<# 
Copyright (c) 2019 Michael Cameron  mcameron@dreich.net


Listing everything in your datalakestoragegen2/path/list


# Rest documentation:
# https://docs.microsoft.com/en-us/rest/api/storageservices/datalakestoragegen2/path/list
# API:
# GET http://{accountName}.{dnsSuffix}/{filesystem}?directory={directory}&recursive={recursive}&continuation={continuation}&maxResults={maxResults}&upn={upn}&resource=filesystem&timeout={timeout}


	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
#>

[CmdletBinding()]
Param(
  [Parameter(Mandatory=$true,Position=1)] [string] $StorageAccountName,
  [Parameter(Mandatory=$True,Position=2)] [string] $FilesystemName,
  [Parameter(Mandatory=$True,Position=3)] [string] $AccessKey
)

$progressPreference = 'silentlyContinue'   # suppresses the status bar for Invoke-WebRequest

Function listPaths(){

	$headerDate = [System.DateTime]::UtcNow.ToString("R")   # creates a string from current time using the RFC1123 pattern, e.g. 2009-06-15T13:45:30 -> Mon, 15 Jun 2009 20:45:30 GMT
	$headerVersion = "2018-11-09"							# use this version of the API
	$method = "GET"											# GET has to be used to read the list of files
	$dnsSuffix = "dfs.core.windows.net"
	$directory = ""
	$recursive = "true"
	$myToken = $global:continuationToken
	$maxResults = ""
	$upn = ""
	$resource = "filesystem"
	$timeout = "30"

	# Set up an array of parameters for signing
	$signatureParams =
		$method,								# method, e.g. GET, PUT
		"",										# content encoding
		"",										# content language
		"",										# content length
		"",										# content MD5
		"",										# content type
		"",										# date
		"",										# if modified since
		"",										# if match
		"",										# if no match
		"",										# if unmodified since
		"",										# range
		"x-ms-date:$headerDate",				# date
		"x-ms-version:$headerVersion",			# version
		"/$StorageAccountName/$FilesystemName",	# file system name
		"continuation:$myToken",				# continuation token
		#"directory:$directory",				# directory name
		"maxresults:$maxResults",				# maximum number of results (limit is 5000)
		"recursive:$recursive",					# recursion flag
		"resource:$resource"					# resource type, must be filesystem for storage service API
		#"timeout:$timeout"						# timeout in seconds
		#"upn:$upn"								# upn

	# create a string to sign by joining the array with newlines
	$stringToSign = $signatureParams -join "`n"

	# create a cryptography object for signing the string using the access key provided
	$hasher = New-Object System.Security.Cryptography.HMACSHA256
	$sharedKey = [System.Convert]::FromBase64String($AccessKey)
	$hasher.Key = $sharedKey

	# sign the string
	$signedSignature = [System.Convert]::ToBase64String($hasher.ComputeHash([System.Text.Encoding]::UTF8.GetBytes($stringToSign)))

	$authHeader = "SharedKey ${StorageAccountName}:$signedSignature"

	# set up headers for calling API
	$headers = @{"x-ms-date"=$headerDate} 
	$headers.Add("x-ms-version",$headerVersion)
	$headers.Add("Authorization",$authHeader)

	# define the API address
	$URI = "https://{0}.{1}/{2}?continuation={3}&maxresults={4}&recursive={5}&resource={6}" -f $StorageAccountName, $dnsSuffix, $FilesystemName, ([uri]::EscapeDataString($myToken)), $maxResults, $recursive, $resource

	# call the REST API
	try {
		$response = Invoke-WebRequest -method $method -Uri $URI -Headers $headers
	}
	catch {
		Write-Error $_.Exception
		Write-Error $response
		break
	}
	if ($response.headers."x-ms-continuation") {
		$global:continuationToken = ($response.headers."x-ms-continuation")
	} else {
		$global:continuationToken = ""
	}
	foreach ($path in (ConvertFrom-Json $response.content).paths) 
	{
		Write-Output (($path.name,$path.owner,$path.group, $path.permissions,$path.lastModified) -join ", ")
	}
}

Do {
	listPaths("")
} while ($global:continuationToken)