I have developed an API using RapidAPI and deployed it on Heroku. I included my API on the RapidAPI marketplace, where it relies on the x-rapidapi-proxy-secret header to restrict access solely through RapidAPI. In my API, I implemented the following code:
app = FastAPI()
proxy_secret = os.environ.get('PROXY_SECRET', None)
@app.middleware('http')
async def validate_rapidapi_header(request: Request, call_next):
# Validate if the 'secret' is known to the server
if proxy_secret:
req_headers = request.headers
# Deny the request if the header is absent or doesn't match the expected value
if (
'X-RapidAPI-Proxy-Secret' not in req_headers
or req_headers['X-RapidAPI-Proxy-Secret'] != proxy_secret
):
return PlainTextResponse(
'Access directly to the API is forbidden', status_code=403
)
response = await call_next(request)
return response
Upon receiving requests through RapidAPI, they include the x-rapidapi-proxy-secret; however, when Heroku forwards the request to the dyno, this header is missing. Here are logs from Heroku showing the request redirection along with my print statements displaying the request headers:
2022-05-13T09:49:58.118798+00:00 heroku[router]: at=info method=GET path='/endpoint?phrase=example_input' host=exampleapi.herokuapp.com request_id=801e146f-6175-491e-8b2f-aae28390e1e6 fwd='176.12.151.31' dyno=web.1 connect=0ms service=21ms status=307 bytes=235 protocol=https
2022-05-13T09:49:58.117345+00:00 app[web.1]: Headers({'host': 'exampleapi.herokuapp.com', 'x-real-ip': '176.12.151.31', 'accept-encoding': 'gzip, deflate', ...})
Ultimately, the request does not contain the key header once it reaches the worker dyno, leading to a response indicating that direct access to the API is not permitted. Is there a way to ensure Heroku forwards this header, or should I consider a different approach for verifying the x-rapidapi-proxy-secret in my API?
To resolve this issue, consider using a custom header forwarding approach. When deploying on Heroku with headers like x-rapidapi-proxy-secret, you may run into restrictions.
Solution: Use a middleware to manually forward the headers with a custom prefix and update your validation code.
Steps:
- Update RapidAPI request: Add a custom header (e.g.,
x-custom-rapidapi-proxy-secret) in your requests through RapidAPI that mirrors x-rapidapi-proxy-secret. Rename the header since original x- prefixed headers might not forward correctly by default.
- Modify middleware: Update your FastAPI validation code to check for this new custom header.
app = FastAPI()
proxy_secret = os.environ.get('PROXY_SECRET', None)
@app.middleware('http')
async def validate_rapidapi_header(request: Request, call_next):
if proxy_secret:
req_headers = request.headers
if ('x-custom-rapidapi-proxy-secret' not in req_headers
or req_headers['x-custom-rapidapi-proxy-secret'] != proxy_secret):
return PlainTextResponse(
'Access directly to the API is forbidden', status_code=403
)
response = await call_next(request)
return response
Ensure this custom header is configured correctly in your RapidAPI dashboard. This strategy ensures Heroku’s restrictions don’t affect your security measures while keeping your API protected.
Fix: You can handle this by manually adding a custom header and modifying your middleware to check that instead.
Steps:
- Change your RapidAPI settings to send
x-custom-rapidapi-proxy-secret instead of x-rapidapi-proxy-secret.
- Update your FastAPI middleware:
app = FastAPI()
proxy_secret = os.environ.get('PROXY_SECRET', None)
@app.middleware('http')
async def validate_rapidapi_header(request: Request, call_next):
if proxy_secret:
req_headers = request.headers
if ('x-custom-rapidapi-proxy-secret' not in req_headers
or req_headers['x-custom-rapidapi-proxy-secret'] != proxy_secret):
return PlainTextResponse(
'Access directly to the API is forbidden', status_code=403
)
response = await call_next(request)
return response
This approach bypasses Heroku's header stripping, retaining your API security.
Dealing with header forwarding issues on platforms like Heroku can indeed be tricky, especially with headers starting with x-. While the existing answer suggests an effective workaround by introducing a custom header, I would like to propose a slightly different angle to ensure reliable header transmission while preserving API security.
Alternative Solution
Another approach involves utilizing the flexibility of both Heroku and FastAPI to ensure that the desired header reaches your application correctly.
- Check Heroku Configuration: First, ensure there's no intermediary layer, such as an addon or routing configuration, on Heroku that might strip headers. This might involve reviewing application settings or the behavior of any additional middleware elements.
- Utilize Proxy Headers Support: Check your Heroku configuration for proper forwarding headers. Sometimes setting match rules for headers can be helpful.
- Informational Logging: Temporarily adjust your logging to dump all received headers to further diagnose which ones make it through and which do not. This can reveal unintended transformations or stripping.
- Implement Secure Tunnels or Connectors: As an alternative, you might explore using a secure reverse proxy or a tunnel, like Ngrok, particularly if the requests always originate from known sources (like RapidAPI), providing another layer of reliability.
By exploring these measures, you might address both the symptoms and root causes of the header transmission issue, offering another reliable safeguard path for secure transactions with your API through RapidAPI.