API access to a Token-based REST service (Python/requests)

token-demo.py

#! /usr/bin/env python

import os
import base64

# Use the Python requests module
# (you'll need to have PIP-installed this - it's not part of core Python)
import requests

# The keycloak credentials (sensitive).
# Required!
KEYCLOAK_USERNAME: str = os.environ['KEYCLOAK_USERNAME']
KEYCLOAK_PASSWORD: str = os.environ['KEYCLOAK_PASSWORD']
KEYCLOAK_CLIENT_SECRET: str = os.environ['KEYCLOAK_CLIENT_SECRET']


def get_csrf(REQ_URL):
    client = requests.session()
    # Retrieve the CSRF token first
    client.get(REQ_URL)  # sets cookie
    if 'csrftoken' in client.cookies:
        # Django 1.6 and up
        csrftoken = client.cookies['csrftoken']
    else:
        # older versions
        csrftoken = client.cookies['csrf']
    return csrftoken


def get_keycloak_access_token(*,
                              keycloak_url: str,
                              keycloak_realm: str,
                              keycloak_client_id: str) -> str:
    """Gets an 'access token' from Keycloak.
    If successful we'll get the token (a big long string)
    """
    realm_url: str = f"{keycloak_url}/realms/{keycloak_realm}"
    url = f"{realm_url}/protocol/openid-connect/token"
    data = (
        f"client_id={keycloak_client_id}"
        f"&grant_type=password"
        f"&username={KEYCLOAK_USERNAME}"
        f"&password={KEYCLOAK_PASSWORD}"
        f"&client_secret={KEYCLOAK_CLIENT_SECRET}"
    )
    headers = {"Content-Type": "application/x-www-form-urlencoded"}
    resp = requests.post(url, headers=headers, data=data, timeout=4.0)
    assert resp.status_code == 200
    assert "access_token" in resp.json()
    return resp.json()["access_token"]


# Get a Keycloak/OIDC access token
# ----------------------------
access_token = get_keycloak_access_token(
    keycloak_url = "https://????/auth",
    keycloak_realm = "xchem",
    keycloak_client_id = "????")
print(f"access_token='{access_token}'")

# Call a Fragalysis API Method (using OIDC authentication)
# ----------------------------
# Now, using the token, we can call the Fragalysis REST API.
# Here we're just using a GET that needs no extra parameters.
# What _you_ need to provide in terms of URL and associated DATA is up to you.
fragalysis_hostname = "????"
method = "viewer/upload_cset"
url = f"https://{fragalysis_hostname}/{method}/"
csrf_token = get_csrf(url)
headers = {"X-CSRFToken": csrf_token,
           "Cookie": f"csrftoken={csrf_token}",
           "Authorization": f"Bearer {access_token}"}
resp = requests.get(url, headers=headers)
print(resp)
assert resp is not None
print(resp.text)

# Call a Fragalysis API Method (using Basic authentication)
# ----------------------------
basic = str(base64.b64encode(f"{KEYCLOAK_USERNAME}:{KEYCLOAK_PASSWORD}".encode("utf-8")), "utf-8")
csrf_token = get_csrf(url)
headers = {"X-CSRFToken": csrf_token,
           "Cookie": f"csrftoken={csrf_token}",
           "Authorization": f"Basic {basic}"}
resp = requests.get(url, headers=headers)
assert resp is not None
print(resp)
print(resp.text)