Add MongoDB example (#2535)

examples/mongodb/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "example-mongodb"
+version = "0.1.0"
+edition = "2021"
+publish = false
+
+[dependencies]
+axum = { path = "../../axum" }
+mongodb = "2.8.0"
+serde = { version = "1.0", features = ["derive"] }
+tokio = { version = "1.0", features = ["full"] }
+tower-http = { version = "0.5.0", features = ["add-extension", "trace"] }
+tracing = "0.1"
+tracing-subscriber = { version = "0.3", features = ["env-filter"] }

examples/mongodb/src/main.rs

@@ -0,0 +1,131 @@
+//! Run with
+//!
+//! ```not_rust
+//! cargo run -p example-mongodb
+//! ```
+
+use axum::{
+    extract::{Path, State},
+    http::StatusCode,
+    routing::{delete, get, post, put},
+    Json, Router,
+};
+use mongodb::{
+    bson::doc,
+    results::{DeleteResult, InsertOneResult, UpdateResult},
+    Client, Collection,
+};
+use serde::{Deserialize, Serialize};
+use tower_http::trace::TraceLayer;
+use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};
+
+#[tokio::main]
+async fn main() {
+    // connecting to mongodb
+    let db_connection_str = std::env::var("DATABASE_URL").unwrap_or_else(|_| {
+        "mongodb://admin:password@127.0.0.1:27017/?authSource=admin".to_string()
+    });
+    let client = Client::with_uri_str(db_connection_str).await.unwrap();
+
+    // pinging the database
+    client
+        .database("axum-mongo")
+        .run_command(doc! { "ping": 1 }, None)
+        .await
+        .unwrap();
+    println!("Pinged your database. Successfully connected to MongoDB!");
+
+    // logging middleware
+    tracing_subscriber::registry()
+        .with(
+            tracing_subscriber::EnvFilter::try_from_default_env()
+                .unwrap_or_else(|_| "example_mongo=debug,tower_http=debug".into()),
+        )
+        .with(tracing_subscriber::fmt::layer())
+        .init();
+
+    // run it
+    let listener = tokio::net::TcpListener::bind("127.0.0.1:3000")
+        .await
+        .unwrap();
+    tracing::debug!("Listening on {}", listener.local_addr().unwrap());
+    axum::serve(listener, app(client)).await.unwrap();
+}
+
+// defining routes and state
+fn app(client: Client) -> Router {
+    let collection: Collection<Member> = client.database("axum-mongo").collection("members");
+
+    Router::new()
+        .route("/create", post(create_member))
+        .route("/read/:id", get(read_member))
+        .route("/update", put(update_member))
+        .route("/delete/:id", delete(delete_member))
+        .layer(TraceLayer::new_for_http())
+        .with_state(collection)
+}
+
+// handler to create a new member
+async fn create_member(
+    State(db): State<Collection<Member>>,
+    Json(input): Json<Member>,
+) -> Result<Json<InsertOneResult>, (StatusCode, String)> {
+    let result = db.insert_one(input, None).await.map_err(internal_error)?;
+
+    Ok(Json(result))
+}
+
+// handler to read an existing member
+async fn read_member(
+    State(db): State<Collection<Member>>,
+    Path(id): Path<u32>,
+) -> Result<Json<Option<Member>>, (StatusCode, String)> {
+    let result = db
+        .find_one(doc! { "_id": id }, None)
+        .await
+        .map_err(internal_error)?;
+
+    Ok(Json(result))
+}
+
+// handler to update an existing member
+async fn update_member(
+    State(db): State<Collection<Member>>,
+    Json(input): Json<Member>,
+) -> Result<Json<UpdateResult>, (StatusCode, String)> {
+    let result = db
+        .replace_one(doc! { "_id": input.id }, input, None)
+        .await
+        .map_err(internal_error)?;
+
+    Ok(Json(result))
+}
+
+// handler to delete an existing member
+async fn delete_member(
+    State(db): State<Collection<Member>>,
+    Path(id): Path<u32>,
+) -> Result<Json<DeleteResult>, (StatusCode, String)> {
+    let result = db
+        .delete_one(doc! { "_id": id }, None)
+        .await
+        .map_err(internal_error)?;
+
+    Ok(Json(result))
+}
+
+fn internal_error<E>(err: E) -> (StatusCode, String)
+where
+    E: std::error::Error,
+{
+    (StatusCode::INTERNAL_SERVER_ERROR, err.to_string())
+}
+
+// defining Member type
+#[derive(Debug, Deserialize, Serialize)]
+struct Member {
+    #[serde(rename = "_id")]
+    id: u32,
+    name: String,
+    active: bool,
+}