mirror of
https://github.com/tokio-rs/axum.git
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107 lines
3 KiB
Rust
107 lines
3 KiB
Rust
//! Run with
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//!
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//! ```not_rust
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//! cargo run --example tokio_postgres
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//! ```
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use axum::{
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async_trait,
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extract::{Extension, FromRequest, RequestParts},
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prelude::*,
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AddExtensionLayer,
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};
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use bb8::{Pool, PooledConnection};
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use bb8_postgres::PostgresConnectionManager;
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use http::StatusCode;
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use std::net::SocketAddr;
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use tokio_postgres::NoTls;
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#[tokio::main]
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async fn main() {
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// Set the RUST_LOG, if it hasn't been explicitly defined
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if std::env::var("RUST_LOG").is_err() {
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std::env::set_var("RUST_LOG", "tokio_postgres=debug")
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}
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tracing_subscriber::fmt::init();
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// setup connection pool
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let manager =
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PostgresConnectionManager::new_from_stringlike("host=localhost user=postgres", NoTls)
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.unwrap();
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let pool = Pool::builder().build(manager).await.unwrap();
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// build our application with some routes
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let app = route(
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"/",
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get(using_connection_pool_extractor).post(using_connection_extractor),
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)
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.layer(AddExtensionLayer::new(pool));
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// run it with hyper
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let addr = SocketAddr::from(([127, 0, 0, 1], 3000));
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tracing::debug!("listening on {}", addr);
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axum::Server::bind(&addr)
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.serve(app.into_make_service())
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.await
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.unwrap();
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}
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type ConnectionPool = Pool<PostgresConnectionManager<NoTls>>;
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// we can exact the connection pool with `Extension`
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async fn using_connection_pool_extractor(
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Extension(pool): Extension<ConnectionPool>,
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) -> Result<String, (StatusCode, String)> {
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let conn = pool.get().await.map_err(internal_error)?;
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let row = conn
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.query_one("select 1 + 1", &[])
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.await
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.map_err(internal_error)?;
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let two: i32 = row.try_get(0).map_err(internal_error)?;
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Ok(two.to_string())
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}
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// we can also write a custom extractor that grabs a connection from the pool
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// which setup is appropriate depends on your application
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struct DatabaseConnection(PooledConnection<'static, PostgresConnectionManager<NoTls>>);
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#[async_trait]
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impl<B> FromRequest<B> for DatabaseConnection
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where
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B: Send,
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{
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type Rejection = (StatusCode, String);
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async fn from_request(req: &mut RequestParts<B>) -> Result<Self, Self::Rejection> {
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let Extension(pool) = Extension::<ConnectionPool>::from_request(req)
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.await
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.map_err(internal_error)?;
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let conn = pool.get_owned().await.map_err(internal_error)?;
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Ok(Self(conn))
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}
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}
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async fn using_connection_extractor(
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DatabaseConnection(conn): DatabaseConnection,
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) -> Result<String, (StatusCode, String)> {
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let row = conn
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.query_one("select 1 + 1", &[])
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.await
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.map_err(internal_error)?;
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let two: i32 = row.try_get(0).map_err(internal_error)?;
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Ok(two.to_string())
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}
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/// Utility function for mapping any error into a `500 Internal Server Error`
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/// response.
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fn internal_error<E>(err: E) -> (StatusCode, String)
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where
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E: std::error::Error,
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{
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(StatusCode::INTERNAL_SERVER_ERROR, err.to_string())
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}
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