mirror of
https://github.com/tokio-rs/axum.git
synced 2026-08-22 00:00:17 +02:00
David Pedersen
5c12328892
* Replace `hyper::Server` with `axum::Server` in docs * Change readme as well
554 lines
15 KiB
Rust
554 lines
15 KiB
Rust
//! Types and traits for extracting data from requests.
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//!
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//! A handler function is an async function take takes any number of
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//! "extractors" as arguments. An extractor is a type that implements
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//! [`FromRequest`](crate::extract::FromRequest).
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//!
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//! For example, [`Json`] is an extractor that consumes the request body and
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//! deserializes it as JSON into some target type:
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//!
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//! ```rust,no_run
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//! use axum::prelude::*;
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//! use serde::Deserialize;
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//!
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//! #[derive(Deserialize)]
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//! struct CreateUser {
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//! email: String,
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//! password: String,
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//! }
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//!
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//! async fn create_user(payload: extract::Json<CreateUser>) {
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//! let payload: CreateUser = payload.0;
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//!
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//! // ...
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//! }
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//!
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//! let app = route("/users", post(create_user));
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//! # async {
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//! # axum::Server::bind(&"".parse().unwrap()).serve(app.into_make_service()).await.unwrap();
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//! # };
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//! ```
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//!
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//! # Defining custom extractors
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//!
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//! You can also define your own extractors by implementing [`FromRequest`]:
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//!
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//! ```rust,no_run
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//! use axum::{async_trait, extract::{FromRequest, RequestParts}, prelude::*};
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//! use http::{StatusCode, header::{HeaderValue, USER_AGENT}};
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//!
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//! struct ExtractUserAgent(HeaderValue);
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//!
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//! #[async_trait]
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//! impl<B> FromRequest<B> for ExtractUserAgent
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//! where
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//! B: Send,
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//! {
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//! type Rejection = (StatusCode, &'static str);
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//!
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//! async fn from_request(req: &mut RequestParts<B>) -> Result<Self, Self::Rejection> {
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//! let user_agent = req.headers().and_then(|headers| headers.get(USER_AGENT));
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//!
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//! if let Some(user_agent) = user_agent {
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//! Ok(ExtractUserAgent(user_agent.clone()))
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//! } else {
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//! Err((StatusCode::BAD_REQUEST, "`User-Agent` header is missing"))
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//! }
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//! }
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//! }
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//!
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//! async fn handler(user_agent: ExtractUserAgent) {
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//! let user_agent: HeaderValue = user_agent.0;
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//!
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//! // ...
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//! }
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//!
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//! let app = route("/foo", get(handler));
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//! # async {
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//! # axum::Server::bind(&"".parse().unwrap()).serve(app.into_make_service()).await.unwrap();
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//! # };
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//! ```
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//!
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//! # Multiple extractors
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//!
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//! Handlers can also contain multiple extractors:
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//!
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//! ```rust,no_run
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//! use axum::prelude::*;
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//! use std::collections::HashMap;
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//!
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//! async fn handler(
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//! // Extract captured parameters from the URL
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//! params: extract::UrlParamsMap,
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//! // Parse query string into a `HashMap`
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//! query_params: extract::Query<HashMap<String, String>>,
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//! // Buffer the request body into a `Bytes`
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//! bytes: bytes::Bytes,
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//! ) {
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//! // ...
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//! }
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//!
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//! let app = route("/foo", get(handler));
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//! # async {
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//! # axum::Server::bind(&"".parse().unwrap()).serve(app.into_make_service()).await.unwrap();
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//! # };
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//! ```
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//!
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//! Note that only one extractor can consume the request body. If multiple body extractors are
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//! applied a `500 Internal Server Error` response will be returned.
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//!
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//! # Optional extractors
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//!
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//! Wrapping extractors in `Option` will make them optional:
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//!
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//! ```rust,no_run
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//! use axum::{extract::Json, prelude::*};
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//! use serde_json::Value;
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//!
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//! async fn create_user(payload: Option<Json<Value>>) {
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//! if let Some(payload) = payload {
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//! // We got a valid JSON payload
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//! } else {
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//! // Payload wasn't valid JSON
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//! }
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//! }
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//!
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//! let app = route("/users", post(create_user));
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//! # async {
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//! # axum::Server::bind(&"".parse().unwrap()).serve(app.into_make_service()).await.unwrap();
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//! # };
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//! ```
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//!
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//! Wrapping extractors in `Result` makes them optional and gives you the reason
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//! the extraction failed:
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//!
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//! ```rust,no_run
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//! use axum::{extract::{Json, rejection::JsonRejection}, prelude::*};
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//! use serde_json::Value;
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//!
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//! async fn create_user(payload: Result<Json<Value>, JsonRejection>) {
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//! match payload {
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//! Ok(payload) => {
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//! // We got a valid JSON payload
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//! }
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//! Err(JsonRejection::MissingJsonContentType(_)) => {
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//! // Request didn't have `Content-Type: application/json`
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//! // header
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//! }
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//! Err(JsonRejection::InvalidJsonBody(_)) => {
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//! // Couldn't deserialize the body into the target type
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//! }
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//! Err(JsonRejection::BodyAlreadyExtracted(_)) => {
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//! // Another extractor had already consumed the body
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//! }
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//! Err(_) => {
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//! // `JsonRejection` is marked `#[non_exhaustive]` so match must
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//! // include a catch-all case.
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//! }
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//! }
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//! }
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//!
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//! let app = route("/users", post(create_user));
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//! # async {
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//! # axum::Server::bind(&"".parse().unwrap()).serve(app.into_make_service()).await.unwrap();
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//! # };
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//! ```
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//!
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//! # Reducing boilerplate
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//!
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//! If you're feeling adventorous you can even deconstruct the extractors
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//! directly on the function signature:
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//!
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//! ```rust,no_run
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//! use axum::{extract::Json, prelude::*};
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//! use serde_json::Value;
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//!
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//! async fn create_user(Json(value): Json<Value>) {
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//! // `value` is of type `Value`
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//! }
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//!
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//! let app = route("/users", post(create_user));
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//! # async {
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//! # axum::Server::bind(&"".parse().unwrap()).serve(app.into_make_service()).await.unwrap();
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//! # };
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//! ```
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//!
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//! # Request body extractors
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//!
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//! Most of the time your request body type will be [`body::Body`] (a re-export
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//! of [`hyper::Body`]), which is directly supported by all extractors.
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//!
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//! However if you're applying a tower middleware that changes the response you
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//! might have to apply a different body type to some extractors:
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//!
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//! ```rust
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//! use std::{
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//! task::{Context, Poll},
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//! pin::Pin,
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//! };
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//! use tower_http::map_request_body::MapRequestBodyLayer;
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//! use axum::prelude::*;
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//!
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//! struct MyBody<B>(B);
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//!
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//! impl<B> http_body::Body for MyBody<B>
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//! where
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//! B: http_body::Body + Unpin,
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//! {
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//! type Data = B::Data;
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//! type Error = B::Error;
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//!
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//! fn poll_data(
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//! mut self: Pin<&mut Self>,
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//! cx: &mut Context<'_>,
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//! ) -> Poll<Option<Result<Self::Data, Self::Error>>> {
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//! Pin::new(&mut self.0).poll_data(cx)
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//! }
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//!
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//! fn poll_trailers(
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//! mut self: Pin<&mut Self>,
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//! cx: &mut Context<'_>,
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//! ) -> Poll<Result<Option<headers::HeaderMap>, Self::Error>> {
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//! Pin::new(&mut self.0).poll_trailers(cx)
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//! }
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//! }
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//!
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//! let app =
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//! // `String` works directly with any body type
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//! route(
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//! "/string",
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//! get(|_: String| async {})
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//! )
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//! .route(
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//! "/body",
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//! // `extract::Body` defaults to `axum::body::Body`
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//! // but can be customized
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//! get(|_: extract::Body<MyBody<Body>>| async {})
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//! )
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//! .route(
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//! "/body-stream",
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//! // same for `extract::BodyStream`
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//! get(|_: extract::BodyStream<MyBody<Body>>| async {}),
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//! )
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//! .route(
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//! // and `Request<_>`
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//! "/request",
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//! get(|_: Request<MyBody<Body>>| async {})
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//! )
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//! // middleware that changes the request body type
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//! .layer(MapRequestBodyLayer::new(MyBody));
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//! # async {
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//! # axum::Server::bind(&"".parse().unwrap()).serve(app.into_make_service()).await.unwrap();
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//! # };
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//! ```
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//!
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//! [`body::Body`]: crate::body::Body
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use crate::response::IntoResponse;
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use async_trait::async_trait;
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use http::{header, Extensions, HeaderMap, Method, Request, Uri, Version};
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use rejection::*;
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use std::convert::Infallible;
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pub mod connect_info;
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pub mod extractor_middleware;
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pub mod rejection;
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mod content_length_limit;
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mod extension;
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mod form;
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mod json;
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mod query;
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mod raw_query;
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mod request_parts;
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mod tuple;
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mod url_params;
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mod url_params_map;
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#[doc(inline)]
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pub use self::{
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connect_info::ConnectInfo,
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content_length_limit::ContentLengthLimit,
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extension::Extension,
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extractor_middleware::extractor_middleware,
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form::Form,
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json::Json,
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query::Query,
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raw_query::RawQuery,
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request_parts::{Body, BodyStream},
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url_params::UrlParams,
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url_params_map::UrlParamsMap,
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};
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#[cfg(feature = "multipart")]
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#[cfg_attr(docsrs, doc(cfg(feature = "multipart")))]
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pub mod multipart;
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#[cfg(feature = "multipart")]
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#[cfg_attr(docsrs, doc(cfg(feature = "multipart")))]
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#[doc(inline)]
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pub use self::multipart::Multipart;
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#[cfg(feature = "headers")]
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#[cfg_attr(docsrs, doc(cfg(feature = "headers")))]
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mod typed_header;
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#[cfg(feature = "headers")]
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#[cfg_attr(docsrs, doc(cfg(feature = "headers")))]
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#[doc(inline)]
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pub use self::typed_header::TypedHeader;
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/// Types that can be created from requests.
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///
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/// See the [module docs](crate::extract) for more details.
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#[async_trait]
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pub trait FromRequest<B>: Sized {
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/// If the extractor fails it'll use this "rejection" type. A rejection is
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/// a kind of error that can be converted into a response.
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type Rejection: IntoResponse;
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/// Perform the extraction.
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async fn from_request(req: &mut RequestParts<B>) -> Result<Self, Self::Rejection>;
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}
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/// The type used with [`FromRequest`] to extract data from requests.
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///
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/// Has several convenience methods for getting owned parts of the request.
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#[derive(Debug)]
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pub struct RequestParts<B> {
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method: Option<Method>,
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uri: Option<Uri>,
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version: Option<Version>,
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headers: Option<HeaderMap>,
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extensions: Option<Extensions>,
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body: Option<B>,
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}
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impl<B> RequestParts<B> {
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pub(crate) fn new(req: Request<B>) -> Self {
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let (
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http::request::Parts {
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method,
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uri,
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version,
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headers,
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extensions,
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..
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},
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body,
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) = req.into_parts();
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RequestParts {
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method: Some(method),
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uri: Some(uri),
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version: Some(version),
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headers: Some(headers),
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extensions: Some(extensions),
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body: Some(body),
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}
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}
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#[allow(clippy::wrong_self_convention)]
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pub(crate) fn into_request(&mut self) -> Request<B> {
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let Self {
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method,
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uri,
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version,
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headers,
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extensions,
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body,
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} = self;
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let mut req = Request::new(body.take().expect("body already extracted"));
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if let Some(method) = method.take() {
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*req.method_mut() = method;
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}
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if let Some(uri) = uri.take() {
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*req.uri_mut() = uri;
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}
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if let Some(version) = version.take() {
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*req.version_mut() = version;
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}
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if let Some(headers) = headers.take() {
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*req.headers_mut() = headers;
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}
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if let Some(extensions) = extensions.take() {
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*req.extensions_mut() = extensions;
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}
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req
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}
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/// Gets a reference to the request method.
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///
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/// Returns `None` if the method has been taken by another extractor.
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pub fn method(&self) -> Option<&Method> {
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self.method.as_ref()
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}
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/// Gets a mutable reference to the request method.
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///
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/// Returns `None` if the method has been taken by another extractor.
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pub fn method_mut(&mut self) -> Option<&mut Method> {
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self.method.as_mut()
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}
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/// Takes the method out of the request, leaving a `None` in its place.
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pub fn take_method(&mut self) -> Option<Method> {
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self.method.take()
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}
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/// Gets a reference to the request URI.
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///
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/// Returns `None` if the URI has been taken by another extractor.
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pub fn uri(&self) -> Option<&Uri> {
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self.uri.as_ref()
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}
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/// Gets a mutable reference to the request URI.
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///
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/// Returns `None` if the URI has been taken by another extractor.
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pub fn uri_mut(&mut self) -> Option<&mut Uri> {
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self.uri.as_mut()
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}
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/// Takes the URI out of the request, leaving a `None` in its place.
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pub fn take_uri(&mut self) -> Option<Uri> {
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self.uri.take()
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}
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/// Gets a reference to the request HTTP version.
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///
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/// Returns `None` if the HTTP version has been taken by another extractor.
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pub fn version(&self) -> Option<Version> {
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self.version
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}
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/// Gets a mutable reference to the request HTTP version.
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///
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/// Returns `None` if the HTTP version has been taken by another extractor.
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pub fn version_mut(&mut self) -> Option<&mut Version> {
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self.version.as_mut()
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}
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/// Takes the HTTP version out of the request, leaving a `None` in its place.
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pub fn take_version(&mut self) -> Option<Version> {
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self.version.take()
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}
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/// Gets a reference to the request headers.
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///
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/// Returns `None` if the headers has been taken by another extractor.
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pub fn headers(&self) -> Option<&HeaderMap> {
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self.headers.as_ref()
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}
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/// Gets a mutable reference to the request headers.
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///
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/// Returns `None` if the headers has been taken by another extractor.
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pub fn headers_mut(&mut self) -> Option<&mut HeaderMap> {
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self.headers.as_mut()
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}
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/// Takes the headers out of the request, leaving a `None` in its place.
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pub fn take_headers(&mut self) -> Option<HeaderMap> {
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self.headers.take()
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}
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/// Gets a reference to the request extensions.
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///
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/// Returns `None` if the extensions has been taken by another extractor.
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pub fn extensions(&self) -> Option<&Extensions> {
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self.extensions.as_ref()
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}
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/// Gets a mutable reference to the request extensions.
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///
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/// Returns `None` if the extensions has been taken by another extractor.
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pub fn extensions_mut(&mut self) -> Option<&mut Extensions> {
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self.extensions.as_mut()
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}
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/// Takes the extensions out of the request, leaving a `None` in its place.
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pub fn take_extensions(&mut self) -> Option<Extensions> {
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self.extensions.take()
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}
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/// Gets a reference to the request body.
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///
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/// Returns `None` if the body has been taken by another extractor.
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pub fn body(&self) -> Option<&B> {
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self.body.as_ref()
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}
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/// Gets a mutable reference to the request body.
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///
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/// Returns `None` if the body has been taken by another extractor.
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pub fn body_mut(&mut self) -> Option<&mut B> {
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self.body.as_mut()
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}
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/// Takes the body out of the request, leaving a `None` in its place.
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pub fn take_body(&mut self) -> Option<B> {
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self.body.take()
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}
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}
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#[async_trait]
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impl<T, B> FromRequest<B> for Option<T>
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where
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T: FromRequest<B>,
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B: Send,
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{
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type Rejection = Infallible;
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async fn from_request(req: &mut RequestParts<B>) -> Result<Option<T>, Self::Rejection> {
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Ok(T::from_request(req).await.ok())
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}
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}
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#[async_trait]
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impl<T, B> FromRequest<B> for Result<T, T::Rejection>
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where
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T: FromRequest<B>,
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B: Send,
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{
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type Rejection = Infallible;
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async fn from_request(req: &mut RequestParts<B>) -> Result<Self, Self::Rejection> {
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Ok(T::from_request(req).await)
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}
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}
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fn has_content_type<B>(
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req: &RequestParts<B>,
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expected_content_type: &str,
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) -> Result<bool, HeadersAlreadyExtracted> {
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let content_type = if let Some(content_type) = req
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.headers()
|
|
.ok_or(HeadersAlreadyExtracted)?
|
|
.get(header::CONTENT_TYPE)
|
|
{
|
|
content_type
|
|
} else {
|
|
return Ok(false);
|
|
};
|
|
|
|
let content_type = if let Ok(content_type) = content_type.to_str() {
|
|
content_type
|
|
} else {
|
|
return Ok(false);
|
|
};
|
|
|
|
Ok(content_type.starts_with(expected_content_type))
|
|
}
|
|
|
|
fn take_body<B>(req: &mut RequestParts<B>) -> Result<B, BodyAlreadyExtracted> {
|
|
req.take_body().ok_or(BodyAlreadyExtracted)
|
|
}
|