XML Broker Health Check

I saw an interesting question in the Citrix support forum today, and thought I’d share. Scott Curtsinger asked the following:

Does anyone know what the easiest way is to check the health of the XML service on XenDesktop 5.6? I’m seeing a lot of information on the web for XenApp but not very much for XenDesktop beyond leveraging devices like a NetScaler.

My first instinct is that this could easily be done via PowerShell, so I did a quick search and found this blog post by Jason Pettys. I also found this great article on working with the Citrix XML service, and quickly put together the following script which I tested against my XenDesktop 5.6 XML broker:

$url = "http://localhost/scripts/wpnbr.dll"
$parameters = '<?xml version="1.0" encoding="utf-8"?><!DOCTYPE NFuseProtocol SYSTEM "NFuse.dtd"><NFuseProtocol version="5.1"><RequestCapabilities></RequestCapabilities></NFuseProtocol>'
$http_request = New-Object -ComObject Msxml2.XMLHTTP
$http_request.open('POST', $url, $false)
$http_request.setRequestHeader("Content-type", "text/xml")
$http_request.setRequestHeader("Content-length", $parameters.Length)
$http_request.setRequestHeader("Connection", "close")
$http_request.send($parameters)
$http_request.statusText
$http_request.responseText

Running this script in PowerShell on my XML broker returned the following list of capabilities, which is a good indication that the XML broker is up and running:

<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE NFuseProtocol SYSTEM "NFuse.dtd"> <NFuseProtocol version="5.1"> <ResponseCapabilities> <CapabilityId>separate-credentials-validation</CapabilityId> <CapabilityId>multi-image-icons</CapabilityId> <CapabilityId>launch-reference</CapabilityId> <CapabilityId>user-identity</CapabilityId> <CapabilityId>full-icon-data</CapabilityId> <CapabilityId>full-icon-hash</CapabilityId> <CapabilityId>accepts-client-identity-for-power-off</CapabilityId> <CapabilityId>session-sharing</CapabilityId> </ResponseCapabilities> </NFuseProtocol>

This simple script lays a nice foundation to perform XML broker health checks via PoSH. I then took the script a little bit further to test some other XML requests:

param($server, $port)
if ($port){$port = 80}
$creds = Get-Credential
$domainuser= $creds.UserName.Split('\')
$domain = $domainuser[0]
$user = $domainuser[1]
[String]$pw = [Runtime.InteropServices.Marshal]::PtrToStringAuto([Runtime.InteropServices.Marshal]::SecureStringToBSTR($creds.Password))
$nwINFO = Get-WmiObject -ComputerName $env:COMPUTERNAME Win32_NetworkAdapterConfiguration | Where-Object { $_.IPAddress -ne $null }
$ip = $nwINFO.IPAddress
$fqdn = $nwINFO.DNSHostName
$xmlcreds = '<Credentials><UserName>' + $user + '</UserName><Password encoding="cleartext">' + $pw + '</Password><Domain Type="NT">' + $domain + '</Domain></Credentials>'
$envelope = '<?xml version="1.0" encoding="utf-8"?><!DOCTYPE NFuseProtocol SYSTEM "NFuse.dtd"><NFuseProtocol version="5.1">'
$clienttype = '<ClientType>ica30</ClientType>'
$clientdetails = '<ClientName>' + $env:COMPUTERNAME + '</ClientName><ClientAddress addresstype="dot">' + $ip[0] + '</ClientAddress>'
function request ($parameters)
{
 $http_request = New-Object -ComObject Msxml2.XMLHTTP
 $http_request.open('POST', $url, $false)
 $http_request.setRequestHeader("Content-type", "text/xml")
 $http_request.setRequestHeader("Content-length", $parameters.Length)
 $http_request.setRequestHeader("Connection", "close")
 $http_request.send($parameters)
 $http_request.statusText
 $http_request.responseText
}
$url = "http://" + $server + ":" + $port + "/scripts/wpnbr.dll"
$capabilities = request ($envelope + '<RequestCapabilities></RequestCapabilities></NFuseProtocol>')
if (!$capabilities[1].contains('error'))
{
 $testcreds = request ($envelope + '<RequestValidateCredentials>' + $xmlcreds + '</RequestValidateCredentials></NFuseProtocol>')
 if (!$testcreds[1].contains('bad'))
 {
 $appdatareq = request ($envelope + '<RequestAppData><Scope traverse="subtree"></Scope><DesiredDetails>rade-offline-mode</DesiredDetails><ServerType>all</ServerType>' + $clienttype + '<ClientType>content</ClientType>' + $xmlcreds + $clientdetails + '</RequestAppData></NFuseProtocol>')
 $app = $appdatareq[1] -split "<FName>"
 $app = $app[1] -split "</FName>"
 $launchreq = request ($envelope + '<RequestAddress><Name><AppName>' + $app[0] + '</AppName></Name>' + $clientdetails + '<ServerAddress addresstype="dns-port"></ServerAddress>' + $xmlcreds + $clienttype + '</RequestAddress></NFuseProtocol>')
 $launchreq
 }
}

This script takes the server and port, prompts for the credentials that you’re testing (password is sent in clear text), and sends a RequestCapabilities request, followed by RequestValidateCredentials, RequestAppData, and RequestAddress requests. To avoid dependencies on NFuse.dtd, I used a -split on the XML results of the RequestAppData results to get the ‘friendly name’ of the first application returned by RequestAppData, which I used for the RequestAddress post.

From here I’m going to develop a C# service that can monitor the XML service, though I’d like to figure out how to encode the password into the ‘ctx1’ format so that I’m not sending it in clear text.

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