functions/configuration/Set-PSFConfig.ps1

function Set-PSFConfig
{
<#
    .SYNOPSIS
        Sets configuration entries.
     
    .DESCRIPTION
        This function creates or changes configuration values.
        These can be used to provide dynamic configuration information outside the PowerShell variable system.
     
    .PARAMETER FullName
        The full name of a configuration element. Must be namespaced <Module>.<Name>.
        The name can have any number of sub-segments, in order to better group configurations thematically.
     
    .PARAMETER Name
        Name of the configuration entry. If an entry of exactly this non-casesensitive name already exists, its value will be overwritten.
        Duplicate names across different modules are possible and will be treated separately.
        If a name contains namespace notation and no module is set, the first namespace element will be used as module instead of name. Example:
        -Name "Nordwind.Server"
        Is Equivalent to
        -Name "Server" -Module "Nordwind"
     
    .PARAMETER Module
        This allows grouping configuration elements into groups based on the module/component they serve.
        If this parameter is not set, the configuration element must have a module name in the name parameter (the first segment will be taken, irrespective of whether that makes sense).
     
    .PARAMETER Value
        The value to assign to the named configuration element.
     
    .PARAMETER Description
        Using this, the configuration setting is given a description, making it easier for a user to comprehend, what a specific setting is for.
     
    .PARAMETER Validation
        The name of the validation script used for input validation.
        These can be used to validate make sure that input is of the proper data type.
        New validation scripts can be registered using Register-PSFConfigValidation
     
    .PARAMETER Handler
        A scriptblock that is executed when a value is being set.
        Is only executed if the validation was successful (assuming there was a validation, of course)
     
    .PARAMETER Hidden
        Setting this parameter hides the configuration from casual discovery. Configurations with this set will only be returned by Get-Config, if the parameter "-Force" is used.
        This should be set for all system settings a user should have no business changing (e.g. for Infrastructure related settings such as mail server).
     
    .PARAMETER Default
        Setting this parameter causes the system to treat this configuration as a default setting. If the configuration already exists, no changes will be performed.
        Useful in scenarios where for some reason it is not practical to automatically set defaults before loading userprofiles.
     
    .PARAMETER Initialize
        Use this when setting configurations as part of module import.
        When initializing a configuration, it will only do a thing if the configuration hasn't already been initialized (So if you load the module multiple times or in multiple runspaces, it won't make a difference)
        Also, if there already was a non-initialized setting set for a given configuration, it will then try to set the old value again.
        This value will be processed by handlers, if any are set.
     
    .PARAMETER DisableValidation
        This parameters disables the input validation - if any - when processing a setting.
        Normally this shouldn't be circumvented, but just in case, it can be disabled.
     
    .PARAMETER DisableHandler
        This parameter disables the configuration handlers.
        Configuration handlers are designed to automatically process input set to a config value, in addition to writing the value.
        In many cases, this is used to improve performance, by forking the value location also to a static C#-field, which is then used, rather than searching a Hashtable.
        Normally these shouldn't be circumvented, but just in case, it can be disabled.
     
    .PARAMETER EnableException
        Replaces user friendly yellow warnings with bloody red exceptions of doom!
        Use this if you want the function to throw terminating errors you want to catch.
     
    .EXAMPLE
        PS C:\> Set-PSFConfig -FullName 'MyModule.User' -Value "Friedrich" -Description "The user under which the show must go on."
         
        Creates a configuration entry under the module "MyModule" named "User" with the value "Friedrich"
     
    .EXAMPLE
        PS C:\> Set-PSFConfig -Name 'mymodule.User' -Value "Friedrich" -Description "The user under which the show must go on." -Handler $scriptBlock -Initialize -Validation String
         
        Creates a configuration entry ...
        - Named "mymodule.user"
        - With the value "Friedrich"
        - It adds a description as noted
        - It registers the scriptblock stored in $scriptBlock as handler
        - It initializes the script. This block only executes the first time a it is run like this. Subsequent calls will be ignored.
        - It registers the basic string input type validator
        This is the default example for modules using the configuration system.
        Note: While the -Handler parameter is optional, it is important to add it at the initial initialize call, if you are planning to add it.
        Only then will the system validate previous settings (such as what a user might have placed in his user profile)
     
    .EXAMPLE
        PS C:\> Set-PSFConfig 'Company' 'ConfigLink' 'https://www.example.com/config.xml' -Hidden
         
        Creates a configuration entry named "ConfigLink" in the "Company" module with the value 'https://www.example.com/config.xml'.
        This entry is hidden from casual discovery using Get-PSFConfig.
     
    .EXAMPLE
        PS C:\> Set-PSFConfig 'Network.Firewall' '10.0.0.2' -Default
         
        Creates a configuration entry named "Firewall" in the "Network" module with the value '10.0.0.2'
        This is only set, if the setting does not exist yet. If it does, this command will apply no changes.
#>

    [Diagnostics.CodeAnalysis.SuppressMessageAttribute("PSUseShouldProcessForStateChangingFunctions", "")]
    [CmdletBinding(DefaultParameterSetName = "FullName")]
    Param (
        [Parameter(ParameterSetName = "FullName", Position = 0, Mandatory = $true)]
        [string]
        $FullName,
        
        [Parameter(ParameterSetName = "Module", Position = 1, Mandatory = $true)]
        [string]
        $Name,
        
        [Parameter(ParameterSetName = "Module", Position = 0)]
        [string]
        $Module,
        
        [Parameter(ParameterSetName = "FullName", Position = 1)]
        [Parameter(ParameterSetName = "Module", Position = 2)]
        [AllowNull()]
        [AllowEmptyCollection()]
        [AllowEmptyString()]
        $Value,
        
        [string]
        $Description,
        
        [string]
        $Validation,
        
        [System.Management.Automation.ScriptBlock]
        $Handler,
        
        [switch]
        $Hidden,
        
        [switch]
        $Default,
        
        [switch]
        $Initialize,
        
        [switch]
        $DisableValidation,
        
        [switch]
        $DisableHandler,
        
        [switch]
        $EnableException
    )
    
    #region Prepare Names
    if ($PSCmdlet.ParameterSetName -eq "FullName")
    {
        if (-not $FullName.Trim(".").Contains("."))
        {
            Stop-PSFFunction -Message "Invalid Name: $FullName ! At least one '.' is required, to separate module from name" -EnableException $EnableException -Category InvalidArgument
            return
        }
        
        $Module = $FullName.Split(".")[0].ToLower().Trim(".")
        $Name = $FullName.Substring(($Module.Length + 1)).ToLower().Trim(".")
        $internalFullName = $FullName.ToLower().Trim(".")
    }
    else
    {
        $Name = $Name.ToLower().Trim(".")
        if ($Module) { $Module = $Module.ToLower().Trim(".") }
        
        if ((Test-PSFParameterBinding -ParameterName "Module" -Not) -and ($Name -match ".+\..+"))
        {
            $r = $Name | select-string "^(.+?)\..+" -AllMatches
            $Module = $r.Matches[0].Groups[1].Value
            $Name = $Name.Substring($Module.Length + 1)
        }
        elseif ((Test-PSFParameterBinding -ParameterName "Module" -Not) -and ($Name -notmatch ".+\..+"))
        {
            Stop-PSFFunction -Message "Invalid Name: $Name ! At least one '.' is required when not explicitly specifying a module name, to separate module from name" -EnableException $EnableException -Category InvalidArgument
            return
        }
        
        If ($Module) { $internalFullName = $Module, $Name -join "." }
        else { $internalFullName = $Name }
    }
    #endregion Prepare Names
    
    #region Prepare runtime and kill execution as needed
    if ([PSFramework.Configuration.ConfigurationHost]::Configurations.ContainsKey($internalFullName))
    {
        $itExists = $true
        $itIsInitialized = [PSFramework.Configuration.ConfigurationHost]::Configurations[$internalFullName].Initialized
        $itIsEnforced = [PSFramework.Configuration.ConfigurationHost]::Configurations[$internalFullName].PolicyEnforced
    }
    else
    {
        $itExists = $false
        $itIsInitialized = $false
        $itIsEnforced = $false
    }
    
    if ($itExists -and $Default) { return }
    if ($itIsInitialized -and $Initialize) { return }
    if ($itIsEnforced -and (-not $Initialize))
    {
        Stop-PSFFunction -Message "Could not update configuration due to policy settings: $internalFullName" -EnableException $EnableException -Category PermissionDenied
        return
    }
    
    if (Test-PSFParameterBinding -ParameterName "Validation")
    {
        if (-not ([PSFramework.Configuration.ConfigurationHost]::Validation.Keys -contains $Validation.ToLower()))
        {
            Stop-PSFFunction -Message "Invalid validation name: $Validation. Supported validations: $([PSFramework.Configuration.ConfigurationHost]::Validation.Keys -join ", ")" -Category InvalidArgument -Target $Name
            return
        }
    }
    #endregion Prepare runtime and kill execution as needed
    
    #region Initializing a configuration
    if ($Initialize)
    {
        if ($itExists)
        {
            $oldValue = [PSFramework.Configuration.ConfigurationHost]::Configurations[$internalFullName].Value
            $cfg = [PSFramework.Configuration.ConfigurationHost]::Configurations[$internalFullName]
        }
        else { $cfg = New-Object PSFramework.Configuration.Config }
        $cfg.Name = $Name
        $cfg.Module = $Module
        $cfg.Description = $Description
        $cfg.Value = $Value
        $cfg.Handler = $Handler
        if ($Validation) { $cfg.Validation = [PSFramework.Configuration.ConfigurationHost]::Validation[$Validation.ToLower()] }
        $cfg.Hidden = $Hidden
        $cfg.Initialized = $true
        [PSFramework.Configuration.ConfigurationHost]::Configurations[$internalFullName] = $cfg
        
        if ($itExists) { Set-PSFConfig -Name $internalFullName -Value $oldValue }
    }
    #endregion Initializing a configuration
    
    #region Regular configuration update
    else
    {
        if (-not $itExists)
        {
            $cfg = New-Object PSFramework.Configuration.Config
            $cfg.Name = $Name
            $cfg.Module = $Module
            $cfg.Description = $Description
            $cfg.Handler = $Handler
            if ($Validation) { $cfg.Validation = [PSFramework.Configuration.ConfigurationHost]::Validation[$Validation.ToLower()] }
            $cfg.Hidden = $Hidden
            [PSFramework.Configuration.ConfigurationHost]::Configurations[$internalFullName] = $cfg
            
            Set-PSFConfig -Name $internalFullName -Value $Value
            return
        }
        
        else
        {
            [PSFramework.Configuration.Config]$cfg = [PSFramework.Configuration.ConfigurationHost]::Configurations[$internalFullName]
            if ((-not $DisableValidation) -and ($cfg.Validation) -and (Test-PSFParameterBinding -ParameterName "Value"))
            {
                $testResult = $cfg.Validation.Invoke($Value)
                if (-not $TestResult.Success)
                {
                    Stop-PSFFunction -Message "Could not update configuration $internalFullName | Failed validation: $($testResult.Message)" -EnableException $EnableException -Category InvalidResult -Target $internalFullName
                    return
                }
                $Value = $testResult.Value
            }
            if ((-not $DisableHandler) -and ($cfg.Handler) -and (Test-PSFParameterBinding -ParameterName "Value"))
            {
                try { $cfg.Handler.Invoke($Value) }
                catch
                {
                    Stop-PSFFunction -Message "Could not update configuration $internalFullName | Failed handling $_" -EnableException $EnableException -Category InvalidResult -Target $internalFullName
                    return
                }
            }
            
            if (Test-PSFParameterBinding -ParameterName "Hidden") { [PSFramework.Configuration.ConfigurationHost]::Configurations[$internalFullName].Hidden = $Hidden }
            if (Test-PSFParameterBinding -ParameterName "Value") { [PSFramework.Configuration.ConfigurationHost]::Configurations[$internalFullName].Value = $Value }
            if (Test-PSFParameterBinding -ParameterName "Description") { [PSFramework.Configuration.ConfigurationHost]::Configurations[$internalFullName].Description = $Description }
            if (Test-PSFParameterBinding -ParameterName "Handler") { [PSFramework.Configuration.ConfigurationHost]::Configurations[$internalFullName].Handler = $Handler }
            if (Test-PSFParameterBinding -ParameterName "Validation") { [PSFramework.Configuration.ConfigurationHost]::Configurations[$internalFullName].Validation = [PSFramework.Configuration.ConfigurationHost]::Validation[$Validation.ToLower()] }
        }
    }
    #endregion Regular configuration update
}