feat: add extractor functions with better API than extract (closes …

…#1755) (#1859)

integrations/actix/src/lib.rs

@@ -27,7 +27,12 @@ use leptos_meta::*;
 use leptos_router::*;
 use parking_lot::RwLock;
 use regex::Regex;
-use std::{fmt::Display, future::Future, pin::Pin, sync::Arc};
+use std::{
+    fmt::{Debug, Display},
+    future::Future,
+    pin::Pin,
+    sync::Arc,
+};
 #[cfg(debug_assertions)]
 use tracing::instrument;
 /// This struct lets you define headers and override the status of the Response from an Element or a Server Function
@@ -1410,13 +1415,66 @@ where
     Ok(f.call(input).await)
 }
 
+/// A helper to make it easier to use Axum extractors in server functions, with a
+/// simpler API than [`extract`].
+///
+/// It is generic over some type `T` that implements [`FromRequestParts`] and can
+/// therefore be used in an extractor. The compiler can often infer this type.
+///
+/// Any error that occurs during extraction is converted to a [`ServerFnError`].
+///
+/// ```rust,ignore
+/// // MyQuery is some type that implements `Deserialize + Serialize`
+/// #[server]
+/// pub async fn query_extract() -> Result<MyQuery, ServerFnError> {
+///     use actix_web::web::Query;
+///     use leptos_actix::*;
+///     let Query(data) = extractor().await?;
+///     Ok(data)
+/// }
+/// ```
+pub async fn extractor<T>() -> Result<T, ServerFnError>
+where
+    T: actix_web::FromRequest,
+    <T as FromRequest>::Error: Debug,
+{
+    let req = use_context::<actix_web::HttpRequest>()
+        .expect("HttpRequest should have been provided via context");
+
+    if let Some(body) = use_context::<Bytes>() {
+        let (_, mut payload) = actix_http::h1::Payload::create(false);
+        payload.unread_data(body);
+        T::from_request(&req, &mut dev::Payload::from(payload))
+    } else {
+        T::extract(&req)
+    }
+    .await
+    .map_err(|e| ServerFnError::ServerError(format!("{e:?}")))
+}
+
+/// A macro that makes it easier to use extractors in server functions. The macro
+/// takes a type or types, and extracts them from the request, returning from the
+/// server function with an `Err(_)` if there is an error during extraction.
+/// ```rust,ignore
+/// let info = extract!(ConnectionInfo);
+/// let Query(data) = extract!(Query<Search>);
+/// let (info, Query(data)) = extract!(ConnectionInfo, Query<Search>);
+/// ```
+#[macro_export]
+macro_rules! extract {
+    ($($x:ty),+) => {
+        $crate::extract(|fields: ($($x),+)| async move { fields }).await?
+    };
+}
+
 // Drawn from the Actix Handler implementation
 // https://github.com/actix/actix-web/blob/19c9d858f25e8262e14546f430d713addb397e96/actix-web/src/handler.rs#L124
 pub trait Extractor<T> {
     type Future;
 
     fn call(self, args: T) -> Self::Future;
 }
+
 macro_rules! factory_tuple ({ $($param:ident)* } => {
     impl<Func, Fut, $($param,)*> Extractor<($($param,)*)> for Func
     where

integrations/axum/Cargo.toml

@@ -8,7 +8,9 @@ repository = "https://github.com/leptos-rs/leptos"
 description = "Axum integrations for the Leptos web framework."
 
 [dependencies]
-axum = { version = "0.6", default-features = false, features=["matched-path"] }
+axum = { version = "0.6", default-features = false, features = [
+	"matched-path",
+] }
 futures = "0.3"
 http = "0.2.8"
 hyper = "0.14.23"
@@ -28,4 +30,4 @@ cfg-if = "1.0.0"
 nonce = ["leptos/nonce"]
 wasm = []
 default = ["tokio/full", "axum/macros"]
-experimental-islands = ["leptos_integration_utils/experimental-islands"]
+experimental-islands = ["leptos_integration_utils/experimental-islands"]

integrations/axum/src/lib.rs

@@ -35,7 +35,7 @@ use leptos_meta::{generate_head_metadata_separated, MetaContext};
 use leptos_router::*;
 use once_cell::sync::OnceCell;
 use parking_lot::RwLock;
-use std::{io, pin::Pin, sync::Arc, thread::available_parallelism};
+use std::{fmt::Debug, io, pin::Pin, sync::Arc, thread::available_parallelism};
 use tokio_util::task::LocalPoolHandle;
 use tracing::Instrument;
 /// A struct to hold the parts of the incoming Request. Since `http::Request` isn't cloneable, we're forced
@@ -1826,6 +1826,40 @@ where
     extract_with_state((), f).await
 }
 
+/// A helper to make it easier to use Axum extractors in server functions, with a
+/// simpler API than [`extract`].
+///
+/// It is generic over some type `T` that implements [`FromRequestParts`] and can
+/// therefore be used in an extractor. The compiler can often infer this type.
+///
+/// Any error that occurs during extraction is converted to a [`ServerFnError`].
+///
+/// ```rust,ignore
+/// // MyQuery is some type that implements `Deserialize + Serialize`
+/// #[server]
+/// pub async fn query_extract() -> Result<MyQuery, ServerFnError> {
+///     use axum::{extract::Query, http::Method};
+///     use leptos_axum::*;
+///     let Query(query) = extractor().await?;
+///
+///     Ok(query)
+/// }
+/// ```
+pub async fn extractor<T>() -> Result<T, ServerFnError>
+where
+    T: Sized + FromRequestParts<()>,
+    T::Rejection: Debug,
+{
+    let ctx = use_context::<ExtractorHelper>().expect(
+        "should have had ExtractorHelper provided by the leptos_axum \
+         integration",
+    );
+    let mut parts = ctx.parts.lock().await;
+    T::from_request_parts(&mut parts, &())
+        .await
+        .map_err(|e| ServerFnError::ServerError(format!("{e:?}")))
+}
+
 /// A helper to make it easier to use Axum extractors in server functions. This takes
 /// a handler function and state as its arguments. The handler rules similar to Axum
 /// [handlers](https://docs.rs/axum/latest/axum/extract/index.html#intro): it is an async function