Add a connectionString to Web.config

webconfig.ps1

function AddAttribute([System.Xml.XmlNode] $node, $name , $value){
    $attrib = $node.OwnerDocument.CreateAttribute($name)
    $attrib.Value = $value
    $node.Attributes.Append($attrib)
}

function AddConnectionString($webconfigFile, $name, $connectionString){
    [xml]$document = Get-Content $webconfigFile
    $configElement = $document.SelectSingleNode("configuration")
    $connectionStringsElement = $configElement.SelectSingleNode("connectionStrings")
    [System.Xml.XmlNode]$add = $document.CreateElement("add")
    AddAttribute $add "name" $name
    AddAttribute $add "connectionString" $connectionString
    $connectionStringsElement.AppendChild($add)
    $document.Save($webconfigFile)

}


AddConnectionString C:\temp\2.3.48.1547065790761\api\Web.config "test" "testConnectionString"