add new rule file

rule_sample/rule_reverse_proxy.js

@@ -0,0 +1,23 @@
+/*
+read the following wiki before using rule file
+https://github.com/alibaba/anyproxy/wiki/What-is-rule-file-and-how-to-write-one
+*/
+module.exports = {
+
+    summary:function(){
+        return "reverse proxy - assign an IP adress for some request";
+    },
+
+    replaceRequestOption : function(req,option){
+        var newOption = option;
+        
+        //options : http://nodejs.org/api/http.html#http_http_request_options_callback
+        if(newOption.headers.host == "www.taobao.com"){
+            newOption.hostname = "127.0.0.1";
+            newOption.port     = "80";
+        }
+
+        return newOption;
+    }
+
+};