If-Modified-Since header support for the /entries and /treatments API

lib/api/entries/index.js

@@ -71,6 +71,23 @@ function configure (app, wares, ctx) {
       return es.map(sync);
     }
 
+    function ifModifiedSince (req, res, next) {
+    
+      var lastEntryDate = new Date(_.last(res.entries).dateString);
+      res.setHeader('Last-Modified', lastEntryDate.toUTCString());
+      
+      var ifModifiedSince = req.get('If-Modified-Since');
+
+      if (!ifModifiedSince) { return next(); }
+      
+      if (lastEntryDate <= new Date(ifModifiedSince)) {
+        res.status(304).send({status:304, message: 'Not modified', type:'internal'});
+        return;
+      }
+      
+      return next();
+    }
+
     /**
       * @method format_entries
       * A final middleware to send payloads assembled by previous middlewares
@@ -248,7 +265,7 @@ function configure (app, wares, ctx) {
         res.entries_err = err;
         return next( );
       });
-    }, format_entries);
+    }, ifModifiedSince, format_entries);
 
     /**
       * @module get#/entries/:spec
@@ -280,7 +297,7 @@ function configure (app, wares, ctx) {
         prepReqModel(req, req.params.model);
         query_models(req, res, next);
       }
-    }, format_entries);
+    }, ifModifiedSince, format_entries);
 
 
     /**
@@ -292,7 +309,7 @@ function configure (app, wares, ctx) {
       * `find[date]`.
       *
       */
-    api.get('/entries', query_models, format_entries);
+    api.get('/entries', query_models, [ifModifiedSince, format_entries]);
 
     /**
       * @function echo_query