Add query params support for filter, order & limit

This adds query params to filter, order and limit for the GET interface
/api/places.

Author: chrismayer

controller/place.controller.js

@@ -4,11 +4,14 @@
  * @author C. Mayer (meggsimum)
  */
 const db = require('../config/db.config.js');
+const queryResolver = require('../query/resolver');
 const Places = db.places;
 
 // fetch all places
 exports.findAll = (req, res) => {
-  Places.findAll().then(places => {
+  // resolve query params (filter, limit, ...) as Sequelize opts
+  const seqOpts = queryResolver.getSequelizeOpts(req.query);
+  Places.findAll(seqOpts).then(places => {
     // send all Customers to Client
     res.json(places);
   }).catch(err => {

query/resolver.js

@@ -0,0 +1,43 @@
+/**
+ * Resolves a query string to a Sequelize DB query options object.
+ *
+ * @param {*} query The Express request query object
+ *
+ * @author C. Mayer (meggsimum)
+ */
+exports.getSequelizeOpts = (query) => {
+  let order = null;
+  let where = null;
+  let limit = null;
+
+  // ORDER BY
+  const orderByColumn = query.order_by;
+  if (orderByColumn && orderByColumn !== '') {
+    const orderByDir = query.order_dir || 'ASC';
+    order = [
+      [orderByColumn, orderByDir]
+    ];
+  }
+
+  // LIMIT
+  limit = query.limit ? Number(query.limit) : null;
+
+  // FILTER (equals)
+  const filterParts = query.filter ? query.filter.split('=') : null;
+  if (filterParts && filterParts.length === 2) {
+    const whereProp = filterParts[0];
+    const whereVal = filterParts[1];
+    where = {};
+
+    const { Op } = require('sequelize');
+    where[whereProp] = {
+      [Op.eq]: whereVal
+    };
+  }
+
+  return {
+    where: where,
+    limit: limit,
+    order: order
+  }
+};

route/place.route.js

@@ -15,6 +15,32 @@ module.exports = function (app) {
    *  /api/places:
    *    get:
    *      summary: Retrieve all places
+   *      parameters:
+   *        - in: query
+   *          name: limit
+   *          schema:
+   *            type: integer
+   *            required: false
+   *          description: Maximum number of result objects
+   *        - in: query
+   *          name: filter
+   *          schema:
+   *            type: string
+   *            required: false
+   *          description: CQL-like filter (only 'equals' at the moment) in the form 'name=Mutterstadt'
+   *        - in: query
+   *          name: order_by
+   *          schema:
+   *            type: string
+   *            required: false
+   *          description: Field to use to order results by
+   *        - in: query
+   *          name: order_dir
+   *          schema:
+   *            type: string
+   *            required: false
+   *            default: ASC
+   *          description: Order direction, either 'ASC' or 'DESC'
    *      responses:
    *        "200":
    *          description: JSON with all places objects as array