How to mirror the list of server blocks from another Mastodon instance

If you're bringing up a new Mastodon server, there will probably come a time when you want, or have to block another server. I've heard there are some unsavoury ones out there. AD-blocking software had had the concept of a blocklist of many years, but I haven't really found a good central repository of blocked servers, and most importantly, the reasons they are blocked.

This set of PowerShell functions will let you pull the server block list from another Mastodon instance. If we ever decide to put together a master block list, these can easily be adapted to use that list as a source.

# You need to run the .ps file in PowerShell so that the functions get
# loaded but after that you can just use them like regular commands.
#
# e.g.
# Get-MastodonServerBlock `
#     -domain source.social `
#     -accessToken "source_domain_token" |
# Foreach-Object {
#     Add-MastodonServerBlock `
#         -domain target.social `
#         -accessToken "target_domain_token" `
#         -block $_
# }
#
# If you don't have admin access to another server, and that server is
# publicly allowing their blocks to bee seen, you can leave off the 
# -accessToken parameter and get that version of the list. Some of the
# domains may be obfuscated in this case, and the obfuscated domains
# will be ignored by Add-MastodonServerBlock.

##########################################################################

# Creates an object used by Add-MastodonServerBlock from its constituent
# parameters. Really just a helper method.
function New-MastodonServerBlock {
    param (
        [Parameter(Mandatory = $true)][string] $domain,
        [Parameter(Mandatory = $true)][string] $severity,
        [Parameter(Mandatory = $false)][string] $justification = "",
        [Parameter(Mandatory = $false)][string] $comment = "",
        [Parameter(Mandatory = $false)][switch] $rejectMedia = $false,
        [Parameter(Mandatory = $false)][switch] $rejectReports = $false,
        [Parameter(Mandatory = $false)][switch] $obfuscate = $false
    )

    $block = @{
        domain          = $domain
        severity        = $severity
        public_comment  = $justification
        private_comment = $comment
        reject_media    = $rejectMedia
        reject_reports  = $rejectReports
        obfuscate       = $obfuscate
    }

    New-Object -TypeName PSObject -Property $block
}

# Retrieves the list of server blocks from a server.
# If the accessToken is specified, it will attempt to use the admin
# API otherwise if will use the instance API where domains names may
# be obfuscated.
function Get-MastodonServerBlock {
    param (
        [Parameter(Mandatory = $true)][string] $domain,
        [Parameter(Mandatory = $false)][string] $accessToken = $null
    )
    if ($accesstoken -ne $null) {
        (Invoke-WebRequest `
            -Uri "https://$domain/api/v1/admin/domain_blocks" `
            -Method GET `
            -Headers @{ Authorization = "Bearer $accesstoken" }).Content | ConvertFrom-Json
    }
    else {
        (Invoke-WebRequest `
            -Uri "https://$domain/api/v1/instance/domain_blocks" `
            -Method GET).Content | ConvertFrom-Json
    }
}

# Adds a server block to a server.
# Requires an access token with appropriate access.
function Add-MastodonServerBlock {
    param (
        [Parameter(Mandatory = $true)][string] $domain,
        [Parameter(Mandatory = $true)][string] $accesstoken,
        [Parameter(Mandatory = $true, ValueFromPipeline = $true)] $block
    )

    if ($block.domain.IndexOf("*") -ge 0) {
        Write-Warning "Ignoring obfuscated domain $($_.domain)"
        return
    }

    Invoke-WebRequest `
        -Uri "https://$domain/api/v1/admin/domain_blocks" `
        -Method POST `
        -Headers @{ Authorization = "Bearer $accesstoken" } `
        -Body $($_ | ConvertTo-Json) `
        -ContentType "application/json"
}