Initial pile of hacks

This commit is contained in:
David Pedersen 2021-05-29 21:13:06 +02:00
commit 07294378b3
3 changed files with 453 additions and 0 deletions

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.gitignore vendored Normal file
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/target
Cargo.lock

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Cargo.toml Normal file
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[package]
name = "tower-web"
version = "0.1.0"
authors = ["David Pedersen <david.pdrsn@gmail.com>"]
edition = "2018"
[dependencies]
async-trait = "0.1"
bytes = "1.0"
http = "0.2"
http-body = "0.4"
hyper = "0.14"
serde = "1.0"
serde_urlencoded = "0.7"
serde_json = "1.0"
futures-util = "0.3"
tower = { version = "0.4", features = ["util"] }
thiserror = "1.0"
[dev-dependencies]
tokio = { version = "1.6.1", features = ["macros", "rt"] }
serde = { version = "1.0", features = ["derive"] }

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src/lib.rs Normal file
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#![allow(unused_imports, dead_code)]
/*
Improvements to make:
Somehow return generic "into response" kinda types without having to manually
create hyper::Body for everything
Don't make Query and Json contain a Result, instead make generic wrapper
for "optional" inputs
Make it possible to convert QueryError and JsonError into responses
Support wrapping single routes in tower::Layer
Support putting a tower::Service at a Route
Don't require the response body to be hyper::Body, wont work if we're wrapping
single routes in layers
Support extracting headers, perhaps via `headers::Header`?
Implement `FromRequest` for more functions, with macro
Tests
*/
use async_trait::async_trait;
use bytes::Bytes;
use futures_util::future;
use http::{Method, Request, Response, StatusCode};
use serde::{de::DeserializeOwned, Deserialize, Serialize};
use std::{
future::Future,
marker::PhantomData,
task::{Context, Poll},
};
use tower::{Service, ServiceExt};
pub use hyper::body::Body;
pub fn app() -> App<EmptyRouter> {
App {
router: EmptyRouter(()),
}
}
#[derive(Clone)]
pub struct App<R> {
router: R,
}
impl<R> App<R> {
pub fn at(self, route_spec: &str) -> RouteBuilder<R> {
RouteBuilder {
app: self,
route_spec: Bytes::copy_from_slice(route_spec.as_bytes()),
}
}
}
pub struct RouteBuilder<R> {
app: App<R>,
route_spec: Bytes,
}
impl<R> RouteBuilder<R> {
pub fn get<F, T>(self, handler_fn: F) -> RouteBuilder<Route<HandlerSvc<F, T>, R>>
where
F: Handler<T>,
{
self.add_route(handler_fn, Method::GET)
}
pub fn post<F, T>(self, handler_fn: F) -> RouteBuilder<Route<HandlerSvc<F, T>, R>>
where
F: Handler<T>,
{
self.add_route(handler_fn, Method::POST)
}
pub fn at(self, route_spec: &str) -> Self {
self.app.at(route_spec)
}
pub fn into_service(self) -> App<R> {
self.app
}
fn add_route<H, T>(self, handler: H, method: Method) -> RouteBuilder<Route<HandlerSvc<H, T>, R>>
where
H: Handler<T>,
{
let new_app = App {
router: Route {
handler: HandlerSvc {
handler,
_input: PhantomData,
},
route_spec: RouteSpec {
method,
spec: self.route_spec.clone(),
},
fallback: self.app.router,
},
};
RouteBuilder {
app: new_app,
route_spec: self.route_spec,
}
}
}
#[derive(Debug, thiserror::Error)]
#[non_exhaustive]
pub enum Error {}
#[async_trait]
pub trait Handler<Out> {
async fn call(self, req: Request<Body>) -> Result<Response<Body>, Error>;
}
#[async_trait]
#[allow(non_snake_case)]
impl<F, Fut> Handler<()> for F
where
F: Fn(Request<Body>) -> Fut + Send + Sync,
Fut: Future<Output = Result<Response<Body>, Error>> + Send,
{
async fn call(self, req: Request<Body>) -> Result<Response<Body>, Error> {
let res = self(req).await?;
Ok(res)
}
}
#[async_trait]
#[allow(non_snake_case)]
impl<F, Fut, T1> Handler<(T1,)> for F
where
F: Fn(Request<Body>, T1) -> Fut + Send + Sync,
Fut: Future<Output = Result<Response<Body>, Error>> + Send,
T1: FromRequest + Send,
{
async fn call(self, mut req: Request<Body>) -> Result<Response<Body>, Error> {
let T1 = T1::from_request(&mut req).await;
let res = self(req, T1).await?;
Ok(res)
}
}
#[async_trait]
#[allow(non_snake_case)]
impl<F, Fut, T1, T2> Handler<(T1, T2)> for F
where
F: Fn(Request<Body>, T1, T2) -> Fut + Send + Sync,
Fut: Future<Output = Result<Response<Body>, Error>> + Send,
T1: FromRequest + Send,
T2: FromRequest + Send,
{
async fn call(self, mut req: Request<Body>) -> Result<Response<Body>, Error> {
let T1 = T1::from_request(&mut req).await;
let T2 = T2::from_request(&mut req).await;
let res = self(req, T1, T2).await?;
Ok(res)
}
}
pub struct HandlerSvc<H, T> {
handler: H,
_input: PhantomData<fn() -> T>,
}
impl<H, T> Clone for HandlerSvc<H, T>
where
H: Clone,
{
fn clone(&self) -> Self {
Self {
handler: self.handler.clone(),
_input: PhantomData,
}
}
}
impl<H, T> Service<Request<Body>> for HandlerSvc<H, T>
where
H: Handler<T> + Clone + 'static,
{
type Response = Response<Body>;
type Error = Error;
type Future = future::BoxFuture<'static, Result<Self::Response, Self::Error>>;
fn poll_ready(&mut self, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
// HandlerSvc can only be constructed from async functions which are always ready
Poll::Ready(Ok(()))
}
fn call(&mut self, req: Request<Body>) -> Self::Future {
let handler = self.handler.clone();
Box::pin(Handler::call(handler, req))
}
}
#[async_trait]
pub trait FromRequest: Sized {
async fn from_request(req: &mut Request<Body>) -> Self;
}
pub struct Query<T>(Result<T, QueryError>);
impl<T> Query<T> {
pub fn into_inner(self) -> Result<T, QueryError> {
self.0
}
}
#[derive(Debug, thiserror::Error)]
#[non_exhaustive]
pub enum QueryError {
#[error("URI contained no query string")]
Missing,
#[error("failed to deserialize query string")]
Deserialize(#[from] serde_urlencoded::de::Error),
}
#[async_trait]
impl<T> FromRequest for Query<T>
where
T: DeserializeOwned,
{
async fn from_request(req: &mut Request<Body>) -> Self {
let result = (|| {
let query = req.uri().query().ok_or(QueryError::Missing)?;
let value = serde_urlencoded::from_str(query)?;
Ok(value)
})();
Query(result)
}
}
pub struct Json<T>(Result<T, JsonError>);
impl<T> Json<T> {
pub fn into_inner(self) -> Result<T, JsonError> {
self.0
}
}
#[derive(Debug, thiserror::Error)]
#[non_exhaustive]
pub enum JsonError {
#[error("failed to consume the body")]
ConsumeBody(#[from] hyper::Error),
#[error("failed to deserialize the body")]
Deserialize(#[from] serde_json::Error),
}
#[async_trait]
impl<T> FromRequest for Json<T>
where
T: DeserializeOwned,
{
async fn from_request(req: &mut Request<Body>) -> Self {
// TODO(david): require the body to have `content-type: application/json`
let body = std::mem::take(req.body_mut());
let result = async move {
let bytes = hyper::body::to_bytes(body).await?;
let value = serde_json::from_slice(&bytes)?;
Ok(value)
}
.await;
Json(result)
}
}
#[derive(Clone, Copy)]
pub struct EmptyRouter(());
impl Service<Request<Body>> for EmptyRouter {
type Response = Response<Body>;
type Error = Error;
type Future = future::Ready<Result<Self::Response, Self::Error>>;
fn poll_ready(&mut self, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
Poll::Ready(Ok(()))
}
fn call(&mut self, _req: Request<Body>) -> Self::Future {
let mut res = Response::new(Body::empty());
*res.status_mut() = StatusCode::NOT_FOUND;
future::ready(Ok(res))
}
}
#[derive(Clone)]
pub struct Route<H, F> {
handler: H,
route_spec: RouteSpec,
fallback: F,
}
#[derive(Clone)]
struct RouteSpec {
method: Method,
spec: Bytes,
}
impl RouteSpec {
fn matches<B>(&self, req: &Request<B>) -> bool {
// TODO(david): support dynamic placeholders like `/users/:id`
req.method() == self.method && req.uri().path().as_bytes() == self.spec
}
}
impl<H, F> Service<Request<Body>> for Route<H, F>
where
H: Service<Request<Body>, Response = Response<Body>, Error = Error> + Clone + Send + 'static,
H::Future: Send,
F: Service<Request<Body>, Response = Response<Body>, Error = Error> + Clone + Send + 'static,
F::Future: Send,
{
type Response = Response<Body>;
type Error = Error;
type Future = future::BoxFuture<'static, Result<Self::Response, Self::Error>>;
fn poll_ready(&mut self, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
// TODO(david): do we need to drive readiness in `call`?
Poll::Ready(Ok(()))
}
fn call(&mut self, req: Request<Body>) -> Self::Future {
if self.route_spec.matches(&req) {
let handler_clone = self.handler.clone();
let mut handler = std::mem::replace(&mut self.handler, handler_clone);
Box::pin(async move { handler.ready().await?.call(req).await })
} else {
let fallback_clone = self.fallback.clone();
let mut fallback = std::mem::replace(&mut self.fallback, fallback_clone);
Box::pin(async move { fallback.ready().await?.call(req).await })
}
}
}
impl<R> Service<Request<Body>> for App<R>
where
R: Service<Request<Body>, Response = Response<Body>, Error = Error> + Clone,
{
type Response = Response<Body>;
type Error = Error;
type Future = R::Future;
// TODO(david): handle backpressure
fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
self.router.poll_ready(cx)
}
fn call(&mut self, req: Request<Body>) -> Self::Future {
self.router.call(req)
}
}
#[cfg(test)]
mod tests {
#![allow(warnings)]
use super::*;
#[tokio::test]
async fn basic() {
let mut app = app()
.at("/")
.get(root)
.at("/users")
.get(users_index)
.post(users_create)
.into_service();
let req = Request::builder()
.method(Method::POST)
.uri("/users")
.body(Body::from(r#"{ "username": "bob" }"#))
.unwrap();
let res = app.ready().await.unwrap().call(req).await.unwrap();
let body = body_to_string(res).await;
dbg!(&body);
}
async fn body_to_string(res: Response<Body>) -> String {
let bytes = hyper::body::to_bytes(res.into_body()).await.unwrap();
String::from_utf8(bytes.to_vec()).unwrap()
}
async fn root(req: Request<Body>) -> Result<Response<Body>, Error> {
Ok(Response::new(Body::from("Hello, World!")))
}
async fn users_index(
req: Request<Body>,
pagination: Query<Pagination>,
) -> Result<Response<Body>, Error> {
dbg!(pagination.into_inner());
Ok(Response::new(Body::from("users#index")))
}
#[derive(Debug, Deserialize)]
struct Pagination {
page: usize,
per_page: usize,
}
async fn users_create(
req: Request<Body>,
payload: Json<UsersCreate>,
) -> Result<Response<Body>, Error> {
dbg!(payload.into_inner());
Ok(Response::new(Body::from("users#create")))
}
#[derive(Debug, Deserialize)]
struct UsersCreate {
username: String,
}
}