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</pre><pre class="rust"><code><span class="doccomment">//! Rate limiter using a fixed window counter for arbitrary keys, backed by Redis for Actix Web.
//!
//! ```toml
//! [dependencies]
//! actix-web = "4"
</span><span class="attribute">#![doc = <span class="macro">concat!</span>(<span class="string">"actix-limitation = \""</span>, <span class="macro">env!</span>(<span class="string">"CARGO_PKG_VERSION_MAJOR"</span>), <span class="string">"."</span>, <span class="macro">env!</span>(<span class="string">"CARGO_PKG_VERSION_MINOR"</span>),<span class="string">"\""</span>)]
</span><span class="doccomment">//! ```
//!
//! ```no_run
//! use std::{sync::Arc, time::Duration};
//! use actix_web::{dev::ServiceRequest, get, web, App, HttpServer, Responder};
//! use actix_session::SessionExt as _;
//! use actix_limitation::{Limiter, RateLimiter};
//!
//! #[get("/{id}/{name}")]
//! async fn index(info: web::Path<(u32, String)>) -> impl Responder {
//! format!("Hello {}! id:{}", info.1, info.0)
//! }
//!
//! #[actix_web::main]
//! async fn main() -> std::io::Result<()> {
//! let limiter = web::Data::new(
//! Limiter::builder("redis://127.0.0.1")
//! .key_by(|req: &ServiceRequest| {
//! req.get_session()
//! .get(&"session-id")
//! .unwrap_or_else(|_| req.cookie(&"rate-api-id").map(|c| c.to_string()))
//! })
//! .limit(5000)
//! .period(Duration::from_secs(3600)) // 60 minutes
//! .build()
//! .unwrap(),
//! );
//!
//! HttpServer::new(move || {
//! App::new()
//! .wrap(RateLimiter::default())
//! .app_data(limiter.clone())
//! .service(index)
//! })
//! .bind(("127.0.0.1", 8080))?
//! .run()
//! .await
//! }
//! ```
</span><span class="attribute">#![forbid(unsafe_code)]
#![deny(rust_2018_idioms, nonstandard_style)]
#![warn(future_incompatible, missing_docs, missing_debug_implementations)]
#![doc(html_logo_url = <span class="string">"https://actix.rs/img/logo.png"</span>)]
#![doc(html_favicon_url = <span class="string">"https://actix.rs/favicon.ico"</span>)]
</span><span class="kw">use </span>std::{borrow::Cow, fmt, sync::Arc, time::Duration};
<span class="kw">use </span>actix_web::dev::ServiceRequest;
<span class="kw">use </span>redis::Client;
<span class="kw">mod </span>builder;
<span class="kw">mod </span>errors;
<span class="kw">mod </span>middleware;
<span class="kw">mod </span>status;
<span class="kw">pub use </span><span class="self">self</span>::{builder::Builder, errors::Error, middleware::RateLimiter, status::Status};
<span class="doccomment">/// Default request limit.
</span><span class="kw">pub const </span>DEFAULT_REQUEST_LIMIT: usize = <span class="number">5000</span>;
<span class="doccomment">/// Default period (in seconds).
</span><span class="kw">pub const </span>DEFAULT_PERIOD_SECS: u64 = <span class="number">3600</span>;
<span class="doccomment">/// Default cookie name.
</span><span class="kw">pub const </span>DEFAULT_COOKIE_NAME: <span class="kw-2">&</span>str = <span class="string">"sid"</span>;
<span class="doccomment">/// Default session key.
</span><span class="attribute">#[cfg(feature = <span class="string">"session"</span>)]
</span><span class="kw">pub const </span>DEFAULT_SESSION_KEY: <span class="kw-2">&</span>str = <span class="string">"rate-api-id"</span>;
<span class="doccomment">/// Helper trait to impl Debug on GetKeyFn type
</span><span class="kw">trait </span>GetKeyFnT: Fn(<span class="kw-2">&</span>ServiceRequest) -> <span class="prelude-ty">Option</span><String> {}
<span class="kw">impl</span><T> GetKeyFnT <span class="kw">for </span>T <span class="kw">where </span>T: Fn(<span class="kw-2">&</span>ServiceRequest) -> <span class="prelude-ty">Option</span><String> {}
<span class="doccomment">/// Get key function type with auto traits
</span><span class="kw">type </span>GetKeyFn = <span class="kw">dyn </span>GetKeyFnT + Send + Sync;
<span class="doccomment">/// Get key resolver function type
</span><span class="kw">impl </span>fmt::Debug <span class="kw">for </span>GetKeyFn {
<span class="kw">fn </span>fmt(<span class="kw-2">&</span><span class="self">self</span>, f: <span class="kw-2">&mut </span>fmt::Formatter<<span class="lifetime">'_</span>>) -> fmt::Result {
<span class="macro">write!</span>(f, <span class="string">"GetKeyFn"</span>)
}
}
<span class="doccomment">/// Wrapped Get key function Trait
</span><span class="kw">type </span>GetArcBoxKeyFn = Arc<GetKeyFn>;
<span class="doccomment">/// Rate limiter.
</span><span class="attribute">#[derive(Debug, Clone)]
</span><span class="kw">pub struct </span>Limiter {
client: Client,
limit: usize,
period: Duration,
get_key_fn: GetArcBoxKeyFn,
}
<span class="kw">impl </span>Limiter {
<span class="doccomment">/// Construct rate limiter builder with defaults.
///
/// See [`redis-rs` docs](https://docs.rs/redis/0.21/redis/#connection-parameters) on connection
/// parameters for how to set the Redis URL.
</span><span class="attribute">#[must_use]
</span><span class="kw">pub fn </span>builder(redis_url: <span class="kw">impl </span>Into<String>) -> Builder {
Builder {
redis_url: redis_url.into(),
limit: DEFAULT_REQUEST_LIMIT,
period: Duration::from_secs(DEFAULT_PERIOD_SECS),
get_key_fn: <span class="prelude-val">None</span>,
cookie_name: Cow::Borrowed(DEFAULT_COOKIE_NAME),
<span class="attribute">#[cfg(feature = <span class="string">"session"</span>)]
</span>session_key: Cow::Borrowed(DEFAULT_SESSION_KEY),
}
}
<span class="doccomment">/// Consumes one rate limit unit, returning the status.
</span><span class="kw">pub async fn </span>count(<span class="kw-2">&</span><span class="self">self</span>, key: <span class="kw">impl </span>Into<String>) -> <span class="prelude-ty">Result</span><Status, Error> {
<span class="kw">let </span>(count, reset) = <span class="self">self</span>.track(key).<span class="kw">await</span><span class="question-mark">?</span>;
<span class="kw">let </span>status = Status::new(count, <span class="self">self</span>.limit, reset);
<span class="kw">if </span>count > <span class="self">self</span>.limit {
<span class="prelude-val">Err</span>(Error::LimitExceeded(status))
} <span class="kw">else </span>{
<span class="prelude-val">Ok</span>(status)
}
}
<span class="doccomment">/// Tracks the given key in a period and returns the count and TTL for the key in seconds.
</span><span class="kw">async fn </span>track(<span class="kw-2">&</span><span class="self">self</span>, key: <span class="kw">impl </span>Into<String>) -> <span class="prelude-ty">Result</span><(usize, usize), Error> {
<span class="kw">let </span>key = key.into();
<span class="kw">let </span>expires = <span class="self">self</span>.period.as_secs();
<span class="kw">let </span><span class="kw-2">mut </span>connection = <span class="self">self</span>.client.get_tokio_connection().<span class="kw">await</span><span class="question-mark">?</span>;
<span class="comment">// The seed of this approach is outlined Atul R in a blog post about rate limiting using
// NodeJS and Redis. For more details, see https://blog.atulr.com/rate-limiter
</span><span class="kw">let </span><span class="kw-2">mut </span>pipe = redis::pipe();
pipe.atomic()
.cmd(<span class="string">"SET"</span>) <span class="comment">// Set key and value
</span>.arg(<span class="kw-2">&</span>key)
.arg(<span class="number">0</span>)
.arg(<span class="string">"EX"</span>) <span class="comment">// Set the specified expire time, in seconds.
</span>.arg(expires)
.arg(<span class="string">"NX"</span>) <span class="comment">// Only set the key if it does not already exist.
</span>.ignore() <span class="comment">// --- ignore returned value of SET command ---
</span>.cmd(<span class="string">"INCR"</span>) <span class="comment">// Increment key
</span>.arg(<span class="kw-2">&</span>key)
.cmd(<span class="string">"TTL"</span>) <span class="comment">// Return time-to-live of key
</span>.arg(<span class="kw-2">&</span>key);
<span class="kw">let </span>(count, ttl) = pipe.query_async(<span class="kw-2">&mut </span>connection).<span class="kw">await</span><span class="question-mark">?</span>;
<span class="kw">let </span>reset = Status::epoch_utc_plus(Duration::from_secs(ttl))<span class="question-mark">?</span>;
<span class="prelude-val">Ok</span>((count, reset))
}
}
<span class="attribute">#[cfg(test)]
</span><span class="kw">mod </span>tests {
<span class="kw">use super</span>::<span class="kw-2">*</span>;
<span class="attribute">#[test]
</span><span class="kw">fn </span>test_create_limiter() {
<span class="kw">let </span><span class="kw-2">mut </span>builder = Limiter::builder(<span class="string">"redis://127.0.0.1:6379/1"</span>);
<span class="kw">let </span>limiter = builder.build();
<span class="macro">assert!</span>(limiter.is_ok());
<span class="kw">let </span>limiter = limiter.unwrap();
<span class="macro">assert_eq!</span>(limiter.limit, <span class="number">5000</span>);
<span class="macro">assert_eq!</span>(limiter.period, Duration::from_secs(<span class="number">3600</span>));
}
}
</code></pre></div>
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