Get all domains and alias/alternate domains from CP REST API.

Get-DomainsAltAlias.ps1

function Get-XapiSignature($userAgent, $apiKey, $apiSecret) {
    $dateTime = [DateTime]::UtcNow.ToString("yyyyMMddHHmmss");
    $dataToSign = [String]::Format("{0}{1}{2}{3}", $apikey, $userAgent, $dateTime, $apiSecret);
    $sha1 = [System.Security.Cryptography.SHA1]::Create();
    $signedBytes = $sha1.ComputeHash([System.Text.Encoding]::UTF8.GetBytes($dataToSign));
    $signature = [System.Convert]::ToBase64String($signedBytes);
    $sha1.Dispose()
    [String]::Format("{0}:{1}:{2}", $apikey, $dateTime, $signature);
}

function Start-Throttle() {
    ## You have to throttle REST API requests.
    Start-Sleep -Seconds 2
}

function Get-AllDomains($header, $baseUrl) {
    $allDomains = New-Object System.Collections.ArrayList
    $offset = 0
    $size = 100
    do {
        if ($offset -gt 0) { Start-Throttle; }
        $url = "/customers/all/domains?size=$size&offset=$offset"
        $address = $baseUrl+$url
        $domains = Invoke-RestMethod -Uri $address -Method Get -Headers $header
        foreach ($domain in $domains.domains) { $allDomains.Add($domain.name) | Out-Null; }
        $offset = $offset + $size
    } while ($domains.domains.Count -eq $size)
    $allDomains
}

function Get-AllAlternateAndAliases($listOfDomains, $header, $baseUrl) {
    $allAlternatesAndAlises = @{}
    foreach ($domain in $listOfDomains) {
        Write-Host "Getting alias/alt for $domain."
        Start-Throttle
        $url = "/customers/all/domains/$domain/alternatedomains"
        $address = $baseUrl+$url
        $altDomains = Invoke-RestMethod -Uri $address -Method Get -Headers $header
        if ($altDomains.alternateDomains.Count -gt 0) {
            Write-Host "Found alias/alternate domains for $domain."
            foreach ($altDomain in $altDomains.alternateDomains) {
                $allAlternatesAndAlises.Add($altDomain)
            }
        }
    }
}

$apiKey = "***Put api key here..."
$apiSecret = "***Put api secret here..."
$userAgent = "query"
$baseUrl = "https://api.emailsrvr.com/v1"
$signature = Get-XapiSignature $userAgent $apiKey $apiSecret
$header = @{ "User-Agent"=$userAgent; "Accept"="application/json"; "X-Api-Signature"=$signature }

$listOfDomains = Get-AllDomains $header $baseUrl

$listOfAliasAlts = Get-AllAlternateAndAliases $listOfDomains $header $baseUrl