From 50c3e75bc32baf12b7df549170ee07d7bf47e1b8 Mon Sep 17 00:00:00 2001
From: Ross <rosssullivan101@gmail.com>
Date: Wed, 11 Sep 2024 22:51:39 +0900
Subject: [PATCH] Added documentation for `from_fn` and `wrap` in middleware
 page (#451)

* Added documentation for from_fn and wrap in middleware page

* Update docs/middleware.md

---------

Co-authored-by: Rob Ede <robjtede@icloud.com>
---
 docs/middleware.md                 |  6 ++++++
 examples/middleware/src/from_fn.rs | 24 ++++++++++++++++++++++++
 examples/middleware/src/main.rs    |  1 +
 3 files changed, 31 insertions(+)
 create mode 100644 examples/middleware/src/from_fn.rs

diff --git a/docs/middleware.md b/docs/middleware.md
index e98273c..a8551a4 100644
--- a/docs/middleware.md
+++ b/docs/middleware.md
@@ -27,6 +27,10 @@ Alternatively, for simple use cases, you can use [_wrap_fn_][wrap_fn] to create
 
 <CodeBlock example="middleware" file="wrap_fn.rs" section="wrap-fn" />
 
+You can also use [_from_fn_][from_fn] to in combination with [_wrap_][wrap] to create a function as middlware.
+
+<CodeBlock example="middleware" file="from_fn.rs" section="from-fn" />
+
 > Actix Web provides several useful middleware, such as _logging_, _user sessions_, _compress_, etc.
 
 **Warning: if you use `wrap()` or `wrap_fn()` multiple times, the last occurrence will be executed first.**
@@ -111,3 +115,5 @@ You can use the `ErrorHandlers::handler()` method to register a custom error han
 [servicetrait]: https://docs.rs/actix-web/4/actix_web/dev/trait.Service.html
 [transformtrait]: https://docs.rs/actix-web/4/actix_web/dev/trait.Transform.html
 [wrap_fn]: https://docs.rs/actix-web/4/actix_web/struct.App.html#method.wrap_fn
+[from_fn]: https://docs.rs/actix-web/4/actix_web/middleware/fn.from_fn.html
+[wrap]: https://docs.rs/actix-web/4/actix_web/struct.App.html#method.wrap
diff --git a/examples/middleware/src/from_fn.rs b/examples/middleware/src/from_fn.rs
new file mode 100644
index 0000000..2c5ccc0
--- /dev/null
+++ b/examples/middleware/src/from_fn.rs
@@ -0,0 +1,24 @@
+#![allow(dead_code, unused_variables)]
+
+// <from-fn>
+use actix_web::{
+    body::MessageBody,
+    dev::{ServiceRequest, ServiceResponse},
+    middleware::{from_fn, Next},
+    App, Error,
+};
+
+async fn my_midleware(
+    req: ServiceRequest,
+    next: Next<impl MessageBody>,
+) -> Result<ServiceResponse<impl MessageBody>, Error> {
+    // pre-processing
+    next.call(req).await
+    // post-processing
+}
+
+#[actix_web::main]
+async fn main() {
+    let app = App::new().wrap(from_fn(my_midleware));
+}
+// </from-fn>
diff --git a/examples/middleware/src/main.rs b/examples/middleware/src/main.rs
index 3aadfd6..a59268e 100644
--- a/examples/middleware/src/main.rs
+++ b/examples/middleware/src/main.rs
@@ -1,5 +1,6 @@
 pub mod default_headers;
 pub mod errorhandler;
+pub mod from_fn;
 pub mod logger;
 pub mod user_sessions;
 pub mod wrap_fn;