Powershell try块没有';t释放catch块的文件句柄
我正在编写一个脚本,尝试用两种文件下载方法下载一个文件。 我不打算详细介绍,但结果函数如下所示:Powershell try块没有';t释放catch块的文件句柄,powershell,powershell-2.0,webclient,Powershell,Powershell 2.0,Webclient,我正在编写一个脚本,尝试用两种文件下载方法下载一个文件。 我不打算详细介绍,但结果函数如下所示: function Download-FileRobust($url, $targetFile) { try { Download-File $url $targetFile } catch { Download-FileWget $url $targetFile } } 当下载文件功能失败时,PowerShell不会松开位置$targ
function Download-FileRobust($url, $targetFile) {
try {
Download-File $url $targetFile
}
catch {
Download-FileWget $url $targetFile
}
}
当下载文件
功能失败时,PowerShell不会松开位置$targetFile
处创建的文件上的句柄,并且下载文件集
无法写入该位置
我已经习惯了Python,所以我花了很长时间才解决这个问题
其他两个函数的源代码如下:
function Download-FileWget($url, $targetFile){
$wgetDir = (Get-ChildItem -Path "$env:userprofile\Downloads\wget*win32").FullName
if($env:Path -notlike "*$wgetDir*"){
$env:Path = "$wgetDir;$env:Path"
}
Invoke-Expression "wget '$url' -O '$targetFile'"
}
function Download-File($url, $targetFile){
$uri = New-Object "System.Uri" "$url"
$request = [System.Net.HttpWebRequest]::Create($uri)
$request.set_Timeout(15000) #15 second timeout
$response = $request.GetResponse()
$totalLength = [System.Math]::Floor($response.get_ContentLength()/1024)
$responseStream = $response.GetResponseStream()
$targetStream = New-Object -TypeName System.IO.FileStream -ArgumentList $targetFile, Create
$buffer = new-object byte[] 10KB
$count = $responseStream.Read($buffer,0,$buffer.length)
$downloadedBytes = $count
while ($count -gt 0){
$targetStream.Write($buffer, 0, $count)
$count = $responseStream.Read($buffer,0,$buffer.length)
$downloadedBytes = $downloadedBytes + $count
Write-Progress -activity "Downloading file '$($url.split('/') | Select -Last 1)'" -status "Downloaded ($([System.Math]::Floor($downloadedBytes/1024))K of $($totalLength)K): " -PercentComplete ((([System.Math]::Floor($downloadedBytes/1024)) / $totalLength) * 100)
}
Write-Progress -activity "Finished downloading file '$($url.split('/') | Select -Last 1)'"
$targetStream.Flush()
$targetStream.Close()
$targetStream.Dispose()
$responseStream.Dispose()
}
在
下载文件
功能中,您实际上从未做过任何事情来确保$targetStream
被正确刷新和处理。您需要将流包装在try/catch/finally
块中:
function Download-File {
param([string]$url, [string]$targetFile)
$uri = New-Object "System.Uri" "$url"
$request = [System.Net.HttpWebRequest]::Create($uri)
$request.set_Timeout(15000) #15 second timeout
$response = $request.GetResponse()
$totalLength = [System.Math]::Floor($response.get_ContentLength()/1024)
$responseStream = $response.GetResponseStream()
try {
$targetStream = New-Object -TypeName System.IO.FileStream -ArgumentList $targetFile, Create
try {
$buffer = new-object byte[] 10KB
$count = $responseStream.Read($buffer,0,$buffer.length)
$downloadedBytes = $count
while ($count -gt 0){
$targetStream.Write($buffer, 0, $count)
$count = $responseStream.Read($buffer,0,$buffer.length)
$downloadedBytes = $downloadedBytes + $count
Write-Progress -activity "Downloading file '$($url.split('/') | Select -Last 1)'" -status "Downloaded ($([System.Math]::Floor($downloadedBytes/1024))K of $($totalLength)K): " -PercentComplete ((([System.Math]::Floor($downloadedBytes/1024)) / $totalLength) * 100)
}
Write-Progress -activity "Finished downloading file '$($url.split('/') | Select -Last 1)'"
}
catch {
throw
}
finally {
if($targetStream){
$targetStream.Flush()
$targetStream.Close()
$targetStream.Dispose()
}
}
}
catch {
throw
}
finally {
$responseStream.Dispose()
}
}
你使用的是哪个版本的powershell?我使用的是2.0版。升级不是一种选择。我正在编写一个脚本,该脚本需要在旧的windows 7机器上立即运行。请发布您的
下载文件的内容和下载文件wget
Powershell不会在$targetFile
位置松开已创建文件的句柄。Powershell不负责这样做<代码>下载文件
负责关闭句柄,不再计划使用。我添加了其他两个函数。如果没有响应返回,我可能必须在下载文件中的$response=$request.GetResponse()
行提前终止函数。此时目标文件尚未打开。谢谢,这正是我所需要的!