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This commit is contained in:
David Pedersen
2021-06-08 22:04:28 +02:00
parent 1f8b39f05d
commit 1cf78fa807
6 changed files with 392 additions and 58 deletions
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src/extract/mod.rs
+308 -10
View File
@@ -1,4 +1,142 @@
//! Types and traits for extracting data from requests.
//!
//! A handler function must always take `Request<Body>` as its first argument
//! but any arguments following are called "extractors". Any type that
//! implements [`FromRequest`](FromRequest) can be used as an extractor.
//!
//! For example, [`Json`] is an extractor that consumes the request body and
//! deserializes it as JSON into some target type:
//!
//! ```rust,no_run
//! use tower_web::prelude::*;
//! use serde::Deserialize;
//!
//! #[derive(Deserialize)]
//! struct CreateUser {
//! email: String,
//! password: String,
//! }
//!
//! async fn create_user(req: Request<Body>, payload: extract::Json<CreateUser>) {
//! let payload: CreateUser = payload.0;
//!
//! // ...
//! }
//!
//! let app = route("/users", post(create_user));
//! # async {
//! # hyper::Server::bind(&"".parse().unwrap()).serve(tower::make::Shared::new(app)).await;
//! # };
//! ```
//!
//! Technically extractors can also be used as "guards", for example to require
//! that requests are authorized. However the recommended way to do that is
//! using Tower middleware, such as [`tower_http::auth::RequireAuthorization`].
//! Extractors have to be applied to each handler, whereas middleware can be
//! applied to a whole stack at once, which is typically what you want for
//! authorization.
//!
//! # Defining custom extractors
//!
//! You can also define your own extractors by implementing [`FromRequest`]:
//!
//! ```rust,no_run
//! use tower_web::{async_trait, extract::FromRequest, prelude::*};
//! use http::{StatusCode, header::{HeaderValue, USER_AGENT}};
//!
//! struct ExtractUserAgent(HeaderValue);
//!
//! #[async_trait]
//! impl FromRequest for ExtractUserAgent {
//! type Rejection = (StatusCode, &'static str);
//!
//! async fn from_request(req: &mut Request<Body>) -> Result<Self, Self::Rejection> {
//! if let Some(user_agent) = req.headers().get(USER_AGENT) {
//! Ok(ExtractUserAgent(user_agent.clone()))
//! } else {
//! Err((StatusCode::BAD_REQUEST, "`User-Agent` header is missing"))
//! }
//! }
//! }
//!
//! async fn handler(req: Request<Body>, user_agent: ExtractUserAgent) {
//! let user_agent: HeaderValue = user_agent.0;
//!
//! // ...
//! }
//!
//! let app = route("/foo", get(handler));
//! # async {
//! # hyper::Server::bind(&"".parse().unwrap()).serve(tower::make::Shared::new(app)).await;
//! # };
//! ```
//!
//! # Multiple extractors
//!
//! Handlers can also contain multiple extractors:
//!
//! ```rust,no_run
//! use tower_web::prelude::*;
//! use std::collections::HashMap;
//!
//! async fn handler(
//! req: Request<Body>,
//! // Extract captured parameters from the URL
//! params: extract::UrlParamsMap,
//! // Parse query string into a `HashMap`
//! query_params: extract::Query<HashMap<String, String>>,
//! // Buffer the request body into a `Bytes`
//! bytes: bytes::Bytes,
//! ) {
//! // ...
//! }
//!
//! let app = route("/foo", get(handler));
//! # async {
//! # hyper::Server::bind(&"".parse().unwrap()).serve(tower::make::Shared::new(app)).await;
//! # };
//! ```
//!
//! # Optional extractors
//!
//! Wrapping extractors in `Option` will make them optional:
//!
//! ```rust,no_run
//! use tower_web::{extract::Json, prelude::*};
//! use serde_json::Value;
//!
//! async fn create_user(req: Request<Body>, payload: Option<Json<Value>>) {
//! if let Some(payload) = payload {
//! // We got a valid JSON payload
//! } else {
//! // Payload wasn't valid JSON
//! }
//! }
//!
//! let app = route("/users", post(create_user));
//! # async {
//! # hyper::Server::bind(&"".parse().unwrap()).serve(tower::make::Shared::new(app)).await;
//! # };
//! ```
//!
//! # Reducing boilerplate
//!
//! If you're feeling adventorous you can even deconstruct the extractors
//! directly on the function signature:
//!
//! ```rust,no_run
//! use tower_web::{extract::Json, prelude::*};
//! use serde_json::Value;
//!
//! async fn create_user(req: Request<Body>, Json(value): Json<Value>) {
//! // `value` is of type `Value`
//! }
//!
//! let app = route("/users", post(create_user));
//! # async {
//! # hyper::Server::bind(&"".parse().unwrap()).serve(tower::make::Shared::new(app)).await;
//! # };
//! ```
use crate::{body::Body, response::IntoResponse};
use async_trait::async_trait;
@@ -7,17 +145,23 @@ use http::{header, Request, Response};
use rejection::{
BodyAlreadyTaken, FailedToBufferBody, InvalidJsonBody, InvalidUrlParam, InvalidUtf8,
LengthRequired, MissingExtension, MissingJsonContentType, MissingRouteParams, PayloadTooLarge,
QueryStringMissing,
QueryStringMissing, UrlParamsAlreadyTaken,
};
use serde::de::DeserializeOwned;
use std::{collections::HashMap, convert::Infallible, str::FromStr};
pub mod rejection;
/// Types that can be created from requests.
///
/// See the [module docs](crate::extract) for more details.
#[async_trait]
pub trait FromRequest: Sized {
/// If the extractor fails it'll use this "rejection" type. A rejection is
/// a kind of error that can be converted into a response.
type Rejection: IntoResponse;
/// Perform the extraction.
async fn from_request(req: &mut Request<Body>) -> Result<Self, Self::Rejection>;
}
@@ -33,6 +177,34 @@ where
}
}
/// Extractor that deserializes query strings into some type.
///
/// `T` is expected to implement [`serde::Deserialize`].
///
/// # Example
///
/// ```rust,no_run
/// use tower_web::prelude::*;
/// use serde::Deserialize;
///
/// #[derive(Deserialize)]
/// struct Pagination {
/// page: usize,
/// per_page: usize,
/// }
///
/// // This will parse query strings like `?page=2&per_page=30` into `Pagination`
/// // structs.
/// async fn list_things(req: Request<Body>, pagination: extract::Query<Pagination>) {
/// let pagination: Pagination = pagination.0;
///
/// // ...
/// }
/// let app = route("/list_things", get(list_things));
/// ```
///
/// If the query string cannot be parsed it will reject the request with a `404
/// Bad Request` response.
#[derive(Debug, Clone, Copy, Default)]
pub struct Query<T>(pub T);
@@ -50,6 +222,35 @@ where
}
}
/// Extractor that deserializes request bodies into some type.
///
/// `T` is expected to implement [`serde::Deserialize`].
///
/// # Example
///
/// ```rust,no_run
/// use tower_web::prelude::*;
/// use serde::Deserialize;
///
/// #[derive(Deserialize)]
/// struct CreateUser {
/// email: String,
/// password: String,
/// }
///
/// async fn create_user(req: Request<Body>, payload: extract::Json<CreateUser>) {
/// let payload: CreateUser = payload.0;
///
/// // ...
/// }
///
/// let app = route("/users", post(create_user));
/// ```
///
/// If the query string cannot be parsed it will reject the request with a `404
/// Bad Request` response.
///
/// The request is required to have a `Content-Type: application/json` header.
#[derive(Debug, Clone, Copy, Default)]
pub struct Json<T>(pub T);
@@ -61,15 +262,17 @@ where
type Rejection = Response<Body>;
async fn from_request(req: &mut Request<Body>) -> Result<Self, Self::Rejection> {
use bytes::Buf;
if has_content_type(req, "application/json") {
let body = take_body(req).map_err(IntoResponse::into_response)?;
let bytes = hyper::body::to_bytes(body)
let buf = hyper::body::aggregate(body)
.await
.map_err(InvalidJsonBody::from_err)
.map_err(IntoResponse::into_response)?;
let value = serde_json::from_slice(&bytes)
let value = serde_json::from_reader(buf.reader())
.map_err(InvalidJsonBody::from_err)
.map_err(IntoResponse::into_response)?;
@@ -96,6 +299,35 @@ fn has_content_type<B>(req: &Request<B>, expected_content_type: &str) -> bool {
content_type.starts_with(expected_content_type)
}
/// Extractor that gets a value from request extensions.
///
/// This is commonly used to share state across handlers.
///
/// # Example
///
/// ```rust,no_run
/// use tower_web::{AddExtensionLayer, prelude::*};
/// use std::sync::Arc;
///
/// // Some shared state used throughout our application
/// struct State {
/// // ...
/// }
///
/// async fn handler(req: Request<Body>, state: extract::Extension<Arc<State>>) {
/// // ...
/// }
///
/// let state = Arc::new(State { /* ... */ });
///
/// let app = route("/", get(handler))
/// // Add middleware that inserts the state into all incoming request's
/// // extensions.
/// .layer(AddExtensionLayer::new(state));
/// ```
///
/// If the extension is missing it will reject the request with a `500 Interal
/// Server Error` response.
#[derive(Debug, Clone, Copy)]
pub struct Extension<T>(pub T);
@@ -163,6 +395,21 @@ impl FromRequest for Body {
}
}
/// Extractor that will buffer request bodies up to a certain size.
///
/// # Example
///
/// ```rust,no_run
/// use tower_web::prelude::*;
///
/// async fn handler(req: Request<Body>, body: extract::BytesMaxLength<1024>) {
/// // ...
/// }
///
/// let app = route("/", post(handler));
/// ```
///
/// This requires the request to have a `Content-Length` header.
#[derive(Debug, Clone)]
pub struct BytesMaxLength<const N: u64>(pub Bytes);
@@ -193,39 +440,86 @@ impl<const N: u64> FromRequest for BytesMaxLength<N> {
}
}
/// Extractor that will get captures from the URL.
///
/// # Example
///
/// ```rust,no_run
/// use tower_web::prelude::*;
///
/// async fn users_show(req: Request<Body>, params: extract::UrlParamsMap) {
/// let id: Option<&str> = params.get("id");
///
/// // ...
/// }
///
/// let app = route("/users/:id", get(users_show));
/// ```
///
/// Note that you can only have one URL params extractor per handler. If you
/// have multiple it'll response with `500 Internal Server Error`.
#[derive(Debug)]
pub struct UrlParamsMap(HashMap<String, String>);
impl UrlParamsMap {
/// Look up the value for a key.
pub fn get(&self, key: &str) -> Option<&str> {
self.0.get(key).map(|s| &**s)
}
pub fn get_typed<T>(&self, key: &str) -> Option<T>
/// Look up the value for a key and parse it into a value of type `T`.
pub fn get_typed<T>(&self, key: &str) -> Option<Result<T, T::Err>>
where
T: FromStr,
{
self.get(key)?.parse().ok()
self.get(key).map(str::parse)
}
}
#[async_trait]
impl FromRequest for UrlParamsMap {
type Rejection = MissingRouteParams;
type Rejection = Response<Body>;
async fn from_request(req: &mut Request<Body>) -> Result<Self, Self::Rejection> {
if let Some(params) = req
.extensions_mut()
.get_mut::<Option<crate::routing::UrlParams>>()
{
let params = params.take().expect("params already taken").0;
Ok(Self(params.into_iter().collect()))
if let Some(params) = params.take() {
Ok(Self(params.0.into_iter().collect()))
} else {
Err(UrlParamsAlreadyTaken.into_response())
}
} else {
Err(MissingRouteParams)
Err(MissingRouteParams.into_response())
}
}
}
/// Extractor that will get captures from the URL and parse them.
///
/// # Example
///
/// ```rust,no_run
/// use tower_web::{extract::UrlParams, prelude::*};
/// use uuid::Uuid;
///
/// async fn users_teams_show(
/// req: Request<Body>,
/// UrlParams(params): UrlParams<(Uuid, Uuid)>,
/// ) {
/// let user_id: Uuid = params.0;
/// let team_id: Uuid = params.1;
///
/// // ...
/// }
///
/// let app = route("/users/:user_id/team/:team_id", get(users_teams_show));
/// ```
///
/// Note that you can only have one URL params extractor per handler. If you
/// have multiple it'll response with `500 Internal Server Error`.
#[derive(Debug)]
pub struct UrlParams<T>(pub T);
macro_rules! impl_parse_url {
@@ -246,7 +540,11 @@ macro_rules! impl_parse_url {
.extensions_mut()
.get_mut::<Option<crate::routing::UrlParams>>()
{
params.take().expect("params already taken").0
if let Some(params) = params.take() {
params.0
} else {
return Err(UrlParamsAlreadyTaken.into_response());
}
} else {
return Err(MissingRouteParams.into_response())
};
src/extract/rejection.rs
+7
View File
@@ -125,6 +125,13 @@ define_rejection! {
pub struct MissingRouteParams;
}
define_rejection! {
#[status = INTERNAL_SERVER_ERROR]
#[body = "Cannot have two URL capture extractors for a single handler"]
/// Rejection type used if you try and extract the URL params more than once.
pub struct UrlParamsAlreadyTaken;
}
define_rejection! {
#[status = INTERNAL_SERVER_ERROR]
#[body = "Cannot have two request body extractors for a single handler"]