From 0f692a3bfb1bdf1791e8e0efaf00676379b9160c Mon Sep 17 00:00:00 2001
From: Sven-Hendrik Haase <svenstaro@gmail.com>
Date: Wed, 11 Sep 2019 15:12:08 +0200
Subject: [PATCH] Add middleware example for reading the Request body

---
 middleware/Cargo.toml       |  3 +-
 middleware/README.md        |  1 -
 middleware/src/main.rs      |  3 ++
 middleware/src/read_body.rs | 70 +++++++++++++++++++++++++++++++++++++
 4 files changed, 75 insertions(+), 2 deletions(-)
 create mode 100644 middleware/src/read_body.rs

diff --git a/middleware/Cargo.toml b/middleware/Cargo.toml
index 76ecbf1c..da904716 100644
--- a/middleware/Cargo.toml
+++ b/middleware/Cargo.toml
@@ -9,4 +9,5 @@ workspace = ".."
 actix-service = "0.4.1"
 actix-web = "1.0.0"
 futures = "0.1.25"
-env_logger = "0.6"
\ No newline at end of file
+env_logger = "0.6"
+bytes = "0.4"
diff --git a/middleware/README.md b/middleware/README.md
index 1cd2b732..9c901cb6 100644
--- a/middleware/README.md
+++ b/middleware/README.md
@@ -8,4 +8,3 @@ cargo run
 
 Look in `src/main.rs` and comment the different middlewares in/out to see how
 they function.
-
diff --git a/middleware/src/main.rs b/middleware/src/main.rs
index 0496db27..5beb0a9b 100644
--- a/middleware/src/main.rs
+++ b/middleware/src/main.rs
@@ -3,6 +3,8 @@ use actix_web::{web, App, HttpServer};
 #[allow(dead_code)]
 mod redirect;
 #[allow(dead_code)]
+mod read_body;
+#[allow(dead_code)]
 mod simple;
 
 fn main() -> std::io::Result<()> {
@@ -12,6 +14,7 @@ fn main() -> std::io::Result<()> {
     HttpServer::new(|| {
         App::new()
             .wrap(redirect::CheckLogin)
+            .wrap(read_body::Logging)
             .wrap(simple::SayHi)
             .service(web::resource("/login").to(|| {
                 "You are on /login. Go to src/redirect.rs to change this behavior."
diff --git a/middleware/src/read_body.rs b/middleware/src/read_body.rs
new file mode 100644
index 00000000..48aed2cc
--- /dev/null
+++ b/middleware/src/read_body.rs
@@ -0,0 +1,70 @@
+use actix_service::{Service, Transform};
+use actix_web::error::PayloadError;
+use actix_web::{dev::ServiceRequest, dev::ServiceResponse, Error, HttpMessage};
+use bytes::BytesMut;
+use futures::future::{ok, FutureResult};
+use futures::stream::Stream;
+use futures::{Future, Poll};
+use std::cell::RefCell;
+use std::rc::Rc;
+
+pub struct Logging;
+
+impl<S: 'static, B> Transform<S> for Logging
+where
+    S: Service<Request = ServiceRequest, Response = ServiceResponse<B>, Error = Error>,
+    S::Future: 'static,
+    B: 'static,
+{
+    type Request = ServiceRequest;
+    type Response = ServiceResponse<B>;
+    type Error = Error;
+    type InitError = ();
+    type Transform = LoggingMiddleware<S>;
+    type Future = FutureResult<Self::Transform, Self::InitError>;
+
+    fn new_transform(&self, service: S) -> Self::Future {
+        ok(LoggingMiddleware {
+            service: Rc::new(RefCell::new(service)),
+        })
+    }
+}
+
+pub struct LoggingMiddleware<S> {
+    // This is special: We need this to avoid lifetime issues.
+    service: Rc<RefCell<S>>,
+}
+
+impl<S, B> Service for LoggingMiddleware<S>
+where
+    S: Service<Request = ServiceRequest, Response = ServiceResponse<B>, Error = Error>
+        + 'static,
+    S::Future: 'static,
+    B: 'static,
+{
+    type Request = ServiceRequest;
+    type Response = ServiceResponse<B>;
+    type Error = Error;
+    type Future = Box<dyn Future<Item = Self::Response, Error = Self::Error>>;
+
+    fn poll_ready(&mut self) -> Poll<(), Self::Error> {
+        self.service.poll_ready()
+    }
+
+    fn call(&mut self, mut req: ServiceRequest) -> Self::Future {
+        let mut svc = self.service.clone();
+
+        Box::new(
+            req.take_payload()
+                .fold(BytesMut::new(), move |mut body, chunk| {
+                    body.extend_from_slice(&chunk);
+                    Ok::<_, PayloadError>(body)
+                })
+                .map_err(|e| e.into())
+                .and_then(move |bytes| {
+                    println!("request body: {:?}", bytes);
+                    svc.call(req).and_then(|res| Ok(res))
+                }),
+        )
+    }
+}