(PowerBuilder) Refresh HMRC OAuth2 Access Token

Demonstrates how to refresh an HMRC access token.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

integer li_rc
oleobject loo_JsonToken
integer li_Success
oleobject loo_Oauth2
oleobject loo_DtExpire
oleobject loo_SbJson

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

// See Get HMRC Access Token 
// for sample code showing how to obtain a HMRC access token for desktop apps.

// It is assumed we previously obtained an OAuth2 access token for HMRC.

loo_JsonToken = create oleobject
// Use "Chilkat_9_5_0.JsonObject" for versions of Chilkat < 10.0.0
li_rc = loo_JsonToken.ConnectToNewObject("Chilkat.JsonObject")
if li_rc < 0 then
    destroy loo_JsonToken
    MessageBox("Error","Connecting to COM object failed")
    return
end if
li_Success = loo_JsonToken.LoadFile("qa_data/tokens/hmrc.json")
if li_Success <> 1 then
    Write-Debug "Failed to load hmrc.json"
    destroy loo_JsonToken
    return
end if

// The access token JSON looks something like this:

// {
//   "token_type": "Bearer",
//   "scope": "user_impersonation",
//   "expires_in": "3599",
//   "ext_expires_in": "0",
//   "expires_on": "1524783438",
//   "not_before": "1524779538",
//   "resource": "https://mydomain.api.crm.dynamics.com",
//   "access_token": "...",
//   "refresh_token": "...",
//   "id_token": "..."
// }

loo_Oauth2 = create oleobject
// Use "Chilkat_9_5_0.OAuth2" for versions of Chilkat < 10.0.0
li_rc = loo_Oauth2.ConnectToNewObject("Chilkat.OAuth2")

loo_Oauth2.TokenEndpoint = "https://test-api.service.hmrc.gov.uk/oauth/token"

// Replace these with actual values.
loo_Oauth2.ClientId = "HMRC-CLIENT-ID"
loo_Oauth2.ClientSecret = "HMRC-CLIENT-SECRET"

// Get the "refresh_token"
loo_Oauth2.RefreshToken = loo_JsonToken.StringOf("refresh_token")

// Send the HTTP POST to refresh the access token..
li_Success = loo_Oauth2.RefreshAccessToken()
if li_Success <> 1 then
    Write-Debug loo_Oauth2.LastErrorText
    destroy loo_JsonToken
    destroy loo_Oauth2
    return
end if

// Load the access token response into the json object 
loo_JsonToken.Load(loo_Oauth2.AccessTokenResponse)

// If an "expires_on" member does not exist, then add the JSON member by
// getting the current system date/time and adding the "expires_in" seconds.
// This way we'll know when the token expires.
if loo_JsonToken.HasMember("expires_on") = 0 then
    loo_DtExpire = create oleobject
    // Use "Chilkat_9_5_0.CkDateTime" for versions of Chilkat < 10.0.0
    li_rc = loo_DtExpire.ConnectToNewObject("Chilkat.CkDateTime")

    loo_DtExpire.SetFromCurrentSystemTime()
    loo_DtExpire.AddSeconds(loo_JsonToken.IntOf("expires_in"))
    loo_JsonToken.AppendString("expires_on",loo_DtExpire.GetAsUnixTimeStr(0))
end if

// Save the new JSON access token response to a file.
// The access + refresh tokens contained in this JSON will be needed for the next refresh.
loo_SbJson = create oleobject
// Use "Chilkat_9_5_0.StringBuilder" for versions of Chilkat < 10.0.0
li_rc = loo_SbJson.ConnectToNewObject("Chilkat.StringBuilder")

loo_JsonToken.EmitCompact = 0
loo_JsonToken.EmitSb(loo_SbJson)
loo_SbJson.WriteFile("qa_data/tokens/hmrc.json","utf-8",0)

Write-Debug "OAuth2 authorization granted!"
Write-Debug "New Access Token = " + loo_Oauth2.AccessToken


destroy loo_JsonToken
destroy loo_Oauth2
destroy loo_DtExpire
destroy loo_SbJson