#![doc(html_root_url = "https://docs.rs/actix-ratelimit/0.3.1")]
//! Rate limiting middleware framework for [actix-web](https://actix.rs/)
//!
//! This crate provides an asynchronous and concurrent rate limiting middleware based on [actor](https://www.wikiwand.com/en/Actor_model)
//! model which can be wraped around an [Actix](https://actix.rs/) application. Middleware contains a store which is used to
//! identify client request.
//!
//! Check out the [documentation here](https://docs.rs/actix-ratelimit/).
//!
//! Comments, suggesstions and critiques are welcomed!
//!
//! # Usage
//! Add this to your Cargo.toml:
//! ```toml
//! [dependencies]
//! actix-ratelimit = "0.3.1"
//! ```
//!
//! Minimal example:
//!
//! ```
//! # #[cfg(feature = "default")] {
//! # use std::time::Duration;
//! use actix_web::{web, App, HttpRequest, HttpServer, Responder};
//! use actix_ratelimit::{RateLimiter, MemoryStore, MemoryStoreActor};
//!
//! async fn greet(req: HttpRequest) -> impl Responder{
//!     let name = req.match_info().get("name").unwrap_or("World!");
//!     format!("Hello {}!", &name)
//! }
//!
//! #[actix_web::main]
//! async fn main() -> std::io::Result<()> {
//!     // Initialize store
//!     let store = MemoryStore::new();
//!     HttpServer::new(move ||{
//!         App::new()
//!             // Register the middleware
//!             // which allows for a maximum of
//!             // 100 requests per minute per client
//!             // based on IP address
//!             .wrap(
//!                 RateLimiter::new(
//!                 MemoryStoreActor::from(store.clone()).start())
//!                     .with_interval(Duration::from_secs(60))
//!                     .with_max_requests(100)
//!             )
//!             .route("/", web::get().to(greet))
//!             .route("/{name}", web::get().to(greet))
//!     })
//!     .bind("127.0.0.1:8000")?
//!     .run()
//!     .await
//! }
//! # }
//! ```
//! Sending a request returns a response with the ratelimiting headers:
//! ```shell
//! $ curl -i "http://localhost:8000/"
//!
//! HTTP/1.1 200 OK
//! content-length: 13
//! content-type: text/plain; charset=utf-8
//! x-ratelimit-remaining: 99
//! x-ratelimit-reset: 52
//! x-ratelimit-limit: 100
//! date: Tue, 04 Feb 2020 21:53:27 GMT
//!
//! Hello World!
//! ```
//! Exceeding the limit returns HTTP 429 Error code.
//!
//! # Stores
//!
//! A _store_ is a data structure, database connection or anything which can be used to store
//! _ratelimit_ data associated with a _client_. A _store actor_ which acts on this store is
//! responsible for performiing all sorts of operations(SET, GET, DEL, etc). It is Important to
//! note that there are multiple store actors acting on a _single_ store.
//!
//!
//! ## Supported
//! - In-memory (based on concurrent [hashmap](https://github.com/xacrimon/dashmap))
//! - Redis (based on [redis-rs](https://github.com/mitsuhiko/redis-rs))
//!
//! ## Planned
//! - Memcached (not yet implemented)
//!
//! # Implementing your own store
//!
//! To implement your own store, you have to implement an [Actor](https://actix.rs/actix/actix/trait.Actor.html) which can handle [ActorMessage](enum.ActorMessage.html) type
//! and return [ActorResponse](enum.ActorResponse.html) type. Check the [module level documentation](stores/index.html) for
//! more details and a basic example.
//!
//! # Note to developers
//!
//! * To use redis store, put this to your Cargo.toml:
//! ```toml
//! [dependencies]
//! actix-ratelimit = {version = "0.3.1", default-features = false, features = ["redis-store"]}
//! ```
//!
//! * By default, the client's IP address is used as the identifier which can be customized
//! using [ServiceRequest](https://docs.rs/actix-web/3.3.2/actix_web/dev/struct.ServiceRequest.html) instance.
//! For example, using api key header to identify client:
//! ```rust
//! # #[cfg(feature = "default")] {
//! # use std::time::Duration;
//! # use actix_web::{web, App, HttpRequest, HttpServer, Responder};
//! # use actix_ratelimit::{RateLimiter, MemoryStore, MemoryStoreActor};
//! # async fn greet(req: HttpRequest) -> impl Responder{
//! #     let name = req.match_info().get("name").unwrap_or("World!");
//! #     format!("Hello {}!", &name)
//! # }
//! #[actix_web::main]
//! async fn main() -> std::io::Result<()> {
//!     // Initialize store
//!     let store = MemoryStore::new();
//!     HttpServer::new(move ||{
//!         App::new()
//!             .wrap(
//!                 RateLimiter::new(
//!                 MemoryStoreActor::from(store.clone()).start())
//!                     .with_interval(Duration::from_secs(60))
//!                     .with_max_requests(100)
//!                     .with_identifier(|req| {
//!                         let key = req.headers().get("x-api-key").unwrap();
//!                         let key = key.to_str().unwrap();
//!                         Ok(key.to_string())
//!                     })
//!             )
//!             .route("/", web::get().to(greet))
//!             .route("/{name}", web::get().to(greet))
//!     })
//!     .bind("127.0.0.1:8000")?
//!     .run()
//!     .await
//! }
//! # }
//! ```
//!
//! * It is **important** to initialize store before creating HttpServer instance, or else a store
//! will be created for each web worker. This may lead to instability and inconsistency! For
//! example, initializing your app in the following manner would create more than one stores:
//! ```rust
//! # #[cfg(feature = "default")] {
//! # use std::time::Duration;
//! # use actix_web::{web, App, HttpRequest, HttpServer, Responder};
//! # use actix_ratelimit::{RateLimiter, MemoryStore, MemoryStoreActor};
//! # async fn greet(req: HttpRequest) -> impl Responder{
//! #     let name = req.match_info().get("name").unwrap_or("World!");
//! #     format!("Hello {}!", &name)
//! # }
//! #[actix_web::main]
//! async fn main() -> std::io::Result<()> {
//!     HttpServer::new(move ||{
//!         App::new()
//!             .wrap(
//!                 RateLimiter::new(
//!                 MemoryStoreActor::from(MemoryStore::new()).start())
//!                     .with_interval(Duration::from_secs(60))
//!                     .with_max_requests(100)
//!             )
//!             .route("/", web::get().to(greet))
//!             .route("/{name}", web::get().to(greet))
//!     })
//!     .bind("127.0.0.1:8000")?
//!     .run()
//!     .await
//! }
//! # }
//! ```
//!
//! * The exception is redis, where multiple connections will be
//! created for each worker. Since redis store is based on Multiplexed connection, sharing once
//! connection across multiple store actors should suffice for most use cases.
//!
//!
//! # Status
//! This project has not reached v1.0, so some instability and breaking changes are to be expected
//! till then.
//!
//! You can use the [issue tracker](https://github.com/TerminalWitchcraft/actix-ratelimit/issues) in case you encounter any problems.
//!
//! # LICENSE
//! This project is licensed under MIT license.

pub mod errors;
pub mod middleware;
pub mod stores;
use errors::ARError;
pub use middleware::RateLimiter;

#[cfg(feature = "memory")]
pub use stores::memory::{MemoryStore, MemoryStoreActor};
#[cfg(feature = "redis-store")]
pub use stores::redis::{RedisStore, RedisStoreActor};
#[cfg(feature = "memcached")]
pub use stores::memcached::{MemcacheStore, MemcacheStoreActor};

use std::future::Future;
use std::marker::Send;
use std::pin::Pin;
use std::time::Duration;

use actix::dev::*;

/// Represents message that can be handled by a `StoreActor`
pub enum ActorMessage {
    /// Get the remaining count based on the provided identifier
    Get(String),
    /// Set the count of the client identified by `key` to `value` valid for `expiry`
    Set {
        key: String,
        value: usize,
        expiry: Duration,
    },
    /// Change the value of count for the client identified by `key` by `value`
    Update { key: String, value: usize },
    /// Get the expiration time for the client.
    Expire(String),
    /// Remove the client from the store
    Remove(String),
}

impl Message for ActorMessage {
    type Result = ActorResponse;
}

/// Wrapper type for `Pin<Box<dyn Future>>` type
pub type Output<T> = Pin<Box<dyn Future<Output = Result<T, ARError>> + Send>>;

/// Represents data returned in response to `Messages` by a `StoreActor`
pub enum ActorResponse {
    /// Returned in response to [Messages::Get](enum.Messages.html)
    Get(Output<Option<usize>>),
    /// Returned in response to [Messages::Set](enum.Messages.html)
    Set(Output<()>),
    /// Returned in response to [Messages::Update](enum.Messages.html)
    Update(Output<usize>),
    /// Returned in response to [Messages::Expire](enum.Messages.html)
    Expire(Output<Duration>),
    /// Returned in response to [Messages::Remove](enum.Messages.html)
    Remove(Output<usize>),
}

impl<A, M> MessageResponse<A, M> for ActorResponse
where
    A: Actor,
    M: actix::Message<Result = ActorResponse>,
{
    fn handle<R: ResponseChannel<M>>(self, _: &mut A::Context, tx: Option<R>) {
        if let Some(tx) = tx {
            tx.send(self);
        }
    }
}