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：

<sftpConfig>
    <Protocol>SftpProtocol>
    <HostName>127.0.0.1HostName>
    <UserName>adminUserName>
    <Password>PasswordPassword>
    <SshHostKeyFingerprint>ssh-rsa 2048 32:af:45:6b:a0:e5:0d:f3:1e:b0:44:b7:de:ec:77:b3SshHostKeyFingerprint>
 <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。