Set application settings in IIS through PowerShell - powershell

Question

How can I set application settings in IIS through PowerShell?
I tried using Set-WebConfigurationProperty as
Set-WebConfigurationProperty "/appSettings/add[#key='someKey']" -PSPath "IIS:\Sites\Default Web Site\someSite" -name "someKey" -Value "someValue"
But I am getting
WARNING: Target configuration object '/appSettings/add[#key='someKey'] is not found at path 'MACHINE/WEBROOT/APPHOST/Default Web Site/someSite'.

Answer 1

The easiest way to do this I find is to build the PowerShell from IIS configuration editor.
To do this;
1) Open Inetmgr (IIS)
2) Click on the site you want to target.
3) Feature View, Configuration Editor down at the bottom left.
4) From here, browse to the section of the configuration you want to edit, and
make the change
5) Then click "Generate Script" on the top right.
This will generate multiple different scripts for configuring this, choose PowerShell and there you go.
For example, changing Windows authentication to Forms
Set-WebConfigurationProperty -pspath 'MACHINE/WEBROOT/APPHOST/Somewebsite' -filter "system.web/authentication" -name "mode" -value "Forms"
You can learn how to do just about anything from here.
There is also the get-webconfigurationproperty command that will get you the config before you edit it, this is just run from PowerShell.
A key to remember is is SET-WebConfigurationProperty will override everything and often not do what you want.
Where Add-WebConfigurationProperty will add, not override and add additional config.
Hope that helps!
Rich

Answer 2

And how exactly to use Add-WebConfigurationProperty? Because it must be used in case the app setting is yet missing (Set-WebConfigurationProperty will fail).
So, given the following configuration, a site "SiteOne" with a virtual directory "VirtualDirOne":
<?xml version="1.0" encoding="utf-8"?>
<configuration xmlns:xdt="http://schemas.microsoft.com/XML-Document-Transform">
<appSettings>
<add key="first" value="a" />
</appSettings>
</configuration>
When I want to change the value to "b":
Set-WebConfigurationProperty -pspath "iis:\Sites\SiteOne\VirtualDirOne" -filter "/appSettings/add[#key='first']" -name value -value "b"
When I want to add another setting:
Add-WebConfigurationProperty -pspath "iis:\Sites\SiteOne\VirtualDirOne" -filter "/appSettings" -name "." -value #{key='second'; value='x'}
When I want to get the value:
Get-WebConfigurationProperty -pspath "iis:\Sites\SiteOne\VirtualDirOne" -filter "/appSettings/add[#key='second']" -name "value.Value"
And finally, to remove the setting:
Clear-WebConfiguration -pspath "iis:\Sites\SiteOne\VirtualDirOne" -filter "/appSettings/add[#key='second']"
There many examples here.