Write bytes to a file natively in PowerShell

Question

I have a script for testing an API which returns a base64 encoded image. My current solution is this.

$e = (curl.exe -H "Content-Type: multipart/form-data" -F "[email protected]" localhost:5000) $decoded = [System.Convert]::FromBase64CharArray($e, 0, $e.Length) [io.file]::WriteAllBytes('out.png', $decoded) # <--- line in question  Get-Content('out.png') | Format-Hex 

This works, but I would like to be able to write the byte array natively in PowerShell, without having to source from [io.file].

My attempts of writing $decoded in PowerShell all resulted in writing a string-encoded list of the integer byte values. (e.g.)

42 125 230 12 34 ... 

How do you do this properly?

Answer 1

The Set-Content cmdlet lets you write raw bytes to a file by using the Byte encoding:

$decoded = [System.Convert]::FromBase64CharArray($e, 0, $e.Length) Set-Content out.png -Value $decoded -Encoding Byte 

(However, BACON points out in a comment that Set-Content is slow: in a test, it took 10 seconds, and 360 MB of RAM, to write 10 MB of data. So, I recommend not using Set-Content if that's too slow for your application.)