Python SDK

The Supertab Connect Python SDK lets publishers implement Really Simple Licensing (RSL) and the Crawler Authentication Protocol (CAP) in Python applications.

The SDK handles license token verification, bot detection, enforcement decisions, analytics recording, and customer-side license token acquisition.

Requirements: Python 3.12+.

Installation

Install the SDK from PyPI:

pip install supertab-connect-sdk

Initializing the Client

The merchant client is async and uses httpx.Request for request handling.

from supertab_connect import (
    EnforcementMode,
    SupertabConnect,
    SupertabConnectConfig,
    default_bot_detector,
)

client = SupertabConnect(
    SupertabConnectConfig(
        api_key="stc_live_your_api_key",  # read from environment variables or secrets management
        enforcement=EnforcementMode.SOFT,
        bot_detector=default_bot_detector,
        debug=False,
    )
)

Configuration Options

Property	Type	Required	Default	Description
api_key	str	Yes	—	Your Supertab Merchant API Key
enforcement	EnforcementMode	No	SOFT	How to handle bots without a valid token
bot_detector	BotDetector | None	No	None	Function that receives an httpx.Request and returns whether it is a bot
debug	bool	No	False	Enables verbose SDK logging through Python logging

The SDK enforces a singleton pattern per API key. Creating another client with the same key returns the existing instance. Creating one with a different key raises an error unless you call SupertabConnect.reset_instance() or pass reset=True.

Common Workflows

Handle a Protected Request

Use handle_request() when you want the SDK to manage the full lifecycle:

1. Extract a token from the Authorization: License <token> header.
2. Verify the token against the Supertab JWKS.
3. Record an analytics event.
4. If no token is present, run bot detection and apply the enforcement mode.

import httpx

from supertab_connect import (
    EnforcementMode,
    HandlerAction,
    SupertabConnect,
    SupertabConnectConfig,
    default_bot_detector,
)

client = SupertabConnect(
    SupertabConnectConfig(
        api_key="stc_live_your_api_key",
        enforcement=EnforcementMode.STRICT,
        bot_detector=default_bot_detector,
    )
)

request = httpx.Request(
    "GET",
    "https://example.com/premium/article",
    headers={
        "Authorization": "License your.jwt.token",
        "User-Agent": "Mozilla/5.0",
        "Accept": "text/html",
        "Accept-Language": "en-US",
        "Sec-CH-UA": '"Chromium";v="123"',
    },
)

# Inside an async function
async with client:
    result = await client.handle_request(request)

if result["action"] is HandlerAction.BLOCK:
    status = result["status"]
    headers = result["headers"]
    body = result["body"]
    # Return this response from your framework
else:
    headers = result.get("headers", {})
    # Apply returned headers, then serve content

Framework Integration

Create an httpx.Request from your framework request object, then translate the HandlerResult back to a framework response. For example, in FastAPI:

from contextlib import asynccontextmanager

from fastapi import FastAPI, Request, Response
import httpx

from supertab_connect import (
    EnforcementMode,
    HandlerAction,
    SupertabConnect,
    SupertabConnectConfig,
    default_bot_detector,
)

connect = SupertabConnect(
    SupertabConnectConfig(
        api_key="stc_live_your_api_key",
        enforcement=EnforcementMode.SOFT,
        bot_detector=default_bot_detector,
    )
)


@asynccontextmanager
async def lifespan(_app: FastAPI):
    try:
        yield
    finally:
        await connect.aclose()


app = FastAPI(lifespan=lifespan)


@app.get("/premium/article")
async def premium_article(request: Request):
    sdk_request = httpx.Request(
        request.method,
        str(request.url),
        headers=dict(request.headers),
    )

    result = await connect.handle_request(sdk_request)

    if result["action"] is HandlerAction.BLOCK:
        return Response(
            content=result["body"],
            status_code=result["status"],
            headers=result["headers"],
        )

    return Response(
        content="Premium content",
        headers=result.get("headers", {}),
    )

Verify a Token and Record Usage

Use verify_and_record() when you need custom routing or response handling but still want analytics and billing events.

from supertab_connect import EnforcementMode, SupertabConnect, SupertabConnectConfig

client = SupertabConnect(
    SupertabConnectConfig(
        api_key="stc_live_your_api_key",
        enforcement=EnforcementMode.SOFT,
    )
)

# Inside an async function
async with client:
    result = await client.verify_and_record(
        token="your.jwt.token",
        resource_url="https://example.com/premium/article",
        user_agent="Mozilla/5.0",
        request_headers={
            "Accept": "text/html",
            "Accept-Language": "en-US",
        },
    )

if not result.valid:
    # Return 401 or another response appropriate for your application
    print(result.error)

Verify Without Recording

Use the static verify() method when you only need to check token validity and do not want analytics side effects.

from supertab_connect import SupertabConnect

# Inside an async function
result = await SupertabConnect.verify(
    token="your.jwt.token",
    resource_url="https://example.com/premium/article",
)

if not result.valid:
    print(result.error)

Obtaining a License Token

Use obtain_license_token() when you are building a crawler or client that needs to access protected resources. The SDK fetches the publisher’s license.xml, finds the best matching content rule, exchanges your client credentials for a token, and caches tokens in memory until shortly before expiry.

from supertab_connect import obtain_license_token

# Inside an async function
token = await obtain_license_token(
    client_id="your_client_id",
    client_secret="your_client_secret",
    resource_url="https://example.com/premium/article",
)

if token is not None:
    headers = {"Authorization": f"License {token}"}
    # Use these headers on the resource request

If you pass a usage value and the matching RSL content permits that usage without a token server, the function returns None because no token is required.

from supertab_connect import UsageType, obtain_license_token

# Inside an async function
token = await obtain_license_token(
    client_id="your_client_id",
    client_secret="your_client_secret",
    resource_url="https://example.com/public-resource",
    usage=UsageType.AI_INPUT,
)

Important Types

EnforcementMode

Enforcement modes determine what happens when a bot is detected without a valid license token.

• STRICT: Blocks the request immediately with a 401 Unauthorized (missing or invalid token) or 403 Forbidden (token valid but wrong audience).
• SOFT (Default): Allows the request but attaches RSL headers (Link, X-RSL-Status) to signal that a license is required.
• DISABLED: No enforcement, signaling, or analytics recording. Requests are allowed without licensing intervention.

Non-bot requests are always allowed regardless of mode. Invalid tokens are always blocked except in DISABLED mode.

HandlerResult

Returned by handle_request():

• { "action": HandlerAction.ALLOW, "headers": ... }: The request should proceed. Apply returned headers if present.
• { "action": HandlerAction.BLOCK, "status": ..., "body": ..., "headers": ... }: The request should be rejected with the provided response data.

RSLVerificationResult

Returned by verify() and verify_and_record():

Field	Type	Description
valid	bool	Whether the token is valid for the requested resource
error	str | None	Error message when invalid

Error Handling

The high-level helpers return framework-friendly result shapes rather than typed invalid-token reason codes:

• handle_request() returns a HandlerResult with action, and when blocked, response status, body, and headers.
• verify() and verify_and_record() return RSLVerificationResult(valid=False, error=...).

Treat error as a message for logs or responses. If your application needs to branch on a machine-readable reason, call the lower-level verify_license_token() function and inspect InvalidLicenseToken.reason.

Common invalid-token reasons include:

• missing_license_token: No license token was provided.
• invalid_license_header: The JWT header is malformed.
• invalid_license_algorithm: The token uses an unsupported signing algorithm.
• invalid_license_payload: The JWT payload is malformed.
• invalid_license_issuer: The token issuer is not recognized.
• license_signature_verification_failed: The token signature could not be verified.
• license_token_expired: The token has expired.
• invalid_license_audience: The token is valid but does not cover the requested URL.
• server_error: The SDK could not validate the token because of a platform-side or JWKS fetch error.

Tips and Pitfalls

Pass a bot detector for enforcement. By default, bot_detector is None, so requests without tokens are treated as non-bot traffic. Use default_bot_detector or provide your own detector if you expect handle_request() to signal or block missing-token bots.

Apply returned headers. In SOFT mode, the SDK signals licensing requirements through response headers. If you drop those headers, crawlers will not receive the correct RSL signal.

Use the async context manager. async with client: closes shared HTTP clients used for event recording and JWKS fetching. For long-lived web apps, create one client at startup and close it during shutdown.

Cache behavior is in-memory. obtain_license_token() caches license.xml by origin and license tokens by client, token server, and matched URL pattern. Process restarts clear that cache.

API Reference

Static and Module Functions

Method	Description
SupertabConnect.verify(*, token, resource_url, ...)	Verify a token without analytics recording
obtain_license_token(*, client_id, client_secret, resource_url, ...)	Acquire a license token as a crawler client
verify_license_token(token, request_url, supertab_base_url, ...)	Lower-level token verification with typed valid/invalid results
SupertabConnect.reset_instance()	Clear the singleton, allowing fresh client initialization
SupertabConnect.set_base_url(url)	Override the default Supertab Connect API base URL

Instance Methods

Method	Description
handle_request(request)	Handle a request end-to-end: token extraction, verification, bot detection, enforcement, and analytics
verify_and_record(*, token, resource_url, user_agent, ...)	Verify a token and record a usage event
aclose()	Close SDK-managed async HTTP clients