Rust Web 全栈开发之 Web Service 中的错误处理Web Service 中的统一错误处理Actix Web Service 自定义错误类型 -> 自定义错误转为 HTTP Response
- 数据库
- 数据库错误
- 串行化
- serde 错误
- I/O 操作
- I/O 错误
- Actix-Web 库
- Actix 错误
- 用户非法输入
- 用户非法输入错误
Actix-Web 的错误处理
- 编程语言常用的两种错误处理方式:
- 异常
- 返回值( Rust 使用这种)
- Rust 希望开发者显式的处理错误,因此,可能出错的函数返回Result 枚举类型,其定义如下:
enum Result { Ok(T),Err(E),}
例子
use std::num::ParseIntError;fn main() { let result = square("25"); println!("{:?}", result);}fn square(val: &str) -> Result { match val.parse::() { Ok(num) => Ok(num.pow(2)), Err(e) => Err(3), }}
? 运算符
- 在某函数中使用 ? 运算符,该运算符尝试从 Result 中获取值:
- 如果不成功,它就会接收 Error ,中止函数执行,并把错误传播到调用该函数的函数。
use std::num::ParseIntError;fn main() { let result = square("25"); println!("{:?}", result);}fn square(val: &str) -> Result { let num = val.parse::()?; Ok(num ^ 2)}
自定义错误类型
- 创建一个自定义错误类型,它可以是多种错误类型的抽象。
- 例如:
#[derive(Debug)]pub enum MyError { ParseError,IOError,}
Actix-Web 把错误转化为 HTTP Response
- Actix-Web 定义了一个通用的错误类型( struct ):
actix_web::error::Error
- 它实现了
std::error::Error
这个 trait
- 它实现了
- 任何实现了标准库 Error trait 的类型,都可以通过 ? 运算符,转化为 Actix 的 Error 类型
- Actix 的 Error 类型会自动的转化为 HTTP Response ,返回给客户端。
- ResponseError trait :任何实现该 trait 的错误均可转化为HTTP Response 消息。
- 内置的实现: Actix-Web 对于常见错误有内置的实现,例如:
- Rust 标准 I/O 错误
- Serde 错误
- Web 错误,例如: ProtocolError 、 Utf8Error 、 ParseError 等等
- 其它错误类型:内置实现不可用时,需要自定义实现错误到 HTTP Response 的转换
创建自定义错误处理器
- 创建一个自定义错误类型
- 实现 From trait ,用于把其它错误类型转化为该类型
- 为自定义错误类型实现 ResponseError trait
- 在 handler 里返回自定义错误类型
- Actix 会把错误转化为 HTTP 响应
项目目录
ws on main [✘!?] via ? 1.67.1 via ? base ➜ tree -a -I target .├── .env├── .git├── .gitignore├── Cargo.lock├── Cargo.toml├── README.md└── webservice ├── Cargo.toml └── src ├── bin │ ├── server1.rs │ └── teacher-service.rs ├── db_access.rs ├── errors.rs ├── handlers.rs ├── main.rs ├── models.rs ├── routers.rs └── state.rs40 directories, 47 filesws on main [✘!?] via ? 1.67.1 via ? base
webservice/src/errors.rs
use actix_web::{error, http::StatusCode, HttpResponse, Result};use serde::Serialize;use sqlx::error::Error as SQLxError;use std::fmt;#[derive(Debug, Serialize)]pub enum MyError { DBError(String), ActixError(String), NotFound(String),}#[derive(Debug, Serialize)]pub struct MyErrorResponse { error_message: String,}impl MyError { fn error_response(&self) -> String { match self { MyError::DBError(msg) => { println!("Database error occurred: {:?}", msg); "Database error".into() } MyError::ActixError(msg) => { println!("Server error occurred: {:?}", msg); "Internal server error".into() } MyError::NotFound(msg) => { println!("Not found error occurred: {:?}", msg); msg.into() } } }}impl error::ResponseError for MyError { fn status_code(&self) -> StatusCode { match self { MyError::DBError(msg) | MyError::ActixError(msg) => StatusCode::INTERNAL_SERVER_ERROR, MyError::NotFound(msg) => StatusCode::NOT_FOUND, } } fn error_response(&self) -> HttpResponse { HttpResponse::build(self.status_code()).json(MyErrorResponse { error_message: self.error_response(), }) }}impl fmt::Display for MyError { fn fmt(&self, f: &mut fmt::Formatter) -> Result { write!(f, "{}", self) }}impl From for MyError { fn from(err: actix_web::error::Error) -> Self { MyError::ActixError(err.to_string()) }}impl From for MyError { fn from(err: SQLxError) -> Self { MyError::DBError(err.to_string()) }}
webservice/src/bin/teacher-service.rs
use actix_web::{web, App, HttpServer};use dotenv::dotenv;use sqlx::postgres::PgPoolOptions;use std::env;use std::io;use std::sync::Mutex;#[path = "../db_access.rs"]mod db_access;#[path = "../errors.rs"]mod errors;#[path = "../handlers.rs"]mod handlers;#[path = "../models.rs"]mod models;#[path = "../routers.rs"]mod routers;#[path = "../state.rs"]mod state;use routers::*;use state::AppState;#[actix_rt::main]async fn main() -> io::Result { dotenv().ok(); let database_url = env::var("DATABASE_URL").expect("DATABASE_URL is not set."); let db_pool = PgPoolOptions::new().connect(&database_url).await.unwrap(); let shared_data = web::Data::new(AppState { health_check_response: "I'm Ok.".to_string(), visit_count: Mutex::new(0), // courses: Mutex::new(vec![]), db: db_pool, }); let app = move || { App::new() .app_data(shared_data.clone()) .configure(general_routes) .configure(course_routes) // 路由注册 }; HttpServer::new(app).bind("127.0.0.1:3000")?.run().await}
webservice/src/db_access.rs
use super::errors::MyError;use super::models::*;use chrono::NaiveDateTime;use sqlx::postgres::PgPool;pub async fn get_courses_for_teacher_db( pool: &PgPool, teacher_id: i32,) -> Result<Vec, MyError> { let rows = sqlx::query!( r#"SELECT id, teacher_id, name, time FROM course WHERE teacher_id = $1"#, teacher_id ) .fetch_all(pool) .await?; let courses: Vec = rows .iter() .map(|row| Course { id: Some(row.id), teacher_id: row.teacher_id, name: row.name.clone(), time: Some(NaiveDateTime::from(row.time.unwrap())), }) .collect(); match courses.len() { 0 => Err(MyError::NotFound("Courses not found teacher".into())), _ => Ok(courses), }}pub async fn get_courses_detail_db(pool: &PgPool, teacher_id: i32, course_id: i32) -> Course { let row = sqlx::query!( r#"SELECT id, teacher_id, name, time FROM course WHERE teacher_id = $1 and id = $2"#, teacher_id, course_id ) .fetch_one(pool) .await .unwrap(); Course { id: Some(row.id), teacher_id: row.teacher_id, name: row.name.clone(), time: Some(NaiveDateTime::from(row.time.unwrap())), }}pub async fn post_new_course_db(pool: &PgPool, new_course: Course) -> Course { let row = sqlx::query!( r#"INSERT INTO course (id, teacher_id, name) VALUES ($1, $2, $3) RETURNING id, teacher_id, name, time"#, new_course.id, new_course.teacher_id, new_course.name ) .fetch_one(pool) .await .unwrap(); Course { id: Some(row.id), teacher_id: row.teacher_id, name: row.name.clone(), time: Some(NaiveDateTime::from(row.time.unwrap())), }}
webservice/src/handlers.rs
use super::db_access::*;use super::errors::MyError;use super::state::AppState;use actix_web::{web, HttpResponse};pub async fn health_check_handler(app_state: web::Data) -> HttpResponse { let health_check_response = &app_state.health_check_response; let mut visit_count = app_state.visit_count.lock().unwrap(); let response = format!("{} {} times", health_check_response, visit_count); *visit_count += 1; HttpResponse::Ok().json(&response)}use super::models::Course;pub async fn new_course( new_course: web::Json, app_state: web::Data,) -> HttpResponse { let course = post_new_course_db(&app_state.db, new_course.into()).await; HttpResponse::Ok().json(course)}pub async fn get_courses_for_tescher( app_state: web::Data, params: web::Path,) -> Result { let teacher_id = i32::try_from(params.into_inner()).unwrap(); get_courses_for_teacher_db(&app_state.db, teacher_id) .await .map(|courses| HttpResponse::Ok().json(courses))}pub async fn get_courses_detail( app_state: web::Data, params: web::Path,) -> HttpResponse { let teacher_id = i32::try_from(params.0).unwrap(); let course_id = i32::try_from(params.1).unwrap(); let course = get_courses_detail_db(&app_state.db, teacher_id, course_id).await; HttpResponse::Ok().json(course)}#[cfg(test)]mod tests { use super::*; use actix_web::http::StatusCode; use dotenv::dotenv; use sqlx::postgres::PgPoolOptions; use std::env; use std::sync::Mutex; #[actix_rt::test] // 异步测试 async fn post_course_test() { dotenv().ok(); let db_url = env::var("DATABASE_URL").expect("DATABASE_URL is not set"); let db_pool = PgPoolOptions::new().connect(&db_url).await.unwrap(); let app_state: web::Data = web::Data::new(AppState { health_check_response: "".to_string(), visit_count: Mutex::new(0), db: db_pool, }); let course = web::Json(Course { teacher_id: 1, name: "Test course".into(), id: Some(3), // serial time: None, }); let resp = new_course(course, app_state).await; assert_eq!(resp.status(), StatusCode::OK); } #[actix_rt::test] async fn get_all_courses_success() { dotenv().ok(); let db_url = env::var("DATABASE_URL").expect("DATABASE_URL is not set"); let db_pool = PgPoolOptions::new().connect(&db_url).await.unwrap(); let app_state: web::Data = web::Data::new(AppState { health_check_response: "".to_string(), visit_count: Mutex::new(0), db: db_pool, }); let teacher_id: web::Path = web::Path::from(1); let resp = get_courses_for_tescher(app_state, teacher_id) .await .unwrap(); assert_eq!(resp.status(), StatusCode::OK); } #[actix_rt::test] async fn get_one_course_success() { dotenv().ok(); let db_url = env::var("DATABASE_URL").expect("DATABASE_URL is not set"); let db_pool = PgPoolOptions::new().connect(&db_url).await.unwrap(); let app_state: web::Data = web::Data::new(AppState { health_check_response: "".to_string(), visit_count: Mutex::new(0), db: db_pool, }); let params: web::Path = web::Path::from((1, 1)); let resp = get_courses_detail(app_state, params).await; assert_eq!(resp.status(), StatusCode::OK); }}
测试
ws on main via ? 1.67.1 via ? base ➜ cargo test --bin teacher-service get_all_courses_success Compiling webservice v0.1.0 (/Users/qiaopengjun/rust/ws/webservice)warning: unused variable: `msg` --> webservice/src/bin/../errors.rs:39:30 |39 | MyError::DBError(msg) | MyError::ActixError(msg) => StatusCode::INTERNAL_SERVER_ERROR, | ^^^ ^^^ | = note: `#[warn(unused_variables)]` on by defaulthelp: if this is intentional, prefix it with an underscore |39 | MyError::DBError(_msg) | MyError::ActixError(_msg) => StatusCode::INTERNAL_SERVER_ERROR, | ~~~~ ~~~~warning: unused variable: `msg` --> webservice/src/bin/../errors.rs:40:31 |40 | MyError::NotFound(msg) => StatusCode::NOT_FOUND, | ^^^ help: if this is intentional, prefix it with an underscore: `_msg`warning: `webservice` (bin "teacher-service" test) generated 2 warnings (run `cargo fix --bin "teacher-service" --tests` to apply 2 suggestions) Finished test [unoptimized + debuginfo] target(s) in 1.55s Running unittests src/bin/teacher-service.rs (target/debug/deps/teacher_service-32d6a48d6ee3c4b4)running 1 testtest handlers::tests::get_all_courses_success ... oktest result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 2 filtered out; finished in 0.01sws on main [✘!?] via ? 1.67.1 via ? base took 2.1s ➜
webservice/src/db_access.rs
use super::errors::MyError;use super::models::*;use chrono::NaiveDateTime;use sqlx::postgres::PgPool;pub async fn get_courses_for_teacher_db( pool: &PgPool, teacher_id: i32,) -> Result<Vec, MyError> { let rows = sqlx::query!( r#"SELECT id, teacher_id, name, time FROM course WHERE teacher_id = $1"#, teacher_id ) .fetch_all(pool) .await?; let courses: Vec = rows .iter() .map(|row| Course { id: Some(row.id), teacher_id: row.teacher_id, name: row.name.clone(), time: Some(NaiveDateTime::from(row.time.unwrap())), }) .collect(); match courses.len() { 0 => Err(MyError::NotFound("Courses not found teacher".into())), _ => Ok(courses), }}pub async fn get_courses_detail_db( pool: &PgPool, teacher_id: i32, course_id: i32,) -> Result { let row = sqlx::query!( r#"SELECT id, teacher_id, name, time FROM course WHERE teacher_id = $1 and id = $2"#, teacher_id, course_id ) .fetch_one(pool) .await; if let Ok(row) = row { Ok(Course { id: Some(row.id), teacher_id: row.teacher_id, name: row.name.clone(), time: Some(NaiveDateTime::from(row.time.unwrap())), }) } else { Err(MyError::NotFound("Course Id not found".into())) }}pub async fn post_new_course_db(pool: &PgPool, new_course: Course) -> Result { let row = sqlx::query!( r#"INSERT INTO course (id, teacher_id, name) VALUES ($1, $2, $3) RETURNING id, teacher_id, name, time"#, new_course.id, new_course.teacher_id, new_course.name ) .fetch_one(pool) .await?; Ok(Course { id: Some(row.id), teacher_id: row.teacher_id, name: row.name.clone(), time: Some(NaiveDateTime::from(row.time.unwrap())), })}
webservice/src/handlers.rs
use super::db_access::*;use super::errors::MyError;use super::state::AppState;use actix_web::{web, HttpResponse};pub async fn health_check_handler(app_state: web::Data) -> HttpResponse { let health_check_response = &app_state.health_check_response; let mut visit_count = app_state.visit_count.lock().unwrap(); let response = format!("{} {} times", health_check_response, visit_count); *visit_count += 1; HttpResponse::Ok().json(&response)}use super::models::Course;pub async fn new_course( new_course: web::Json, app_state: web::Data,) -> Result { post_new_course_db(&app_state.db, new_course.into()) .await .map(|course| HttpResponse::Ok().json(course))}pub async fn get_courses_for_tescher( app_state: web::Data, params: web::Path,) -> Result { let teacher_id = i32::try_from(params.into_inner()).unwrap(); get_courses_for_teacher_db(&app_state.db, teacher_id) .await .map(|courses| HttpResponse::Ok().json(courses))}pub async fn get_courses_detail( app_state: web::Data, params: web::Path,) -> Result { let teacher_id = i32::try_from(params.0).unwrap(); let course_id = i32::try_from(params.1).unwrap(); get_courses_detail_db(&app_state.db, teacher_id, course_id) .await .map(|course| HttpResponse::Ok().json(course))}#[cfg(test)]mod tests { use super::*; use actix_web::http::StatusCode; use dotenv::dotenv; use sqlx::postgres::PgPoolOptions; use std::env; use std::sync::Mutex; #[ignore] #[actix_rt::test] // 异步测试 async fn post_course_test() { dotenv().ok(); let db_url = env::var("DATABASE_URL").expect("DATABASE_URL is not set"); let db_pool = PgPoolOptions::new().connect(&db_url).await.unwrap(); let app_state: web::Data = web::Data::new(AppState { health_check_response: "".to_string(), visit_count: Mutex::new(0), db: db_pool, }); let course = web::Json(Course { teacher_id: 1, name: "Test course".into(), id: Some(5), // serial time: None, }); let resp = new_course(course, app_state).await.unwrap(); assert_eq!(resp.status(), StatusCode::OK); } #[actix_rt::test] async fn get_all_courses_success() { dotenv().ok(); let db_url = env::var("DATABASE_URL").expect("DATABASE_URL is not set"); let db_pool = PgPoolOptions::new().connect(&db_url).await.unwrap(); let app_state: web::Data = web::Data::new(AppState { health_check_response: "".to_string(), visit_count: Mutex::new(0), db: db_pool, }); let teacher_id: web::Path = web::Path::from(1); let resp = get_courses_for_tescher(app_state, teacher_id) .await .unwrap(); assert_eq!(resp.status(), StatusCode::OK); } #[actix_rt::test] async fn get_one_course_success() { dotenv().ok(); let db_url = env::var("DATABASE_URL").expect("DATABASE_URL is not set"); let db_pool = PgPoolOptions::new().connect(&db_url).await.unwrap(); let app_state: web::Data = web::Data::new(AppState { health_check_response: "".to_string(), visit_count: Mutex::new(0), db: db_pool, }); let params: web::Path = web::Path::from((1, 1)); let resp = get_courses_detail(app_state, params).await.unwrap(); assert_eq!(resp.status(), StatusCode::OK); }}
测试
ws on main [✘!?] via ? 1.67.1 via ? base took 2.1s ➜ cargo test --bin teacher-service Compiling webservice v0.1.0 (/Users/qiaopengjun/rust/ws/webservice)warning: unused variable: `msg` --> webservice/src/bin/../errors.rs:39:30 |39 | MyError::DBError(msg) | MyError::ActixError(msg) => StatusCode::INTERNAL_SERVER_ERROR, | ^^^ ^^^ | = note: `#[warn(unused_variables)]` on by defaulthelp: if this is intentional, prefix it with an underscore |39 | MyError::DBError(_msg) | MyError::ActixError(_msg) => StatusCode::INTERNAL_SERVER_ERROR, | ~~~~ ~~~~warning: unused variable: `msg` --> webservice/src/bin/../errors.rs:40:31 |40 | MyError::NotFound(msg) => StatusCode::NOT_FOUND, | ^^^ help: if this is intentional, prefix it with an underscore: `_msg`warning: `webservice` (bin "teacher-service" test) generated 2 warnings (run `cargo fix --bin "teacher-service" --tests` to apply 2 suggestions) Finished test [unoptimized + debuginfo] target(s) in 1.27s Running unittests src/bin/teacher-service.rs (target/debug/deps/teacher_service-32d6a48d6ee3c4b4)running 3 teststest handlers::tests::get_one_course_success ... oktest handlers::tests::get_all_courses_success ... oktest handlers::tests::post_course_test ... oktest result: ok. 3 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.02sws on main [✘!?] via ? 1.67.1 via ? base ➜ ws on main [✘!?] via ? 1.67.1 via ? base ➜ cargo test --bin teacher-service Compiling webservice v0.1.0 (/Users/qiaopengjun/rust/ws/webservice)warning: unused variable: `msg` --> webservice/src/bin/../errors.rs:39:30 |39 | MyError::DBError(msg) | MyError::ActixError(msg) => StatusCode::INTERNAL_SERVER_ERROR, | ^^^ ^^^ | = note: `#[warn(unused_variables)]` on by defaulthelp: if this is intentional, prefix it with an underscore |39 | MyError::DBError(_msg) | MyError::ActixError(_msg) => StatusCode::INTERNAL_SERVER_ERROR, | ~~~~ ~~~~warning: unused variable: `msg` --> webservice/src/bin/../errors.rs:40:31 |40 | MyError::NotFound(msg) => StatusCode::NOT_FOUND, | ^^^ help: if this is intentional, prefix it with an underscore: `_msg`warning: `webservice` (bin "teacher-service" test) generated 2 warnings (run `cargo fix --bin "teacher-service" --tests` to apply 2 suggestions) Finished test [unoptimized + debuginfo] target(s) in 0.71s Running unittests src/bin/teacher-service.rs (target/debug/deps/teacher_service-32d6a48d6ee3c4b4)running 3 teststest handlers::tests::post_course_test ... ignoredtest handlers::tests::get_one_course_success ... oktest handlers::tests::get_all_courses_success ... oktest result: ok. 2 passed; 0 failed; 1 ignored; 0 measured; 0 filtered out; finished in 0.01sws on main [✘!?] via ? 1.67.1 via ? base ➜
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