I use iTunes on Windows only because I have to. I don't really care for it as a music organizer and besides, I rarely listen to music on my computer. I have an iPod though and what I do like about iTunes is that I can just plug in my iPod and it will automatically sync everything without any intervention from me. I also like that iTunes allows me to subscribe to podcasts. It annoys me though that unless I have iTunes running it will not update my podcast subscriptions. Since I only use iTunes for syncing my iPod, iTunes is never running.

Luckily iTunes has an COM automation interface that you can use to force it to update your podcasts. With a bit of PowerShell scripting I am now able to automatically update all of my podcasts in the middle of the night when I don't have to be bothered with the fact that iTunes is running. I used PowerShell for this scripting task as again, it seems perfect for a task like this.

My script is a little more complicated than just starting up iTunes and then starting the podcast downloads. Since I am scheduling this process to run nightly I also wanted to be able to close iTunes once it was finished. Unfortunately the iTunes COM automation interface provides no way to tell whether or not iTunes is busy downloading new podcasts. However it seems that iTunes creates a pretty predictable temporary download folder structure, which it then removes when it has finished downloading all of the podcasts that it updates. I used this bit of knowledge in my script to detect when iTunes was busy downloading new podcasts. I just watch for those directories, waiting for iTunes to finish and then I shut down iTunes. So far this has worked pretty well although I'm sure it is not complete robust under all circumstances.

Here is the PowerShell script I developed. If you want to use it you'll have to tweak the directory path that is checked in the script to match your computer. I should also mention that on at least one of my machines iTunes creates the temporary 'downloads\podcast' directory in a different place under the iTunes music folder. I have not found a setting in iTunes that determines where the temporary folder gets created so you may have to poke around a little while iTunes is downloading podcast updates to figure out where it is on your machine if this does not work.


# update iTunes pod casts

function test-Downloading
    if(test-path 'C:\Documents and Settings\MusicBox\My Documents\My Music\iTunes\iTunes Music\Downloads\Podcasts')
        return $True
    return $False

$iTunes = new-Object -comobject iTunes.Application
if($iTunes -ne $null)
    'iTunes started' | out-Host

    # start iTunes podcasts update
    'updating podcasts' | out-Host

    # set a time out time
    $TimeOut = (get-Date).AddMinutes(30)

    # wait a few minutes and check if it is downloading
    'waiting for downloads to start...' | out-Host
    start-sleep (30)

    # loop while iTunes seems to be downloading (presence of temporary download folder)
    'checking for download activity' | out-Host
    while(test-Downloading -and ((get-Date) -lt $TimeOut))
        # give it some more time
        'download activity detected, waiting...' | out-Host
        start-sleep (60)

    if((get-Date) -ge $TimeOut)
        'downloading timed-out' | out-Host

    # now quit iTunes after a little settling time
    start-Sleep (30)
    'quitting iTunes' | out-Host
    $iTunes = $null

Flux and Mutability

The mutable notebook of David Jade