Add todos example (#38)

Cargo.toml

@@ -54,7 +54,7 @@ tokio = { version = "1.6.1", features = ["macros", "rt", "rt-multi-thread"] }
 tokio-postgres = "0.7.2"
 tracing = "0.1"
 tracing-subscriber = "0.2"
-uuid = { version = "0.8", features = ["serde"] }
+uuid = { version = "0.8", features = ["serde", "v4"] }
 
 [dev-dependencies.tower]
 version = "0.4"

examples/todos.rs

@@ -0,0 +1,164 @@
+//! Provides a RESTful web server managing some Todos.
+//!
+//! API will be:
+//!
+//! - `GET /todos`: return a JSON list of Todos.
+//! - `POST /todos`: create a new Todo.
+//! - `PUT /todos/:id`: update a specific Todo.
+//! - `DELETE /todos/:id`: delete a specific Todo.
+
+use axum::{
+    extract::{Extension, Json, Query, UrlParams},
+    prelude::*,
+    response::IntoResponse,
+    service::ServiceExt,
+};
+use http::StatusCode;
+use serde::{Deserialize, Serialize};
+use std::{
+    collections::HashMap,
+    convert::Infallible,
+    net::SocketAddr,
+    sync::{Arc, RwLock},
+    time::Duration,
+};
+use tower::{BoxError, ServiceBuilder};
+use tower_http::{add_extension::AddExtensionLayer, trace::TraceLayer};
+use uuid::Uuid;
+
+#[tokio::main]
+async fn main() {
+    tracing_subscriber::fmt::init();
+
+    let db = Db::default();
+
+    // Compose the routes
+    let app = route("/todos", get(todos_index).post(todos_create))
+        .route("/todos/:id", patch(todos_update).delete(todos_delete))
+        // Add middleware to all routes
+        .layer(
+            ServiceBuilder::new()
+                .timeout(Duration::from_secs(10))
+                .layer(TraceLayer::new_for_http())
+                .layer(AddExtensionLayer::new(db))
+                .into_inner(),
+        )
+        // If the timeout fails, map the error to a response
+        .handle_error(|error: BoxError| {
+            let result = if error.is::<tower::timeout::error::Elapsed>() {
+                Ok(StatusCode::REQUEST_TIMEOUT)
+            } else {
+                Err((
+                    StatusCode::INTERNAL_SERVER_ERROR,
+                    format!("Unhandled internal error: {}", error),
+                ))
+            };
+
+            Ok::<_, Infallible>(result)
+        })
+        // Make sure all errors have been handled
+        .check_infallible();
+
+    let addr = SocketAddr::from(([127, 0, 0, 1], 3000));
+    tracing::debug!("listening on {}", addr);
+    hyper::Server::bind(&addr)
+        .serve(app.into_make_service())
+        .await
+        .unwrap();
+}
+
+// The query parameters for todos index
+#[derive(Debug, Deserialize, Default)]
+pub struct Pagination {
+    pub offset: Option<usize>,
+    pub limit: Option<usize>,
+}
+
+async fn todos_index(
+    pagination: Option<Query<Pagination>>,
+    Extension(db): Extension<Db>,
+) -> impl IntoResponse {
+    let todos = db.read().unwrap();
+
+    let Query(pagination) = pagination.unwrap_or_default();
+
+    let todos = todos
+        .values()
+        .cloned()
+        .skip(pagination.offset.unwrap_or(0))
+        .take(pagination.limit.unwrap_or(std::usize::MAX))
+        .collect::<Vec<_>>();
+
+    response::Json(todos)
+}
+
+#[derive(Debug, Deserialize)]
+struct CreateTodo {
+    text: String,
+}
+
+async fn todos_create(
+    Json(input): Json<CreateTodo>,
+    Extension(db): Extension<Db>,
+) -> impl IntoResponse {
+    let todo = Todo {
+        id: Uuid::new_v4(),
+        text: input.text,
+        completed: false,
+    };
+
+    db.write().unwrap().insert(todo.id, todo.clone());
+
+    (StatusCode::CREATED, response::Json(todo))
+}
+
+#[derive(Debug, Deserialize)]
+struct UpdateTodo {
+    text: Option<String>,
+    completed: Option<bool>,
+}
+
+async fn todos_update(
+    UrlParams((id,)): UrlParams<(Uuid,)>,
+    Json(input): Json<UpdateTodo>,
+    Extension(db): Extension<Db>,
+) -> Result<impl IntoResponse, StatusCode> {
+    let mut todo = db
+        .read()
+        .unwrap()
+        .get(&id)
+        .cloned()
+        .ok_or(StatusCode::NOT_FOUND)?;
+
+    if let Some(text) = input.text {
+        todo.text = text;
+    }
+
+    if let Some(completed) = input.completed {
+        todo.completed = completed;
+    }
+
+    db.write().unwrap().insert(todo.id, todo.clone());
+
+    Ok(response::Json(todo))
+}
+
+async fn todos_delete(
+    UrlParams((id,)): UrlParams<(Uuid,)>,
+    Extension(db): Extension<Db>,
+) -> impl IntoResponse {
+    if db.write().unwrap().remove(&id).is_some() {
+        StatusCode::NO_CONTENT
+    } else {
+        StatusCode::NOT_FOUND
+    }
+}
+
+type Db = Arc<RwLock<HashMap<Uuid, Todo>>>;
+
+#[derive(Debug, Serialize, Clone)]
+struct Todo {
+    id: Uuid,
+    text: String,
+    completed: bool,
+}