Add single consent library

- adds code to include and manage our use of the single consent API code
- init is called by the cookie banner code on every page, which determines which API endpoint to use (staging or prod) and creates the GovSingleConsent object
- useConsentApi is called across the code to check whether or not to use the consent API, this will be set in static
- the default callback for the consent object checks the returned response and if the user has consented, triggers the cookie-consent event, which will initialise analytics and hide the cookie banner
- setPreferences allows user consent to be set through the API

app/assets/javascripts/govuk_publishing_components/lib/single-consent-functions.js

@@ -0,0 +1,63 @@
+/* global GovSingleConsent */
+// = require govuk-single-consent/dist/singleconsent.iife.js
+
+(function (root) {
+  'use strict'
+  window.GOVUK = window.GOVUK || {}
+
+  window.GOVUK.singleConsent = {
+    init: function (callback) {
+      if (!this.useConsentApi()) {
+        return
+      }
+      callback = callback || this.apiCallBack
+      // determine where we are and set the consent api URL accordingly
+      if (!this.url) {
+        this.url = 'staging'
+        var environment = window.GOVUK.loadAnalytics.getEnvironment(window.GOVUK.analyticsGa4.core.trackFunctions.getHostname())
+        if (environment && environment.name === 'production') {
+          this.url = 'production'
+        }
+      }
+      // create the consent API object
+      this.consentApiObj = new GovSingleConsent(callback, this.url)
+    },
+
+    useConsentApi: function () {
+      if (window.GOVUK.useSingleConsentApi) {
+        return true
+      }
+    },
+
+    apiCallBack: function (consents, consentsPreferencesSet, error) {
+      if (error) {
+        console.error('Single consent error: ', error, window.location)
+        return
+      }
+      if (consentsPreferencesSet) {
+        if (consents && consents.usage) {
+          window.GOVUK.triggerEvent(window, 'cookie-consent')
+        }
+      }
+    },
+
+    setPreferences: function (type, options) {
+      if (this.useConsentApi()) {
+        try {
+          switch (type) {
+            case 'accept':
+              this.consentApiObj.setConsents(GovSingleConsent.ACCEPT_ALL)
+              break
+            case 'reject':
+              this.consentApiObj.setConsents(GovSingleConsent.REJECT_ALL)
+              break
+            default:
+              this.consentApiObj.setConsents(options)
+          }
+        } catch (e) {
+          console.error('Single consent ' + type + ' error: ', e, window.location)
+        }
+      }
+    }
+  }
+}(window))

spec/javascripts/govuk_publishing_components/lib/single-consent-functions-spec.js

@@ -0,0 +1,214 @@
+/* eslint-env jasmine */
+
+describe('The single consent cookie code', function () {
+  var acceptAll = {
+    essential: true,
+    usage: true,
+    campaigns: true,
+    settings: true
+  }
+  var rejectAll = {
+    essential: true,
+    usage: false,
+    campaigns: false,
+    settings: false
+  }
+  var mix = {
+    essential: true,
+    usage: false,
+    campaigns: true,
+    settings: true
+  }
+
+  beforeEach(function () {
+    spyOn(window.GOVUK, 'triggerEvent').and.callThrough()
+    spyOn(window.GOVUK.singleConsent, 'apiCallBack').and.callThrough()
+    jasmine.Ajax.install()
+  })
+
+  afterEach(function () {
+    jasmine.Ajax.uninstall()
+    delete window.GOVUK.singleConsent.consentApiObj
+    delete window.GOVUK.singleConsent.url
+    delete window.GOVUK.useSingleConsentApi
+  })
+
+  describe('if the single consent API should not be used', function () {
+    beforeEach(function () {
+      delete window.GOVUK.useSingleConsentApi
+    })
+
+    it('will not initialise', function () {
+      window.GOVUK.singleConsent.init()
+      expect(window.GOVUK.singleConsent.consentApiObj).not.toBeDefined()
+    })
+
+    it('confirms that it should do nothing', function () {
+      expect(window.GOVUK.singleConsent.useConsentApi()).toEqual(undefined)
+    })
+  })
+
+  describe('if the single consent API should be used', function () {
+    beforeEach(function () {
+      window.GOVUK.useSingleConsentApi = true
+    })
+
+    afterEach(function () {
+      delete window.GOVUK.useSingleConsentApi
+    })
+
+    it('does nothing if there is no unique user id', function () {
+      window.GOVUK.singleConsent.init()
+      expect(window.GOVUK.singleConsent.consentApiObj).toBeDefined()
+      expect(jasmine.Ajax.requests.count()).toEqual(0)
+      expect(window.GOVUK.singleConsent.apiCallBack).toHaveBeenCalledWith(null, false, null)
+      expect(window.GOVUK.triggerEvent).not.toHaveBeenCalled()
+    })
+
+    it('accepts a function for the callback', function () {
+      var test = {
+        testFunction: function () {}
+      }
+      spyOn(test, 'testFunction')
+      window.GOVUK.singleConsent.init(test.testFunction)
+      expect(test.testFunction).toHaveBeenCalled()
+    })
+
+    it('accepts a function with parameters for the callback', function () {
+      var test = {
+        testFunction: function () {}
+      }
+      spyOn(test, 'testFunction')
+      window.GOVUK.singleConsent.init(test.testFunction('this', 'works'))
+      expect(window.GOVUK.singleConsent.consentApiObj).toBeDefined()
+      expect(test.testFunction).toHaveBeenCalledWith('this', 'works')
+    })
+
+    describe('when determining the environment', function () {
+      it('starts without a URL for the consent API', function () {
+        expect(window.GOVUK.singleConsent.url).toBeFalsy()
+      })
+
+      it('defaults to staging if the environment is not recognised', function () {
+        spyOn(window.GOVUK.analyticsGa4.core.trackFunctions, 'getHostname').and.returnValue('moo')
+        window.GOVUK.singleConsent.init()
+        expect(window.GOVUK.singleConsent.url).toEqual('staging')
+      })
+
+      it('switches to production when on production', function () {
+        spyOn(window.GOVUK.analyticsGa4.core.trackFunctions, 'getHostname').and.returnValue('www.gov.uk')
+        window.GOVUK.singleConsent.init()
+        expect(window.GOVUK.singleConsent.url).toEqual('production')
+      })
+    })
+
+    describe('when there is a user id', function () {
+      beforeEach(function () {
+        window.GOVUK.cookie('gov_singleconsent_uid', '1234')
+        window.GOVUK.singleConsent.init()
+      })
+
+      afterEach(function () {
+        window.GOVUK.cookie('gov_singleconsent_uid', null)
+      })
+
+      it('does everything expected when full consent is given', function () {
+        window.GOVUK.singleConsent.setPreferences('accept')
+        jasmine.Ajax.requests.mostRecent().respondWith({
+          status: 200,
+          contentType: 'text/plain',
+          responseText: '{ "uid": "1234", "status": ' + JSON.stringify(acceptAll) + '}'
+        })
+
+        expect(window.GOVUK.singleConsent.consentApiObj).toBeDefined()
+        expect(window.GOVUK.singleConsent.apiCallBack).toHaveBeenCalledWith(acceptAll, true, null)
+        expect(window.GOVUK.triggerEvent).toHaveBeenCalled()
+        expect(window.GOVUK.cookie('cookies_policy')).toEqual('{"essential":true,"usage":true,"campaigns":true,"settings":true}')
+      })
+
+      it('does everything expected when consent is rejected', function () {
+        window.GOVUK.singleConsent.setPreferences('reject')
+        jasmine.Ajax.requests.mostRecent().respondWith({
+          status: 200,
+          contentType: 'text/plain',
+          responseText: '{ "uid": "1234", "status": ' + JSON.stringify(rejectAll) + '}'
+        })
+
+        expect(window.GOVUK.singleConsent.consentApiObj).toBeDefined()
+        expect(window.GOVUK.singleConsent.apiCallBack).toHaveBeenCalledWith(rejectAll, true, null)
+        expect(window.GOVUK.triggerEvent).not.toHaveBeenCalled()
+        expect(window.GOVUK.cookie('cookies_policy')).toEqual('{"essential":true,"usage":false,"campaigns":false,"settings":false}')
+      })
+
+      it('allows individual cookies to be set', function () {
+        window.GOVUK.singleConsent.setPreferences(false, mix)
+        jasmine.Ajax.requests.mostRecent().respondWith({
+          status: 200,
+          contentType: 'text/plain',
+          responseText: '{ "uid": "1234", "status": ' + JSON.stringify(mix) + '}'
+        })
+
+        expect(window.GOVUK.singleConsent.consentApiObj).toBeDefined()
+        expect(window.GOVUK.singleConsent.apiCallBack).toHaveBeenCalledWith(mix, true, null)
+        expect(window.GOVUK.triggerEvent).not.toHaveBeenCalled()
+        expect(window.GOVUK.cookie('cookies_policy')).toEqual('{"essential":true,"usage":false,"campaigns":true,"settings":true}')
+      })
+    })
+
+    describe('when there is a problem', function () {
+      beforeEach(function () {
+        jasmine.clock().install()
+        window.GOVUK.cookie('gov_singleconsent_uid', '1234')
+      })
+
+      afterEach(function () {
+        jasmine.clock().uninstall()
+        window.GOVUK.cookie('gov_singleconsent_uid', null)
+      })
+
+      it('handles a timeout gracefully', function () {
+        window.GOVUK.singleConsent.init()
+        window.GOVUK.singleConsent.setPreferences('accept')
+        jasmine.Ajax.requests.mostRecent().responseTimeout()
+        expect(window.GOVUK.singleConsent.consentApiObj).toBeDefined()
+        expect(window.GOVUK.cookie('cookies_policy')).toEqual('{"essential":true,"usage":false,"campaigns":false,"settings":false}')
+      })
+
+      it('fails gracefully if pointed at an incorrect endpoint URL', function () {
+        window.GOVUK.singleConsent.init()
+        window.GOVUK.singleConsent.setPreferences('accept')
+        jasmine.Ajax.requests.mostRecent().respondWith({
+          status: 404,
+          contentType: 'text/plain',
+          responseText: 'error not found'
+        })
+        expect(window.GOVUK.singleConsent.consentApiObj).toBeDefined()
+        expect(window.GOVUK.cookie('cookies_policy')).toEqual('{"essential":true,"usage":false,"campaigns":false,"settings":false}')
+      })
+
+      it('fails gracefully when the server errors', function () {
+        window.GOVUK.singleConsent.init()
+        window.GOVUK.singleConsent.setPreferences('accept')
+        jasmine.Ajax.requests.mostRecent().respondWith({
+          status: 500,
+          contentType: 'text/plain',
+          responseText: 'error not found'
+        })
+        expect(window.GOVUK.singleConsent.consentApiObj).toBeDefined()
+        expect(window.GOVUK.cookie('cookies_policy')).toEqual('{"essential":true,"usage":false,"campaigns":false,"settings":false}')
+      })
+
+      it('fails gracefully when the response is not as expected', function () {
+        window.GOVUK.singleConsent.init()
+        window.GOVUK.singleConsent.setPreferences('accept')
+        jasmine.Ajax.requests.mostRecent().respondWith({
+          status: 200,
+          contentType: 'text/plain',
+          responseText: 'surprise!'
+        })
+        expect(window.GOVUK.singleConsent.consentApiObj).toBeDefined()
+        expect(window.GOVUK.cookie('cookies_policy')).toEqual('{"essential":true,"usage":false,"campaigns":false,"settings":false}')
+      })
+    })
+  })
+})