feat: add Actix `extract` helper (#936)

integrations/actix/src/lib.rs

@@ -13,7 +13,7 @@ use actix_web::{
     web::Bytes,
     *,
 };
-use futures::{Future, Stream, StreamExt};
+use futures::{Stream, StreamExt};
 use http::StatusCode;
 use leptos::{
     leptos_dom::ssr::render_to_stream_with_prefix_undisposed_with_context,
@@ -26,7 +26,7 @@ use leptos_meta::*;
 use leptos_router::*;
 use parking_lot::RwLock;
 use regex::Regex;
-use std::sync::Arc;
+use std::{fmt::Display, future::Future, sync::Arc};
 use tracing::instrument;
 /// This struct lets you define headers and override the status of the Response from an Element or a Server Function
 /// Typically contained inside of a ResponseOptions. Setting this is useful for cookies and custom responses.
@@ -1094,3 +1094,94 @@ where
         router
     }
 }
+
+/// A helper to make it easier to use Axum extractors in server functions. This takes
+/// a handler function as its argument. The handler follows similar rules to an Actix
+/// [Handler](actix_web::Handler): it is an async function that receives arguments that  
+/// will be extracted from the request and returns some value.
+///
+/// ```rust,ignore
+/// use leptos::*;
+/// use serde::Deserialize;
+/// #[derive(Deserialize)]
+/// struct Search {
+///     q: String,
+/// }
+///
+/// #[server(ExtractoServerFn, "/api")]
+/// pub async fn extractor_server_fn(cx: Scope) -> Result<String, ServerFnError> {
+///     use actix_web::dev::ConnectionInfo;
+///     use actix_web::web::{Data, Query};
+///
+///     extract(
+///         cx,
+///         |data: Data<String>, search: Query<Search>, connection: ConnectionInfo| async move {
+///             format!(
+///                 "data = {}\nsearch = {}\nconnection = {:?}",
+///                 data.into_inner(),
+///                 search.q,
+///                 connection
+///             )
+///         },
+///     )
+///     .await
+/// }
+/// ```
+pub async fn extract<F, E>(
+    cx: leptos::Scope,
+    f: F,
+) -> Result<<<F as Extractor<E>>::Future as Future>::Output, ServerFnError>
+where
+    F: Extractor<E>,
+    E: actix_web::FromRequest,
+    <E as actix_web::FromRequest>::Error: Display,
+    <F as Extractor<E>>::Future: Future,
+{
+    let req = use_context::<actix_web::HttpRequest>(cx)
+        .expect("HttpRequest should have been provided via context");
+    let input = E::extract(&req)
+        .await
+        .map_err(|e| ServerFnError::ServerError(e.to_string()))?;
+    Ok(f.call(input).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
+        Func: Fn($($param),*) -> Fut + Clone + 'static,
+        Fut: Future,
+    {
+        type Future = Fut;
+
+        #[inline]
+        #[allow(non_snake_case)]
+        fn call(&self, ($($param,)*): ($($param,)*)) -> Self::Future {
+            (self)($($param,)*)
+        }
+    }
+});
+
+factory_tuple! {}
+factory_tuple! { A }
+factory_tuple! { A B }
+factory_tuple! { A B C }
+factory_tuple! { A B C D }
+factory_tuple! { A B C D E }
+factory_tuple! { A B C D E F }
+factory_tuple! { A B C D E F G }
+factory_tuple! { A B C D E F G H }
+factory_tuple! { A B C D E F G H I }
+factory_tuple! { A B C D E F G H I J }
+factory_tuple! { A B C D E F G H I J K }
+factory_tuple! { A B C D E F G H I J K L }
+factory_tuple! { A B C D E F G H I J K L M }
+factory_tuple! { A B C D E F G H I J K L M N }
+factory_tuple! { A B C D E F G H I J K L M N O }
+factory_tuple! { A B C D E F G H I J K L M N O P }