Functions/Get-ScheduledTask.ps1

# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

function Get-ScheduledTask
{
    <#
    .SYNOPSIS
    Gets the scheduled tasks for the current computer.
 
    .DESCRIPTION
    The `Get-ScheduledTask` function gets the scheduled tasks on the current computer. It returns `Carbon.TaskScheduler.TaskInfo` objects for each one.
 
    With no parameters, `Get-ScheduledTask` returns all scheduled tasks. To get a specific scheduled task, use the `Name` parameter, which must be the full name of the task, i.e. path plus name. The name parameter accepts wildcards. If a scheduled task with the given name isn't found, an error is written.
 
    This function has the same name as the built-in `Get-ScheduledTask` function that comes on Windows 2012/8 and later. It returns objects with the same properties, but if you want to use the built-in function, use the `ScheduledTasks` qualifier, e.g. `ScheduledTasks\Get-ScheduledTask`.
 
    .LINK
    Test-ScheduledTask
 
    .EXAMPLE
    Get-ScheduledTask
 
    Demonstrates how to get all scheduled tasks.
 
    .EXAMPLE
    Get-ScheduledTask -Name 'AutoUpdateMyApp'
 
    Demonstrates how to get a specific task.
 
    .EXAMPLE
    Get-ScheduledTask -Name '*Microsoft*'
 
    Demonstrates how to get all tasks that match a wildcard pattern.
 
    .EXAMPLE
    ScheduledTasks\Get-ScheduledTask
 
    Demonstrates how to call the `Get-ScheduledTask` function in the `ScheduledTasks` module which ships on Windows 2012/8 and later.
    #>

    [CmdletBinding()]
    [OutputType([Carbon.TaskScheduler.TaskInfo])]
    param(
        [Parameter()]
        [Alias('TaskName')]
        [string]
        # The name of the scheduled task to return. Wildcards supported. This must be the *full task name*, i.e. the task's path/location and its name.
        $Name
    )

    Set-StrictMode -Version 'Latest'

    Use-CallerPreference -Cmdlet $PSCmdlet -Session $ExecutionContext.SessionState

    function ConvertFrom-RepetitionElement
    {
        param(
            [Xml.XmlElement]
            $TriggerElement
        )

        Set-StrictMode -Version 'Latest'

        [Carbon.TaskScheduler.ScheduleType]$scheduleType = [Carbon.TaskScheduler.ScheduleType]::Unknown
        $interval = $null
        $modifier = $null
        $duration = $null
        $stopAtEnd = $false
        [TimeSpan]$delay = [TimeSpan]::Zero

        if( $TriggerElement.GetElementsByTagName('Repetition').Count -gt 0 )
        {
            $repetition = $TriggerElement.Repetition

            $interval = $repetition.Interval
            if( $interval -match 'PT(\d+)(.*)$' )
            {
                $modifier = $Matches[1]
                $unit = $Matches[2]

                $hour = 0
                $minute = 0
                $second = 0
                switch( $unit )
                {
                    'H' { $hour = $modifier }
                    'M' { $minute = $modifier }
                }

                $scheduleTypes = @{
                                        'H' = 'Hourly';
                                        'M' = 'Minute';
                                  }
                if( $scheduleTypes.ContainsKey( $unit ) )
                {
                    $scheduleType = $scheduleTypes[$unit]
                }
                $timespan = New-Object 'TimeSpan' $hour,$minute,$second
                switch( $scheduleType )
                {
                    'Hourly' { $modifier = $timespan.TotalHours }
                    'Minute' { $modifier = $timespan.TotalMinutes }
                }
            }
        
            if( $repetition | Get-Member -Name 'Duration' )
            {
                $duration = $repetition.Duration
                if( $duration -match 'PT((\d+)H)?((\d+)M)?((\d+)S)?$' )
                {
                    $hours = $Matches[2]
                    $minutes = $Matches[4]
                    $seconds = $Matches[6]
                    $duration = New-Object -TypeName 'TimeSpan' -ArgumentList $hours,$minutes,$seconds
                }
            }

            if( $repetition | Get-Member -Name 'StopAtDurationEnd' )
            {
                $stopAtEnd = ($repetition.StopAtDurationEnd -eq 'true')
            }
        }

        if( $TriggerElement | Get-Member -Name 'Delay' )
        {
            $delayExpression = $TriggerElement.Delay
            if( $delayExpression -match '^PT(\d+)M(\d+)S$' )
            {
                $delay = New-Object 'TimeSpan' 0,$Matches[1],$Matches[2]
            }
        }

        return $scheduleType,$modifier,$duration,$stopAtEnd,$delay
    }

    $optionalArgs = @()
    $wildcardSearch = $false
    if( $Name )
    {
        if( [Management.Automation.WildcardPattern]::ContainsWildcardCharacters($Name) )
        {
            $wildcardSearch = $true
        }
        else
        {
            $Name = Join-Path -Path '\' -ChildPath $Name
            $optionalArgs = @( '/tn', $Name )
        }
    }

    $originalErrPreference = $ErrorActionPreference
    $ErrorActionPreference = 'Continue'
    $errFile = Join-Path -Path $env:TEMP -ChildPath ('Carbon+Get-ScheduledTask+{0}' -f [IO.Path]::GetRandomFileName())
    [object[]]$output = schtasks /query /v /fo csv $optionalArgs 2> $errFile | ConvertFrom-Csv | Where-Object { $_.HostName -ne 'HostName' } 
    $ErrorActionPreference = $originalErrPreference

    if( $LASTEXITCODE )
    {
        if( (Test-Path -Path $errFile -PathType Leaf) )
        {
            $error = (Get-Content -Path $errFile) -join ([Environment]::NewLine)
            try
            {
                if( $error -like '*The system cannot find the file specified.*' )
                {
                    Write-Error ('Scheduled task ''{0}'' not found.' -f $Name)
                }
                else
                {
                    Write-Error ($error)
                }
            }
            finally
            {
                Remove-Item -Path $errFile
            }
        }
        return
    }

    if( -not $output )
    {
        return
    }

    for( $idx = 0; $idx -lt $output.Count; ++$idx )
    {
        $csvTask = $output[$idx]

        $xml = schtasks /query /tn $csvTask.TaskName /xml | Where-Object { $_ }
        $xml = $xml -join ([Environment]::NewLine)
        $xmlDoc = [xml]$xml

        $taskPath = Split-Path -Parent -Path $csvTask.TaskName
        # Get-ScheduledTask on Win2012/8 has a trailing slash so we include it here.
        if( $taskPath -ne '\' )
        {
            $taskPath = '{0}\' -f $taskPath
        }
        $taskName = Split-Path -Leaf -Path $csvTask.TaskName

        $xmlTask = $xmlDoc.Task
        $principal = $xmlTask.Principals.Principal
        $isInteractive = $false
        $noPassword = $false
        if( $principal | Get-Member 'LogonType' )
        {
            $isInteractive = $principal.LogonType -eq 'InteractiveTokenOrPassword'
            $noPassword = $principal.LogonType -eq 'S4U'
        }

        $highestRunLevel = $false
        if( $principal | Get-Member 'RunLevel' )
        {
            $highestRunLevel = ($principal.RunLevel -eq 'HighestAvailable')
        }

        $createDate = [DateTime]::MinValue
        if( $xmlTask | Get-Member -Name 'RegistrationInfo' )
        {
            $regInfo = $xmlTask.RegistrationInfo 
            if( $regInfo | Get-Member -Name 'Date' )
            {
                $createDate = [datetime]$regInfo.Date
            }
        }

        $taskToRun = $csvTask.'Task To Run'
        if( ($xmlTask | Get-Member -Name 'Actions') -and $xmlTask.Actions.ChildNodes.Count -eq 1 )
        {
            $actions = $xmlTask.Actions
            if( ($actions | Get-Member -Name 'Exec') -and ($actions.Exec | Measure-Object | Select-Object -ExpandProperty 'Count') -eq 1)
            {
                $exec = $actions.Exec

                if( $exec | Get-Member -Name 'Command' )
                {
                    $taskToRun = $exec.Command
                }

                if( $exec | Get-Member -Name 'Arguments' )
                {
                    $taskToRun = '{0} {1}' -f $taskToRun,$exec.Arguments
                }
            }
        }

        $ctorArgs = @(
                        $csvTask.HostName,
                        $taskPath,
                        $taskName,
                        $csvTask.'Next Run Time',
                        $csvTask.Status,
                        $csvTask.'Logon Mode',
                        $csvTask.'Last Run Time',
                        $csvTask.Author,
                        $createDate,
                        $taskToRun,
                        $csvTask.'Start In',
                        $csvTask.Comment,
                        $csvTask.'Scheduled Task State',
                        $csvTask.'Idle Time',
                        $csvTask.'Power Management',
                        $csvTask.'Run As User',
                        $isInteractive,
                        $noPassword,
                        $highestRunLevel,
                        $csvTask.'Delete Task If Not Rescheduled'
                    )

        $task = New-Object -TypeName 'Carbon.TaskScheduler.TaskInfo' -ArgumentList $ctorArgs

        $scheduleIdx = 0
        while( $idx -lt $output.Count -and $output[$idx].TaskName -eq $csvTask.TaskName )
        {
            $csvTask = $output[$idx++]
            [Carbon.TaskScheduler.ScheduleType]$scheduleType = [Carbon.TaskScheduler.ScheduleType]::Unknown

            [int[]]$days = @()
            [int]$csvDay = 0
            if( [int]::TryParse($csvTask.Days, [ref]$csvDay) )
            {
                $days = @( $csvDay )
            }

            $duration = $csvTask.'Repeat: Until: Duration'
            [Carbon.TaskScheduler.Month[]]$months = @()
            $modifier = $null
            $stopAtEnd = $false
            [int]$interval = 0
            [TimeSpan]$endTime = [TimeSpan]::Zero
            [DayOfWeek[]]$daysOfWeek = @()
            [TimeSpan]$delay = [TimeSpan]::Zero
            [int]$idleTime = 0
            $eventChannelName = $null

            $triggers = $xmlTask.GetElementsByTagName('Triggers') | Select-Object -First 1
            if( -not $triggers -or $triggers.ChildNodes.Count -eq 0 )
            {
                $scheduleType = [Carbon.TaskScheduler.ScheduleType]::OnDemand
            }
            elseif( $triggers.ChildNodes.Count -gt 0 )
            {
                [Xml.XmlElement]$trigger = $triggers.ChildNodes.Item($scheduleIdx++)
                if( $trigger | Get-Member -Name 'EndBoundary' )
                {
                    $endDateTime = [datetime]$trigger.EndBoundary
                    $endTime = New-TimeSpan -Hours $endDateTime.Hour -Minutes $endDateTime.Minute -Seconds $endDateTime.Second
                }

                $scheduleType,$modifier,$duration,$stopAtEnd,$delay = ConvertFrom-RepetitionElement $trigger
                if( $trigger.Name -eq 'TimeTrigger' )
                {
                    $days = @( )
                    if( $csvTask.'Schedule Type' -eq 'One Time Only' )
                    {
                        $scheduleType = 'Once'
                        $interval = $modifier
                        $modifier = $null
                    }
                }
                elseif( $trigger.Name -eq 'LogonTrigger' )
                {
                    $scheduleType = 'OnLogon'
                    $interval = 0
                    $modifier = $null
                }
                elseif( $trigger.Name -eq 'BootTrigger' )
                {
                    $scheduleType = 'OnStart'
                    $interval = 0
                    $modifier = $null
                }
                elseif( $trigger.Name -eq 'IdleTrigger' )
                {
                    $scheduleType = 'OnIdle'
                    $interval = 0
                    $modifier = $null
                    $settingsNode = $xmlTask.Settings
                    if( $settingsNode | Get-Member 'IdleSettings' )
                    {
                        $idleSettingsNode = $settingsNode.IdleSettings
                        if( $idleSettingsNode | Get-Member 'Duration' )
                        {
                            $idleExpression = $xmlTask.Settings.IdleSettings.Duration
                            if( $idleExpression -match '^PT(\d+)M$' )
                            {
                                $idleTime = $Matches[1]
                            }
                        }
                    }
                }
                elseif( $trigger.Name -eq 'EventTrigger' )
                {
                    $scheduleType = 'OnEvent'
                    $subscription = [xml]$trigger.Subscription
                    $selectNode = $subscription.QueryList.Query.Select
                    $modifier = $selectNode.InnerText
                    $eventChannelName = $selectNode.GetAttribute('Path')
                }
                elseif( $trigger.Name -eq 'SessionStateChangeTrigger' )
                {
                    $scheduleType = [Carbon.TaskScheduler.ScheduleType]::SessionStateChange
                }
                elseif( $trigger.Name -eq 'RegistrationTrigger' )
                {
                    $scheduleType = [Carbon.TaskScheduler.ScheduleType]::Registration
                }
                elseif( $trigger.Name -eq 'CalendarTrigger' )
                {
                    if( $trigger.GetElementsByTagName('ScheduleByDay').Count -eq 1 )
                    {
                        $scheduleType = 'Daily'
                        $modifier = $trigger.ScheduleByDay.DaysInterval
                        $null,$interval,$null,$null = ConvertFrom-RepetitionElement $trigger
                    }
                    elseif( $trigger.GetElementsByTagName('ScheduleByWeek').Count -eq 1 )
                    {
                        $scheduleType = 'Weekly'
                        $interval = $modifier
                        $modifier = $trigger.ScheduleByWeek.WeeksInterval
                        $days = @( )
                        $daysOfWeek = $trigger.ScheduleByWeek.DaysOfWeek.ChildNodes | ForEach-Object { [DayOfWeek]$_.Name }
                    }
                    elseif( $trigger.GetElementsByTagName('ScheduleByMonth').Count -eq 1 )
                    {
                        $scheduleType = 'Monthly'
                        $monthsNode = $trigger.ScheduleByMonth.Months
                        $daysOfMonth = $trigger.ScheduleByMonth.DaysOfMonth.ChildNodes | ForEach-Object { $_.InnerText }
                        if( $daysOfMonth -eq 'Last' )
                        {
                            $interval = $modifier
                            $modifier = 'LastDay'
                            $days = @()
                        }
                        else
                        {
                            $days = $daysOfMonth | ForEach-Object { [int]$_ }
                            $interval = $modifier
                            # Monthly tasks.
                            if( $monthsNode.ChildNodes.Count -eq 12 )
                            {
                                $modifier = 1
                            }
                            else
                            {
                                # Non-monthly tasks.
                                $modifier = $null
                            }
                        }

                        [Carbon.TaskScheduler.Month[]]$months = $monthsNode.ChildNodes | ForEach-Object { ([Carbon.TaskScheduler.Month]$_.Name) }
                    }
                    elseif( $triggers.GetElementsByTagName('ScheduleByMonthDayOfWeek').Count -eq 1 )
                    {
                        $scheduleType = 'Monthly'
                        $interval = $modifier
                        $scheduleNode = $trigger.ScheduleByMonthDayOfWeek
                        $daysOfWeek = $scheduleNode.DaysOfWeek.ChildNodes | ForEach-Object { [DayOfWeek]$_.Name }
                        $months = $scheduleNode.Months.ChildNodes | ForEach-Object { ([Carbon.TaskScheduler.Month]$_.Name) }
                        switch( $scheduleNode.Weeks.Week )
                        {
                            1 { $modifier = 'First' }
                            2 { $modifier = 'Second' }
                            3 { $modifier = 'Third' }
                            4 { $modifier = 'Fourth' }
                            'Last' { $modifier = 'Last' }
                        }
                    }
                }
            }

            function ConvertFrom-SchtasksDate
            {
                param(
                    [Parameter(Mandatory=$true)]
                    [string]
                    $SchtasksDate,

                    [Parameter(Mandatory=$true)]
                    [DateTime]
                    $DefaultValue
                )

                Set-StrictMode -Version 'Latest'

                [DateTime]$dateTime = $DefaultValue
                if( -not [DateTime]::TryParse( $SchtasksDate, [ref] $dateTime ) )
                {
                    return $DefaultValue
                }
                return New-Object 'DateTime' $dateTime.Year,$dateTime.Month,$dateTime.Day
            }

            function ConvertFrom-SchtasksTime
            {
                param(
                    [Parameter(Mandatory=$true)]
                    [string]
                    $SchtasksTime
                )

                Set-StrictMode -Version 'Latest'

                [TimeSpan]$timespan = [TimeSpan]::Zero
                [DateTime]$dateTime = New-Object 'DateTime' 2015,11,6
                $schtasksTime = '{0} {1}' -f (Get-Date).ToString('d'),$SchtasksTime
                if( -not [DateTime]::TryParse( $SchtasksTime, [ref] $dateTime ) )
                {
                    return $timespan
                }

                return New-Object 'TimeSpan' $dateTime.Hour,$dateTime.Minute,$dateTime.Second
            }

            $startDate = ConvertFrom-SchtasksDate $csvTask.'Start Date' -DefaultValue ([DateTime]::MinValue)
            $startTime = ConvertFrom-SchtasksTime $csvTask.'Start Time'
            $endDate = ConvertFrom-SchtasksDate $csvTask.'End Date' -DefaultValue ([DateTime]::MaxValue)

            $scheduleCtorArgs = @(
                                    $csvTask.'Last Result',
                                    $csvTask.'Stop Task If Runs X Hours And X Mins',
                                    $scheduleType,
                                    $modifier,
                                    $interval,
                                    $startTime,
                                    $startDate,
                                    $endTime,
                                    $endDate,
                                    $daysOfWeek,
                                    $days,
                                    $months,
                                    $csvTask.'Repeat: Every',
                                    $csvTask.'Repeat: Until: Time',
                                    $duration,
                                    $csvTask.'Repeat: Stop If Still Running',
                                    $stopAtEnd,
                                    $delay,
                                    $idleTime,
                                    $eventChannelName
                                )

            $schedule = New-Object -TypeName 'Carbon.TaskScheduler.ScheduleInfo' -ArgumentList $scheduleCtorArgs 
            $task.Schedules.Add( $schedule )
        }
        --$idx;

        if( -not $wildcardSearch -or $task.FullName -like $Name )
        {
            $task
        }
    }

}