peer_addr/1 function

src/cowboy_http_req.erl

@@ -22,7 +22,7 @@
 -module(cowboy_http_req).
 
 -export([
-	method/1, version/1, peer/1,
+	method/1, version/1, peer/1, peer_addr/1,
 	host/1, host_info/1, raw_host/1, port/1,
 	path/1, path_info/1, raw_path/1,
 	qs_val/2, qs_val/3, qs_vals/1, raw_qs/1,
@@ -71,6 +71,31 @@ peer(Req=#http_req{socket=Socket, transport=Transport, peer=undefined}) ->
 peer(Req) ->
 	{Req#http_req.peer, Req}.
 
+
+%% @doc Returns the calculated peer addr in binary form, calculated from headers
+-spec peer_addr(#http_req{}) -> {inet:ip_address(), #http_req{}}.
+peer_addr(Req = #http_req{}) ->
+  {RealIp, Req1} = header(<<"X-Real-Ip">>, Req),
+  {ForwardedForRaw, Req2} = header(<<"X-Forwarded-For">>, Req1),
+  {{PeerIp, _}, Req3} = peer(Req2),
+  ForwardedFor = case ForwardedForRaw of
+    undefined -> 
+      undefined;
+    _ -> 
+      case re:run(ForwardedForRaw, "^(?<first_ip>[^\\,]+)", [{capture,[first_ip],binary}]) of
+        {match, [FirstIp]} -> FirstIp;
+        _ -> undefined
+      end
+  end,
+
+  {ok, PeerAddr} = if
+    is_binary(RealIp) -> inet_parse:address(RealIp);
+    is_binary(ForwardedFor) -> inet_parse:address(ForwardedFor);
+    true -> {ok, PeerIp}
+  end,
+  {PeerAddr, Req3}.
+
+
 %% @doc Return the tokens for the hostname requested.
 -spec host(#http_req{}) -> {cowboy_dispatcher:tokens(), #http_req{}}.
 host(Req) ->