Adds histogram support, a bit of code duplication

lib/cartodb/controllers/layergroup.js

@@ -73,6 +73,9 @@ LayergroupController.prototype.register = function(app) {
         '/:token/:layer/list/:listName', cors(), userMiddleware,
         this.list.bind(this));
 
+    app.get(app.base_url_mapconfig +
+            '/:token/:layer/histogram/:histogramName', cors(), userMiddleware,
+        this.histogram.bind(this));
 };
 
 LayergroupController.prototype.list = function(req, res) {
@@ -103,6 +106,34 @@ LayergroupController.prototype.list = function(req, res) {
 
 };
 
+LayergroupController.prototype.histogram = function(req, res) {
+    var self = this;
+
+    step(
+        function setupParams() {
+            self.req2params(req, this);
+        },
+        function retrieveList(err) {
+            assert.ifError(err);
+
+            var mapConfigProvider = new MapStoreMapConfigProvider(
+                self.mapStore, req.context.user, self.userLimitsApi, req.params
+            );
+            self.widgetBackend.getHistogram(mapConfigProvider, req.params, this);
+        },
+        function finish(err, tile, stats) {
+            req.profiler.add(stats || {});
+
+            if (err) {
+                self.sendError(req, res, err, 'GET LIST');
+            } else {
+                self.sendResponse(req, res, tile, 200);
+            }
+        }
+    );
+
+};
+
 LayergroupController.prototype.attributes = function(req, res) {
     var self = this;
 

test/acceptance/histograms.js

@@ -0,0 +1,117 @@
+var assert      = require('../support/assert');
+var step        = require('step');
+
+var helper = require(__dirname + '/../support/test_helper');
+var LayergroupToken = require('../../lib/cartodb/models/layergroup_token');
+
+var CartodbWindshaft = require('../../lib/cartodb/server');
+var serverOptions = require('../../lib/cartodb/server_options');
+var server = new CartodbWindshaft(serverOptions);
+server.setMaxListeners(0);
+
+
+describe('lists', function() {
+
+    var keysToDelete;
+
+    beforeEach(function() {
+        keysToDelete = {};
+    });
+
+    afterEach(function(done) {
+        helper.deleteRedisKeys(keysToDelete, done);
+    });
+
+
+    it("should expose layer histogram", function(done) {
+
+        var layergroup =  {
+            version: '1.5.0',
+            layers: [
+                {
+                    type: 'mapnik',
+                    options: {
+                        sql: 'select * from populated_places_simple_reduced',
+                        cartocss: '#layer { marker-fill: red; marker-width: 32; marker-allow-overlap: true; }',
+                        cartocss_version: '2.3.0'
+                    },
+                    widgets: {
+                        pop_max: {
+                            type: 'histogram',
+                            options: {
+                                column: 'pop_max'
+                            }
+                        }
+                    }
+                }
+            ]
+        };
+
+        var layergroupId;
+        step(
+            function createLayergroup() {
+                var next = this;
+                assert.response(server,
+                    {
+                        url: '/api/v1/map',
+                        method: 'POST',
+                        headers: {
+                            host: 'localhost',
+                            'Content-Type': 'application/json'
+                        },
+                        data: JSON.stringify(layergroup)
+                    },
+                    {
+                        status: 200,
+                        headers: {
+                            'Content-Type': 'application/json; charset=utf-8'
+                        }
+                    },
+                    function(res, err) {
+                        if (err) {
+                            return next(err);
+                        }
+                        return next(null, JSON.parse(res.body).layergroupid);
+                    }
+                );
+            },
+            function getList(err, _layergroupId) {
+                assert.ifError(err);
+
+                var next = this;
+                layergroupId = _layergroupId;
+
+                assert.response(server,
+                    {
+                        url: '/api/v1/map/' + layergroupId + '/0/histogram/pop_max',
+                        method: 'GET',
+                        headers: {
+                            host: 'localhost'
+                        }
+                    },
+                    {
+                        status: 200,
+                        headers: {
+                            'Content-Type': 'application/json; charset=utf-8'
+                        }
+                    },
+                    function(res, err) {
+                        if (err) {
+                            return next(err);
+                        }
+
+                        console.log(JSON.parse(res.body));
+
+                        next(null);
+                    }
+                );
+            },
+            function finish(err) {
+                keysToDelete['map_cfg|' + LayergroupToken.parse(layergroupId).token] = 0;
+                keysToDelete['user:localhost:mapviews:global'] = 5;
+                done(err);
+            }
+        );
+    });
+
+});