Added near by search support

README.md

@@ -130,6 +130,60 @@ Add `q`
 GET /posts?q=internet
 ```
 
+### Near by search
+
+Add `near` and `distance`
+
+```
+GET /cities?near=lat,lon&distance=meters
+```
+
+Add `cities` in db.json 
+
+```json
+{
+  "posts": [
+    { "id": 1, "title": "json-server", "author": "typicode" }
+  ],
+  "comments": [
+    { "id": 1, "body": "some comment", "postId": 1 }
+  ],
+  "profile": { "name": "typicode" },
+  "cities": []
+}
+```
+
+start posting your cities
+```
+POST /cities
+```
+with data 
+```json
+{
+  "id": 1,
+  "city": "Jeogiwe",
+  "lat": -28.12785,
+  "lon": -145.96895
+}
+```
+to search
+```
+GET /cities?near=-28.12785,-145.96895&distance=5000
+```
+output is
+```json
+[
+  {
+    "id": 1,
+    "city": "Jeogiwe",
+    "lat": -28.12785,
+    "lon": -145.96895,
+    "geohash": 344516337195371
+  }
+]
+``` 
+When the data is posted to server a geohash property is added in data. This near search works on [geohash](https://en.wikipedia.org/wiki/Geohash) concept. To precalculate the geohash in your existing data use [node-geohash](https://github.com/sunng87/node-geohash)'s `encode_int` method. 
+
 ### Relationships
 
 To include children resources, add `_embed`

package.json

@@ -15,11 +15,13 @@
     "cors": "^2.3.0",
     "errorhandler": "^1.2.0",
     "express": "^4.9.5",
+    "geo-nearby": "^1.1.1",
     "got": "^3.3.0",
     "lodash": "^3.9.2",
     "lowdb": "^0.10.0",
     "method-override": "^2.1.2",
     "morgan": "^1.3.1",
+    "ngeohash": "^0.6.0",
     "node-uuid": "^1.4.2",
     "object-assign": "^4.0.1",
     "pluralize": "^1.1.2",
@@ -61,7 +63,10 @@
     "rest",
     "data",
     "dummy",
-    "sandbox"
+    "sandbox",
+    "geo",
+    "near",
+    "spatial"
   ],
   "author": "Typicode <[email protected]>",
   "license": "MIT",

src/cli/index.js

@@ -63,6 +63,21 @@ module.exports = function () {
         alias: 'c',
         description: 'Path to config file',
         default: 'json-server.json'
+      },
+      lattitude: {
+        alias: 'y',
+        description: 'Latitude property',
+        default: 'lat'
+      },
+      longitude: {
+        alias: 'x',
+        description: 'Longitude property',
+        default: 'lon'
+      },
+      geohash: {
+        alias: 'g',
+        description: 'Geohash property',
+        default: 'geohash'
       }
     })
     .boolean('watch')

src/cli/run.js

@@ -65,6 +65,9 @@ function createApp (source, object, routes, argv) {
   }
 
   router.db._.id = argv.id
+  router.db._.geohash = argv.geohash || 'geohash'
+  router.db._.lat = argv.lat || 'lat'
+  router.db._.lon = argv.lon || 'lon'
   app.db = router.db
   app.use(router)
 

src/server/mixins.js

@@ -1,10 +1,14 @@
 var uuid = require('node-uuid')
 var pluralize = require('pluralize')
+var geo = require('geo-nearby')
+var ngeohash = require('ngeohash')
 
 module.exports = {
   getRemovable: getRemovable,
   createId: createId,
-  deepQuery: deepQuery
+  deepQuery: deepQuery,
+  nearBy: nearBy,
+  calGeohash: calGeohash
 }
 
 // Returns document ids that have unsatisfied relations
@@ -75,3 +79,12 @@ function deepQuery (value, q) {
     }
   }
 }
+// extends lowdb instance with nearBy function
+function nearBy (db, lat, lon, distance) {
+  var _ = this
+  return geo(db, {geo: _.geohash || 'geohash'}).nearBy(lat, lon, distance)
+}
+// extends lowdb instace with geohash function
+function calGeohash (lat, lon) {
+  return ngeohash.encode_int(lat, lon)
+}

src/server/router/index.js

@@ -34,6 +34,11 @@ module.exports = function (source) {
   // Add specific mixins
   db._.mixin(mixins)
 
+  // Defualt near properties
+  db._.lat = 'lat'
+  db._.lon = 'lon'
+  db._.geohash = 'geohash'
+
   // Expose database
   router.db = db
 

src/server/router/plural.js

@@ -35,6 +35,7 @@ module.exports = function (db, name) {
 
   // GET /name
   // GET /name?q=
+  // GET /name?near=lat,lon&distance=
   // GET /name?attr=&attr=
   // GET /name?_end=&
   // GET /name?_start=&_end=&
@@ -47,6 +48,8 @@ module.exports = function (db, name) {
     // Remove q, _start, _end, ... from req.query to avoid filtering using those
     // parameters
     var q = req.query.q
+    var near = req.query.near
+    var distance = req.query.distance
     var _start = req.query._start
     var _end = req.query._end
     var _sort = req.query._sort
@@ -55,6 +58,8 @@ module.exports = function (db, name) {
     var _embed = req.query._embed
     var _expand = req.query._expand
     delete req.query.q
+    delete req.query.near
+    delete req.query.distance
     delete req.query._start
     delete req.query._end
     delete req.query._sort
@@ -97,6 +102,21 @@ module.exports = function (db, name) {
 
     }
 
+    // nearBy query
+    if (near && distance) {
+      var latLong = near.split(',').map(function (val) {
+        return parseFloat(val)
+      })
+      if (
+        latLong.length === 2
+        && !isNaN(latLong[0])
+        && !isNaN(latLong[1])
+        && !isNaN(distance)
+      ) {
+        chain = chain.nearBy(latLong[0], latLong[1], distance)
+      }
+    }
+
     Object.keys(req.query).forEach(function (key) {
       // Don't take into account JSONP query parameters
       // jQuery adds a '_' query parameter too
@@ -209,6 +229,12 @@ module.exports = function (db, name) {
       req.body[key] = utils.toNative(req.body[key])
     }
 
+    // check if it has location data then create geohash
+    if (req.body[db._.lat] && req.body[db._.lon]) {
+      req.body[db._.geohash] = db._.calGeohash(
+        req.body[db._.lat], req.body[db._.lon])
+    }
+
     var resource = db(name)
       .insert(req.body)
 
@@ -226,6 +252,14 @@ module.exports = function (db, name) {
 
     var id = utils.toNative(req.params.id)
 
+    // check if it has location data then create geohash
+    if (req.body[db._.lat] || req.body[db._.lon]) {
+      var old = db(name).getById(id)
+      var lat = req.body[db._.lat] || old.lat
+      var lon = req.body[db._.lon] || old.lon
+      req.body[db._.geohash] = db._.calGeohash(lat, lon)
+    }
+
     var resource = req.method === 'PATCH' ?
       db(name).updateById(id, req.body) :
       db(name).replaceById(id, req.body)

src/server/router/singular.js

@@ -10,12 +10,24 @@ module.exports = function (db, name) {
   }
 
   function create (req, res, next) {
+    // check if it has location data then create geohash
+    if (req.body[db._.lat] && req.body[db._.lon]) {
+      req.body[db._.geohash] = db._.calGeohash(
+        req.body[db._.lat], req.body[db._.lon])
+    }
     res.locals.data = db.object[name] = req.body
     res.status(201)
     next()
   }
 
   function update (req, res, next) {
+    // check if it has location data then create geohash
+    if (req.body[db._.lat] || req.body[db._.lon]) {
+      var old = db.object[name]
+      var lat = req.body[db._.lat] || old.lat
+      var lon = req.body[db._.lon] || old.lon
+      req.body[db._.geohash] = db._.calGeohash(lat, lon)
+    }
     if (req.method === 'PUT') {
       delete db.object[name]
       db.object[name] = {}