AWS S3 Get file with PowerShell

s3get.ps1

function S3-Get([string]$uri, [string]$bucket) {
  $date = Get-Date -format "ddd, dd MMM yyyy HH:mm:ss zz00"
  $content_type = "text/plain"
  $request = "GET`n`n${content_type}`n${date}`n${bucket}"

  #
  # Bash equivalent is:
  #   $ echo -en ... | openssl sha1 -hmac ... -binary | base64
  #

  $hmacsha = New-Object System.Security.Cryptography.HMACSHA1
  $hmacsha.key = [Text.Encoding]::ASCII.GetBytes($AWS_SECRET_ACCESS_KEY)
  $signature = $hmacsha.ComputeHash([Text.Encoding]::ASCII.GetBytes($request))
  $signature = [Convert]::ToBase64String($signature)

  curl --insecure `
    -H "Date: ${date}" `
    -H "Content-Type: ${content_type}" `
    -H "Authorization: AWS ${AWS_ACCESS_KEY_ID}:${signature}" "${uri}${bucket}"
}

# Exemple:
# S3-Get "s3_url ... " "/my_bucket"

Require curl for Windows, install with chocolatey:

$ choco install curl