Change rate limit & app rate limit handling

[svenseeberg]

When sending a few messages in row, the rate limit blocks requests too often.

[svenseeberg]

When using the chat normally (one tab), the rate limit is sufficient. However, we should improve the error handling in the UI -> HTTP 429 should be displayed as a "Please slow down" message while keeping the currently loaded messages visible.

[steffenkleinle]

@svenseeberg can we apply the rate limit only for asking new questions (i.e. the post endpoint) and increase the limit for the get endpoint?

[svenseeberg]

The rate limit should also protect against scanning for existing conversations. However, this is not a strong protection anyways as it can be circumvented with multiple source IPs. So yes, this should be possible.

[steffenkleinle]

The rate limit should also protect against scanning for existing conversations. However, this is not a strong protection anyways as it can be circumvented with multiple source IPs. So yes, this should be possible.

We could also just increase the number for the get endpoint perhaps? Alternatively, we can also try to fix this app-side or just don't mind actually. We display a meaningful error, probably that is also enough. If users do unexpected things, maybe we can do unexpected things as well :D

[svenseeberg]

Yes, raising the limit a bit should be okay.