rate_limit

Sliding-window rate limiting middleware backed by ETS.

Types

pub type RateLimitOptions {
  RateLimitOptions(
    limit: Int,
    window_ms: Int,
    key_fn: fn(Conn(Connection)) -> String,
  )
}

Functions

options

pub fn options(limit limit: Int, window_ms window_ms: Int) -> RateLimitOptions

Create options with the default key function (client IP from X-Forwarded-For, X-Real-IP, or host).

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with_key

pub fn with_key(opts: RateLimitOptions, key_fn: fn(Conn(Connection)) -> String) -> RateLimitOptions

Override the key function. Use to rate-limit by user ID, API token, or any other dimension.

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middleware

pub fn middleware(opts: RateLimitOptions) -> Middleware(Connection)

Returns a middleware function. Allows up to opts.limit requests per opts.window_ms milliseconds per key. Exceeding the limit returns 429 with a Retry-After header. Passing requests receive X-RateLimit-Limit and X-RateLimit-Remaining headers.