src/application.ps1
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function New-ApplicationTemplate { <# .SYNOPSIS Create new application template file for writing a new "scrapp" (script + application) #> [CmdletBinding()] Param( [Parameter(Position=0)] [String] $Name = 'app', [Switch] $Save ) $Data = @{ Name = $Name; Dollar = '$'; Grave = '`' } $Template = " [CmdletBinding()] Param( [String] {{ Dollar }}Id, [Switch] {{ Dollar }}Clear ) $Empty {{ Dollar }}InitialState = @{ Data = 0 } $Empty {{ Dollar }}Init = { Clear-Host {{ Dollar }}State = {{ Dollar }}args[0] {{ Dollar }}Id = {{ Dollar }}State.Id 'Application Information:' | Write-Color `"ID = {{#green {{ Dollar }}Id}}`" | Write-Label -Color Gray -Indent 2 -NewLine 'Name = {{#green {{ Name }}}}' | Write-Label -Color Gray -Indent 2 -NewLine { Invoke-Speak 'Goodbye' {{ Dollar }}Id = {{ Dollar }}Event.MessageData.State.Id `"`{{ Grave }}nApplication ID: {{ Dollar }}Id`{{ Grave }}n`" | Write-Color -Magenta } | Invoke-ListenTo 'application:exit' | Out-Null '' | Write-Color Start-Sleep 2 } $Empty {{ Dollar }}Loop = { Clear-Host {{ Dollar }}State = {{ Dollar }}args[0] {{ Dollar }}Count = {{ Dollar }}State.Data `"Current count is {{#green {{ Dollar }}Count}}`" | Write-Color -Cyan {{ Dollar }}State.Data++ Save-State {{ Dollar }}State.Id {{ Dollar }}State | Out-Null Start-Sleep 1 } $Empty Invoke-RunApplication {{ Dollar }}Init {{ Dollar }}Loop {{ Dollar }}InitialState -Id {{ Dollar }}Id -ClearState:{{ Dollar }}Clear " | New-Template -Data $Data | Remove-Indent if ($Save) { $Template | Out-File "${Name}.ps1" } else { $Template } } function Invoke-RunApplication { <# .SYNOPSIS Entry point for Powershell CLI application .PARAMETER Init Function to initialize application, executed when application is started. .PARAMETER Loop Code to execute during every application loop, executed when ShouldContinue returns True. .PARAMETER BeforeNext Code to execute at the end of each application loop. It should be used to update the return of ShouldContinue. .PARAMETER SingleRun As its name implies - use this flag to execute one loop of the application .PARAMETER NoCleanup Use this switch to disable removing the application event listeners when the application exits. Application event listeners can be removed manually with: 'application:' | Invoke-StopListen .EXAMPLE # Make a simple app # Initialize your app - $Init is only run once $Init = { 'Getting things ready...' | Write-Color -Green } # Define what your app should do every iteration - $Loop is executed until ShouldContinue returns False $Loop = { Clear-Host 'Doing something super important...' | Write-Color -Gray Start-Sleep 5 } # Start your app Invoke-RunApplication $Init $Loop .EXAMPLE # Make a simple app with state # Note: State is passed to Init, Loop, ShouldContinue, and BeforeNext New-ApplicationTemplate -Save .EXAMPLE # Applications trigger events throughout their lifecycle which can be listened to (most commonly within the Init scriptblock). { say 'Hello' } | on 'application:init' { say 'Wax on' } | on 'application:loop:before' { say 'Wax off' } | on 'application:loop:after' { say 'Goodbye' } | on 'application:exit' # The triggered event will include State as MessageData { $Id = $Event.MessageData.State.Id "`nApplication ID: $Id" | Write-Color -Green } | Invoke-ListenTo 'application:init' #> [CmdletBinding()] Param( [Parameter(Mandatory=$true, Position=0)] [ScriptBlock] $Init, [Parameter(Mandatory=$true, Position=1)] [ScriptBlock] $Loop, [Parameter(Position=2)] [ApplicationState] $State, [String] $Id, [ScriptBlock] $ShouldContinue, [ScriptBlock] $BeforeNext, [Switch] $ClearState, [Switch] $SingleRun, [Switch] $NoCleanup ) if ($Id.Length -gt 0) { $Path = Join-Path $Env:temp "state-$Id.xml" if ($ClearState -and (Test-Path $Path)) { Remove-Item $Path } if (Test-Path $Path) { "==> Resolved state with ID: $Id" | Write-Verbose try { [ApplicationState]$State = Get-State $Id $State.Id = $Id } catch { "==> Failed to get state with ID: $Id" | Write-Verbose $State = [ApplicationState]@{ Id = $Id } } } else { $State = [ApplicationState]@{ Id = $Id } } } if (-not $State) { $State = [ApplicationState]@{} } if (-not $ShouldContinue) { $ShouldContinue = { $State.Continue -eq $true } } if (-not $BeforeNext) { $BeforeNext = { "`n`nContinue?" | Write-Label -NewLine $State.Continue = ('yes','no' | Invoke-Menu) -eq 'yes' } } "Application ID: $($State.Id)" | Write-Verbose 'application:init' | Invoke-FireEvent & $Init $State if ($SingleRun) { 'application:loop:before' | Invoke-FireEvent -Data @{ State = $State } & $Loop $State 'application:loop:after' | Invoke-FireEvent -Data @{ State = $State } } else { While (& $ShouldContinue $State) { 'application:loop:before' | Invoke-FireEvent -Data @{ State = $State } & $Loop $State 'application:loop:after' | Invoke-FireEvent -Data @{ State = $State } & $BeforeNext $State } } 'application:exit' | Invoke-FireEvent -Data @{ State = $State } if (-not $NoCleanup) { 'application:' | Invoke-StopListen } $State.Id } enum ApplicationStatus { Init; Busy; Idle; Done } class ApplicationState { [String] $Id = (New-Guid) [ApplicationStatus] $Status = 0 [Bool] $Continue = $true [String] $Name = 'Application Name' $Data } function Save-State { <# .SYNOPSIS .EXAMPLE Set-State -Id 'abc-def-ghi' -State @{ Data = 0 } .EXAMPLE Set-State 'abc-def-ghi' @{ Data = 0 } .EXAMPLE [ApplicationState]@{ Data = 0 } | Set-State 'abc-def-ghi' #> [CmdletBinding(SupportsShouldProcess=$true)] Param( [Parameter(Mandatory=$true, Position=0)] [String] $Id, [Parameter(Mandatory=$true, Position=1)] [ApplicationState] $State, [String] $Path ) if (-not $Path) { $Path = Join-Path $Env:temp "state-$Id.xml" } if ($PSCmdlet.ShouldProcess($Path)) { $State | Export-Clixml -Path $Path "==> Saved state to $Path" | Write-Verbose } else { "==> Would have saved state to $Path" | Write-Verbose } $Path } function Get-State { <# .SYNOPSIS .EXAMPLE $State = Get-State -Id 'abc-def-ghi' .EXAMPLE $State = 'abc-def-ghi' | Get-State #> [CmdletBinding()] Param( [Parameter(Position=0, ValueFromPipeline=$true)] [String] $Id, [AllowEmptyString()] [String] $Path ) if ($Path.Length -gt 0 -and (Test-Path $Path)) { "==> Resolved $Path" | Write-Verbose } else { $Path = Join-Path $Env:temp "state-$Id.xml" } "==> Loading state from $Path" | Write-Verbose Import-Clixml -Path $Path } |