Powershell-从.zip存档读取文件失败

Question

I'm currently trying to read the contents of a specific .xml file in a .zip archive without extracting it.
The code is simple, but somehow a couple of bytes slip into the buffer, making it impossible to use the contents of the file.

This is the respective code:

    [void] [System.Reflection.Assembly]::LoadWithPartialName("System.IO.Compression.FileSystem")
    $arch = [System.IO.Compression.ZipFile]::OpenRead("C:\file.zip")

    $entr = $arch.Entries | ?{$_.Name -like "test.xml"}
    if(!$entr)
    {throw [System.Exception] "Could not find the .xml file"}

    $buf = New-Object System.Byte[]($entr.Length)
    $entr.Open().Read($buf, 0, $entr.Length) | Out-Null

    $xml = [xml] ([System.Text.Encoding]::Unicode.GetString($buf))

The code is pretty straightforward I'd say, but sadly the first two bytes of $buf seem always equal to 255 and 254 , which causes Powershell's xml parser to throw an exception.
As a temporary workaround I tried omitting the first two bytes, but that simply caused the same problem to occur with the last two bytes.

That leads me to my question, how is it possible that the buffer is messed up?
Is my way of doing this wrong? What did I miss?

Any help is higly appreciated!

UPDATE:

Well, it seems as Windows uses UTF-16 as internal encoding, which would mean that the two first bytes are the Byte Order Mark (BOM) . I would expect the GetString() method to recognize the BOM , could someone clarify on this?

Answer 1

You'll want to wrap your Stream into a StreamReader and then use the ReadToEnd() method, I'd expect that to respect the BOM:

$reader = new-object System.IO.StreamReader($entr.Open())
$contents = $reader.ReadToEnd()
$reader.Close()