A PowerShell script that uses the Dean Evans EMS API to retrieve a complete list of all buildings, rooms, and bookings in those rooms for the next calendar year.

EMSAPI-GetRoomsAndBookings.ps1

#This script queries the EMS API for all bookings in all rooms in all buildings for the next calendar year.
#It requires the EMS Read-Only API and an authorised user on the EMS database.

#Date math

$today = Get-Date
$lastYear = $today.AddYears(-1)
$nextYear = $today.AddYears(1)
$todayString = $today.ToString("MMMM dd, yyyy")
$lastYearString = $lastYear.ToString("MMMM dd, yyyy")
$nextYearString = $nextYear.ToString("MMMM dd, yyyy")

#Define API connection parameters

$url = "http://ems.yourdomain.com/emsapi/service.asmx"
$apiuser = "yourapiuser"
$apipw = "yourapipassword"

#Define API endpoints

$endpoint_buildings = "/GetBuildings"
$uri_buildings = $url+$endpoint_buildings

$endpoint_rooms = "/GetAllRooms"
$uri_rooms = $url+$endpoint_rooms

$endpoint_bookings = "/GetAllRoomBookings"
$uri_bookings = $url+$endpoint_bookings

#Get Buildings

$query_buildings = "
    UserName=$apiuser
    Password=$apipw
"

$urlencode_buildings = $query_buildings.Trim() -replace("`r`n","&") -replace(" ")

$buildings_wr = Invoke-RestMethod -Uri $uri_buildings -Method Post -Body $urlencode_buildings
$buildings = ($buildings_wr.string.'#text' | ConvertFrom-Json).data

#Uncomment this line to see a grid view of all buildings.
#$buildings | Out-GridView

#Get Rooms in Buildings

$allRooms = @()
$buildings | ForEach-Object {
    $buildingID = $_.ID
    $query_rooms = "
        UserName=$apiuser
        Password=$apipw
        BuildingID=$buildingID
    "
    $urlencode_rooms = $query_rooms.Trim() -replace("`r`n","&") -replace(" ")

    $rooms_wr = Invoke-RestMethod -Uri $uri_rooms -Method Post -Body $urlencode_rooms
    $rooms = ($rooms_wr.string.'#text' | ConvertFrom-Json).data
    $allRooms += $rooms
}

#Uncomment this line to see a grid view of all rooms.
#$allRooms | Sort BuildingCode | Out-GridView

#Get All Appointments in All Rooms

$allBookings = @()
$allRooms | ForEach-Object {
    $roomID = $_.ID
    $query_bookings = "
        UserName=$apiuser
        Password=$apipw
        StartDate=$todayString
        EndDate=$nextYearString
        RoomID=$roomID
        ViewComboRoomComponents=false
    "
    #URL encode bookings query.
    $urlencode_bookings = $query_bookings.Trim() -replace("`r`n","&") -replace(" ")

    $bookings_wr = Invoke-RestMethod -Uri $uri_bookings -Method Post -Body $urlencode_bookings
    $bookings = ($bookings_wr.string.'#text' | ConvertFrom-Json).data
    $allBookings += $bookings
}

#Uncomment this line to see a grid view of all bookings.
#$allBookings | Out-GridView

Assuming the API is installed and configured on your EMS server, you can retrieve a list of available API endpoints at this URL: http(s)://ems.yourdomain.com/emsapi/service.asmx

Additional configuration is required to instruct the API to return JSON instead of XML.

JD,
Thanks for sharing this. There is almost zero code out on the web for this particular API.
Here is an alternate way to do this as well.... (Though we are using XML here.)

Function Get-RoomsAndBookings {
# A PowerShell script that uses the Dean Evans EMS API to retrieve a complete list of all buildings, rooms, and bookings in those rooms for the next calendar year.

# Constants
$allBuildings = -1  # Building Code -1 is ALL buildings
$ViewComboRoomComponents = $false

# Set up the Date Variables
$today = Get-Date
$nextYear = $today.AddYears(1)

# EMS API Connection Variables
$url = "http://ems.yourdomain.com/EMSAPI/Service.asmx"
$username = "youremsapiuser"
$password = "youremsapipassword"

# Set up the EMS Connection
$EmsConnector = New-WebServiceProxy -Uri $url

# Get a Listing of all rooms in all buildings
[xml]$Rooms = $EmsConnector.GetAllRooms($username, $password, $allBuildings)
$RoomArray = $Rooms.Rooms.Data

# Get a Listing of all bookings in all rooms
$AllBookingsArray = @()
$RoomArray | ForEach-Object {
    $roomID = $_.ID
    [xml]$bookingsReturn = $EmsConnector.GetAllRoomBookings($username, $password, $today, $nextyear, $roomID, $ViewComboRoomComponents)
    $bookings = $bookingsReturn.Bookings.Data
    $AllBookingsArray += $bookings
}

return $AllBookingsArray
}