Merge pull request #41 from apigee/xff-client-analytics

Updating to use xff header to set the client_ip in analytics.

analytics/index.js

diff --git a/analytics/index.js b/analytics/index.js
index 175ca09..d2d7bdf 100644
--- a/analytics/index.js
+++ b/analytics/index.js
@@ -18,6 +18,12 @@
       record.request_path = config.mask_request_path;
     }
     
+
+    var xffHeader = req.headers['x-forwarded-for'];
+    if(xffHeader) {
+      record.client_ip = xffHeader;
+    }
+
     cb(null, record);
   };