Problem details updates (#130)

* Problem details updates
* added app,route/group helpers for  registering problem details
* updates for problem! macro

Author: RomanEmreis

examples/global_error_handler/Cargo.toml

@@ -8,7 +8,7 @@ publish = false
 tokio = "1.46.1"
 tracing = "0.1.41"
 tracing-subscriber = { version = "0.3.19", features = ["env-filter"] }
-volga = { path = "../../volga", features = ["tracing","problem-details"] }
+volga = { path = "../../volga", features = ["tracing"] }
 
 [lints]
 workspace = true

examples/global_error_handler/src/main.rs

@@ -4,7 +4,7 @@
 //! cargo run -p global_error_handler
 //! ```
 
-use volga::{App, problem};
+use volga::{App, status};
 use std::io::Error;
 use tracing_subscriber::prelude::*;
 
@@ -27,13 +27,8 @@ async fn main() -> std::io::Result<()> {
     // Enabling global error handler
     app.map_err(|error: volga::error::Error| async move {
         tracing::error!("{:?}", error);
-        let (status, instance, err) = error.into_parts();
-        problem! {
-            "status": status.as_u16(),
-            "detail": (err.to_string()),
-            "instance": instance,
-        }
-    });
+        status!(error.status.as_u16(), "{error}")
+    });   
 
     app.run().await
 }

examples/problem_details/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "problem_details"
+version = "0.1.0"
+edition = "2024"
+publish = false
+
+[dependencies]
+tokio = "1.46.1"
+tracing = "0.1.41"
+tracing-subscriber = { version = "0.3.19", features = ["env-filter"] }
+volga = { path = "../../volga", features = ["tracing","problem-details"] }
+serde = { version = "1.0.219", features = ["serde_derive"] }
+
+[lints]
+workspace = true

examples/problem_details/src/main.rs

@@ -0,0 +1,59 @@
+//! Run with:
+//!
+//! ```no_rust
+//! cargo run -p problem_details
+//! ```
+
+use volga::{App, error::Problem};
+use std::io::Error;
+use serde::Serialize;
+use tracing_subscriber::prelude::*;
+
+#[tokio::main]
+async fn main() -> std::io::Result<()> {
+    tracing_subscriber::registry()
+        .with(tracing_subscriber::fmt::layer())
+        .init();
+
+    let mut app = App::new()
+        .with_tracing(|tracing| tracing.with_header());
+
+    app.use_tracing();
+
+    // Enabling global error handler that produces
+    // error responses in Problem details format
+    app.use_problem_details();  
+
+    app.map_get("/error", || async {
+        tracing::trace!("producing error");
+        Error::other("some error")
+    });
+
+    app.map_get("/problem", || async {
+        // Always producing a problem
+
+        Problem::new(400)
+            .with_detail("Missing Parameter")
+            .with_instance("/problem")
+            .with_extensions(ValidationError {
+                invalid_params: vec![InvalidParam { 
+                    name: "id".into(), 
+                    reason: "The ID must be provided".into()
+                }]
+            })
+    });
+
+    app.run().await
+}
+
+#[derive(Default, Serialize)]
+struct ValidationError {
+    #[serde(rename = "invalid-params")]
+    invalid_params: Vec<InvalidParam>,
+}
+
+#[derive(Default, Serialize)]
+struct InvalidParam {
+    name: String,
+    reason: String,
+}

volga/Cargo.toml

@@ -18,7 +18,7 @@ keywords = ["async", "server", "http", "web", "framework"]
 bytes = "1.11.0"
 futures-util = { version = "0.3.31", default-features = false, features = ["alloc"] }
 http-body-util = "0.1.3"
-itoa = "1.0.15"
+itoa = "1.0.16"
 indexmap = "2.12.1"
 memchr = "2.7.6"
 mime = "0.3.17"
@@ -96,7 +96,7 @@ di = ["dep:volga-di"]
 macros = ["dep:volga-macros"]
 middleware = []
 multipart = ["dep:multer"]
-problem-details = []
+problem-details = ["serde/derive"]
 static-files = ["dep:chrono", "dep:handlebars", "dep:sha1"]
 tls = ["middleware", "dep:tokio-rustls", "tokio-rustls?/tls12", "tokio-rustls?/ring"]
 tracing = ["middleware", "dep:tracing"]

volga/src/error.rs

@@ -25,7 +25,7 @@ pub use self::{
 };
 
 #[cfg(feature = "problem-details")]
-pub use self::problem::Problem;
+pub use self::problem::{Problem, ProblemDetails};
 
 pub mod handler;
 pub mod fallback;
@@ -201,7 +201,7 @@ impl App {
     /// 
     /// # Example
     /// ```no_run
-    /// use volga::{App, error::Error, status};
+    ///  use volga::{App, error::Error, status};
     /// 
     /// # #[tokio::main]
     /// # async fn main() -> std::io::Result<()> {