Backup / migrate Microsoft To Do tasks with PowerShell and Microsoft Graph

For more than a year, I’ve foolishly been using a developer Office 365 subscription for some personal stuff. You know, the subscription where they delete your data if “development activity” isn’t detected every few months. As such, I’ve periodically had to fake some development activity in order to keep the clock ticking.

Not a sustainable situation, and it’s time to sort it out…

For me, this involves moving data from one subscription’s OneDrive to another. I’m fairly confident that Rclone will be able to handle this – it’s an excellent bit of software.

It also means moving Microsoft To Do tasks between subscriptions. Ah.

Not so easy

I couldn’t find an easy way of backing up To Do. There is mention of an Outlook backup option in the docs, but it’s missing on my account. And To Do will happily suck in data from Wunderlist but I can’t see an equivalent to get data out. Where’s the Justice Department when you need them?

Luckily Microsoft Graph has a To Do API in preview and I was able to put together a script to do the lifting for me.

Ironically, this has involved an intense burst of real developer activity…

Enter the Dragon

The full script is over on GitHub.

It provides two functions:

  • Export-MicrosoftTodo saves every Microsoft To Do list and task to an XML file.
  • Import-MicrosoftTodo loads this XML file and restores all lists and tasks.

This is what a backup looks like:

Here’s a restore:

And this is what the client sees:

You can see that the completed status of the tasks has been copied. This is also true of created/modified dates, reminders, notes, and so on.

The script is quite long, so I won’t paste the whole thing here, but here are a few interesting bits:

Emotional support

Thankfully, for the comfort of our technology-addled minds, Microsoft To Do lets you decorate your lists with little emojis. Internally, it looks like if the first character of the name is an emoji, it gets special treatment in the UI.

I was having difficulty creating these special list names but the fix was simply to add charset=utf-8 to Invoke-RestMethod‘s ContentType:

$params = @{
    "Method"         = "Post"
    "Uri"            = ($graphBaseUri + "/me/todo/lists")
    "Authentication" = "OAuth"
    "Token"          = $accessToken
    "Body"           = @{
        "displayName" = $list.displayName
    } | ConvertTo-Json
    # utf-8 makes emojis work. Life priorities are correct.
    "ContentType"    = "application/json; charset=utf-8"
}
Invoke-RestMethod @params

Before and after:

Jason Bateman

The basic aim of the script is to retrieve data from one API endpoint and to later submit the same data to another endpoint.

I found that PowerShell’s – er – adorable magic got in the way a bit. Specifically, the JSON (de-)serialisation done by Convert*-Json / Invoke-RestMethod didn’t preserve empty properties, and the conversion to/from a DateTime object didn’t match the format expected by the API – and I couldn’t see an easy way to override this behaviour.

My solution was to use an alternative JSON parser available in .NET to grab the appropriate bit of the HTTP response, remove a few properties, and store the resulting JSON as a string, to be later POSTed back to the API verbatim:

$response = Invoke-WebRequest -Uri $uri -Authentication OAuth -Token $accessToken
# Invoke-RestMethod / ConvertFrom-Json mangles the response, which I resent,
# so we're using an alternative parser and storing the JSON as a string
# https://stackoverflow.com/a/58169326/12055271
$json = [Newtonsoft.Json.JsonConvert]::DeserializeObject($response.Content)
ForEach ($task in $json.value) {
    # Don't need ID - Graph API can generate a new one
    $task.Remove("id") | Out-Null
    # Don't need ETag
    $task.Remove("@odata.etag") | Out-Null
    $results += $task.ToString()

I also chose to save the exported data to disk using PowerShell’s CLI XML format – rather than JSON – as an easy way of guarantee the string stays as it is.

Token effort

The script needs an OAuth2 token in order to authenticate with your Microsoft account.

An easy way to get going (and slightly hacky but fine for personal use) is to grant yourself all Tasks.* permissions in Graph Explorer and copy its token, as demoed here:

(Thanks GoToGuy for this blog post.)

Please read the following license agreement carefully

A few notes on the design of the script:

  • It worked well for me and 5000(!) tasks, but please do your own testing. You can create a test Microsoft account with a secondary email address, or make an Azure tenant for free.
  • Tested with PowerShell 7 only. Get with the times.
  • Export-MicrosoftTodo currently backs up every task and Import-MicrosoftTodo restores every task.
  • If you run Import-MicrosoftTodo twice you’ll end up with duplicates.
  • The account used for export/import is the one that generated the OAuth token. You can backup from one account and restore to another simply by providing different tokens.
  • The script does not currently migrate linkedResources – these “represent[…] an item in a partner application related to a todoTask.” Shrug.
  • Nor does it share any lists as part of data import.
  • Currently, the script needs to be run interactively, in order to receive the OAuth token and to confirm a restore.
  • I’d be open to making improvements in these areas if there’s interest! The script could backup individual lists, for example, or backup someone else’s account (with the appropriate permissions).
  • Unfortunately, I don’t think there’s currently any way to retain list groups.

And in conclusion

Thanks for reading!

This has been a fun project and hopefully you can get some use out of the methods used or the script itself.

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