feat: look for proxied ip headers

This enables support for using the proxied IP from cloudflare. The damus
relay is behind cloudflare, so to get accurate remote ip logging we need
to look at the headers instead of the socket address.

Signed-off-by: William Casarin <jb55@jb55.com>

src/server.rs

@@ -13,6 +13,7 @@ use crate::nip05;
 use crate::subscription::Subscription;
 use futures::SinkExt;
 use futures::StreamExt;
+use http::header::HeaderMap;
 use hyper::header::ACCEPT;
 use hyper::service::{make_service_fn, service_fn};
 use hyper::upgrade::Upgraded;
@@ -85,7 +86,8 @@ async fn handle_web_request(
                                 )
                                 .await;
                                 // spawn server with info... but include IP here.
-                                let remote_ip = remote_addr.ip().to_string();
+                                let remote_ip =
+                                    get_remote_ip_string(&remote_addr, request.headers());
                                 tokio::spawn(nostr_server(
                                     pool, remote_ip, settings, ws_stream, broadcast, event_tx,
                                     shutdown,
@@ -151,6 +153,23 @@ async fn handle_web_request(
     }
 }
 
+fn get_remote_ip_string(remote_addr: &SocketAddr, headers: &HeaderMap) -> String {
+    if let Some(ip) = get_cloudflare_remote_ip(headers) {
+        return ip;
+    }
+
+    return remote_addr.ip().to_string();
+}
+
+fn get_cloudflare_remote_ip(headers: &HeaderMap) -> Option<String> {
+    if let Some(val) = headers.get("CF-Connecting-IP") {
+        if let Ok(s) = val.to_str() {
+            return Some(s.to_string());
+        }
+    }
+    return None;
+}
+
 // return on a control-c or internally requested shutdown signal
 async fn ctrl_c_or_signal(mut shutdown_signal: Receiver<()>) {
     let mut term_signal = tokio::signal::unix::signal(tokio::signal::unix::SignalKind::terminate())