added support for _delay in query string to delay response of request on per request basis (#673)

* added support for passing _delay as query parameter to delay response by X milliseconds

* added tests / fixed linting error

src/server/router/delay.js

@@ -0,0 +1,11 @@
+const pause = require('connect-pause')
+
+module.exports = function delay(req, res, next) {
+  // NOTE: for some reason unknown to me, if the default is 0, the tests seems to add 2 seconds
+  // NOTE: to each test, a default value of 1 does not seem to be effected by that issue
+  const _delay = !isNaN(parseFloat(req.query._delay))
+    ? parseFloat(req.query._delay)
+    : 1
+  delete req.query._delay
+  pause(_delay)(req, res, next)
+}

src/server/router/nested.js

@@ -1,8 +1,10 @@
 const express = require('express')
 const pluralize = require('pluralize')
+const delay = require('./delay')
 
 module.exports = opts => {
   const router = express.Router()
+  router.use(delay)
 
   // Rewrite URL (/:resource/:id/:nested -> /:nested) and request query
   function get(req, res, next) {

src/server/router/plural.js

@@ -4,10 +4,12 @@ const pluralize = require('pluralize')
 const write = require('./write')
 const getFullURL = require('./get-full-url')
 const utils = require('../utils')
+const delay = require('./delay')
 
 module.exports = (db, name, opts) => {
   // Create router
   const router = express.Router()
+  router.use(delay)
 
   // Embed function used in GET /name and GET /name/id
   function embed(resource, e) {

src/server/router/singular.js

@@ -1,9 +1,11 @@
 const express = require('express')
 const write = require('./write')
 const getFullURL = require('./get-full-url')
+const delay = require('./delay')
 
 module.exports = (db, name) => {
   const router = express.Router()
+  router.use(delay)
 
   function show(req, res, next) {
     res.locals.data = db.get(name).value()

test/server/plural.js

@@ -501,6 +501,18 @@ describe('Server', () => {
     })
   })
 
+  describe('GET /:resource>_delay=', () => {
+    it('should delay response', done => {
+      const start = new Date()
+      request(server)
+        .get('/posts?_delay=1100')
+        .expect(200, function(err) {
+          const end = new Date()
+          done(end - start > 1000 ? err : new Error("Request wasn't delayed"))
+        })
+    })
+  })
+
   describe('POST /:resource', () => {
     it('should respond with json, create a resource and increment id', async () => {
       await request(server)
@@ -546,6 +558,19 @@ describe('Server', () => {
         .expect(201))
   })
 
+  describe('POST /:resource?_delay=', () => {
+    it('should delay response', done => {
+      const start = new Date()
+      request(server)
+        .post('/posts?_delay=1100')
+        .send({ body: 'foo', booleanValue: true, integerValue: 1 })
+        .expect(201, function(err) {
+          const end = new Date()
+          done(end - start > 1000 ? err : new Error("Request wasn't delayed"))
+        })
+    })
+  })
+
   describe('PUT /:resource/:id', () => {
     it('should respond with json and replace resource', async () => {
       const post = { id: 1, booleanValue: true, integerValue: 1 }
@@ -573,6 +598,20 @@ describe('Server', () => {
         .expect(404))
   })
 
+  describe('PUT /:resource:id?_delay=', () => {
+    it('should delay response', done => {
+      const start = new Date()
+      request(server)
+        .put('/posts/1?_delay=1100')
+        .set('Accept', 'application/json')
+        .send({ id: 1, booleanValue: true, integerValue: 1 })
+        .expect(200, function(err) {
+          const end = new Date()
+          done(end - start > 1000 ? err : new Error("Request wasn't delayed"))
+        })
+    })
+  })
+
   describe('PATCH /:resource/:id', () => {
     it('should respond with json and update resource', async () => {
       const partial = { body: 'bar' }
@@ -597,6 +636,20 @@ describe('Server', () => {
         .expect(404))
   })
 
+  describe('PATCH /:resource:id?_delay=', () => {
+    it('should delay response', done => {
+      const start = new Date()
+      request(server)
+        .patch('/posts/1?_delay=1100')
+        .send({ body: 'bar' })
+        .send({ id: 1, booleanValue: true, integerValue: 1 })
+        .expect(200, function(err) {
+          const end = new Date()
+          done(end - start > 1000 ? err : new Error("Request wasn't delayed"))
+        })
+    })
+  })
+
   describe('DELETE /:resource/:id', () => {
     it('should respond with empty data, destroy resource and dependent resources', async () => {
       await request(server)
@@ -615,6 +668,19 @@ describe('Server', () => {
         .expect(404))
   })
 
+  describe('DELETE /:resource:id?_delay=', () => {
+    it('should delay response', done => {
+      const start = new Date()
+      request(server)
+        .del('/posts/1?_delay=1100')
+        .send({ id: 1, booleanValue: true, integerValue: 1 })
+        .expect(200, function(err) {
+          const end = new Date()
+          done(end - start > 1000 ? err : new Error("Request wasn't delayed"))
+        })
+    })
+  })
+
   describe('Static routes', () => {
     describe('GET /', () => {
       it('should respond with html', () =>