PowerShell之SFTP下载文件

SFTP是一种加密的安全的文件传输协议。通过PowerShell脚本进行SFTP传输相当方便，还可用于定时任务。我们将一些配置项写入到一个xml文件中，通过PowerShell读取xml内容。

下面是download.xml的代码：

<?xml version="1.0" ?>
<sftpConfig>
<Protocol>Sftp</Protocol>
<HostName>127.0.0.1</HostName>
<UserName>admin</UserName>
<Password>Password</Password>
<SshHostKeyFingerprint>ssh-rsa 2048 32:af:45:6b:a0:e5:0d:f3:1e:b0:44:b7:de:ec:77:b3</SshHostKeyFingerprint>
<RemotePath>/E/test/path/data/</RemotePath>
<LocalPath>e:\test\path\data\</LocalPath>
</sftpConfig>

下面是download.ps1脚本的代码：

param (
$xmlData=[xml](Get-Content "E:\test\path\scripts\download.xml"),
$localPath = $xmlData.sftpConfig.LocalPath,
$remotePath = $xmlData.sftpConfig.RemotePath,
$dataFile = (Get-Date).toString("yyyy-MM-dd")+".txt",
$flagFile = "flag_"+(Get-Date).toString("yyyyMMdd")+".txt"
)

function wait10sec
{
$step=10
$add=0
$t=(get-date)
$step-(($t.Hour*3600+$t.Minute*60+$t.Second)%$step)+$add
}

try
{
# Load WinSCP .NET assembly
    Add-Type -Path "E:\test\path\scripts\WinSCPnet.dll"

# Setup session options
$sessionOptions = New-Object WinSCP.SessionOptions
$sessionOptions.Protocol = [WinSCP.Protocol]$xmlData.sftpConfig.Protocol
$sessionOptions.HostName = $xmlData.sftpConfig.HostName
$sessionOptions.UserName = $xmlData.sftpConfig.UserName
$sessionOptions.Password = $xmlData.sftpConfig.Password
$sessionOptions.SshHostKeyFingerprint = $xmlData.sftpConfig.SshHostKeyFingerprint

$session = New-Object WinSCP.Session

try
    {
# Connect
$session.Open($sessionOptions)

# Detect the flag file
while(! $session.FileExists($remoteRawPath+$flagFile))
        {
            Get-Date
            Start-Sleep -s (wait10sec)
        }

        write-host "Start Downloading..."

#if the data file or flag file exists,delete file first
if((Test-Path ($localPath+$dataFile)) -or (Test-Path ($localPath+$flagFile)))
        {
            {
                write-host $dataFile" exists and will be removed!"
                Remove-Item ($localPath+$dataFile)
            }
if(Test-Path ($localPath+$flagFile))
            {
                write-host $finishFile" exists and will be removed!"
                Remove-Item ($localPath+$flagFile)
            }
        }

$session.GetFiles($session.EscapeFileMask($remotePath + $dataFile), $localPath).Check()

New-Item ($localPath+$flagFile) -ItemType file
        write-host "End Download"

    }
finally
    {
# Disconnect, clean up
$session.Dispose()
    }

exit 0
}
catch [Exception]
{
    Write-Host ("Error: {0}" -f $_.Exception.Message)
exit 1
}

该脚本是通过WinSCP进行SFTP连接的，因此需要添加一个WinSCPnet.dll动态文件。