(VB.NET) HMRC Validate Fraud Prevention Headers

Demonstrates how to test (validate) HMRC fraud prevention headers.

Chilkat .NET Downloads Chilkat .NET Framework Chilkat for .NET Core

' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.


Dim rest As New Chilkat.Rest

Dim success As Boolean = rest.Connect("test-api.service.hmrc.gov.uk",443,True,True)
If (success = False) Then
    Debug.WriteLine(rest.LastErrorText)
    Exit Sub
End If


' Load the previously fetched access token.
Dim json As New Chilkat.JsonObject
success = json.LoadFile("qa_data/tokens/hmrc.json")
Dim accessToken As String = json.StringOf("access_token")
Debug.WriteLine("Using access toke: " & accessToken)

Dim sbAuthHeaderValue As New Chilkat.StringBuilder
sbAuthHeaderValue.Append("Bearer ")
sbAuthHeaderValue.Append(accessToken)

rest.AddHeader("Accept","application/vnd.hmrc.1.0+json")
rest.AddHeader("Authorization",sbAuthHeaderValue.GetAsString())

' Add the fraud prevention headers.
' See https://developer.service.hmrc.gov.uk/api-documentation/docs/fraud-prevention
rest.AddHeader("gov-client-connection-method","DESKTOP_APP_DIRECT")

' This should be generated by an application and persistently stored on the device. The identifier should not expire.
rest.AddHeader("gov-client-device-id","beec798b-b366-47fa-b1f8-92cede14a1ce")

' See https://developer.service.hmrc.gov.uk/api-documentation/docs/fraud-prevention
rest.AddHeader("gov-client-user-ids","os=user123")

' Your local IP addresses (comma separated), such as addresses beginning with "192.168." or "172.16."
rest.AddHeader("gov-client-local-ips","172.16.16.23")
' You'll need to find a way to get your MAC address.  Chilkat does not yet provide this ability...
rest.AddHeader("gov-client-mac-addresses","7C%3AD3%3A0A%3A25%3ADA%3A1C")

rest.AddHeader("gov-client-timezone","UTC+00:00")

' You can probably just hard-code these so they're always the same with each request.
rest.AddHeader("gov-client-window-size","width=1256&height=800")
rest.AddHeader("gov-client-screens","width=1920&height=1080&scaling-factor=1&colour-depth=16")
rest.AddHeader("gov-client-user-agent","Windows/Server%202012 (Dell%20Inc./OptiPlex%20980)")
rest.AddHeader("gov-vendor-version","My%20Desktop%20Software=1.2.3.build4286")


Dim responseStr As String = rest.FullRequestNoBody("GET","/test/fraud-prevention-headers/validate")
If (rest.LastMethodSuccess = False) Then
    Debug.WriteLine(rest.LastErrorText)
    Exit Sub
End If


' If the status code is 200, then the fraud prevention headers were validated.
' The JSON response may include some warnings..
Debug.WriteLine("Response status code = " & rest.ResponseStatusCode)
Debug.WriteLine("Response JSON body: ")
Debug.WriteLine(responseStr)