sequential extractor

meilisearch-http/src/extractors/authentication/mod.rs

@@ -41,10 +41,7 @@ impl<P, D> GuardedData<P, D> {
                 }),
                 None => Err(AuthenticationError::IrretrievableState.into()),
             },
-            (token, None) => {
-                let token = token.to_string();
-                Err(AuthenticationError::InvalidToken(token).into())
-            }
+            (token, None) => Err(AuthenticationError::InvalidToken(token).into()),
         }
     }
 

meilisearch-http/src/extractors/mod.rs

@@ -1,3 +1,4 @@
 pub mod payload;
 #[macro_use]
 pub mod authentication;
+pub mod sequential_extractor;

meilisearch-http/src/extractors/sequential_extractor.rs

@@ -0,0 +1,148 @@
+#![allow(non_snake_case)]
+use std::{future::Future, pin::Pin, task::Poll};
+
+use actix_web::{dev::Payload, FromRequest, Handler, HttpRequest};
+use pin_project_lite::pin_project;
+
+/// `SeqHandler` is an actix `Handler` that enforces that extractors errors are returned in the
+/// same order as they are defined in the wrapped handler. This is needed because, by default, actix
+/// to resolves the extractors concurrently, whereas we always need the authentication extractor to
+/// throw first.
+#[derive(Clone)]
+pub struct SeqHandler<H>(pub H);
+
+pub struct SeqFromRequest<T>(T);
+
+/// This macro implements `FromRequest` for arbitrary arity handler, except for one, which is
+/// useless anyway.
+macro_rules! gen_seq {
+    ($ty:ident; $($T:ident)+) => {
+        pin_project! {
+            pub struct $ty<$($T: FromRequest), +> {
+                $(
+                #[pin]
+                $T: ExtractFuture<$T::Future, $T, $T::Error>,
+                )+
+            }
+        }
+
+        impl<$($T: FromRequest), +> Future for $ty<$($T),+> {
+            type Output = Result<SeqFromRequest<($($T),+)>, actix_web::Error>;
+
+            fn poll(self: Pin<&mut Self>, cx: &mut std::task::Context<'_>) -> Poll<Self::Output> {
+                let mut this = self.project();
+
+                let mut count_fut = 0;
+                let mut count_finished = 0;
+
+                $(
+                count_fut += 1;
+                match this.$T.as_mut().project() {
+                    ExtractProj::Future { fut } => match fut.poll(cx) {
+                        Poll::Ready(Ok(output)) => {
+                            count_finished += 1;
+                            let _ = this
+                                .$T
+                                .as_mut()
+                                .project_replace(ExtractFuture::Done { output });
+                        }
+                        Poll::Ready(Err(error)) => {
+                            count_finished += 1;
+                            let _ = this
+                                .$T
+                                .as_mut()
+                                .project_replace(ExtractFuture::Error { error });
+                        }
+                        Poll::Pending => (),
+                    },
+                    ExtractProj::Done { .. } => count_finished += 1,
+                    ExtractProj::Error { .. } => {
+                        // short circuit if all previous are finished and we had an error.
+                        if count_finished == count_fut {
+                            match this.$T.project_replace(ExtractFuture::Empty) {
+                                ExtractReplaceProj::Error { error } => {
+                                    return Poll::Ready(Err(error.into()))
+                                }
+                                _ => unreachable!("Invalid future state"),
+                            }
+                        } else {
+                            count_finished += 1;
+                        }
+                    }
+                    ExtractProj::Empty => unreachable!("From request polled after being finished. {}", stringify!($T)),
+                }
+                )+
+
+                if count_fut == count_finished {
+                    let result = (
+                        $(
+                            match this.$T.project_replace(ExtractFuture::Empty) {
+                                ExtractReplaceProj::Done { output } => output,
+                                ExtractReplaceProj::Error { error } => return Poll::Ready(Err(error.into())),
+                                _ => unreachable!("Invalid future state"),
+                            },
+                        )+
+                    );
+
+                    Poll::Ready(Ok(SeqFromRequest(result)))
+                } else {
+                    Poll::Pending
+                }
+            }
+        }
+
+        impl<$($T: FromRequest,)+> FromRequest for SeqFromRequest<($($T,)+)> {
+            type Error = actix_web::Error;
+
+            type Future = $ty<$($T),+>;
+
+            fn from_request(req: &HttpRequest, payload: &mut Payload) -> Self::Future {
+                $ty {
+                $(
+                    $T: ExtractFuture::Future {
+                        fut: $T::from_request(req, payload),
+                    },
+                )+
+                }
+            }
+        }
+
+    impl<Han, $($T: FromRequest),+> Handler<SeqFromRequest<($($T),+)>> for SeqHandler<Han>
+    where
+        Han: Handler<($($T),+)>,
+    {
+        type Output = Han::Output;
+        type Future = Han::Future;
+
+        fn call(&self, args: SeqFromRequest<($($T),+)>) -> Self::Future {
+            self.0.call(args.0)
+        }
+    }
+    };
+}
+
+// Not working for a single argument, but then, it is not really necessary.
+// gen_seq! { SeqFromRequestFut1; A }
+gen_seq! { SeqFromRequestFut2; A B }
+gen_seq! { SeqFromRequestFut3; A B C }
+gen_seq! { SeqFromRequestFut4; A B C D }
+gen_seq! { SeqFromRequestFut5; A B C D E }
+gen_seq! { SeqFromRequestFut6; A B C D E F }
+
+pin_project! {
+    #[project = ExtractProj]
+    #[project_replace = ExtractReplaceProj]
+    enum ExtractFuture<Fut, Res, Err> {
+        Future {
+            #[pin]
+            fut: Fut,
+        },
+        Done {
+            output: Res,
+        },
+        Error {
+            error: Err,
+        },
+        Empty,
+    }
+}