Web服務調用，如果應用程序正在運行

Question

我正在尋找一種方式來執行Web窗體提交，如果應用程序正在運行。我不確定最好的方法，但我確實創建了一個PowerShell腳本來完成我想要的操作。

while($true) { 
     (Invoke-WebRequest -Method post 'Http://website.com').Content; 
     Start-Sleep -Seconds 600; 
    } 

現在我想要做的是運行這個只有當應用程序正在運行，然後退出如果應用程序不再運行。我懷疑Windows服務可能會是答案嗎？如果是這樣，任何想法我怎麼能做到這一點？ 我也曾考慮過將此作爲Google Chrome擴展程序運行，但之後我的googlefu已經耗盡。對於Chrome，我只需要腳本，不需要檢查.exe。

任何想法或幫助，將不勝感激。再一次，我在這裏深深地發現了自己的需求，但是我們發現需要創造一些東西，所以我們非常需要虛擬步驟。

Answer 1

如果你知道，應用程序運行的進程的名稱，你可以做到以下幾點：

$processname = "thing" 

# Wait until the process is detected 
Do { 
    Sleep 60 
} Until (Get-Process $processName) 

# Once it is detected, run the script 
# < SCRIPT RUN CODE HERE > 

While (1) { 


    # Monitor the process to make sure it is still running 
    If (Get-Process $processName) {  
     Continue    
    } 

    Else { 
     # Stop the script, because the process isn't running. 
     # < SCRIPT STOP CODE HERE > 

     # Wait until the process is detected again 
     Do { 
      Sleep 60 
     } Until (Get-Process $processName) 
     # Once it is detected again, run the script 
     # < SCRIPT RUN CODE HERE > 
    } 

    # You can add in a delay here to slow down the loop 
    # Sleep 60 
} 

Answer 2

我想你要尋找的可能是WMI事件觸發。你可以註冊（並響應）內WMI發生的事件，諸如：

• 當過程開始或停止
• 當一個服務啓動或停止
• 當一個進程超過一定量的存儲器使用
• 當安裝一個新版本的設備驅動程序
• 當計算機被分配給一個新的組織單位
• 當接通或斷開一個用戶登錄
• 當環境變量改變
• 當筆記本電腦的電池下降到低於某個閾值
• 千其他情況下

要WMI事件註冊，使用Register-WmiEvent小命令。您可以使用-Action參數來聲明在檢測到匹配事件時要執行的PowerShell語句。下面是一個簡單的例子：

# 1. Start notepad.exe 
notepad; 

# 2. Register for events when Notepad disappears 
# 2a. Declare the WMI event query 
$WmiEventQuery = "select * from __InstanceDeletionEvent within 5 where TargetInstance ISA 'Win32_Process' and TargetInstance.Name = 'notepad.exe'"; 
# 2b. Declare the PowerShell ScriptBlock that will execute when event is matched 
$Action = { Write-Host -ForegroundColor Green -Object ('Process stopped! {0}' -f $event.SourceEventArgs.NewEvent.TargetInstance.Name) }; 
# 2c. Register for WMI events 
Register-WmiEvent -Namespace root\cimv2 -Query $WmiEventQuery -Action $Action -SourceIdentifier NotepadStopped; 

# 3. Stop notepad.exe 
# Note: For some reason, if you terminate the process as part of the same thread, the event 
#  doesn't seem to fire correctly. So, wrap the Stop-Process command in Start-Job. 
Start-Job -ScriptBlock { Stop-Process -Name notepad; }; 

# 4. Wait for event consumer (action) to fire and clean up the event registration 
Start-Sleep -Seconds 6; 
Unregister-Event -SourceIdentifier NotepadStopped; 

FYI：我開發了一個名爲PowerEvents PowerShell的模塊，在CodePlex上託管。該模塊包含註冊永久性WMI事件訂閱的功能，並且包含30多頁PDF文檔，可幫助您瞭解WMI事件。你可以在http://powerevents.codeplex.com找到這個開源項目。

如果我想讓你的代碼適應一些對你來說更實用的代碼，它可能看起來像下面的例子。您可以使用Windows任務計劃程序定期調用代碼。

# 1. If process is not running, then exit immediately 
if (-not (Get-Process -Name notepad)) { throw 'Process is not running!'; return; } 

# 2. Register for events when Notepad disappears 
# 2a. Declare the WMI event query 
$WmiEventQuery = "select * from __InstanceDeletionEvent within 5 where TargetInstance ISA 'Win32_Process' and TargetInstance.Name = 'notepad.exe'"; 
# 2b. Declare the PowerShell ScriptBlock that will execute when event is matched 
#  In this case, it simply appends the value of the $event automatic variable to a 
#  new, global variable named NotepadEvent. 
$Action = { $global:NotepadEvent += $event; }; 
# 2c. Register for WMI events 
Register-WmiEvent -Namespace root\cimv2 -Query $WmiEventQuery -Action $Action -SourceIdentifier NotepadStopped; 

# 3. Wait indefinitely, or until $global:NotepadEvent variable is NOT $null 
while ($true -and -not $global:NotepadEvent) { 
    Start-Sleep -Seconds 600; 
    (Invoke-WebRequest -Method post 'Http://website.com').Content; 
}