Powershell API Post Variable to Ducksboard - windows

Question

Trying to use the following Powershell script which I've taken from Github to push data into a Ducksboard dashboard. The function works excellently however I need to feed in a variable as part of the data. Of the two calls to the function included below the function which pushes in the actual value 44 works fine, however if I substitute it for my variable $qtybord the function falls over. I've tried a number of options to overcome the var being within the single quotes but cannot get it to work - can anyone help me?
# Squirt data to Duscksboard
function Execute-DucksboardApi
{
param(
[string] $url = $null,
[string] $data = $null,
[string] $apikey = $null,
[string] $contentType = "application/json",
[string] $codePageName = "UTF-8",
[string] $userAgent = $null
);
if ($url -and $data -and $apikey)
{
[System.Net.WebRequest]$webRequest = [System.Net.WebRequest]::Create($url);
$webRequest.ServicePoint.Expect100Continue = $false;
[System.Net.NetworkCredential]$credentials = New-Object System.Net.NetworkCredential($apikey, 'ignored');
$webRequest.Credentials = $credentials.GetCredential($url, 'Basic');
$webRequest.PreAuthenticate = $true;
$webRequest.ContentType = $contentType;
$webRequest.Method = "POST";
if ( $userAgent )
{
$webRequest.UserAgent = $userAgent;
}
$enc = [System.Text.Encoding]::GetEncoding($codePageName);
[byte[]]$bytes = $enc.GetBytes($data);
$webRequest.ContentLength = $bytes.Length;
[System.IO.Stream]$reqStream = $webRequest.GetRequestStream();
$reqStream.Write($bytes, 0, $bytes.Length);
$reqStream.Flush();
$resp = $webRequest.GetResponse();
$rs = $resp.GetResponseStream();
[System.IO.StreamReader]$sr = New-Object System.IO.StreamReader -argumentList $rs;
$sr.ReadToEnd();
}
}
$qtybord = 44
Execute-DucksboardApi -url 'https://push.ducksboard.com/v/123752/' -data '{"value": $qtybord}' -apikey 'tu2j3d3epqytWZD1haHnjJSJ1NqBrmvPe5SONc0VYge4BbIPi0'
Execute-DucksboardApi -url 'https://push.ducksboard.com/v/123752/' -data '{"value": 44}' -apikey 'tu2j3d3epqytWZD1haHnjJSJ1NqBrmvPe5SONc0VYge4BbIPi0'
*

Answer 1

try this:
-data "{`"value`": $qtybord}"
or
-data "{""value"": $qtybord}"
in single quote variable aren't expanded, in double quote you need to escape the double quote inside the string.

Answer 2

So make the -data parameter take $data instead and make $data = '{"value": ' + $qtyboard + '}' or just wrap that whole thing in parens after -data.
Also, if you're on PowerShell v3 you can play with something like this:
$data = New-Object -Type PSObject -Property #{
value = $qtyboard
} | ConvertTo-JSON