(Ruby) Refresh HMRC OAuth2 Access Token

Demonstrates how to refresh an HMRC access token.

Chilkat Ruby Downloads install from rubygems.org gem install chilkat or download... Ruby Library for Windows, MacOS, Linux, Alpine Linux

require 'chilkat'

# 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.

jsonToken = Chilkat::CkJsonObject.new()
success = jsonToken.LoadFile("qa_data/tokens/hmrc.json")
if (success != true)
    print "Failed to load hmrc.json" + "\n";
    exit
end

# 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": "..."
# }

oauth2 = Chilkat::CkOAuth2.new()

oauth2.put_TokenEndpoint("https://test-api.service.hmrc.gov.uk/oauth/token")

# Replace these with actual values.
oauth2.put_ClientId("HMRC-CLIENT-ID")
oauth2.put_ClientSecret("HMRC-CLIENT-SECRET")

# Get the "refresh_token"
oauth2.put_RefreshToken(jsonToken.stringOf("refresh_token"))

# Send the HTTP POST to refresh the access token..
success = oauth2.RefreshAccessToken()
if (success != true)
    print oauth2.lastErrorText() + "\n";
    exit
end

# Load the access token response into the json object 
jsonToken.Load(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 (jsonToken.HasMember("expires_on") == false)
    dtExpire = Chilkat::CkDateTime.new()
    dtExpire.SetFromCurrentSystemTime()
    dtExpire.AddSeconds(jsonToken.IntOf("expires_in"))
    jsonToken.AppendString("expires_on",dtExpire.getAsUnixTimeStr(false))
end

# 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.
sbJson = Chilkat::CkStringBuilder.new()
jsonToken.put_EmitCompact(false)
jsonToken.EmitSb(sbJson)
sbJson.WriteFile("qa_data/tokens/hmrc.json","utf-8",false)

print "OAuth2 authorization granted!" + "\n";
print "New Access Token = " + oauth2.accessToken() + "\n";