fix: server function custom errors set status codes (#4782)

* fix: handling status codes from errors

* add demo

* clippy + check

* fix clippy again

Cargo.toml

@@ -699,6 +699,11 @@ name = "flat_router"
 path = "examples/06-routing/flat_router.rs"
 doc-scrape-examples = true
 
+[[example]]
+name = "server_functions"
+path = "examples/07-fullstack/server_functions.rs"
+doc-scrape-examples = true
+
 [[example]]
 name = "middleware"
 path = "examples/07-fullstack/middleware.rs"

examples/07-fullstack/handling_errors.rs

@@ -22,7 +22,7 @@
 //!
 //! Try running requests against the endpoints directly with `curl` or `postman` to see the actual HTTP responses!
 
-use dioxus::fullstack::{Json, StatusCode};
+use dioxus::fullstack::{AsStatusCode, Json, StatusCode};
 use dioxus::prelude::*;
 use serde::{Deserialize, Serialize};
 
@@ -164,10 +164,32 @@ enum MyCustomError {
     ServerFnError(#[from] ServerFnError),
 }
 
+impl AsStatusCode for MyCustomError {
+    fn as_status_code(&self) -> StatusCode {
+        match self {
+            MyCustomError::BadRequest { .. } => StatusCode::BAD_REQUEST,
+            MyCustomError::NotFound => StatusCode::NOT_FOUND,
+            MyCustomError::ServerFnError(e) => e.as_status_code(),
+        }
+    }
+}
+
 /// Returns a custom typed error (serializable) so clients can handle specific cases.
+///
+/// Our custom error must implement `AsStatusCode` so it can properly set the outgoing HTTP status code.
 #[get("/api/typed-error")]
 async fn get_throws_typed_error() -> Result<(), MyCustomError> {
     Err(MyCustomError::BadRequest {
         custom_name: "Invalid input".into(),
     })
 }
+
+/// Simple POST endpoint used to show a successful server function that returns `StatusCode`.
+#[post("/api/data")]
+async fn get_throws_serverfn_error() -> Result<(), ServerFnError> {
+    Err(ServerFnError::ServerError {
+        message: "Unauthorized access".to_string(),
+        code: StatusCode::UNAUTHORIZED.as_u16(),
+        details: None,
+    })
+}

examples/07-fullstack/server_functions.rs

@@ -0,0 +1,271 @@
+//! This example is a simple showcase of Dioxus Server Functions.
+//!
+//! The other examples in this folder showcase advanced features of server functions like custom
+//! data types, error handling, websockets, and more.
+//!
+//! This example is meant to just be a simple starting point to show how server functions work.
+//!
+//! ## Server Functions
+//!
+//! In Dioxus, Server Functions are `axum` backend endpoints that can be called directly from the client
+//! as if you were simply calling a local Rust function. You can do anything with a server function
+//! that an Axum handler can do like extracting path, query, headers, and body parameters.
+//!
+//! ## Server Function Arguments
+//!
+//! Unlike Axum handlers, the arguments of the server functions have some special magic enabled by
+//! the accompanying `#[get]`/`#[post]` attributes. This magic enables you to choose between
+//! arguments that are purely serializable (i.e. `String`, `i32`, `Vec<T>`, etc) as the JSON body of
+//!
+//! the request *or* arguments that implement Axum's `FromRequest` trait. This magic enables simple
+//! RPC functions but also complex extractors for things like auth, sessions, cookies, and more.
+//!
+//! ## Server Function Return Types
+//!
+//! The return type of the server function is also somewhat magical. Unlike Axum handlers, all server
+//! functions must return a `Result` type, giving the client an opportunity to handle errors properly.
+//!
+//! The `Ok` type can be anything that implements `Serialize + DeserializeOwned` so it can be sent
+//! to the client as JSON, or it can be anything that implements `IntoResponse` just like an Axum handler.
+//!
+//! ## Error Types
+//!
+//! The `Err` type of the server function return type is also somewhat special. The `Err` type can be:
+//! - `anyhow::Error` (the `dioxus_core::Err` type alias) for untyped errors with rich context. Note
+//!   that these errors will always downcast to `ServerFnError` on the client, losing the original
+//!   error stack and type.
+//! - `ServerFnError` for typed errors with a status code and optional message.
+//! - `StatusCode` for returning raw HTTP status codes.
+//! - `HttpError` for returning HTTP status codes with custom messages.
+//! - Any custom errors that implement `From<ServerFnError>` and are `Serialize`/`Deserialize`
+//!
+//! The only way to set the HTTP status code of the response is to use one of the above error types,
+//! or to implement a custom `IntoResponse` type that sets the status code manually.
+//!
+//! The `anyhow::Error` type is the best choice for rapid development, but is somewhat limited when
+//! handling specific error cases on the client since all errors are downcast to `ServerFnError`.
+//!
+//! ## Calling Server Functions from the Client
+//!
+//! Server functions can be called from the client by simply importing the function and calling it
+//! like a normal Rust function. Unlike regular axum handlers, Dioxus server functions have a few
+//! non-obvious restrictions.
+//!
+//! Most importantly, the arguments to the server function must implement either `Deserialize` *or*
+//! `IntoRequest`. The `IntoRequest` trait is a Dioxus abstraction that represents the "inverse" of the
+//! Axum `FromRequest` trait. Anything that is sent to the server from the client must be both extractable
+//! with `FromRequest` on the server *and* constructible with `IntoRequest` on the client.
+//!
+//! Types like `WebsocketOptions` implement `IntoRequest` and pass along things like upgrade headers
+//! to the server so that the server can properly upgrade the connection.
+//!
+//! When receiving data from the server, the return type must implement `Deserialize` *or* `FromResponse`.
+//! The `FromResponse` trait is the inverse of Axum's `IntoResponse` trait, and is implemented
+//! for types like `Websocket` where the raw HTTP response is needed to complete the construction
+//! of the type.
+//!
+//! ## Server-only Extractors
+//!
+//! Because the arguments of the server function define the structure of the public API, some extractors
+//! might not make sense to expose directly, nor would they be possible to construct on the client.
+//! For example, on the web, you typically don't work directly with cookies since the browser handles
+//! them for you. In these cases, the client would omit the `Cookie` header entirely, and we would need
+//! "hoist" our extractor into a "server-only extractor".
+//!
+//! Server-only extractors are function arguments placed after the path in the `#[get]`/`#[post]` attribute.
+//! These arguments are extracted on the server, but not passed in from the client. This lets the
+//! server function remain callable from the client, while still allowing full access to axum's
+//! extractors.
+//!
+//! ```
+//! #[post("/api/authenticate", auth: AuthCookie)]
+//! async fn authenticate() -> Result<User> { /* ... */ }
+//! ```
+//!
+//! ## Automatic Registration
+//!
+//! Unlike axum handlers, server functions do not need to be manually registered with a router.
+//! By default, *all* server functions in your app will be automatically registered with the
+//! server when you call `dioxus::launch` or create a router manually with `dioxus::server::router()`.
+//!
+//! However, not all server functions are automatically registered by default. Server functions that
+//! take a `State<T>` extractor cannot be automatically added to the router since the dioxus router
+//! type does not know how to construct the `T` type.
+//!
+//! These server functions will be registered once the `ServerFnState<T>` layer is added to the app with
+//! `router = router.layer(ServerFnState::new(your_state))`.
+//!
+//! ## Middleware
+//!
+//! Middleware can be added to server functions using the `#[middleware(MiddlewareType)]` attribute.
+//! Middleware will be applied in the order they are specified, and will be applied before any
+//! server-only extractors.
+//!
+//! To add router-level middleware, you can customize the axum `Router` using layers and extensions
+//! as you would in a normal axum app.
+//!
+//! ## Anonymous Server Functions
+//!
+//! The `#[server]` attribute can be used without a path to create an anonymous server function.
+//! These functions are still exposed as HTTP endpoints, but their names are procedurally generated
+//! from the module path, function name, and a hash of the function signature. This makes it hard to
+//! call these functions with `curl` or `postman`, but save you the trouble of coming up with unique
+//! names for simple functions that are only called from your Dioxus app.
+//!
+//! If you're shipping desktop/mobile apps, we don't recommend using anonymous server functions
+//! since the function names could change between builds and thus make older versions of your app
+//! incompatible with newer versions of your server.
+//!
+//! ## Cross-platform Clients
+//!
+//! Server functions can be called from any platform (web, desktop mobile, etc) and use the best
+//! underlying `fetch` implementation available.
+//!
+//! ## More examples
+//!
+//! With Dioxus Fullstack 0.7, pretty much anything you can do with an Axum handler, you can do with
+//! a server function. More advanced examples can be found in this folder showcasing custom data types,
+//! error handling, websockets, and more.
+
+use axum_core::response::IntoResponse;
+use dioxus::prelude::*;
+use dioxus_fullstack::FromResponse;
+use dioxus_fullstack::http::StatusCode;
+use serde::{Deserialize, Serialize};
+
+fn main() {
+    dioxus::launch(app);
+}
+
+fn app() -> Element {
+    let mut echo_action = use_action(echo);
+    let mut chat_action = use_action(chat);
+    let mut dog_data = use_action(get_data);
+    let mut custom_data = use_action(get_custom_data);
+    let mut anonymous_action = use_action(anonymous);
+    let mut custom_anonymous_action = use_action(custom_anonymous);
+
+    rsx! {
+        h1 { "Server Functions Example" }
+        div {
+            display: "flex",
+            flex_direction: "column",
+            gap: "8px",
+
+            button { onclick: move |_| echo_action.call("Hello from client".into()), "Echo: Hello" }
+            button { onclick: move |_| chat_action.call(42u32, Some(7u32)), "Chat (user 42, room 7)" }
+            button { onclick: move |_| dog_data.call(), "Get dog data" }
+            button { onclick: move |_| custom_data.call(), "Get custom data" }
+            button { onclick: move |_| anonymous_action.call(), "Call anonymous" }
+            button { onclick: move |_| custom_anonymous_action.call(), "Call custom anonymous" }
+
+            button {
+                onclick: move |_| {
+                    echo_action.reset();
+                    chat_action.reset();
+                    dog_data.reset();
+                    custom_data.reset();
+                    anonymous_action.reset();
+                    custom_anonymous_action.reset();
+                },
+                "Clear results"
+            }
+
+            pre { "Echo result: {echo_action.result():#?}" }
+            pre { "Chat result: {chat_action.result():#?}" }
+            pre { "Dog data: {dog_data.result():#?}" }
+            pre { "Custom data: {custom_data.result():#?}" }
+            pre { "Anonymous: {anonymous_action.result():#?}" }
+            pre { "Custom anonymous: {custom_anonymous_action.result():#?}" }
+        }
+    }
+}
+
+/// A plain server function at a `POST` endpoint that takes a string and returns it.
+/// Here, we use the `Result` return type which is an alias to `Result<T, anyhow::Error>`.
+#[post("/api/echo")]
+async fn echo(body: String) -> Result<String> {
+    Ok(body)
+}
+
+/// A Server function that takes path and query parameters, as well as a server-only extractor.
+#[post("/api/{user_id}/chat?room_id", headers: dioxus_fullstack::HeaderMap)]
+async fn chat(user_id: u32, room_id: Option<u32>) -> Result<String> {
+    Ok(format!(
+        "User ID: {}, Room ID: {} - Headers: {:#?}",
+        user_id,
+        room_id.map_or("None".to_string(), |id| id.to_string()),
+        headers
+    ))
+}
+
+/// A plain server function at a `GET` endpoint that returns some JSON data. Because `DogData` is
+/// `Serialize` and `Deserialize`, it can be sent to the client as JSON automatically.
+///
+/// You can `curl` this endpoint and it will return a 200 status code with a JSON body:
+///
+/// ```json
+/// {
+///   "name": "Fido",
+///   "age": 4
+/// }
+/// ```
+#[get("/api/dog")]
+async fn get_data() -> Result<DogData> {
+    Ok(DogData {
+        name: "Fido".to_string(),
+        age: 4,
+    })
+}
+
+#[derive(Serialize, Deserialize, Debug)]
+struct DogData {
+    name: String,
+    age: u8,
+}
+
+/// A server function that returns a custom struct as JSON.
+#[get("/api/custom")]
+async fn get_custom_data() -> Result<CustomData> {
+    Ok(CustomData {
+        message: "Hello from the server!".to_string(),
+    })
+}
+
+#[derive(Debug)]
+struct CustomData {
+    message: String,
+}
+impl IntoResponse for CustomData {
+    fn into_response(self) -> axum_core::response::Response {
+        axum_core::response::Response::builder()
+            .status(StatusCode::ACCEPTED)
+            .body(serde_json::to_string(&self.message).unwrap().into())
+            .unwrap()
+    }
+}
+
+impl FromResponse for CustomData {
+    async fn from_response(res: dioxus_fullstack::ClientResponse) -> Result<Self, ServerFnError> {
+        let message = res.json::<String>().await?;
+        Ok(CustomData { message })
+    }
+}
+
+/// An anonymous server function - the url path is generated from the module path and function name.
+///
+/// This will end up as `/api/anonymous_<hash>` where `<hash>` is a hash of the function signature.
+#[server]
+async fn anonymous() -> Result<String> {
+    Ok("Hello from an anonymous server function!".to_string())
+}
+
+/// An anonymous server function with a custom prefix and a fixed endpoint name.
+///
+/// This is less preferred over the `#[get]`/`#[post]` syntax but is still functional for backwards
+/// compatibility. Previously, only the `#[server]` attribute was available, but as of Dioxus 0.7,
+/// the `#[get]`/`#[post]` attributes are preferred for new code.
+#[server(prefix = "/api/custom", endpoint = "my_anonymous")]
+async fn custom_anonymous() -> Result<String> {
+    Ok("Hello from a custom anonymous server function!".to_string())
+}

packages/fullstack-core/src/error.rs

@@ -32,11 +32,11 @@ pub enum ServerFnError {
     /// representation of the error.
     #[error("error running server function: {message} (details: {details:#?})")]
     ServerError {
+        /// A human-readable message describing the error.
         message: String,
 
-        /// Optional HTTP status code associated with the error.
-        #[serde(skip_serializing_if = "Option::is_none")]
-        code: Option<u16>,
+        /// HTTP status code associated with the error.
+        code: u16,
 
         #[serde(skip_serializing_if = "Option::is_none")]
         details: Option<serde_json::Value>,
@@ -89,7 +89,7 @@ impl ServerFnError {
         ServerFnError::ServerError {
             message: f.to_string(),
             details: None,
-            code: None,
+            code: 500,
         }
     }
 
@@ -110,7 +110,7 @@ impl ServerFnError {
 
         ServerFnError::ServerError {
             message,
-            code: Some(status.as_u16()),
+            code: status.as_u16(),
             details: None,
         }
     }
@@ -121,7 +121,7 @@ impl From<anyhow::Error> for ServerFnError {
         ServerFnError::ServerError {
             message: value.to_string(),
             details: None,
-            code: None,
+            code: 500,
         }
     }
 }
@@ -135,11 +135,9 @@ impl From<serde_json::Error> for ServerFnError {
 impl From<ServerFnError> for http::StatusCode {
     fn from(value: ServerFnError) -> Self {
         match value {
-            ServerFnError::ServerError { code, .. } => match code {
-                Some(code) => http::StatusCode::from_u16(code)
-                    .unwrap_or(http::StatusCode::INTERNAL_SERVER_ERROR),
-                None => http::StatusCode::INTERNAL_SERVER_ERROR,
-            },
+            ServerFnError::ServerError { code, .. } => {
+                http::StatusCode::from_u16(code).unwrap_or(http::StatusCode::INTERNAL_SERVER_ERROR)
+            }
             ServerFnError::Request(err) => match err {
                 RequestError::Status(_, code) => http::StatusCode::from_u16(code)
                     .unwrap_or(http::StatusCode::INTERNAL_SERVER_ERROR),
@@ -174,7 +172,7 @@ impl From<HttpError> for ServerFnError {
                     .unwrap_or("Unknown error")
                     .to_string()
             }),
-            code: Some(value.status.as_u16()),
+            code: value.status.as_u16(),
             details: None,
         }
     }
@@ -188,9 +186,8 @@ impl IntoResponse for ServerFnError {
                 code,
                 details,
             } => {
-                let status = code
-                    .and_then(|c| StatusCode::from_u16(c).ok())
-                    .unwrap_or(StatusCode::INTERNAL_SERVER_ERROR);
+                let status =
+                    StatusCode::from_u16(code).unwrap_or(StatusCode::INTERNAL_SERVER_ERROR);
                 let body = if let Some(details) = details {
                     serde_json::json!({
                         "error": message,

packages/fullstack-core/src/streaming.rs

@@ -200,9 +200,9 @@ pub fn current_status() -> StreamingStatus {
 pub fn status_code_from_error(error: &CapturedError) -> StatusCode {
     if let Some(err) = error.downcast_ref::<ServerFnError>() {
         match err {
-            ServerFnError::ServerError {
-                code: Some(code), ..
-            } => return StatusCode::from_u16(*code).unwrap_or(StatusCode::INTERNAL_SERVER_ERROR),
+            ServerFnError::ServerError { code, .. } => {
+                return StatusCode::from_u16(*code).unwrap_or(StatusCode::INTERNAL_SERVER_ERROR)
+            }
             _ => return StatusCode::INTERNAL_SERVER_ERROR,
         }
     }

packages/fullstack-server/src/ssr.rs

@@ -258,15 +258,12 @@ impl SsrRendererPool {
                 // we need to eventually be able to downcast that and get the status code from it
                 if let Some(ServerFnError::ServerError { message, code, .. }) = error.downcast_ref()
                 {
-                    if let Some(code) = code {
-                        status_code = Some(
-                            (*code)
-                                .try_into()
-                                .unwrap_or(StatusCode::INTERNAL_SERVER_ERROR),
-                        );
-                    } else {
-                        status_code = Some(StatusCode::INTERNAL_SERVER_ERROR);
-                    }
+                    status_code = Some(
+                        (*code)
+                            .try_into()
+                            .unwrap_or(StatusCode::INTERNAL_SERVER_ERROR),
+                    );
+
                     out_message = Some(message.clone());
                 }
 

packages/fullstack/src/lib.rs

@@ -54,6 +54,8 @@ pub use client::*;
 pub use axum::extract::Json;
 pub use axum::response::{NoContent, Redirect};
 
+pub use crate::request::{FromResponse, FromResponseParts};
+
 pub use payloads::*;
 pub mod payloads {
     use crate::{ClientRequest, ClientResponse, ClientResult, IntoRequest};

packages/fullstack/src/magic.rs

@@ -89,8 +89,7 @@ pub enum RestEndpointPayload<T, E> {
 pub struct ErrorPayload<E> {
     message: String,
 
-    #[serde(skip_serializing_if = "Option::is_none")]
-    code: Option<u16>,
+    code: u16,
 
     #[serde(skip_serializing_if = "Option::is_none")]
     data: Option<E>,
@@ -280,7 +279,7 @@ mod decode_ok {
                                     if let Ok(text) = String::from_utf8(as_bytes.to_vec()) {
                                         Ok(RestEndpointPayload::Error(ErrorPayload {
                                             message: format!("HTTP {}: {}", status.as_u16(), text),
-                                            code: Some(status.as_u16()),
+                                            code: status.as_u16(),
                                             data: None,
                                         }))
                                     } else {
@@ -397,8 +396,10 @@ mod decode_ok {
                             message: _message,
                             details: _details,
                             code,
-                        } => Err(StatusCode::from_u16(code.unwrap_or(500))
-                            .unwrap_or(StatusCode::INTERNAL_SERVER_ERROR)),
+                        } => {
+                            Err(StatusCode::from_u16(code)
+                                .unwrap_or(StatusCode::INTERNAL_SERVER_ERROR))
+                        }
 
                         ServerFnError::Registration(_) | ServerFnError::MiddlewareError(_) => {
                             Err(StatusCode::INTERNAL_SERVER_ERROR)
@@ -439,7 +440,7 @@ mod decode_ok {
                     Ok(Ok(res)) => Ok(res),
                     Ok(Err(res)) => match res {
                         ServerFnError::ServerError { message, code, .. } => Err(HttpError {
-                            status: StatusCode::from_u16(code.unwrap_or(500))
+                            status: StatusCode::from_u16(code)
                                 .unwrap_or(StatusCode::INTERNAL_SERVER_ERROR),
                             message: Some(message),
                         }),
@@ -617,16 +618,33 @@ mod resp {
         fn make_axum_error(self, result: Result<Response, E>) -> Result<Response, Response>;
     }
 
+    /// Get the status code from the error type if possible.
+    pub trait AsStatusCode {
+        fn as_status_code(&self) -> StatusCode;
+    }
+
+    impl AsStatusCode for ServerFnError {
+        fn as_status_code(&self) -> StatusCode {
+            match self {
+                Self::ServerError { code, .. } => {
+                    StatusCode::from_u16(*code).unwrap_or(StatusCode::INTERNAL_SERVER_ERROR)
+                }
+                _ => StatusCode::INTERNAL_SERVER_ERROR,
+            }
+        }
+    }
+
     impl<T, E> MakeAxumError<E> for &&&ServerFnDecoder<Result<T, E>>
     where
-        E: From<ServerFnError> + Serialize + DeserializeOwned + Display,
+        E: AsStatusCode + From<ServerFnError> + Serialize + DeserializeOwned + Display,
     {
         fn make_axum_error(self, result: Result<Response, E>) -> Result<Response, Response> {
             match result {
                 Ok(res) => Ok(res),
                 Err(err) => {
+                    let status_code = err.as_status_code();
                     let err = ErrorPayload {
-                        code: None,
+                        code: status_code.as_u16(),
                         message: err.to_string(),
                         data: Some(err),
                     };
@@ -636,7 +654,7 @@ mod resp {
                         http::header::CONTENT_TYPE,
                         HeaderValue::from_static("application/json"),
                     );
-                    *resp.status_mut() = StatusCode::INTERNAL_SERVER_ERROR;
+                    *resp.status_mut() = status_code;
                     Err(resp)
                 }
             }
@@ -665,7 +683,7 @@ mod resp {
                         },
                         Ok(other) => ErrorPayload {
                             message: other.to_string(),
-                            code: None,
+                            code: 500,
                             data: None,
                         },
                         Err(err) => match err.downcast::<HttpError>() {
@@ -673,11 +691,11 @@ mod resp {
                                 message: http_err
                                     .message
                                     .unwrap_or_else(|| http_err.status.to_string()),
-                                code: Some(http_err.status.as_u16()),
+                                code: http_err.status.as_u16(),
                                 data: None,
                             },
                             Err(err) => ErrorPayload {
-                                code: None,
+                                code: 500,
                                 message: err.to_string(),
                                 data: None,
                             },
@@ -706,7 +724,7 @@ mod resp {
                 Ok(resp) => Ok(resp),
                 Err(status) => {
                     let body = serde_json::to_string(&ErrorPayload::<()> {
-                        code: Some(status.as_u16()),
+                        code: status.as_u16(),
                         message: status.to_string(),
                         data: None,
                     })
@@ -732,7 +750,7 @@ mod resp {
                 Ok(resp) => Ok(resp),
                 Err(http_err) => {
                     let body = serde_json::to_string(&ErrorPayload::<()> {
-                        code: Some(http_err.status.as_u16()),
+                        code: http_err.status.as_u16(),
                         message: http_err
                             .message
                             .unwrap_or_else(|| http_err.status.to_string()),

packages/native/src/link_handler.rs

@@ -10,9 +10,9 @@ impl NavigationProvider for DioxusNativeNavigationProvider {
         if options.method == Method::GET
             && matches!(options.url.scheme(), "http" | "https" | "mailto")
         {
-            if let Err(err) = webbrowser::open(options.url.as_str()) {
+            if let Err(_err) = webbrowser::open(options.url.as_str()) {
                 #[cfg(feature = "tracing")]
-                tracing::error!("Failed to open URL: {}", err);
+                tracing::error!("Failed to open URL: {}", _err);
             }
         }
     }