CkPython

HMRC OAuth2 Access Token

See more OAuth2 Examples

Demonstrates how to get an HMRC OAuth2 access token from a desktop (installed) application or script. This example gets an HMRC MTD VAT read/write access token. CkPython

import sys
import chilkat

success = False

# To further clarify, see OAuth 2.0 Authorization Flow

oauth2 = chilkat.CkOAuth2()

# This should be the port in the localhost callback URL for your app.
# Important: Make sure the callback URI in your HMRC developer app 
# is exactly "http://localhost:3017/".  Don't forget the ending "/" char.
# The callback URL would look like "http://localhost:3017/" if the port number is 3017.

# IMPORTANT: Don't forget to setup your HMRC application to use the Redirect URI "http://localhost:3017/" as shown
# here: Configure Redirect URI for HMRC application
oauth2.put_ListenPort(3017)

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

# Replace with your actual client ID
oauth2.put_ClientId("HMRC-CLIENT-ID")

# The scopes are documented in the HMRC reference documentation for each API.
# This example gets a read/write access token for the HMRC MTD VAT API.
oauth2.put_Scope("read:vat write:vat")

# Begin the OAuth2 Authorization code flow.  This returns a URL that should be loaded in a browser.
url = oauth2.startAuth()
if (oauth2.get_LastMethodSuccess() != True):
    print(oauth2.lastErrorText())
    sys.exit()

# Launch the default browser on the system and navigate to the url.
# The LaunchBrowser method was added in Chilkat v10.1.2.
success = oauth2.LaunchBrowser(url)
if (success == False):
    print(oauth2.lastErrorText())
    sys.exit()

# Wait for the user to approve or deny authorization in the browser.
numMsWaited = 0
while (numMsWaited < 90000) and (oauth2.get_AuthFlowState() < 3) :
    oauth2.SleepMs(100)
    numMsWaited = numMsWaited + 100

# If the browser does not respond within the specified time, AuthFlowState will be:
# 
# 1: Waiting for Redirect – The OAuth2 background thread is waiting for the browser's redirect request.
# 2: Waiting for Final Response – The thread is awaiting the final access token response.
# In either case, cancel the background task initiated by StartAuth.

if (oauth2.get_AuthFlowState() < 3):
    oauth2.Cancel()
    print("No response from the browser!")
    sys.exit()

# Check AuthFlowState to determine if authorization was granted, denied, or failed:
# 
# 3: Success – OAuth2 flow completed, the background thread exited, and the successful response is in AccessTokenResponse.
# 4: Access Denied – OAuth2 flow completed, the background thread exited, and the error response is in AccessTokenResponse.
# 5: Failure – OAuth2 flow failed before completion, the background thread exited, and error details are in FailureInfo.

if (oauth2.get_AuthFlowState() == 5):
    print("OAuth2 failed to complete.")
    print(oauth2.failureInfo())
    sys.exit()

if (oauth2.get_AuthFlowState() == 4):
    print("OAuth2 authorization was denied.")
    print(oauth2.accessTokenResponse())
    sys.exit()

if (oauth2.get_AuthFlowState() != 3):
    print("Unexpected AuthFlowState:" + str(oauth2.get_AuthFlowState()))
    sys.exit()

print("OAuth2 authorization granted!")
print("Access Token = " + oauth2.accessToken())

# Get the full JSON response:
json = chilkat.CkJsonObject()
json.Load(oauth2.accessTokenResponse())
json.put_EmitCompact(False)
print(json.emit())

# The JSON response looks 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": "..."
# }

# 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 (json.HasMember("expires_on") != True):
    dtExpire = chilkat.CkDateTime()
    dtExpire.SetFromCurrentSystemTime()
    dtExpire.AddSeconds(json.IntOf("expires_in"))
    json.AppendString("expires_on",dtExpire.getAsUnixTimeStr(False))

print(json.emit())

# Save the JSON to a file for future requests.
fac = chilkat.CkFileAccess()
fac.WriteEntireTextFile("qa_data/tokens/hmrc.json",json.emit(),"utf-8",False)