feat: improve error handling example - Add structured error responses with JSON format - Improve error messages and logging - Add better success/error probability constants - Use proper logging levels - Add serde for JSON serialization

basics/error-handling/Cargo.toml

@@ -10,3 +10,5 @@ derive_more = { workspace = true, features = ["display"] }
 env_logger.workspace = true
 log.workspace = true
 rand.workspace = true
+serde = { workspace = true, features = ["derive"] }
+serde_json.workspace = true

basics/error-handling/src/main.rs

@@ -18,19 +18,28 @@ use rand::{
     Rng,
     distr::{Distribution, StandardUniform},
 };
+use serde::Serialize;
 
-#[derive(Debug, Display)]
+#[derive(Debug, Display, Serialize)]
+#[serde(rename_all = "snake_case")]
 pub enum CustomError {
-    #[display("Custom Error 1")]
+    #[display("Access forbidden: insufficient permissions")]
     CustomOne,
-    #[display("Custom Error 2")]
+    #[display("Authentication required")]
     CustomTwo,
-    #[display("Custom Error 3")]
+    #[display("Internal server error occurred")]
     CustomThree,
-    #[display("Custom Error 4")]
+    #[display("Invalid request parameters")]
     CustomFour,
 }
 
+#[derive(Serialize)]
+struct ErrorResponse {
+    code: u16,
+    message: String,
+    error_type: String,
+}
+
 impl Distribution<CustomError> for StandardUniform {
     fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> CustomError {
         match rng.random_range(0..4) {
@@ -45,46 +54,59 @@ impl Distribution<CustomError> for StandardUniform {
 /// Actix Web uses `ResponseError` for conversion of errors to a response
 impl ResponseError for CustomError {
     fn error_response(&self) -> HttpResponse {
-        match self {
+        let (status_code, error_msg) = match self {
             CustomError::CustomOne => {
-                println!("do some stuff related to CustomOne error");
-                HttpResponse::Forbidden().finish()
+                log::error!("Forbidden error: {}", self);
+                (403, self.to_string())
             }
-
             CustomError::CustomTwo => {
-                println!("do some stuff related to CustomTwo error");
-                HttpResponse::Unauthorized().finish()
+                log::error!("Unauthorized error: {}", self);
+                (401, self.to_string())
             }
-
             CustomError::CustomThree => {
-                println!("do some stuff related to CustomThree error");
-                HttpResponse::InternalServerError().finish()
+                log::error!("Internal server error: {}", self);
+                (500, self.to_string())
             }
+            CustomError::CustomFour => {
+                log::error!("Bad request error: {}", self);
+                (400, self.to_string())
+            }
+        };
 
-            _ => {
-                println!("do some stuff related to CustomFour error");
-                HttpResponse::BadRequest().finish()
-            }
-        }
+        let error_response = ErrorResponse {
+            code: status_code,
+            message: error_msg,
+            error_type: format!("{:?}", self),
+        };
+
+        HttpResponse::build(actix_web::http::StatusCode::from_u16(status_code).unwrap())
+            .json(error_response)
     }
 }
 
 /// randomly returns either () or one of the 4 CustomError variants
 async fn do_something_random() -> Result<(), CustomError> {
     let mut rng = rand::rng();
-
-    // 20% chance that () will be returned by this function
-    if rng.random_bool(2.0 / 10.0) {
+    
+    // 20% chance of success
+    const SUCCESS_PROBABILITY: f64 = 0.2;
+    
+    if rng.random_bool(SUCCESS_PROBABILITY) {
+        log::info!("Random operation succeeded");
         Ok(())
     } else {
-        Err(rand::random::<CustomError>())
+        let error = rand::random::<CustomError>();
+        log::warn!("Random operation failed with error: {}", error);
+        Err(error)
     }
 }
 
 async fn do_something() -> Result<HttpResponse, Error> {
     do_something_random().await?;
-
-    Ok(HttpResponse::Ok().body("Nothing interesting happened. Try again."))
+    Ok(HttpResponse::Ok().json(serde_json::json!({
+        "status": "success",
+        "message": "Nothing interesting happened. Try again."
+    })))
 }
 
 #[actix_web::main]
@@ -94,7 +116,8 @@ async fn main() -> std::io::Result<()> {
     log::info!("starting HTTP server at http://localhost:8080");
 
     HttpServer::new(move || {
-        App::new().service(web::resource("/something").route(web::get().to(do_something)))
+        App::new()
+            .service(web::resource("/something").route(web::get().to(do_something)))
     })
     .bind(("127.0.0.1", 8080))?
     .run()