3 ms·

Those are all great points! At Svix (we do webhooks as a service), we disallow redirects because of what you mentioned above, and because it's also just bad for

by tasn 4y ago

Those are all great points! At Svix (we do webhooks as a service), we disallow redirects because of what you mentioned above, and because it's also just bad for performance (for both sides) and is most likely a configuration error anyway. Resolution and timeouts: the aiohttp library for Python is slightly better in terms of letting you configure these things, though it's better to just use a sending proxy that does it all for you and is also located in an isolated VPC to make sure that you're protected.

pyjug 4y ago
Disallowing redirects altogether is probably too big of a hammer. There are legit reasons to use redirects (like migration to new versions). A limit to the number of redirects seems ideal -- that's what Twilio does, for example.
- tasn 4y ago
  Migrating to a new service: you can just update the webhook URL. On the other hand, there are at least a couple of problems with allowing even one redirect: it opens a pandora's box of security implications, and it's a performance penalty that is paid both by the sender and the receiver on every webhook sent. Realistically, 3xx are most likely to be a mis-configurations (e.g. including a trailing slash where one shouldn't) so I think being noisy about it is a great idea. Not saying that there aren't valid use-cases (e.g. maybe some sort of dynamic webhook receiving), I'm just saying that we made this choice given the above, and we would be willing to change it if it's ever a barrier for someone.
  - pyjug 4y ago
    >you can just update the webhook URL Fair enough, but often consumers that use multiple vendors receive webhooks in the same service; think about going from /v1/webhooks -> /v2/webhooks, they'd have to change the URL for every vendor. Easier to redirect first then update the URLs later. I think it's a reasonable expectation that a HTTP client would honor redirects as long as the usage isn't malicious (like loops etc)

by tasn 4y ago

pyjug 4y ago

Disallowing redirects altogether is probably too big of a hammer. There are legit reasons to use redirects (like migration to new versions). A limit to the number of redirects seems ideal -- that's what Twilio does, for example.

tasn 4y ago
Migrating to a new service: you can just update the webhook URL. On the other hand, there are at least a couple of problems with allowing even one redirect: it opens a pandora's box of security implications, and it's a performance penalty that is paid both by the sender and the receiver on every webhook sent. Realistically, 3xx are most likely to be a mis-configurations (e.g. including a trailing slash where one shouldn't) so I think being noisy about it is a great idea. Not saying that there aren't valid use-cases (e.g. maybe some sort of dynamic webhook receiving), I'm just saying that we made this choice given the above, and we would be willing to change it if it's ever a barrier for someone.
- pyjug 4y ago
  >you can just update the webhook URL Fair enough, but often consumers that use multiple vendors receive webhooks in the same service; think about going from /v1/webhooks -> /v2/webhooks, they'd have to change the URL for every vendor. Easier to redirect first then update the URLs later. I think it's a reasonable expectation that a HTTP client would honor redirects as long as the usage isn't malicious (like loops etc)