#Description: Powershell 2.0 script to zip and encrypt a folder using 7zip and then send it to Amazon S3
#Author: Greg Bray (2/19/2010)
#Website: http://codeblog.theg2.net/2010/02/powershell-7-zip-amazon-s3-upload.html
#License: free for personal or commercial use under the Creative Commons Attribution 3.0 United States License.
#Prerequisite: You must first install the latest version of 7Zip from http://www.7-zip.org/ (licensed under the GNU LGPL)
#Prerequisite: You must also install the Amazon Web Services SDK for .NET from http://aws.amazon.com/sdkfornet/ (licensed under the Apache License, Version 2.0)
#Recommended: I recommend using CloudBerry S3 Explorer for managing Amazon S3 files. http://cloudberrylab.com/default.aspx?page=cloudberry-explorer-amazon-s3
#Recommended: I recommend using http://PowerGui.org Script editor if you want to change or debug this script.

#Usage: ps7ZiptoAmazonS3 'BackupFolderPath' 'S3ObjectKey' 'TranscriptLogFile'
#  BackupFolderPath = Folder to backup (do not include a trailing slash)
#  S3ObjectKey = Object key where to store file on Amazon S3. Note: If object already exists on S3 it will be overwritten.
#  TranscriptLogFile = Optional log file where the transcript will be appended.
#NOTE: you also will need to set the Zip and Encrypt settings, Amazon S3 settings, and 7Zip/AWSSDK file paths below

<#Example calling from another powershell script (with log file): 
.'c:\Backups\ps7ZiptoAmazonS3.ps1' 'c:\Backups\DataFolder' 'S3Backups/DataFolder.7z' 'c:\Backups\BackupLog.txt'
#>
<#Example calling from Run or task Scheduler: NOTE: may need to run "Set-ExecutionPolicy RemoteSigned" in powershell to allow unsigned local scripts to execute
powershell.exe -Command &".'c:\Backups\ps7ZiptoAmazonS3.ps1' 'c:\Backups\DataFolder' 'S3Backups/DataFolder.7z' 'c:\Backups\BackupLog.txt'"
#>

#Check arguments and set variables
if ($args.count -ge 2) {
    $FolderPath = $args[0] #Local folder to encrypt and send to S3 (No trailing slash)
    $S3ObjectKey = $args[1] #Destination on S3 where file will be stored. Note: If object exists it will be overwritten.
    if ($args.count -ge 3) { #start logging transcript
        Start-Transcript $args[2] -Append | Out-Null
    }
} else { #Default preset arguments used if no values are provided
    $FolderPath = "c:\Backups\DataFolder"
    $S3ObjectKey = "S3Backups/DataFolder.7z"
}
 
write-host "`r`n`r`n" #Start log file with 2 blank lines 
$dtStart = [System.DateTime]::Now #Save start time to calculate total time below
write-host ($dtStart.ToString() + " - Script started")

#Zip and Encrypt settings
$EncryptionKey = "secret password" #Data is encrypted using Strong AES-256 encryption. Recommended password size is 10-16 characters.
$TemporaryPath = "c:\Temp" #No trailing slash. Used to store zip file localy before uploading. File will be deleted after upload but not if there is an exception (see below).

#Amazon S3 account settings (See http://aws-portal.amazon.com/gp/aws/developer/account/index.html?action=access-key):
$S3AccessKeyID = "ABCDEFGHIJKLMNOPQRST" #Your Amazon S3 Access Ky ID
$S3SecretKeyID = "0123456789abcdefghijklmnopqrstuvwzyz" #Your Amazon S3 Secret Access Key
$S3BucketName = "S3BackupBucket" #S3 Bucket name where the file will be stored
Write-Host ($dtStart.ToString() + " - FolderPath:'$FolderPath' S3BucketName:'$S3BucketName' S3ObjectKey:'$S3ObjectKey'")


#Load AWS Assembly and Initialize 7Zip path (only runs once when debugging script)
if($7ZipPath -eq $null){
    $7ZipPath = "C:\Program Files\7-Zip\7z.exe" #Path to 7Zip
    $AWSDOTNETSDKPath = "C:\Program Files (x86)\AWS SDK for .NET\bin\AWSSDK.dll" #Path to Amazon SDK for x64 system. Remove " (x86)" when running on an x86 machine
    if (-not [System.IO.File]::Exists($AWSDOTNETSDKPath)) { #Try path for x86 system
         $AWSDOTNETSDKPath = $AWSDOTNETSDKPath.Replace(" (x86)","")
         if (-not [System.IO.File]::Exists($AWSDOTNETSDKPath)) { #File not found, throw exception
            write-error "ERROR: Cannot find Amazon Web Services SDK. Please download .NET SDK from http://aws.amazon.com/sdkfornet/ and update AWSDOTNETSDKPath in script."
            exit 2
         }
    }
    #Load AWS Assembly
    [Reflection.Assembly]::LoadFile($AWSDOTNETSDKPath) | Out-Null
}

#Function for computing Amazon S3 MD5 digest (128 bit base64 encoded) using System.Security.Cryptography.MD5
function Hash-MD5 ($file) {
    $cryMD5 = [System.Security.Cryptography.MD5]::Create()
    $fStream = New-Object System.IO.StreamReader ($file)
    $bytHash = $cryMD5.ComputeHash($fStream.BaseStream)
    $fStream.Close()
    return [Convert]::ToBase64String($bytHash)
}

#Zip and Encrypt files
Write-Host ([System.DateTime]::Now.ToString() + " - Zip and Encrypt Files")
$FolderName = $FolderPath.Substring($FolderPath.LastIndexOf("\")+1) #grab the name of the backup folder
$TimeStamp = [datetime]::Now.ToString("yyyy-MM-dd_HHmm") #Create unique timestamp string
$strFile = [String]::Format("{0}\{1}_{2}.7z", $TemporaryPath,$FolderName,$TimeStamp) #Create filename for the zip
#7z options: add, type 7z, Archive filename, Files to add (with wildcard. Change \* to \prefix* or \*.txt to limit files), compression level 9, password, encrypt filenames, Send output to host so it can be logged.
#See http://dotnetperls.com/7-zip-examples or the 7zip help file for more info on command line switches. 
#NOTE: -mx7 and -mx9 get around 10 to 1 compression for text files and take round 5 minutes for 1GB of data. Use -mx3 or -mx5 to increase speed but decrease compression level.
&$7ZipPath a -t7z $strFile $FolderPath\* -mx9 -r -p""$EncryptionKey"" -mhe | out-host #Call 7z.exe to create archive file
if($LASTEXITCODE -ne 0){ #Detect errors from 7Zip. Note: 7z will crash sometimes if file already exists
        Write-Error "ERROR: 7Zip terminated with exit code $LASTEXITCODE. Script halted."
        exit $LASTEXITCODE
}

#Create Amazon PutObjectRequest. Details at http://docs.amazonwebservices.com/sdkfornet/latest/apidocs/html/T_Amazon_S3_Model_PutObjectRequest.htm
Write-Host ([System.DateTime]::Now.ToString()) " - Creating S3 PutObjectRequest"
$AmazonS3 = [Amazon.AWSClientFactory]::CreateAmazonS3Client($S3AccessKeyID, $S3SecretKeyID)
$S3PutRequest = New-Object Amazon.S3.Model.PutObjectRequest 
$S3PutRequest.BucketName = $S3BucketName
$S3PutRequest.Key = $S3ObjectKey
$S3PutRequest.FilePath = $strFile
Write-Host ([System.DateTime]::Now.ToString()) " - Compute File MD5 Digest"
$strMD5 = Hash-MD5($strFile) #NOTE: may take 5-30 seconds to compute digest for 1GB file.
$S3PutRequest.MD5Digest = $strMD5 #Use MD5 digest to ensure data is not corrupted during transport. 

$dFileSize = (Get-Item $strFile).Length / 1MB #Get archive size in MB
Write-Host ([System.DateTime]::Now.ToString()) ([String]::Format(" - Uploading File:'{0}' Size:{1:#,###.#} MB", $strFile, $dFileSize)) 
$S3Response = $AmazonS3.PutObject($S3PutRequest) #NOTE: upload defaults to 20 minute timeout.
#If upload fails it will throw an exception and $S3Response will be $null
if($S3Response -eq $null){
    Write-Error "ERROR: Amazon S3 put requrest failed. Script halted."
    exit 1
}

Write-Host ([System.DateTime]::Now.ToString()) " - Delete Local 7z File:'$strFile'"
Remove-Item $strFile -Force

$dtEnd = [datetime]::Now
$tsTotal = $dtEnd.Subtract($dtStart)
Write-Host ($dtEnd.ToString()) " - Script finished. Total time: " $tsTotal
write-host "`r`n`r`n" #End log file with 2 blank lines 

if ($args.count -ge 3) { #stop transcript
    Stop-Transcript
}