xkcd.psm1

<#
.SYNOPSIS
Gets the details of the comics @ http://xkcd.com/. Optionally can download the comic images.
.DESCRIPTION
The Get-XKCD cmdlet gets the details of one or more comics from the XKCD API: https://xkcd.com/json.html. This includes title, number, image URL, alt text, day, month, year, news, safe_title and transcript.
    
By default, Get-XKCD returns the details of the latest available comic. When you use the -num parameter you can specify one or more specific comics to return.
.EXAMPLE
PS C:\>Get-XKCD
This command gets the details of the latest XKCD comic from the API such as the title, number, image URL and alt text.
.EXAMPLE
PS C:\>Get-XKCD 42
This command returns the details of the 42nd XKCD comic.
.EXAMPLE
PS C:\>Get-XKCD -Random
This command returns the details of a random XKCD comic from the set of all available comics.
.EXAMPLE
PS C:\>Get-XKCD -Random -Min 100 -Max 150
This command returns a random comic that is numbered between 100 and 150.
.EXAMPLE
PS C:\>Get-XKCD -Newest 5
This command returns the details of the latest 5 comics.
.EXAMPLE
PS C:\>Get-XKCD -Download
This command returns the details of the latest comic and downloads the comic image to the current working directory.
.EXAMPLE
PS C:\>Get-XKCD (1..10) -Download -Path C:\Comics
This command returns the details of comic numbers 1 to 10 and downloads each comics image to C:\Comics.
.EXAMPLE
PS C:\>1..10 | % { Get-XKCD -Random | select num,img } | FT -AutoSize
This command returns the details of 10 random comics from the set of all comics and displays the number and image URL of those comics as an autosized table.

.LINK
https://xkcd.com/json.html
#>

Function Get-XKCD{
    [cmdletbinding(DefaultParameterSetName='Specific',SupportsShouldProcess=$true)]
    Param (
        #Gets a random comic.
        [Parameter(ParameterSetName='Random')][switch]$Random,
        #Use with -Random to define a lower bound range within which to return a comic.
        [Parameter(ParameterSetName='Random')][int]$Min = 1,
        #Use with -Random to define an upper bound range within which to return a comic. -Max is the latest comic number by default.
        [Parameter(ParameterSetName='Random')][int]$Max = (Invoke-RestMethod "http://xkcd.com/info.0.json").num,        
        #Gets the specified number of the most recent comics.
        [Parameter(ParameterSetName='Newest')][int]$Newest,
        #Downloads the images of all returned comics to the local computer.
        [switch]$Download,
        #Use with -Download to specify a local directory to download to. By default this is the current working directory.
        [ValidateScript({Test-Path $_ -PathType 'Container'})] 
        [string]$Path = $PWD,
        #Gets the specified comics. Accepts array input.
        [Parameter(ParameterSetName='Specific',ValueFromPipeline=$True,Position=0)][int[]]$Num = $Max     
    )
    Begin{
        If ($Random) { $Num = Get-Random -min $Min -max $Max }
        If ($Newest) { $Num = (($Max - $Newest) + 1)..$Max }
    }
    Process{
        $Num | ForEach-Object { 
            $Comic = Invoke-RestMethod "http://xkcd.com/$_/info.0.json"
            If ($Download -and $PSCmdlet.ShouldProcess($Comic.img,"Save as $_.jpg")) { Invoke-WebRequest $Comic.img -OutFile $(Join-Path $Path "$_.jpg") }

            Return $Comic
        }
    }
}