Did it again. I’m back here this evening to write another post after authoring some PoC code for a project. I’ve got to put it somewhere for later. In doing that, there’s no reason it shouldn’t be content in which others can consume.

In the past, I have absolutely written PowerShell to interact with REST (REpresentational State Transfer) APIs. What I haven’t done until now, is interact with SOAP (Simple Object Access Protocol) APIs. The below example is a full-featured PowerShell function. Its purpose, with the help of W3Schools public SOAP API, is to convert Fahrenheit temperatures to Celsius and vice versa. Typical normal stuff, except that I’m not doing the calculations. Instead, I’m sending off a temperature to an API to be converted. One of the big differences between REST and SOAP is the content of the payload. With SOAP we’re sending XML, whereas, with REST, we’d likely send JSON.

While you can inspect the code yourself, I will at minimum tell you how the function can be invoked. Its name is Convert-Temperature and it includes two parameters: Temperature and TemperatureScale. Enter an integer for the Temperature parameter and either Fahrenheit or Celsius for the TemperatureScale parameter. It’ll send off the information as XML to the API. The returned value will be extracted from the returned XML and rounded to two decimal places. I was going to make the rounding optional but I obviously changed my mind. I didn’t find any value in allowing a user to make this determination.

Here are a couple of invocation examples first, and then, the code. Maybe this will be helpful for you. I suspect it will be for me in time, as I’m going to likely have to make use of a SOAP API.

[PS7.1.0] [C:\] Convert-Temperature -Temperature 212 -TemperatureScale Fahrenheit

TemperatureScale Temperature ConvertedTemperature
---------------- ----------- --------------------
Fahrenheit               212                  100

[PS7.1.0] [C:\] Convert-Temperature -Temperature 100 -TemperatureScale Celsius

TemperatureScale Temperature ConvertedTemperature
---------------- ----------- --------------------
Celsius                  100                  212

Function Convert-Temperature {
	[CmdletBinding()]
	Param (
		[Parameter(Mandatory)]
		[int]$Temperature,

		[Parameter(Mandatory)]
		[ValidateSet('Fahrenheit','Celsius')]
		[string]$TemperatureScale
	) # End Param

	Begin {
		$Headers = @{'Content-Type' = 'text/xml'}
	} # End Begin.

	Process {
		If ($TemperatureScale -eq 'Fahrenheit') {
			$Body = @"
<soap12:Envelope xmlns:xsi=`"http://www.w3.org/2001/XMLSchema-instance`" xmlns:xsd=`"http://www.w3.org/2001/XMLSchema`" xmlns:soap12=`"http://www.w3.org/2003/05/soap-envelope`">
	<soap12:Body>
		<FahrenheitToCelsius xmlns=`"https://www.w3schools.com/xml/`">
			<Fahrenheit>$Temperature</Fahrenheit>
		</FahrenheitToCelsius>
	</soap12:Body>
</soap12:Envelope>
"@
		} Else {
			$Body = @"
<soap12:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap12="http://www.w3.org/2003/05/soap-envelope">
	<soap12:Body>
		<CelsiusToFahrenheit xmlns="https://www.w3schools.com/xml/">
			<Celsius>$Temperature</Celsius>
		</CelsiusToFahrenheit>
	</soap12:Body>
</soap12:Envelope>
"@
		} # End If-Else.
	} # End Process.

	End {
		$Response = Invoke-RestMethod -Uri 'https://www.w3schools.com/xml/tempconvert.asmx' -Method 'POST' -Headers $Headers -Body $Body
		If ($TemperatureScale -eq 'Fahrenheit') {
			$ConvertedTemperature = $([System.Math]::Round($Response.Envelope.Body.FahrenheitToCelsiusResponse.FahrenheitToCelsiusResult,2))
		} Else {
			$ConvertedTemperature = ([System.Math]::Round($Response.Envelope.Body.CelsiusToFahrenheitResponse.CelsiusToFahrenheitResult,2))
		} # End If-Else.

		[PSCustomObject]@{
			TemperatureScale = $TemperatureScale
			Temperature = $Temperature
			ConvertedTemperature = $ConvertedTemperature
		}
	} # End End.
} # End Function: Convert-Temperature.