mirror of
https://github.com/actix/examples
synced 2025-02-02 09:39:03 +01:00
74 lines
2.8 KiB
Rust
74 lines
2.8 KiB
Rust
//! Actix Web Asynchronous Database Example
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//!
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//! This project illustrates expensive and blocking database requests that runs
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//! in a thread-pool using `web::block` with two examples:
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//!
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//! 1. An asynchronous handler that executes 4 queries in *sequential order*,
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//! collecting the results and returning them as a single serialized json object
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//!
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//! 2. An asynchronous handler that executes 4 queries in *parallel*,
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//! collecting the results and returning them as a single serialized json object
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//!
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//! Note: The use of sleep(Duration::from_secs(2)); in db.rs is to make performance
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//! improvement with parallelism more obvious.
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use std::io;
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use actix_web::{middleware, web, App, Error as AWError, HttpResponse, HttpServer};
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use futures_util::future::join_all;
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use r2d2_sqlite::{self, SqliteConnectionManager};
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mod db;
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use db::{Pool, Queries};
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/// Version 1: Calls 4 queries in sequential order, as an asynchronous handler
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async fn asyncio_weather(db: web::Data<Pool>) -> Result<HttpResponse, AWError> {
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let result = vec![
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db::execute(&db, Queries::GetTopTenHottestYears).await?,
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db::execute(&db, Queries::GetTopTenColdestYears).await?,
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db::execute(&db, Queries::GetTopTenHottestMonths).await?,
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db::execute(&db, Queries::GetTopTenColdestMonths).await?,
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];
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Ok(HttpResponse::Ok().json(result))
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}
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/// Version 2: Calls 4 queries in parallel, as an asynchronous handler
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/// Returning Error types turn into None values in the response
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async fn parallel_weather(db: web::Data<Pool>) -> Result<HttpResponse, AWError> {
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let fut_result = vec![
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db::execute(&db, Queries::GetTopTenHottestYears),
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db::execute(&db, Queries::GetTopTenColdestYears),
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db::execute(&db, Queries::GetTopTenHottestMonths),
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db::execute(&db, Queries::GetTopTenColdestMonths),
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];
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let result: Result<Vec<_>, _> = join_all(fut_result).await.into_iter().collect();
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Ok(HttpResponse::Ok().json(result.map_err(AWError::from)?))
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}
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#[actix_web::main]
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async fn main() -> io::Result<()> {
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env_logger::init_from_env(env_logger::Env::new().default_filter_or("info"));
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// connect to SQLite DB
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let manager = SqliteConnectionManager::file("weather.db");
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let pool = Pool::new(manager).unwrap();
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log::info!("starting HTTP server at http://localhost:8080");
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// start HTTP server
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HttpServer::new(move || {
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App::new()
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// store db pool as Data object
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.app_data(web::Data::new(pool.clone()))
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.wrap(middleware::Logger::default())
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.service(web::resource("/asyncio_weather").route(web::get().to(asyncio_weather)))
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.service(web::resource("/parallel_weather").route(web::get().to(parallel_weather)))
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})
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.bind(("127.0.0.1", 8080))?
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.workers(2)
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.run()
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.await
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}
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