pluto/handler/sinks/truelayer.py

# Twisted/Klein imports
from twisted.logger import Logger
from twisted.internet.task import LoopingCall

# Other library imports
import requests
from simplejson.errors import JSONDecodeError
from time import time
import urllib

# Project imports
from settings import settings


class TrueLayer(object):
    """
    Class to manage calls to Open Banking APIs through TrueLayer.
    """

    def __init__(self):
        self.log = Logger("truelayer")
        self.token = None
        self.lc = LoopingCall(self.get_new_token)
        self.lc.start(int(settings.TrueLayer.RefreshSec))

    def create_auth_url(self):
        query = urllib.parse.urlencode(
            {
                "response_type": "code",
                "response_mode": "form_post",
                "client_id": settings.TrueLayer.ID,
                "scope": "info accounts balance transactions offline_access",
                "nonce": int(time()),
                "redirect_uri": settings.TrueLayer.CallbackURL,
                "enable_mock": "true",
            }
        )
        auth_uri = f"{settings.TrueLayer.AuthBase}/?{query}&redirect_uri={settings.TrueLayer.CallbackURL}"
        return auth_uri

    def handle_authcode_received(self, authcode):
        data = {
            "client_id": settings.TrueLayer.ID,
            "client_secret": settings.TrueLayer.Key,
            "code": authcode,
            "grant_type": "authorization_code",
            "redirect_uri": settings.TrueLayer.CallbackURL,
        }
        r = requests.post(f"{settings.TrueLayer.AuthBase}/connect/token", data=data)
        try:
            parsed = r.json()
        except JSONDecodeError:
            return False
        if "error" in parsed:
            self.log.error("Error requesting refresh token: {error}", error=parsed["error"])
            return False
        settings.TrueLayer.RefreshToken = parsed["refresh_token"]
        settings.TrueLayer.AuthCode = authcode
        settings.write()
        self.token = parsed["access_token"]
        self.log.info("Retrieved access/refresh tokens - TrueLayer")

    def get_new_token(self):
        """
        Exchange our refresh token for an access token.
        """
        if not settings.TrueLayer.RefreshToken:
            return
        headers = {"Content-Type": "application/x-www-form-urlencoded"}
        data = {
            "grant_type": "refresh_token",
            "refresh_token": settings.TrueLayer.RefreshToken,
            "client_id": settings.TrueLayer.ID,
            "client_secret": settings.TrueLayer.Key,
        }
        r = requests.post(f"{settings.TrueLayer.AuthBase}/connect/token", data=data, headers=headers)
        try:
            parsed = r.json()
        except JSONDecodeError:
            return False
        if r.status_code == 200:
            if "access_token" in parsed.keys():
                self.token = parsed["access_token"]
                self.log.info("Refreshed access token - TrueLayer")
                return True
            else:
                self.log.error(f"Token refresh didn't contain access token: {parsed}", parsed=parsed)
                return False
        else:
            self.log.error(f"Cannot refresh token: {parsed}", parsed=parsed)
            return False

    def get_accounts(self):
        """
        Get a list of accounts.
        """
        headers = {"Authorization": f"Bearer {self.token}"}
        path = f"{settings.TrueLayer.DataBase}/accounts"
        r = requests.get(path, headers=headers)
        try:
            parsed = r.json()
        except JSONDecodeError:
            self.log.error("Error parsing institutions response: {content}", content=r.content)
            return False

        return parsed