Merge pull request #4292 from picklesrus/backoff-messages

Exponentially back off the time between message polling.

src/components/navigation/www/navigation.jsx

@@ -27,56 +27,62 @@ class Navigation extends React.Component {
         super(props);
         bindAll(this, [
             'getProfileUrl',
-            'handleSearchSubmit'
+            'handleSearchSubmit',
+            'pollForMessages'
         ]);
-        this.state = {
-            messageCountIntervalId: -1 // javascript method interval id for getting messsage count.
-        };
+        // Keep the timeout id so we can cancel it (e.g. when we unmount)
+        this.messageCountTimeoutId = -1;
     }
     componentDidMount () {
         if (this.props.user) {
-            const intervalId = setInterval(() => {
-                this.props.getMessageCount(this.props.user.username);
-            }, 120000); // check for new messages every 2 mins.
-            this.setState({ // eslint-disable-line react/no-did-mount-set-state
-                messageCountIntervalId: intervalId
-            });
+            // Setup polling for messages to start in 2 minutes.
+            const twoMinInMs = 2 * 60 * 1000;
+            this.messageCountTimeoutId = setTimeout(this.pollForMessages.bind(this, twoMinInMs), twoMinInMs);
         }
     }
     componentDidUpdate (prevProps) {
         if (prevProps.user !== this.props.user) {
             this.props.handleCloseAccountNav();
             if (this.props.user) {
-                const intervalId = setInterval(() => {
-                    this.props.getMessageCount(this.props.user.username);
-                }, 120000); // check for new messages every 2 mins.
-                this.setState({ // eslint-disable-line react/no-did-update-set-state
-                    messageCountIntervalId: intervalId
-                });
+                const twoMinInMs = 2 * 60 * 1000;
+                this.messageCountTimeoutId = setTimeout(this.pollForMessages.bind(this, twoMinInMs), twoMinInMs);
             } else {
-                // clear message count check, and set to default id.
-                clearInterval(this.state.messageCountIntervalId);
+                // Clear message count check, and set to default id.
+                if (this.messageCountTimeoutId !== -1) {
+                    clearTimeout(this.messageCountTimeoutId);
+                }
                 this.props.setMessageCount(0);
-                this.setState({ // eslint-disable-line react/no-did-update-set-state
-                    messageCountIntervalId: -1
-                });
+                this.messageCountTimeoutId = -1;
             }
         }
     }
     componentWillUnmount () {
         // clear message interval if it exists
-        if (this.state.messageCountIntervalId !== -1) {
-            clearInterval(this.state.messageCountIntervalId);
+        if (this.messageCountTimeoutId !== -1) {
+            clearTimeout(this.messageCountTimeoutId);
             this.props.setMessageCount(0);
-            this.setState({
-                messageCountIntervalId: -1
-            });
+            this.messageCountTimeoutId = -1;
         }
     }
     getProfileUrl () {
         if (!this.props.user) return;
         return `/users/${this.props.user.username}/`;
     }
+
+    pollForMessages (ms) {
+        this.props.getMessageCount(this.props.user.username);
+        // We only poll if it has been less than 32 minutes.
+        // Chances of someone actively using the page for that long without
+        // a navigation is low.
+        if (ms < 32 * 60 * 1000) { // 32 minutes
+            const nextFetch = ms * 2; // exponentially back off next fetch time.
+            const timeoutId = setTimeout(() => {
+                this.pollForMessages(nextFetch);
+            }, nextFetch);
+            this.messageCountTimeoutId = timeoutId;
+        }
+    }
+
     handleSearchSubmit (formData) {
         let targetUrl = '/search/projects';
         if (formData.q) {

test/unit/components/navigation.test.jsx

 const React = require('react');
-const {shallowWithIntl} = require('../../helpers/intl-helpers.jsx');
+const {shallowWithIntl, mountWithIntl} = require('../../helpers/intl-helpers.jsx');
 import configureStore from 'redux-mock-store';
 const Navigation = require('../../../src/components/navigation/www/navigation.jsx');
 const Registration = require('../../../src/components/registration/registration.jsx');
@@ -11,6 +11,7 @@ describe('Navigation', () => {
 
     beforeEach(() => {
         store = null;
+        jest.useFakeTimers();
     });
 
     const getNavigationWrapper = props => {
@@ -103,4 +104,123 @@ describe('Navigation', () => {
         navWrapper.find('a.registrationLink').simulate('click', {preventDefault () {}});
         expect(navInstance.props.handleClickRegistration).toHaveBeenCalled();
     });
+
+    test('Component sets up message polling when it mounts', () => {
+        store = mockStore({
+            navigation: {
+                registrationOpen: false
+            },
+            messageCount: {
+                messageCount: 5
+            }
+        });
+        const props = {
+            user: {
+                thumbnailUrl: 'scratch.mit.edu',
+                username: 'auser'
+            },
+            getMessageCount: jest.fn()
+        };
+        const intlWrapper = mountWithIntl(
+            <Navigation
+                {...props}
+            />, {context: {store},
+                childContextTypes: {store}
+            });
+
+        const navInstance = intlWrapper.children().find('Navigation')
+            .instance();
+        const twoMin = 2 * 60 * 1000;
+        expect(setTimeout).toHaveBeenLastCalledWith(expect.any(Function), twoMin);
+        expect(navInstance.messageCountTimeoutId).not.toEqual(-1);
+        // Advance timers passed the intial two minutes.
+        jest.advanceTimersByTime(twoMin + 1);
+        expect(setTimeout).toHaveBeenLastCalledWith(expect.any(Function), twoMin * 2);
+        expect(props.getMessageCount).toHaveBeenCalled();
+        expect(navInstance.messageCountTimeoutId).not.toEqual(-1);
+    });
+    test('Component cancels timers when it unmounts', () => {
+        store = mockStore({
+            navigation: {
+                registrationOpen: false
+            },
+            messageCount: {
+                messageCount: 5
+            }
+        });
+        const props = {
+            user: {
+                thumbnailUrl: 'scratch.mit.edu',
+                username: 'auser'
+            },
+            getMessageCount: jest.fn()
+        };
+        const intlWrapper = mountWithIntl(
+            <Navigation
+                {...props}
+            />, {context: {store},
+                childContextTypes: {store}
+            });
+
+        const navInstance = intlWrapper.children().find('Navigation')
+            .instance();
+        const twoMin = 2 * 60 * 1000;
+        expect(setTimeout).toHaveBeenLastCalledWith(expect.any(Function), twoMin);
+        expect(navInstance.messageCountTimeoutId).not.toEqual(-1);
+        navInstance.componentWillUnmount();
+        expect(clearTimeout).toHaveBeenCalledWith(expect.any(Number));
+        expect(navInstance.messageCountTimeoutId).toEqual(-1);
+    });
+
+    test('pollForMessages polls for messages 5 times', () => {
+        store = mockStore({
+            navigation: {
+                registrationOpen: false
+            },
+            messageCount: {
+                messageCount: 5
+            }
+        });
+        const props = {
+            user: {
+                thumbnailUrl: 'scratch.mit.edu',
+                username: 'auser'
+            },
+            getMessageCount: jest.fn()
+        };
+        const intlWrapper = mountWithIntl(
+            <Navigation
+                {...props}
+            />, {context: {store},
+                childContextTypes: {store}
+            });
+
+        const navInstance = intlWrapper.children().find('Navigation')
+            .instance();
+        // Clear the timers and mocks because componentDidMount
+        // has already called pollForMessages.
+        jest.clearAllTimers();
+        jest.clearAllMocks();
+        let twoMinInMs = 2 * 60 * 1000; // 2 minutes in ms.
+        navInstance.pollForMessages(twoMinInMs);
+
+        expect(navInstance.messageCountTimeoutId).not.toEqual(-1);
+        // Check that we set the timeout to backoff exponentially
+        for (let count = 1; count < 5; ++count) {
+            jest.advanceTimersByTime(twoMinInMs + 1);
+            expect(setTimeout).toHaveBeenLastCalledWith(expect.any(Function), twoMinInMs * 2);
+            expect(props.getMessageCount).toHaveBeenCalledTimes(count);
+            twoMinInMs = twoMinInMs * 2;
+        }
+
+        // Exhaust all timers (there shouldn't be any left)
+        jest.runAllTimers();
+        // We exponentially back off checking for messages, starting at 2 min
+        // and stop after 32 minutes so it should happen 5 times total.
+        expect(props.getMessageCount).toHaveBeenCalledTimes(5);
+        // setTimeout happens 1 fewer since the original call to
+        // pollForMessages isn't counted here.
+        expect(setTimeout).toHaveBeenCalledTimes(4);
+        expect(navInstance.messageCountTimeoutId).not.toEqual(-1);
+    });
 });