initial try

Cargo.toml

@@ -3,7 +3,8 @@ name = "warp-real-ip"
 version = "0.1.0"
 authors = ["Robin Appelman <robin@icewind.nl>"]
 edition = "2018"
-
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+keywords = ["warp"]
+categories = ["web-programming::http-server"]
 
 [dependencies]
+warp = { version = "0.2" }

src/lib.rs

@@ -0,0 +1,29 @@
+use std::convert::Infallible;
+use std::net::{IpAddr, SocketAddr};
+use warp::filters::addr::remote;
+use warp::Filter;
+
+/// Creates a `Filter` that provides the "real ip" of the connected client.
+pub fn real_ip<'a>(
+    trusted_proxies: &'a [IpAddr],
+) -> impl Filter<Extract = (Option<IpAddr>,), Error = Infallible> + Clone + 'a {
+    let forwarded_for = warp::header::<IpAddr>("X-FORWARDED-FOR")
+        .or(warp::header("x-real-ip"))
+        .unify()
+        .map(Some)
+        .or(warp::any().map(|| None))
+        .unify();
+
+    remote().and(forwarded_for).map(
+        move |addr: Option<SocketAddr>, forwarded_for: Option<IpAddr>| {
+            addr.map(|addr| {
+                let ip = addr.ip();
+                if trusted_proxies.contains(&ip) {
+                    forwarded_for.unwrap_or(ip)
+                } else {
+                    ip
+                }
+            })
+        },
+    )
+}

src/main.rs

@@ -1,3 +0,0 @@
-fn main() {
-    println!("Hello, world!");
-}