28 lines
918 B
Elixir
28 lines
918 B
Elixir
defmodule MvWeb.JoinRateLimit do
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@moduledoc """
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Rate limiting for the public join form (submit action).
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Uses Hammer with ETS backend. Key is derived from client IP so each IP
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is limited independently. Config from :mv :join_rate_limit (scale_ms, limit).
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"""
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use Hammer, backend: :ets
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@doc """
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Checks if the given key (e.g. client IP) is within rate limit for join form submit.
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Returns:
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- `:allow` - submission allowed
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- `{:deny, _retry_after_ms}` - rate limit exceeded
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"""
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def check(key) when is_binary(key) do
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# Read at runtime so config can be changed without restart (e.g. in tests).
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config = Application.get_env(:mv, :join_rate_limit, [])
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scale_ms = Keyword.get(config, :scale_ms, 60_000)
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limit = Keyword.get(config, :limit, 10)
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case hit(key, scale_ms, limit) do
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{:allow, _count} -> :allow
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{:deny, retry_after} -> {:deny, retry_after}
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end
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end
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end
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