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//! Composable (a)synchronous HTTP request routing, guarding and decoding. //! //! This crate provides [Rocket]-inspired HTTP route definitions based on //! attributes (`#[get("/user/{id}")]`). It is based on the [`hyper`] //! and [`http`] crates, works on **stable Rust**, and supports writing both //! synchronous and asynchronous (via [futures 0.1]) apps. //! //! Check out the examples below for a small taste of how this library can be //! used. If you want to dive in deeper, you can check out the [`FromRequest`] //! trait, which provides the custom derive that powers most of the magic in //! this crate. //! //! [Rocket]: https://rocket.rs/ //! [`hyper`]: https://hyper.rs/ //! [`http`]: https://docs.rs/http //! [futures 0.1]: https://docs.rs/futures/0.1 //! [`FromRequest`]: trait.FromRequest.html //! //! # Examples //! //! Use the hyper service adapter [`AsyncService`] to create your async //! server without much boilerplate: //! //! ``` //! use hyper::{Server, Response, Body}; //! use hyperdrive::{service::AsyncService, FromRequest}; //! use futures::IntoFuture; //! //! #[derive(FromRequest)] //! enum Route { //! #[get("/")] //! Index, //! //! #[get("/users/{id}")] //! UserInfo { id: u32 }, //! } //! //! let srv = Server::bind(&"127.0.0.1:0".parse().unwrap()) //! .serve(AsyncService::new(|route: Route, _| { //! match route { //! Route::Index => { //! Ok(Response::new(Body::from("Hello World!"))).into_future() //! } //! Route::UserInfo { id } => { //! // You could do an async database query to fetch the user data here //! Ok(Response::new(Body::from(format!("User #{}", id)))).into_future() //! } //! } //! })); //! ``` //! //! If your app doesn't need to be asynchronous and you'd prefer to write sync //! code, you can do that by using [`SyncService`]: //! //! ``` //! use hyper::{Server, Response, Body}; //! use hyperdrive::{service::SyncService, FromRequest}; //! //! #[derive(FromRequest)] //! enum Route { //! #[get("/")] //! Index, //! //! #[get("/users/{id}")] //! UserInfo { id: u32 }, //! } //! //! let srv = Server::bind(&"127.0.0.1:0".parse().unwrap()) //! .serve(SyncService::new(|route: Route, _| { //! // This closure can block freely, and has to return a `Response<Body>` //! match route { //! Route::Index => { //! Response::new(Body::from("Hello World!")) //! }, //! Route::UserInfo { id } => { //! Response::new(Body::from(format!("User #{}", id))) //! } //! } //! })); //! ``` //! //! If the provided service adapters aren't sufficient for your use case, you //! can always manually use the [`FromRequest`] methods, and hook it up to your //! hyper `Service` manually: //! //! ``` //! use hyper::{Request, Response, Body, Method, service::Service}; //! use futures::Future; //! use hyperdrive::{FromRequest, DefaultFuture, BoxedError, NoContext}; //! //! #[derive(FromRequest)] //! enum Route { //! #[get("/")] //! Index, //! //! #[get("/users/{id}")] //! UserInfo { id: u32 }, //! } //! //! // Define your hyper `Service`: //! struct MyService; //! //! impl Service for MyService { //! type ReqBody = Body; //! type ResBody = Body; //! type Error = BoxedError; //! type Future = DefaultFuture<Response<Body>, BoxedError>; //! //! fn call(&mut self, req: Request<Body>) -> Self::Future { //! let is_head = req.method() == Method::HEAD; //! let future = Route::from_request(req, NoContext).and_then(|route| Ok(match route { //! Route::Index => { //! Response::new(Body::from("Hello world!")) //! } //! Route::UserInfo { id } => { //! Response::new(Body::from(format!("User #{} is secret!", id))) //! } //! })).map(move |resp| { //! if is_head { //! // Response to HEAD requests must have an empty body //! resp.map(|_| Body::empty()) //! } else { //! resp //! } //! }); //! //! Box::new(future) //! } //! } //! ``` //! //! For detailed documentation on the custom derive syntax, refer to the docs of //! [`FromRequest`]. //! //! [`AsyncService`]: service/struct.AsyncService.html //! [`SyncService`]: service/struct.SyncService.html //! [`FromRequest`]: trait.FromRequest.html /* TODO: * How to handle 2015/2018 compat with the proc-macro? * Good example that fetches a session from a DB */ // Deny certain warnings inside doc tests / examples. When this isn't present, rustdoc doesn't show // *any* warnings at all. #![doc(test(attr(deny(unused_imports, unused_must_use))))] #![doc(html_root_url = "https://docs.rs/hyperdrive/0.2.0")] #![warn(missing_debug_implementations)] #![warn(missing_docs)] #![warn(rust_2018_idioms)] pub mod body; mod error; mod readme; pub mod service; pub use error::*; pub use hyperderive::*; // Reexport public deps for use by the custom derive pub use {futures, http, hyper, serde}; // These are hidden because the user never actually interacts with them. They're // only used by the generated code internally. #[doc(hidden)] pub use {lazy_static::lazy_static, regex}; use futures::{Future, IntoFuture}; use std::sync::Arc; use tokio::runtime::current_thread::Runtime; /// A default boxed future that may be returned from [`FromRequest`], /// [`FromBody`] and [`Guard`] implementations. /// /// The future is required to be `Send` to allow running it on a multi-threaded /// executor. /// /// [`FromRequest`]: trait.FromRequest.html /// [`FromBody`]: trait.FromBody.html /// [`Guard`]: trait.Guard.html pub type DefaultFuture<T, E> = Box<dyn Future<Item = T, Error = E> + Send>; /// A boxed `std::error::Error` that can be used when the actual error type is /// unknown. pub type BoxedError = Box<dyn std::error::Error + Send + Sync>; /// Trait for asynchronous conversion from HTTP requests. /// /// # `#[derive(FromRequest)]` /// /// This trait can be derived for enums to generate a request router and /// decoder. Here's a simple example: /// /// ``` /// use hyperdrive::{FromRequest, body::Json}; /// # use serde::Deserialize; /// /// #[derive(FromRequest)] /// enum Routes { /// #[get("/")] /// Index, /// /// #[get("/users/{id}")] /// User { id: u32 }, /// /// #[post("/login")] /// Login { /// #[body] /// data: Json<Login>, /// }, /// } /// /// #[derive(Deserialize)] /// struct Login { /// email: String, /// password: String, /// } /// ``` /// /// Calling `Routes::from_request` will result in `Routes::Index` for a `GET /` /// request, and in `Routes::User` for a `GET /users/123` request, for example. /// A `POST /login` request will end up as `Routes::Login`, decoding the POSTed /// JSON body. /// /// The generated `FromRequest` implementation will always use /// [`DefaultFuture<Self, BoxedError>`][`DefaultFuture`] as the associated /// `Result` type. /// /// Note that the generated implementation will make use of `.and_then()` to /// chain asynchronous operations instead of running them in parallel using /// `join_all`. This is because it simplifies the code and doesn't require /// making use of boxed futures everywhere in the generated code. Multiple /// requests will still be handled in parallel, so this should not negatively /// affect performance. /// /// In order to keep the implementation simple and user code more easily /// understandable, overlapping paths are not allowed (unless the paths are /// *exactly* the same, and the method differs), so the following will fail to /// compile: /// /// ```compile_fail /// use from_request::{FromRequest, body::Json}; /// # use serde::Deserialize; /// /// #[derive(FromRequest)] //~ ERROR: route `#[get("/users/me")]` overlaps with ... /// enum Routes { /// #[get("/users/{id}")] /// User { id: u32 }, /// /// #[get("/users/me")] /// Me, /// } /// ``` /// /// To fix this, you can define a custom type implementing `FromStr` and use /// that: /// /// ``` /// use hyperdrive::FromRequest; /// # use std::str::FromStr; /// # use std::num::ParseIntError; /// /// #[derive(FromRequest)] /// enum Routes { /// #[get("/users/{id}")] /// User { id: UserId }, /// } /// /// enum UserId { /// /// User by database ID. /// Id(u32), /// /// The currently logged-in user. /// Me, /// } /// /// impl FromStr for UserId { /// type Err = ParseIntError; /// /// fn from_str(s: &str) -> Result<Self, Self::Err> { /// if s == "me" { /// Ok(UserId::Me) /// } else { /// Ok(UserId::Id(s.parse()?)) /// } /// } /// } /// ``` /// /// ## Implicit `HEAD` routes /// /// The custom derive will create a `HEAD` route for every defined `GET` route, /// unless you define one yourself. If your app uses [`AsyncService`] or /// [`SyncService`], those adapters will automatically take care of dropping the /// body from the response to `HEAD` requests. If you manually call /// [`FromRequest::from_request`][`from_request`], you have to make sure no body /// is sent back for `HEAD` requests. /// /// ## Extracting Request Data /// /// The custom derive provides easy access to various kinds of data encoded in a /// request: /// /// * The Request path (`/users/or/other/stuff`) /// * Query parameters (`?name=val`) /// * The request body /// /// ### Extracting Path Segments (`{field}` syntax) /// /// In a route attribute, the `{field}` placeholder syntax will match a path /// segment and convert it to the type of the named field using `FromStr`: /// /// ```notrust /// #[get("/users/{id}")] /// ``` /// /// To extract multiple path segments this way, the `{field...}` syntax can be /// used at the end of the path, which will consume the rest of the path: /// /// ```notrust /// #[get("/static/{path...}")] /// ``` /// /// If the `FromStr` conversion fails, the generated `FromRequest` /// implementation will bail out with an error (in other words, this feature /// cannot be used to try multiple routes in sequence until one matches). /// /// ### Extracting the request body (`#[body]` attribute) /// /// Putting `#[body]` on a field of a variant will deserialize the request body /// using the [`FromBody`] trait and store the result in the annotated field: /// /// ```notrust /// #[post("/login")] /// Login { /// #[body] /// data: Json<Login>, /// }, /// ``` /// /// The type of the field must implement [`FromBody`]. The [`body`] module /// contains predefined adapters implementing that trait, which work with any /// type implementing `Deserialize`. /// /// ### Extracting query parameters (`#[query_params]` attribute) /// /// The route attribute cannot match or extract query parameters (`?name=val`). /// Instead, query parameters can be extracted by marking a field in the struct /// with the `#[query_params]` attribute: /// /// ``` /// use hyperdrive::FromRequest; /// # use serde::Deserialize; /// /// #[derive(FromRequest)] /// enum Routes { /// #[get("/users")] /// UserList { /// #[query_params] /// pagination: Option<Pagination>, /// }, /// } /// /// #[derive(Deserialize)] /// struct Pagination { /// start_id: u32, /// count: u32, /// } /// ``` /// /// A request like `GET /users?start_id=42&count=10` would thus end up with a /// corresponding `Pagination` object, while `GET /users` would store `None` in /// the `pagination` field. /// /// The type of the `#[query_params]` field must implement serde's `Deserialize` /// trait and the conversion will be performed using the `serde_urlencoded` /// crate. /// /// ## Guards /// /// Guards can be used to prevent a route from being called when a condition is /// not fulfilled (for example, when the user isn't logged in). They can also /// extract arbitrary data from the request headers (eg. a session ID, or the /// User-Agent string). /// /// All fields that are neither mentioned in the route path nor annotated with /// an attribute are considered guards and thus must implement the [`Guard`] /// trait. /// /// ``` /// use hyperdrive::{FromRequest, Guard}; /// # use hyperdrive::{BoxedError, NoContext}; /// # use std::sync::Arc; /// /// struct User { /// id: u32, /// // ... /// } /// /// impl Guard for User { /// // (omitted for brevity) /// # type Context = NoContext; /// # type Result = Result<Self, BoxedError>; /// # fn from_request(_: &Arc<http::Request<()>>, _: &NoContext) -> Result<Self, BoxedError> { /// # User { id: 0 }.id; /// # Ok(User { id: 0 }) /// # } /// } /// /// #[derive(FromRequest)] /// enum Route { /// #[get("/login")] /// LoginForm, /// /// #[get("/staff")] /// Staff { /// // Require a logged-in user to make this request /// user: User, /// }, /// } /// ``` /// /// ## Forwarding /// /// A field whose type implements `FromRequest` can be marked with `#[forward]`. /// The library will then generate code that invokes this nested `FromRequest` /// implementation. /// /// This feature can not be combined with `#[body]` inside the same variant, /// since both consume the request body. /// /// Currently, this is limited to `FromRequest` implementations that use the /// same [`RequestContext`] as the outer type (ie. no automatic `AsRef` /// conversion will take place). /// /// A variant or struct defining a `#[forward]` field does not have to define /// a route. If no other route matches, this variant will automatically be /// created, and is considered a *fallback route*. /// /// Combined with generics, this feature can be used to make request wrappers /// that attach a guard or a guard group to any type implementing `FromRequest`: /// /// ``` /// use hyperdrive::{FromRequest, Guard}; /// # use hyperdrive::{NoContext, BoxedError}; /// # use std::sync::Arc; /// /// struct User; /// impl Guard for User { /// // (omitted for brevity) /// # type Context = NoContext; /// # type Result = Result<Self, BoxedError>; /// # fn from_request(_: &Arc<http::Request<()>>, _: &NoContext) -> Result<Self, BoxedError> { /// # Ok(User) /// # } /// } /// /// #[derive(FromRequest)] /// struct Authenticated<T> { /// user: User, /// /// #[forward] /// inner: T, /// } /// ``` /// /// ## Changing the `Context` type /// /// By default, the generated code will use [`NoContext`] as the associated /// `Context` type. You can change this to any other type that implements /// [`RequestContext`] by putting a `#[context(MyContext)]` attribute on the /// type: /// /// ``` /// # struct MyDatabaseConnection; /// use hyperdrive::{FromRequest, RequestContext}; /// /// #[derive(RequestContext)] /// struct MyContext { /// db: MyDatabaseConnection, /// } /// /// #[derive(FromRequest)] /// #[context(MyContext)] /// enum Routes { /// #[get("/users")] /// UserList, /// } /// ``` /// /// For more info on this, refer to the [`RequestContext`] trait. /// /// [`AsyncService`]: service/struct.AsyncService.html /// [`SyncService`]: service/struct.SyncService.html /// [`FromBody`]: trait.FromBody.html /// [`RequestContext`]: trait.RequestContext.html /// [`Guard`]: trait.Guard.html /// [`NoContext`]: struct.NoContext.html /// [`DefaultFuture`]: type.DefaultFuture.html /// [`body`]: body/index.html /// [`from_request`]: #tymethod.from_request pub trait FromRequest: Sized { /// A context parameter passed to [`from_request`]. /// /// This can be used to pass application-specific data like a logger or a /// database connection around. /// /// If no context is needed, this should be set to [`NoContext`], which is a /// context type that can be obtained from any [`RequestContext`] via /// `AsRef`. /// /// [`from_request`]: #tymethod.from_request /// [`NoContext`]: struct.NoContext.html /// [`RequestContext`]: trait.RequestContext.html type Context: RequestContext; /// The future returned by [`from_request`]. /// /// Because `impl Trait` cannot be used inside traits (and named /// existential types aren't yet stable), the type here might not be /// nameable. In that case, you can set it to /// [`DefaultFuture<Self, BoxedError>`][`DefaultFuture`] and box the /// returned future. /// /// [`DefaultFuture`]: type.DefaultFuture.html /// [`from_request`]: #tymethod.from_request type Future: Future<Item = Self, Error = BoxedError> + Send; /// Creates a `Self` from an HTTP request, asynchronously. /// /// This takes the request metadata, body, and a user-defined context. Only /// the body is consumed. /// /// Implementations of this function must not block, since this function is /// always run on a futures executor. If you need to perform blocking I/O or /// long-running computations, you can call [`tokio_threadpool::blocking`]. /// /// # Parameters /// /// * **`request`**: HTTP request data (headers, path, method, etc.). /// * **`body`**: The streamed HTTP body. /// * **`context`**: The user-defined context. /// /// [`tokio_threadpool::blocking`]: ../tokio_threadpool/fn.blocking.html fn from_request_and_body( request: &Arc<http::Request<()>>, body: hyper::Body, context: Self::Context, ) -> Self::Future; /// Create a `Self` from an HTTP request, asynchronously. /// /// This consumes the request *and* the context. /// /// Implementations of this function must not block, since this function is /// always run on a futures executor. If you need to perform blocking I/O or /// long-running computations, you can call [`tokio_threadpool::blocking`]. /// /// A blocking wrapper around this method is provided by /// [`from_request_sync`]. /// /// # Parameters /// /// * **`request`**: An HTTP request from the `http` crate, containing a /// `hyper::Body`. /// * **`context`**: User-defined context. /// /// [`from_request_sync`]: #method.from_request_sync /// [`tokio_threadpool::blocking`]: ../tokio_threadpool/fn.blocking.html fn from_request(request: http::Request<hyper::Body>, context: Self::Context) -> Self::Future { let (parts, body) = request.into_parts(); let request = Arc::new(http::Request::from_parts(parts, ())); Self::from_request_and_body(&request, body, context) } /// Create a `Self` from an HTTP request, synchronously. /// /// This is a blocking version of [`from_request`]. The provided default /// implementation will internally create a single-threaded tokio runtime to /// perform the conversion and receive the request body. /// /// Note that this does not provide a way to *write* a blocking version of /// [`from_request`]. Implementors of this trait must always implement /// [`from_request`] in a non-blocking fashion, even if they *also* /// implement this method. /// /// [`from_request`]: #tymethod.from_request fn from_request_sync( request: http::Request<hyper::Body>, context: Self::Context, ) -> Result<Self, BoxedError> { let mut rt = Runtime::new().expect("couldn't start single-threaded tokio runtime"); rt.block_on(Self::from_request(request, context).into_future()) } } /// A request guard that checks a condition or extracts data out of an incoming /// request. /// /// For example, this could be used to extract an `Authorization` header and /// verify user credentials, or to look up a session token in a database. /// /// A `Guard` can not access the request body. If you need to do that, implement /// [`FromBody`] instead. /// /// # Examples /// /// Define a guard that ensures that required request headers are present: /// /// ``` /// # use hyperdrive::{Guard, NoContext, BoxedError}; /// # use std::sync::Arc; /// struct MustFrobnicate; /// /// impl Guard for MustFrobnicate { /// type Context = NoContext; /// type Result = Result<Self, BoxedError>; /// /// fn from_request(request: &Arc<http::Request<()>>, context: &Self::Context) -> Self::Result { /// if request.headers().contains_key("X-Frobnicate") { /// Ok(MustFrobnicate) /// } else { /// let msg = "request did not contain mandatory `X-Frobnicate` header"; /// Err(String::from(msg).into()) /// } /// } /// } /// ``` /// /// Use server settings stored in a [`RequestContext`] to exclude certain user /// agents: /// /// ``` /// # use hyperdrive::{Guard, RequestContext, BoxedError}; /// # use std::sync::Arc; /// #[derive(RequestContext)] /// struct ForbiddenAgents { /// agents: Vec<String>, /// } /// /// struct RejectForbiddenAgents; /// /// impl Guard for RejectForbiddenAgents { /// type Context = ForbiddenAgents; /// type Result = Result<Self, BoxedError>; /// /// fn from_request(request: &Arc<http::Request<()>>, context: &Self::Context) -> Self::Result { /// let agent = request.headers().get("User-Agent") /// .ok_or_else(|| String::from("No User-Agent header"))?; /// /// if context.agents.iter().any(|f| f == agent) { /// Err(String::from("This User-Agent is forbidden!").into()) /// } else { /// Ok(RejectForbiddenAgents) /// } /// } /// } /// ``` /// /// [`FromBody`]: trait.FromBody.html /// [`RequestContext`]: trait.RequestContext.html pub trait Guard: Sized { /// A context parameter passed to [`Guard::from_request`]. /// /// This can be used to pass application-specific data like a database /// connection or server configuration (eg. for limiting the maximum HTTP /// request size) around. /// /// If no context is needed, this should be set to [`NoContext`]. /// /// [`Guard::from_request`]: #tymethod.from_request /// [`NoContext`]: struct.NoContext.html type Context: RequestContext; /// The result returned by [`Guard::from_request`]. /// /// Because `impl Trait` cannot be used inside traits (and named /// existential types aren't stable), the type here might not be /// nameable. In that case, you can set it to /// [`DefaultFuture<Self, Error>`][`DefaultFuture`] and box the returned /// future. /// /// If your guard doesn't need to return a future (eg. because it's just a /// parsing step), you can set this to `Result<Self, BoxedError>` and /// immediately return the result of the conversion. /// /// [`Guard::from_request`]: #tymethod.from_request /// [`DefaultFuture`]: type.DefaultFuture.html type Result: IntoFuture<Item = Self, Error = BoxedError>; /// Create an instance of this type from HTTP request data, asynchronously. /// /// This can inspect HTTP headers and other data provided by /// [`http::Request`], but can not access the body of the request. If access /// to the body is needed, [`FromBody`] must be implemented instead. /// /// Implementations of this function must not block, since this function is /// always run on a futures executor. If you need to perform blocking I/O or /// long-running computations, you can call [`tokio_threadpool::blocking`]. /// /// # Parameters /// /// * **`request`**: An HTTP request (without body) from the `http` crate. /// * **`context`**: User-defined context needed by the guard. /// /// [`http::Request`]: ../http/request/struct.Request.html /// [`FromBody`]: trait.FromBody.html /// [`tokio_threadpool::blocking`]: ../tokio_threadpool/fn.blocking.html fn from_request(request: &Arc<http::Request<()>>, context: &Self::Context) -> Self::Result; } /// Asynchronous conversion from an HTTP request body. /// /// Types implementing this trait are provided in the [`body`] module. They /// allow easy deserialization from a variety of data formats. /// /// # Examples /// /// Collect the whole body and then deserialize it using a serde data format /// crate `serde_whatever`: /// /// ``` /// # use hyperdrive::{FromBody, NoContext, DefaultFuture, BoxedError}; /// # use futures::prelude::*; /// # use serde_json as serde_whatever; /// # use std::sync::Arc; /// struct CustomFormat<T>(T); /// /// impl<T: serde::de::DeserializeOwned + Send + 'static> FromBody for CustomFormat<T> { /// type Context = NoContext; /// type Result = DefaultFuture<Self, BoxedError>; /// /// fn from_body( /// request: &Arc<http::Request<()>>, /// body: hyper::Body, /// context: &Self::Context, /// ) -> Self::Result { /// Box::new(body.concat2().map_err(Into::into).and_then(|body| { /// match serde_whatever::from_slice(&body) { /// Ok(t) => Ok(CustomFormat(t)), /// Err(e) => Err(e.into()), /// } /// })) /// } /// } /// ``` /// /// Process the body stream on-the-fly and calculate a checksum by adding all /// the bytes: /// /// ``` /// # use hyperdrive::{FromBody, NoContext, DefaultFuture, BoxedError}; /// # use futures::prelude::*; /// # use std::sync::Arc; /// struct BodyChecksum(u8); /// /// impl FromBody for BodyChecksum { /// type Context = NoContext; /// type Result = DefaultFuture<Self, BoxedError>; /// /// fn from_body( /// request: &Arc<http::Request<()>>, /// body: hyper::Body, /// context: &Self::Context, /// ) -> Self::Result { /// Box::new(body /// .map_err(BoxedError::from) /// .fold(0, |checksum, chunk| -> Result<_, BoxedError> { /// Ok(chunk.as_ref().iter() /// .fold(checksum, |checksum: u8, byte| { /// checksum.wrapping_add(*byte) /// })) /// }) /// .map(|checksum| BodyChecksum(checksum)) // wrap it up to create a `Self` /// ) /// } /// } /// ``` /// /// [`body`]: body/index.html pub trait FromBody: Sized { /// A context parameter passed to [`from_body`]. /// /// This can be used to pass application-specific data like a logger or a /// database connection around. /// /// If no context is needed, this should be set to [`NoContext`]. /// /// [`from_body`]: #tymethod.from_body /// [`NoContext`]: struct.NoContext.html type Context: RequestContext; /// The result returned by [`from_body`]. /// /// Because `impl Trait` cannot be used inside traits (and named /// existential types aren't stable), the type here might not be /// nameable. In that case, you can set it to /// [`DefaultFuture<Self, Error>`][`DefaultFuture`] and box the returned /// future. /// /// If your `FromBody` implementation doesn't need to return a future, you /// can set this to `Result<Self, BoxedError>` and immediately return the /// result of the conversion. /// /// [`DefaultFuture`]: type.DefaultFuture.html /// [`from_body`]: #tymethod.from_body type Result: IntoFuture<Item = Self, Error = BoxedError>; /// Create an instance of this type from an HTTP request body, /// asynchronously. /// /// This will consume the body, so only one `FromBody` type can be used for /// every processed request. /// /// Implementations of this function must not block, since this function is /// always run on a futures executor. If you need to perform blocking I/O or /// long-running computations, you can call [`tokio_threadpool::blocking`]. /// /// **Note**: You probably want to limit the size of the body to prevent /// denial of service attacks. /// /// # Parameters /// /// * **`request`**: An HTTP request (without body) from the `http` crate. /// * **`body`**: The body stream. Implements `futures::Stream`. /// * **`context`**: User-defined context. /// /// [`Guard`]: trait.Guard.html /// [`tokio_threadpool::blocking`]: ../tokio_threadpool/fn.blocking.html fn from_body( request: &Arc<http::Request<()>>, body: hyper::Body, context: &Self::Context, ) -> Self::Result; } /// A default [`RequestContext`] containing no data. /// /// This context type should be used in [`FromRequest`], [`FromBody`] and /// [`Guard`] implementations whenever no application-specific context is /// needed. It can be created from any [`RequestContext`] via /// `AsRef<NoContext>`. /// /// [`FromRequest`]: trait.FromRequest.html /// [`FromBody`]: trait.FromBody.html /// [`Guard`]: trait.Guard.html /// [`RequestContext`]: trait.RequestContext.html #[derive(Debug, Copy, Clone, Default)] pub struct NoContext; /// Trait for context types passed to [`FromRequest`], [`FromBody`] and /// [`Guard`]. /// /// # `#[derive(RequestContext)]` /// /// This trait can be derived automatically. This will also implement /// `AsRef<Self>` and `AsRef<NoContext>`. /// /// On structs, fields can also be annotated using `#[as_ref]`, which generates /// an additional implementation of `AsRef` for that field (note that all /// `#[as_ref]` fields must have distinct types). This will automatically use /// the field's type as a context when required by a `FromRequest` impl. /// /// # Examples /// /// Create your own context that allows running database queries in [`Guard`]s /// and elsewhere: /// ``` /// # use hyperdrive::RequestContext; /// # struct ConnectionPool {} /// #[derive(RequestContext)] /// struct MyContext { /// db: ConnectionPool, /// } /// ``` /// /// Create a context that contains the above context and additional data: /// ``` /// # use hyperdrive::RequestContext; /// # struct Logger {} /// # #[derive(RequestContext)] /// # struct MyContext {} /// #[derive(RequestContext)] /// struct BigContext { /// #[as_ref] /// inner: MyContext, /// logger: Logger, /// } /// ``` /// This context can be used in the same places where `MyContext` is accepted, /// but provides additional data that may be used only by a few [`Guard`], /// [`FromRequest`] or [`FromBody`] implementations. /// /// [`Guard`]: trait.Guard.html /// [`FromRequest`]: trait.FromRequest.html /// [`FromBody`]: trait.FromBody.html pub trait RequestContext: AsRef<Self> + AsRef<NoContext> {} impl RequestContext for NoContext {} impl AsRef<NoContext> for NoContext { fn as_ref(&self) -> &Self { &NoContext } } /// Turns a blocking closure into an asynchronous `Future`. /// /// This function takes a blocking closure that does synchronous I/O or heavy /// computations, and turns it into a well-behaved asynchronous `Future` by /// running it on a thread pool. /// /// The returned future will have `'static` lifetime if the passed closure and /// the success and error types do. /// /// This is a convenience wrapper around [`tokio_threadpool::blocking`]. /// /// [`tokio_threadpool::blocking`]: ../tokio_threadpool/fn.blocking.html pub fn blocking<F, T, E>(f: F) -> impl Future<Item = T, Error = E> where F: FnOnce() -> Result<T, E>, { // Needs a small `Option` dance because `poll_fn` takes an `FnMut` let mut f = Some(f); futures::future::poll_fn(move || { tokio_threadpool::blocking(|| f.take().unwrap()()).map_err(|blocking_err| { // `blocking` only returns errors in critical situations: // - when the threadpool has already shut down // - when tokio isn't running // This wrapper just panics in that situation. panic!( "`tokio_threadpool::blocking` returned error: {}", blocking_err ); }) }) .and_then(|result| result) }