A PowerShell function to post a Mastodon status.

Send-MastodonPost.ps1

#requires -version 5.1

<#
Based on a function from https://gist.github.com/dhmacher/2203582502c7ab13015db8f52e94da45

You need an access token that has at least write access to your status

* go to settings -> Development
* Click "New Application"
* Enter a name
* Allow "write:statuse
* Click Submit
* Click on the new application to review the keys
* Copy and securely store the "Access token" for your script.

I use PSDefaultParameterValues.
$PSDefaultParameterValues["Send-MastodonPost:HostName"] = "techhub.social"
$PSDefaultParameterValues["Send-MastodonPost:AccessToken"] = $token

This code is freely available to use and or modify.
#>

#TODO: Post an image with a status including ALT text for the description

Function Send-MastodonPost {
    [cmdletbinding(SupportsShouldProcess)]
    [alias("toot")]
    param (
        [Parameter(Position = 0, Mandatory)]
        [ValidateNotNullOrEmpty()]
        [string] $Message,
        [Parameter(Mandatory, HelpMessage = "Enter your Mastodon instance name, like techhub.social")]
        [ValidateNotNullOrEmpty()]
        [string] $HostName,
        [Parameter(Mandatory, HelpMessage = "Enter your Mastodon access token")]
        [ValidateNotNullOrEmpty()]
        [string] $AccessToken,
        [Parameter(HelpMessage = "Enter a date and time to schedule the post. It must be at least 5 minutes in the future.")]
        [ValidateScript({
            ($_ - (Get-Date)).totalMinutes -ge 5
            })]
        [DateTime]$Scheduled
    )

    $uri = "https://$hostname/api/v1/statuses?access_token=$Accesstoken"
    Write-Verbose "Posting to $uri"

    $body = @{
        status = $message
    }

    Write-Verbose "Posting $($body.status)"
    if ($Scheduled) {
        $isoDate = ("{0:u}" -f $scheduled.ToUniversalTime()).replace(" ", "T")
        $body.add("scheduled_at", $isoDate)
        Write-Verbose "Sending at $($body.scheduled_at)"
    }
    #parameters to splat to Invoke-RestMethod
    $paramHash = @{
        uri         = $uri
        Method      = "POST"
        ContentType = "application/x-www-form-urlencoded"
        Body        = $body
        ErrorAction = "Stop"
    }

    Write-Verbose "Using these parameters:"
    $paramHash | Out-String | Write-Verbose
    if ($pscmdlet.ShouldProcess($message, "Posting to $hostname")) {
        Invoke-RestMethod @paramHash
    }
}