New-WebServiceProxy is a cmdlet that allows us to create a proxy object of any given valid web service.

For our example, we will use the following web service:

http://www.webservicex.net/CurrencyConvertor.asmx?WSDL

Run the following command:

$var = New-WebServiceProxy -Uri http://www.webservicex.net/CurrencyConvertor.asmx?WSDL
$var.ConversionRate

This returns the overload definitions of the conversion rate method, as shown in the following image:

Points marked in the image we just saw are explained as follows:

Here is a simple example of this:

$var = New-WebServiceProxy -Uri http://www.webservicex.net/CurrencyConvertor.asmx?WSDL
$var.ConversionRate('Eur','US')

This returns the output as 1.0979—the current conversion value.

How do we know the currency codes? Just open the following URL in a browser:

http://www.webservicex.net/CurrencyConvertor.asmx?WSDL

This shows the output as illustrated in the following image:

Similarly, we can use the GlobalWeather web service to retrieve information:

http://www.webservicex.net/globalweather.asmx?wsdl

Run the following command:

$weather = New-WebServiceProxy -uri http://www.webservicex.com/globalweather.asmx?WSDL
([XML]$weather.GetWeather('Amsterdam','Netherlands')).CurrentWeather

The output is illustrated in the following image:

Web services are usually limited to XML and SOAP, but they may be in the JSON format as well. So, it's worth considering an example that returns results in the JSON format.

Let's use an Apple iTunes URL, which returns an output in the JSON format:

http://itunes.apple.com/search?term=metallica

If we open this URL in the browser, we will see the output as shown in the following image:

Here, we will not use the Invoke-RestMethod cmdlet because it formats the data by default. Instead, we will use the Invoke-WebRequest cmdlet for the ConvertFrom-Json cmdlet:

$Json = Invoke-WebRequest -Uri "http://itunes.apple.com/search?term=metallica"
$Json

Take a look at the following image:

Now, we will play with the PowerShell code to convert this content into a readable format:

$Json = Invoke-WebRequest -Uri "http://itunes.apple.com/search?term=metallica"
($Json | ConvertFrom-Json).Results | Select WrapperType, trackName | Select -First 25

Now, consider the following image:

Alternatively, we can use the Invoke-RestMethod cmdlet and do the same:

$Json = Invoke-RestMethod -Uri "http://itunes.apple.com/search?term=metallica"
$Json.results | Select WrapperType , trackName | Select -First 25

In this exercise, we will take a look at the steps required to build web services. For this, we will use the following environments:

We configured IIS in WMF5Node03 to demonstrate PowerShell web access; now, let's connect to the same box and build a small web service. Perform the following steps:

Visual Studio builds the basic web service. You can run the following command:

Imports System.Web
Imports System.Web.Services
Imports System.Web.Services.Protocols
' To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line.
' <System.Web.Script.Services.ScriptService()> _
<WebService(Namespace:="http://tempuri.org/")> _
<WebServiceBinding(ConformsTo:=WsiProfiles.BasicProfile1_1)> _
<Global.Microsoft.VisualBasic.CompilerServices.DesignerGenerated()> _
Public Class Service
     Inherits System.Web.Services.WebService
    <WebMethod()> _
    Public Function HelloWorld() As String
        Return "This is a Basic and Default Web Service!"
    End Function
End Class

Take a look at the following image:

So, now we have the URL; we simply changed the Hello World text to something else, as follows:

http://localhost/website/Service.asmx

Okay, spin up PowerShell now!

Points marked in the figure are explained as follows:

Invoke after doing text changes in the code which return your newly updated text

Now, in Service.vb, add the following code:

    <WebMethod()> _
    Public Function Add(a, b) As Int32
        Return a + b
    End Function

We can add two values in Windows PowerShell:

$local.Add(2,3)

Create your own web service and consume Windows PowerShell to use it.