How can I update a changing value in Powershell in a web.config file?

Question

I am trying to update text inside a web.config file with powershell, but I am having a very, very difficult time.

The problem is this line

You see where the Server23 is? this value sometimes can be empty, which will be represented as "" or sometimes it can have a different name like "\Server25\path"

How do I tell PowerShell to replace/insert data if the field is empty/has some text in it?

here is the full code

 $GP_AP= "Server1"
 $NewMD = "\JohnWick"

    Invoke-Command -ComputerName $GP_AP  -ScriptBlock  {
    
    $date= Get-Date -Format "dd_MM_yyyy_HHMM_ss"
    $webfile = "C:\Program Files\TEST\IIS\Web.config"
    
    (Copy-Item -Path $webfile -Destination $webfile_Test_$Date)
    
    #[xml]$webconfigfile = Get-Content "C:\Program Files\TEST\IIS\Web.config"
    #[xml]$2 = Get-Content "\Server1\C$\Program Files\TEST\IIS\Web.config"
    
    $olddata = "*"

    #(Get-Content $webfile -raw).Replace("","") `
     #| Set-Content "C:\Program Files\TEST\IIS\Web.config" -Force -Encoding UTF8 -ErrorAction Stop
    
    (Get-Content $webfile -raw).Replace('',"") `
     | Set-Content "C:\Program Files\TEST\IIS\Web.config" -Force -Encoding UTF8 -ErrorAction Stop
 
    } # end of script block

user_7417433 · Answer

The script below will allow you to set values in a web config's based on key names. All the nodes must exist. This script will not create them. You'll obviously need to edit the script's default params.

param(
    [string] $pathToWebConfig = "$PSScriptRoot\web.config"

    [System.Collections.Hashtable] $appSettings = @{ 
        someKey = 'somevalue'; 
        someOtherKey = 'someOtherValue' 
    }
)

function UpdateXmlConfigAppSettings(
    [Parameter(mandatory=$true)]
    [string] $configFilePath,

    [Parameter(mandatory=$true)]
    [System.Collections.Hashtable] $appSettingsDict 
) {
    [xml] $webConfig = Get-Content $configFilePath
    foreach($key in $appSettingsDict.Keys) {
        $node = $webConfig.SelectSingleNode("//appSettings/add[@key = '$key']")
        if ($null -ne $node) {
            $node.SetAttribute('value', $appSettingsDict[$key])
        }
        else {
            throw "$appSettingsDict[$key] is not a valid key in AppSettings"
        }
    }
    $webConfig.Save($configFilePath)
}

UpdateXmlConfigAppSettings -configFilePath $pathToWebConfig -appSettingsDict $appSettings

user_11661311 · Answer

$path        = '\server\c$\Program Files\TEST\IIS\web.config'

[xml]$config = Get-Content -Path $path -Raw

$stuffIwant  = "\Blah-244"

$config.SelectNodes("//add[@key='Models.Catalog.Repository']") | `  
ForEach-Object { $_.SetAttribute("value", $stuffIwant) }

$config.Save($path)

How can I update a changing value in Powershell in a web.config file?

2 Answers