发生在一个循环中，跨越大小为 1,000 到 10,000 字节的消息。]
我尝试过使用一些自定义字符串连接例程；一个使用数组，一个使用 ADODB.Stream。这些有一点帮助，但我认为如果我有其他方式来编码消息而不是通过我自己的 VBS 函数，它会更有帮助。
是否有其他方式对我的消息进行编码，最好使用本机 Windows 方法？
我最初使用的是 Antonin Foller 的一些 VBScript 代码： Base64 Encode VBS Function和Base64 Decode VBS Function。
搜索 Antonin 的网站，我看到他有一些引用可打印编码的代码，使用 CDO.Message 对象，所以我尝试了一下。
最后，我移植了 Mark 对 VBScript 的回答中提到的代码（也使用了这个SO question 中的一些代码），并使用了Antonin 网站上的Stream___StringToBinary和Stream_BinaryToString函数来获取使用 MSXML 编码的函数。
我运行了一个快速测试来测量所有四种方法中 1,500 个字符的消息（我需要发送到我的 Web 服务的平均消息大小）的编码时间：
结果如下：
迭代次数：10,000 消息大小：1,500 +-------------+------------+ + 方法 | 时间（毫秒） + +-------------+------------+ | VB脚本 | 301,391 | +-------------+------------+ | QP | 12,922 | +-------------+------------+ | QP（二进制）| 13,953 | +-------------+------------+ | MSXML | 3,312 | +-------------+------------+
我还在测试运行时监控了内存利用率（Windows 任务管理器中 cscript.exe 进程的内存使用情况）。我没有任何原始数字，但引用的可打印和 MSXML 解决方案的内存利用率均低于 VBScript 解决方案（前者为 7,000K，VBScript 约为 16,000K）。
我决定为我的驱动程序使用 MSXML 解决方案。对于那些感兴趣的人，这是我正在使用的代码：
base64.vbs
Function Base64Encode(sText)
Dim oXML, oNode
Set oXML = CreateObject("Msxml2.DOMDocument.3.0")
Set oNode = oXML.CreateElement("base64")
oNode.dataType = "bin.base64"
oNode.nodeTypedValue =Stream_StringToBinary(sText)
Base64Encode = oNode.text
Set oNode = Nothing
Set oXML = Nothing
End Function
Function Base64Decode(ByVal vCode)
Dim oXML, oNode
Set oXML = CreateObject("Msxml2.DOMDocument.3.0")
Set oNode = oXML.CreateElement("base64")
oNode.dataType = "bin.base64"
oNode.text = vCode
Base64Decode = Stream_BinaryToString(oNode.nodeTypedValue)
Set oNode = Nothing
Set oXML = Nothing
End Function
'Stream_StringToBinary Function
'2003 Antonin Foller, http://www.motobit.com
'Text - string parameter To convert To binary data
Function Stream_StringToBinary(Text)
Const adTypeText = 2
Const adTypeBinary = 1
'Create Stream object
Dim BinaryStream 'As New Stream
Set BinaryStream = CreateObject("ADODB.Stream")
'Specify stream type - we want To save text/string data.
BinaryStream.Type = adTypeText
'Specify charset For the source text (unicode) data.
BinaryStream.CharSet = "us-ascii"
'Open the stream And write text/string data To the object
BinaryStream.Open
BinaryStream.WriteText Text
'Change stream type To binary
BinaryStream.Position = 0
BinaryStream.Type = adTypeBinary
'Ignore first two bytes - sign of
BinaryStream.Position = 0
'Open the stream And get binary data from the object
Stream_StringToBinary = BinaryStream.Read
Set BinaryStream = Nothing
End Function
'Stream_BinaryToString Function
'2003 Antonin Foller, http://www.motobit.com
'Binary - VT_UI1 | VT_ARRAY data To convert To a string
Function Stream_BinaryToString(Binary)
Const adTypeText = 2
Const adTypeBinary = 1
'Create Stream object
Dim BinaryStream 'As New Stream
Set BinaryStream = CreateObject("ADODB.Stream")
'Specify stream type - we want To save binary data.
BinaryStream.Type = adTypeBinary
'Open the stream And write binary data To the object
BinaryStream.Open
BinaryStream.Write Binary
'Change stream type To text/string
BinaryStream.Position = 0
BinaryStream.Type = adTypeText
'Specify charset For the output text (unicode) data.
BinaryStream.CharSet = "us-ascii"
'Open the stream And get text/string data from the object
Stream_BinaryToString = BinaryStream.ReadText
Set BinaryStream = Nothing
End Function
在没有 ADODB.Stream 和 MSXml2.DOMDocument 的情况下，可以在纯 vbscript 中编码 base64。
例如：
Function btoa(sourceStr)
Dim i, j, n, carr, rarr(), a, b, c
carr = Array("A", "B", "C", "D", "E", "F", "G", "H", _
"I", "J", "K", "L", "M", "N", "O" ,"P", _
"Q", "R", "S", "T", "U", "V", "W", "X", _
"Y", "Z", "a", "b", "c", "d", "e", "f", _
"g", "h", "i", "j", "k", "l", "m", "n", _
"o", "p", "q", "r", "s", "t", "u", "v", _
"w", "x", "y", "z", "0", "1", "2", "3", _
"4", "5", "6", "7", "8", "9", "+", "/")
n = Len(sourceStr)-1
ReDim rarr(n\3)
For i=0 To n Step 3
a = AscW(Mid(sourceStr,i+1,1))
If i < n Then
b = AscW(Mid(sourceStr,i+2,1))
Else
b = 0
End If
If i < n-1 Then
c = AscW(Mid(sourceStr,i+3,1))
Else
c = 0
End If
rarr(i\3) = carr(a\4) & carr((a And 3) * 16 + b\16) & carr((b And 15) * 4 + c\64) & carr(c And 63)
Next
i = UBound(rarr)
If n Mod 3 = 0 Then
rarr(i) = Left(rarr(i),2) & "=="
ElseIf n Mod 3 = 1 Then
rarr(i) = Left(rarr(i),3) & "="
End If
btoa = Join(rarr,"")
End Function
Function char_to_utf8(sChar)
Dim c, b1, b2, b3
c = AscW(sChar)
If c < 0 Then
c = c + &H10000
End If
If c < &H80 Then
char_to_utf8 = sChar
ElseIf c < &H800 Then
b1 = c Mod 64
b2 = (c - b1) / 64
char_to_utf8 = ChrW(&HC0 + b2) & ChrW(&H80 + b1)
ElseIf c < &H10000 Then
b1 = c Mod 64
b2 = ((c - b1) / 64) Mod 64
b3 = (c - b1 - (64 * b2)) / 4096
char_to_utf8 = ChrW(&HE0 + b3) & ChrW(&H80 + b2) & ChrW(&H80 + b1)
Else
End If
End Function
Function str_to_utf8(sSource)
Dim i, n, rarr()
n = Len(sSource)
ReDim rarr(n - 1)
For i=0 To n-1
rarr(i) = char_to_utf8(Mid(sSource,i+1,1))
Next
str_to_utf8 = Join(rarr,"")
End Function
Function str_to_base64(sSource)
str_to_base64 = btoa(str_to_utf8(sSource))
End Function
'test
msgbox btoa("Hello") 'SGVsbG8=
msgbox btoa("Hell") 'SGVsbA==
msgbox str_to_base64("中文한국어") '5Lit5paH7ZWc6rWt7Ja0
如果您的字符串中有宽字符（AscW(c) > 255 或 < 0），您可以在调用 btoa 之前将其转换为 utf-8。
utf-8 转换也可以用纯 vbscript 编写。
所以我还有一些其他完整的编码器和解码器示例：
编码器：
' This script reads jpg picture named SuperPicture.jpg, converts it to base64
' code using encoding abilities of MSXml2.DOMDocument object and saves
' the resulting data to encoded.txt file
Option Explicit
Const fsDoOverwrite = true ' Overwrite file with base64 code
Const fsAsASCII = false ' Create base64 code file as ASCII file
Const adTypeBinary = 1 ' Binary file is encoded
' Variables for writing base64 code to file
Dim objFSO
Dim objFileOut
' Variables for encoding
Dim objXML
Dim objDocElem
' Variable for reading binary picture
Dim objStream
' Open data stream from picture
Set objStream = CreateObject("ADODB.Stream")
objStream.Type = adTypeBinary
objStream.Open()
objStream.LoadFromFile("SuperPicture.jpg")
' Create XML Document object and root node
' that will contain the data
Set objXML = CreateObject("MSXml2.DOMDocument")
Set objDocElem = objXML.createElement("Base64Data")
objDocElem.dataType = "bin.base64"
' Set binary value
objDocElem.nodeTypedValue = objStream.Read()
' Open data stream to base64 code file
Set objFSO = CreateObject("Scripting.FileSystemObject")
Set objFileOut = objFSO.CreateTextFile("encoded.txt", fsDoOverwrite, fsAsASCII)
' Get base64 value and write to file
objFileOut.Write objDocElem.text
objFileOut.Close()
' Clean all
Set objFSO = Nothing
Set objFileOut = Nothing
Set objXML = Nothing
Set objDocElem = Nothing
Set objStream = Nothing
解码器：
' This script reads base64 encoded picture from file named encoded.txt,
' converts it in to back to binary reprisentation using encoding abilities
' of MSXml2.DOMDocument object and saves data to SuperPicture.jpg file
Option Explicit
Const foForReading = 1 ' Open base 64 code file for reading
Const foAsASCII = 0 ' Open base 64 code file as ASCII file
Const adSaveCreateOverWrite = 2 ' Mode for ADODB.Stream
Const adTypeBinary = 1 ' Binary file is encoded
' Variables for reading base64 code from file
Dim objFSO
Dim objFileIn
Dim objStreamIn
' Variables for decoding
Dim objXML
Dim objDocElem
' Variable for write binary picture
Dim objStream
' Open data stream from base64 code filr
Set objFSO = CreateObject("Scripting.FileSystemObject")
Set objFileIn = objFSO.GetFile("encoded.txt")
Set objStreamIn = objFileIn.OpenAsTextStream(foForReading, foAsASCII)
' Create XML Document object and root node
' that will contain the data
Set objXML = CreateObject("MSXml2.DOMDocument")
Set objDocElem = objXML.createElement("Base64Data")
objDocElem.DataType = "bin.base64"
' Set text value
objDocElem.text = objStreamIn.ReadAll()
' Open data stream to picture file
Set objStream = CreateObject("ADODB.Stream")
objStream.Type = adTypeBinary
objStream.Open()
' Get binary value and write to file
objStream.Write objDocElem.NodeTypedValue
objStream.SaveToFile "SuperPicture.jpg", adSaveCreateOverWrite
' Clean all
Set objFSO = Nothing
Set objFileIn = Nothing
Set objStreamIn = Nothing
Set objXML = Nothing
Set objDocElem = Nothing
Set objStream = Nothing
这是一个不使用 ADODB 对象的解码示例。
option explicit
dim inobj,outobj,infile,myname,state,rec,outfile,content,table(256),bits,c,x,outword
state = 0
const r64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
myname = wscript.scriptfullname
set inobj = createobject("Scripting.FileSystemObject")
set outobj = createobject("Scripting.FileSystemObject")
set infile = inobj.opentextfile(myname,1)
set outfile = outobj.createtextfile("q.png")
for x = 1 to 256 step 1
table(x) = -1
next
for x = 1 to 64 step 1
table(1+asc(mid(r64,x,1))) = x - 1
next
bits = 0
do until(infile.atendofstream)
dim size
rec = infile.readline
if (state = 1) then
content = mid(rec,2)
size = len(content)
for x = 1 to size step 1
c = table(1+asc(mid(content,x,1)))
if (c <> -1) then
if (bits = 0) then
outword = c*4
bits = 6
elseif (bits = 2) then
outword = c+outword
outfile.write(chr(clng("&H" & hex(outword mod 256))))
bits = 0
elseif (bits = 4) then
outword = outword + int(c/4)
outfile.write(chr(clng("&H" & hex(outword mod 256))))
outword = c*64
bits = 2
else
outword = outword + int(c/16)
outfile.write(chr(clng("&H" & hex(outword mod 256))))
outword = c*16
bits = 4
end if
end if
next
end if
if (rec = "'PAYLOAD") then
state = 1
end if
loop
infile.close
outfile.close
wscript.echo "q.png created"
wscript.quit
'PAYLOAD
'iVBORw0KGgoAAAANSUhEUgAAAD4AAAA+CAIAAAD8oz8TAAABoklEQVRo3u2awQrDMAxDl7H/
'/+Xu0EsgSDw7hRF7vWywpO0UW5acjOu6Xmde79ex1+f+GGPACfcqzePXdVvvts7iv6rx56Ou
'8FNYkgyZx9xzZ3TVHfg7VEHdR+o6ZsWV54O/yDvUQj2KzYyH5wof5f14fR97xdPrmjy1ArVQ
'55yteMYzEqma5B2qoM5VBK+OuXUrHutjJ8c59l4z/vV6Vv15PbOjiFRunB/rOcYgIz1jEPek
'nnh+rBPsiYbOaRu/DipzKrqkqNOJdgEIF3mNVLGa7jM9YSReg+t6U/UvFTYqmn13gGeUr9C1
'ul85rlCVgVTHnGeo2xGIdnT3PRR3vbUYhjAJqXxRHxTtslfsrxOe8aziWdlnAukRVPGmuX9P
'KnG0y9Wjv+71IPf8JEMIZxeP9ZHDkvO0z6XoXmlF1APTMIpR38R5qd8ZAa7gc76JaMl+ZwR4
'N0vdn6hRf89+ZwRIXZy/e473bks9sd9uterERvmbKP4end6cVlFRHt2n9mxTN9b3PTzfIco5
'4Ip9mGd1ud8bUriS3Oh6RuC318GofwHqKhl/Nn0DHQAAAABJRU5ErkJggg==
So you can use this object to Encode or Decode Base64 = CreateObject("Msxml2.DOMDocument.3.0")
And use Array to Encode or Decode It.
More info VBS_Array
Here is my way :
Function Base64Encode(sText)
Set oNode = CreateObject("Msxml2.DOMDocument.3.0").CreateElement("base64")
oNode.dataType = "bin.base64"
oNode.nodeTypedValue =Stream_StringToBinary(sText)
Base64Encode = oNode.text
Set oNode = Nothing
End Function
Function Base64Decode(ByVal vCode)
Set oNode = CreateObject("Msxml2.DOMDocument.3.0").CreateElement("base64")
oNode.dataType = "bin.base64"
oNode.text = vCode
Base64Decode = Stream_BinaryToString(oNode.nodeTypedValue)
Set oNode = Nothing
End Function
Function Stream_StringToBinary(Text)
Set BinaryStream = CreateObject("ADODB.Stream")
BinaryStream.Type = 2
' All Format => utf-16le - utf-8 - utf-16le
BinaryStream.CharSet = "us-ascii"
BinaryStream.Open
BinaryStream.WriteText Text
BinaryStream.Position = 0
BinaryStream.Type = 1
BinaryStream.Position = 0
Stream_StringToBinary = BinaryStream.Read
Set BinaryStream = Nothing
End Function
Function Stream_BinaryToString(Binary)
Set BinaryStream = CreateObject("ADODB.Stream")
BinaryStream.Type = 1
BinaryStream.Open
BinaryStream.Write Binary
BinaryStream.Position = 0
BinaryStream.Type = 2
' All Format => utf-16le - utf-8 - utf-16le
BinaryStream.CharSet = "utf-8"
Stream_BinaryToString = BinaryStream.ReadText
Set BinaryStream = Nothing
End Function
''''''''''''''''''''''''''''''''''''''''''''''Testing'''''''''''''''''''''''''''''''''''''''''
arr=array("Hello","&Welcome","To My Program")
For Each Endcode In arr
WSH.Echo Base64Encode(Endcode)
Next
arr=array("2LPZhNin2YU==","R29vZA==","QnkhIQ==")
For Each Decode In arr
WSH.Echo Base64Decode(Decode)
Next