adding a naive reverse api endpoint (also, shares most of the search controller). updated search query to include a filter and a sort (calculating a bounding box, given a lat/lon)

controller/search.js

@@ -1,8 +1,9 @@
 
-var query = require('../query/search'),
-    backend = require('../src/backend');
+var backend = require('../src/backend');
 
 function controller( req, res, next ){
+  var required_query = req.required_query ? req.required_query : 'search';
+  var query = require('../query/' + required_query);
   
   // backend command
   var cmd = {

index.js

@@ -16,7 +16,10 @@ app.get( '/', require('./controller/index') );
 app.get( '/suggest', require('./sanitiser/sanitise'), require('./controller/suggest') );
 
 // search API
-app.get( '/search', require('./sanitiser/sanitise'), require('./controller/search') );
+app.get( '/search', require('./sanitiser/sanitise'), require('./middleware/search'), require('./controller/search') );
+
+// reverse API
+app.get( '/reverse', require('./sanitiser/sanitise'), require('./middleware/reverse'), require('./controller/search') );
 
 /** ----------------------- error middleware ----------------------- **/
 

middleware/reverse.js

@@ -0,0 +1,7 @@
+// middleware
+function middleware(req, res, next){
+  req.required_query = "reverse";
+  next();
+}
+
+module.exports = middleware;

middleware/search.js

@@ -0,0 +1,64 @@
+function deg2rad(degrees) {
+	return Math.PI*degrees/180;
+}
+
+function rad2deg(radians) {
+	return 180.0*radians/Math.PI;
+}
+
+// Semi-axes of WGS-84 geoidal reference
+var WGS84_a = 6378137.0;  // Major semiaxis [m]
+var WGS84_b = 6356752.3;  // Minor semiaxis [m]
+
+// Earth radius at a given latitude, according to the WGS-84 ellipsoid [m]
+function WGS84EarthRadius(lat){
+	// http://en.wikipedia.org/wiki/Earth_radius
+    var An = WGS84_a*WGS84_a * Math.cos(lat);
+    var Bn = WGS84_b*WGS84_b * Math.sin(lat);
+    var Ad = WGS84_a * Math.cos(lat);
+    var Bd = WGS84_b * Math.sin(lat);
+    return Math.sqrt( (An*An + Bn*Bn)/(Ad*Ad + Bd*Bd) );
+}
+    
+// Bounding box surrounding the point at given coordinates,
+// assuming local approximation of Earth surface as a sphere
+// of radius given by WGS84
+function boundingBox(latitudeInDegrees, longitudeInDegrees, halfSideInKm) {
+	var lat = deg2rad(latitudeInDegrees);
+    var lon = deg2rad(longitudeInDegrees);
+    var halfSide = 1000*halfSideInKm;
+
+    // Radius of Earth at given latitude
+    var radius = WGS84EarthRadius(lat);
+    // Radius of the parallel at given latitude
+    var pradius = radius*Math.cos(lat);
+
+    var latMin = lat - halfSide/radius;
+    var latMax = lat + halfSide/radius;
+    var lonMin = lon - halfSide/pradius;
+    var lonMax = lon + halfSide/pradius;
+
+    return {
+    	'top_left': {
+    		'lat': rad2deg(latMin), 
+    		'lon': rad2deg(lonMin)
+    	},
+    	'bottom_right': {
+    		'lat': rad2deg(latMax), 
+    		'lon': rad2deg(lonMax)	
+    	} 
+    };
+}
+    
+
+
+// middleware
+function middleware(req, res, next){
+  req.clean = req.clean || {};
+  // ideally, bbox should be part of the req (and not to be calculated)
+  // TBD
+  req.clean.bbox = boundingBox(req.query.lat, req.query.lon, 2000);
+  next();
+}
+
+module.exports = middleware;

query/reverse.js

@@ -0,0 +1,31 @@
+var logger = require('../src/logger');
+
+// Build pelias search query
+function generate( params ){
+  
+  var cmd = {
+    "query":{
+      "filtered" : {
+        "query" : {
+            "match_all" : {}
+        },
+        "filter" : {
+            "geo_distance" : {
+                "distance" : "1km",
+                "center_point" : {
+                  "lat": params.lat, 
+                  "lon": params.lon 
+                }
+            }
+        }
+      }
+    },
+    "size": 1
+  };
+
+  logger.log( 'cmd', JSON.stringify( cmd, null, 2 ) );
+  return cmd;
+
+}
+
+module.exports = generate;

query/search.js

@@ -5,23 +5,36 @@ function generate( params ){
   
   var cmd = {
     "query":{
-      "filtered" : {
-        "query" : {
-            "match" : {
-              "name.default": params.input
-            }
-        },
-        "filter" : {
-            "geo_distance" : {
-                "distance" : "200km",
-                "center_point" : {
-                  "lat": params.lat, 
-                  "lon": params.lon 
-                }
+      "query_string" : {
+          "query": params.input,
+          "fields": ['name.default'],
+          "default_operator": 'OR'
+        }
+      },
+      "filter": {
+        "geo_bounding_box": {
+          "center_point": {
+            "top_left": {
+              "lat": params.bbox.top_left.lat,
+              "lon": params.bbox.top_left.lon
+            },
+            "bottom_right": {
+              "lat": params.bbox.bottom_right.lat,
+              "lon": params.bbox.bottom_right.lon
             }
+          }
         }
-      }
-    },
+      },
+      "sort" : [{
+          "_geo_distance" : {
+              "center_point" : {
+                "lat": params.lat, 
+                "lon": params.lon 
+              },
+              "order": 'asc',
+              "unit": 'km'
+          }
+      }],
     "size": 30
   };