第一部 - サーバーからデータベースを扱う

docs/chapter1/section4/3_rust_and_db.md

@@ -57,6 +57,12 @@ $ source .env
 このコマンドによって読み込んだ環境変数は、コマンドを入力したターミナルを終了すると消えてしまいます。また、コマンドを入力したターミナル以外では環境変数として読み込まれません。新しくターミナルを開きなおした場合などは、もう一度実行してください。
 :::
 
+### クレートの依存関係を追加する
+```sh
+$ cargo add axum anyhow serde serde_json tokio --features tokio/full,serde/derive
+$ cargo add sqlx --features mysql,migrate,chrono,runtime-tokio
+```
+
 ### 実行する
 
 ```sh

docs/chapter1/section4/4_server_and_db.md

@@ -2,7 +2,7 @@
 
 Echo を使い、データベースからデータを取得するサーバーアプリケーションを作りましょう。
 
-<<< @/chapter1/section4/src/server.go{go:line-numbers}
+<<< @/chapter1/section4/src/server.rs{rs:line-numbers}
 
 都市が見つかったら`200`を、見つからなかったら`404`を返しています。
 Postman からリクエストを送ってみましょう。
@@ -26,13 +26,7 @@ Postman からリクエストを送ってみましょう。
 
 :::details 答え
 
-- `main`関数内部
-
-<<< @/chapter1/section4/src/practice_server.go#echo
-
-- `postCityHandler`関数を定義
-
-<<< @/chapter1/section4/src/practice_server.go#func
+<<< @/chapter1/section4/src/practice_server.rs{rs:line-numbers}
 
 :::
 

docs/chapter1/section4/src/practice_server.rs

@@ -0,0 +1,99 @@
+use axum::{
+    extract::{rejection::JsonRejection, Path, State},
+    http::StatusCode,
+    routing::{get, post},
+    Json, Router,
+};
+use sqlx::{mysql::MySqlConnectOptions, Pool};
+use std::env;
+
+#[derive(sqlx::FromRow, serde::Serialize, serde::Deserialize)] // [!code warning]
+#[sqlx(rename_all = "PascalCase")]
+#[serde(rename_all = "camelCase")]
+struct City {
+    #[sqlx(rename = "ID")]
+    id: Option<i32>, // [!code warning]
+    name: String,
+    country_code: String,
+    district: String,
+    population: i32,
+}
+
+fn get_option() -> anyhow::Result<MySqlConnectOptions> {
+    let host = env::var("DB_HOSTNAME")?;
+    let port = env::var("DB_PORT")?.parse()?;
+    let username = env::var("DB_USERNAME")?;
+    let password = env::var("DB_PASSWORD")?;
+    let database = env::var("DB_DATABASE")?;
+    let timezone = Some(String::from("Asia/Tokyo"));
+    let collation = String::from("utf8mb4_unicode_ci");
+
+    Ok(MySqlConnectOptions::new()
+        .host(&host)
+        .port(port)
+        .username(&username)
+        .password(&password)
+        .database(&database)
+        .timezone(timezone)
+        .collation(&collation))
+}
+
+#[tokio::main]
+async fn main() -> anyhow::Result<()> {
+    let options = get_option()?;
+    let pool = sqlx::MySqlPool::connect_with(options).await?;
+
+    let app = Router::new()
+        .route("/cities/:cityName", get(get_city_handler)) 
+        .route("/cities", post(post_city_handler)) // [!code ++]
+        .with_state(pool);
+
+    let listener = tokio::net::TcpListener::bind("127.0.0.1:8080")
+        .await
+        .unwrap();
+
+    println!("listening on {}", listener.local_addr().unwrap());
+    axum::serve(listener, app).await.unwrap();
+
+    Ok(())
+}
+
+async fn get_city_handler(
+    State(pool): State<Pool<sqlx::MySql>>,
+    Path(city_name): Path<String>,
+) -> Result<Json<City>, StatusCode> {
+    let city = sqlx::query_as::<_, City>("SELECT * FROM city WHERE Name = ?")
+        .bind(&city_name)
+        .fetch_one(&pool)
+        .await;
+
+    match city {
+        Ok(city) => Ok(Json(city)),
+        Err(sqlx::Error::RowNotFound) => Err(StatusCode::NOT_FOUND),
+        Err(_) => Err(StatusCode::INTERNAL_SERVER_ERROR),
+    }
+}
+
+async fn post_city_handler( // [!code ++]
+    State(pool): State<Pool<sqlx::MySql>>, // [!code ++]
+    query: Result<Json<City>, JsonRejection>, // [!code ++]
+) -> Result<Json<City>, StatusCode> { // [!code ++]
+    match query { // [!code ++]
+        Ok(Json(mut city)) => {     // [!code ++]
+            let result = sqlx::query( // [!code ++]
+                "INSERT INTO city (Name, CountryCode, District, Population) VALUES (?, ?, ?, ?)", // [!code ++]
+            ) // [!code ++]
+            .bind(&city.name) // [!code ++]
+            .bind(&city.country_code) // [!code ++]
+            .bind(&city.district) // [!code ++]
+            .bind(city.population) // [!code ++]
+            .execute(&pool) // [!code ++]
+            .await // [!code ++]
+            .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?; // [!code ++]
+
+            city.id = Some(result.last_insert_id() as i32); // [!code ++]
+            Ok(Json(city)) // [!code ++]
+        } // [!code ++]
+        Err(_) => Err(StatusCode::BAD_REQUEST), // [!code ++]
+    }   // [!code ++]
+}  // [!code ++]

docs/chapter1/section4/src/server.rs

@@ -0,0 +1,74 @@
+use axum::{
+    extract::{Path, State},
+    http::StatusCode,
+    routing::get,
+    Json, Router,
+};
+use sqlx::{mysql::MySqlConnectOptions, Pool};
+use std::env;
+
+#[derive(sqlx::FromRow, serde::Serialize)]
+#[sqlx(rename_all = "PascalCase")]
+#[serde(rename_all = "camelCase")]
+struct City {
+    #[sqlx(rename = "ID")]
+    id: i32,
+    name: String,
+    country_code: String,
+    district: String,
+    population: i32,
+}
+
+fn get_option() -> anyhow::Result<MySqlConnectOptions> {
+    let host = env::var("DB_HOSTNAME")?;
+    let port = env::var("DB_PORT")?.parse()?;
+    let username = env::var("DB_USERNAME")?;
+    let password = env::var("DB_PASSWORD")?;
+    let database = env::var("DB_DATABASE")?;
+    let timezone = Some(String::from("Asia/Tokyo"));
+    let collation = String::from("utf8mb4_unicode_ci");
+
+    Ok(MySqlConnectOptions::new()
+        .host(&host)
+        .port(port)
+        .username(&username)
+        .password(&password)
+        .database(&database)
+        .timezone(timezone)
+        .collation(&collation))
+}
+
+#[tokio::main]
+async fn main() -> anyhow::Result<()> {
+    let options = get_option()?;
+    let pool = sqlx::MySqlPool::connect_with(options).await?;
+
+    let app = Router::new()
+        .route("/cities/:cityName", get(get_city_handler))
+        .with_state(pool);
+
+    let listener = tokio::net::TcpListener::bind("127.0.0.1:8080")
+        .await
+        .unwrap();
+
+    println!("listening on {}", listener.local_addr().unwrap());
+    axum::serve(listener, app).await.unwrap();
+
+    Ok(())
+}
+
+async fn get_city_handler(
+    State(pool): State<Pool<sqlx::MySql>>,
+    Path(city_name): Path<String>,
+) -> Result<Json<City>, StatusCode> {
+    let city = sqlx::query_as::<_, City>("SELECT * FROM city WHERE Name = ?")
+        .bind(&city_name)
+        .fetch_one(&pool)
+        .await;
+
+    match city {
+        Ok(city) => Ok(Json(city)),
+        Err(sqlx::Error::RowNotFound) => Err(StatusCode::NOT_FOUND),
+        Err(_) => Err(StatusCode::INTERNAL_SERVER_ERROR),
+    }
+}