HTML Examples/WP.iso/wordpress2/wp-includes/js/heartbeat.js

JavaScript | 2017-10-11 | 19.7 KB | 758 lines

/**
 * Heartbeat API
 *
 * Heartbeat is a simple server polling API that sends XHR requests to
 * the server every 15 - 60 seconds and triggers events (or callbacks) upon
 * receiving data. Currently these 'ticks' handle transports for post locking,
 * login-expiration warnings, autosave, and related tasks while a user is logged in.
 *
 * Available PHP filters (in ajax-actions.php):
 * - heartbeat_received
 * - heartbeat_send
 * - heartbeat_tick
 * - heartbeat_nopriv_received
 * - heartbeat_nopriv_send
 * - heartbeat_nopriv_tick
 * @see wp_ajax_nopriv_heartbeat(), wp_ajax_heartbeat()
 *
 * Custom jQuery events:
 * - heartbeat-send
 * - heartbeat-tick
 * - heartbeat-error
 * - heartbeat-connection-lost
 * - heartbeat-connection-restored
 * - heartbeat-nonces-expired
 *
 * @since 3.6.0
 */

( function( $, window, undefined ) {
    var Heartbeat = function() {
        var $document = $(document),
            settings = {
                // Suspend/resume
                suspend: false,

                // Whether suspending is enabled
                suspendEnabled: true,

                // Current screen id, defaults to the JS global 'pagenow' when present (in the admin) or 'front'
                screenId: '',

                // XHR request URL, defaults to the JS global 'ajaxurl' when present
                url: '',

                // Timestamp, start of the last connection request
                lastTick: 0,

                // Container for the enqueued items
                queue: {},

                // Connect interval (in seconds)
                mainInterval: 60,

                // Used when the interval is set to 5 sec. temporarily
                tempInterval: 0,

                // Used when the interval is reset
                originalInterval: 0,

                // Used to limit the number of AJAX requests.
                minimalInterval: 0,

                // Used together with tempInterval
                countdown: 0,

                // Whether a connection is currently in progress
                connecting: false,

                // Whether a connection error occurred
                connectionError: false,

                // Used to track non-critical errors
                errorcount: 0,

                // Whether at least one connection has completed successfully
                hasConnected: false,

                // Whether the current browser window is in focus and the user is active
                hasFocus: true,

                // Timestamp, last time the user was active. Checked every 30 sec.
                userActivity: 0,

                // Flags whether events tracking user activity were set
                userActivityEvents: false,

                checkFocusTimer: 0,
                beatTimer: 0
            };

        /**
         * Set local vars and events, then start
         *
         * @access private
         *
         * @return void
         */
        function initialize() {
            var options, hidden, visibilityState, visibilitychange;

            if ( typeof window.pagenow === 'string' ) {
                settings.screenId = window.pagenow;
            }

            if ( typeof window.ajaxurl === 'string' ) {
                settings.url = window.ajaxurl;
            }

            // Pull in options passed from PHP
            if ( typeof window.heartbeatSettings === 'object' ) {
                options = window.heartbeatSettings;

                // The XHR URL can be passed as option when window.ajaxurl is not set
                if ( ! settings.url && options.ajaxurl ) {
                    settings.url = options.ajaxurl;
                }

                // The interval can be from 15 to 120 sec. and can be set temporarily to 5 sec.
                // It can be set in the initial options or changed later from JS and/or from PHP.
                if ( options.interval ) {
                    settings.mainInterval = options.interval;

                    if ( settings.mainInterval < 15 ) {
                        settings.mainInterval = 15;
                    } else if ( settings.mainInterval > 120 ) {
                        settings.mainInterval = 120;
                    }
                }

                // Used to limit the number of AJAX requests. Overrides all other intervals if they are shorter.
                // Needed for some hosts that cannot handle frequent requests and the user may exceed the allocated server CPU time, etc.
                // The minimal interval can be up to 600 sec. however setting it to longer than 120 sec. will limit or disable
                // some of the functionality (like post locks).
                // Once set at initialization, minimalInterval cannot be changed/overridden.
                if ( options.minimalInterval ) {
                    options.minimalInterval = parseInt( options.minimalInterval, 10 );
                    settings.minimalInterval = options.minimalInterval > 0 && options.minimalInterval <= 600 ? options.minimalInterval * 1000 : 0;
                }

                if ( settings.minimalInterval && settings.mainInterval < settings.minimalInterval ) {
                    settings.mainInterval = settings.minimalInterval;
                }

                // 'screenId' can be added from settings on the front end where the JS global 'pagenow' is not set
                if ( ! settings.screenId ) {
                    settings.screenId = options.screenId || 'front';
                }

                if ( options.suspension === 'disable' ) {
                    settings.suspendEnabled = false;
                }
            }

            // Convert to milliseconds
            settings.mainInterval = settings.mainInterval * 1000;
            settings.originalInterval = settings.mainInterval;

            // Switch the interval to 120 sec. by using the Page Visibility API.
            // If the browser doesn't support it (Safari < 7, Android < 4.4, IE < 10), the interval
            // will be increased to 120 sec. after 5 min. of mouse and keyboard inactivity.
            if ( typeof document.hidden !== 'undefined' ) {
                hidden = 'hidden';
                visibilitychange = 'visibilitychange';
                visibilityState = 'visibilityState';
            } else if ( typeof document.msHidden !== 'undefined' ) { // IE10
                hidden = 'msHidden';
                visibilitychange = 'msvisibilitychange';
                visibilityState = 'msVisibilityState';
            } else if ( typeof document.webkitHidden !== 'undefined' ) { // Android
                hidden = 'webkitHidden';
                visibilitychange = 'webkitvisibilitychange';
                visibilityState = 'webkitVisibilityState';
            }

            if ( hidden ) {
                if ( document[hidden] ) {
                    settings.hasFocus = false;
                }

                $document.on( visibilitychange + '.wp-heartbeat', function() {
                    if ( document[visibilityState] === 'hidden' ) {
                        blurred();
                        window.clearInterval( settings.checkFocusTimer );
                    } else {
                        focused();
                        if ( document.hasFocus ) {
                            settings.checkFocusTimer = window.setInterval( checkFocus, 10000 );
                        }
                    }
                });
            }

            // Use document.hasFocus() if available.
            if ( document.hasFocus ) {
                settings.checkFocusTimer = window.setInterval( checkFocus, 10000 );
            }

            $(window).on( 'unload.wp-heartbeat', function() {
                // Don't connect any more
                settings.suspend = true;

                // Abort the last request if not completed
                if ( settings.xhr && settings.xhr.readyState !== 4 ) {
                    settings.xhr.abort();
                }
            });

            // Check for user activity every 30 seconds.
            window.setInterval( checkUserActivity, 30000 );

            // Start one tick after DOM ready
            $document.ready( function() {
                settings.lastTick = time();
                scheduleNextTick();
            });
        }

        /**
         * Return the current time according to the browser
         *
         * @access private
         *
         * @return int
         */
        function time() {
            return (new Date()).getTime();
        }

        /**
         * Check if the iframe is from the same origin
         *
         * @access private
         *
         * @return bool
         */
        function isLocalFrame( frame ) {
            var origin, src = frame.src;

            // Need to compare strings as WebKit doesn't throw JS errors when iframes have different origin.
            // It throws uncatchable exceptions.
            if ( src && /^https?:\/\//.test( src ) ) {
                origin = window.location.origin ? window.location.origin : window.location.protocol + '//' + window.location.host;

                if ( src.indexOf( origin ) !== 0 ) {
                    return false;
                }
            }

            try {
                if ( frame.contentWindow.document ) {
                    return true;
                }
            } catch(e) {}

            return false;
        }

        /**
         * Check if the document's focus has changed
         *
         * @access private
         *
         * @return void
         */
        function checkFocus() {
            if ( settings.hasFocus && ! document.hasFocus() ) {
                blurred();
            } else if ( ! settings.hasFocus && document.hasFocus() ) {
                focused();
            }
        }

        /**
         * Set error state and fire an event on XHR errors or timeout
         *
         * @access private
         *
         * @param string error The error type passed from the XHR
         * @param int status The HTTP status code passed from jqXHR (200, 404, 500, etc.)
         * @return void
         */
        function setErrorState( error, status ) {
            var trigger;

            if ( error ) {
                switch ( error ) {
                    case 'abort':
                        // do nothing
                        break;
                    case 'timeout':
                        // no response for 30 sec.
                        trigger = true;
                        break;
                    case 'error':
                        if ( 503 === status && settings.hasConnected ) {
                            trigger = true;
                            break;
                        }
                        /* falls through */
                    case 'parsererror':
                    case 'empty':
                    case 'unknown':
                        settings.errorcount++;

                        if ( settings.errorcount > 2 && settings.hasConnected ) {
                            trigger = true;
                        }

                        break;
                }

                if ( trigger && ! hasConnectionError() ) {
                    settings.connectionError = true;
                    $document.trigger( 'heartbeat-connection-lost', [error, status] );
                }
            }
        }

        /**
         * Clear the error state and fire an event
         *
         * @access private
         *
         * @return void
         */
        function clearErrorState() {
            // Has connected successfully
            settings.hasConnected = true;

            if ( hasConnectionError() ) {
                settings.errorcount = 0;
                settings.connectionError = false;
                $document.trigger( 'heartbeat-connection-restored' );
            }
        }

        /**
         * Gather the data and connect to the server
         *
         * @access private
         *
         * @return void
         */
        function connect() {
            var ajaxData, heartbeatData;

            // If the connection to the server is slower than the interval,
            // heartbeat connects as soon as the previous connection's response is received.
            if ( settings.connecting || settings.suspend ) {
                return;
            }

            settings.lastTick = time();

            heartbeatData = $.extend( {}, settings.queue );
            // Clear the data queue, anything added after this point will be send on the next tick
            settings.queue = {};

            $document.trigger( 'heartbeat-send', [ heartbeatData ] );

            ajaxData = {
                data: heartbeatData,
                interval: settings.tempInterval ? settings.tempInterval / 1000 : settings.mainInterval / 1000,
                _nonce: typeof window.heartbeatSettings === 'object' ? window.heartbeatSettings.nonce : '',
                action: 'heartbeat',
                screen_id: settings.screenId,
                has_focus: settings.hasFocus
            };

            if ( 'customize' === settings.screenId  ) {
                ajaxData.wp_customize = 'on';
            }

            settings.connecting = true;
            settings.xhr = $.ajax({
                url: settings.url,
                type: 'post',
                timeout: 30000, // throw an error if not completed after 30 sec.
                data: ajaxData,
                dataType: 'json'
            }).always( function() {
                settings.connecting = false;
                scheduleNextTick();
            }).done( function( response, textStatus, jqXHR ) {
                var newInterval;

                if ( ! response ) {
                    setErrorState( 'empty' );
                    return;
                }

                clearErrorState();

                if ( response.nonces_expired ) {
                    $document.trigger( 'heartbeat-nonces-expired' );
                }

                // Change the interval from PHP
                if ( response.heartbeat_interval ) {
                    newInterval = response.heartbeat_interval;
                    delete response.heartbeat_interval;
                }

                $document.trigger( 'heartbeat-tick', [response, textStatus, jqXHR] );

                // Do this last, can trigger the next XHR if connection time > 5 sec. and newInterval == 'fast'
                if ( newInterval ) {
                    interval( newInterval );
                }
            }).fail( function( jqXHR, textStatus, error ) {
                setErrorState( textStatus || 'unknown', jqXHR.status );
                $document.trigger( 'heartbeat-error', [jqXHR, textStatus, error] );
            });
        }

        /**
         * Schedule the next connection
         *
         * Fires immediately if the connection time is longer than the interval.
         *
         * @access private
         *
         * @return void
         */
        function scheduleNextTick() {
            var delta = time() - settings.lastTick,
                interval = settings.mainInterval;

            if ( settings.suspend ) {
                return;
            }

            if ( ! settings.hasFocus ) {
                interval = 120000; // 120 sec. Post locks expire after 150 sec.
            } else if ( settings.countdown > 0 && settings.tempInterval ) {
                interval = settings.tempInterval;
                settings.countdown--;

                if ( settings.countdown < 1 ) {
                    settings.tempInterval = 0;
                }
            }

            if ( settings.minimalInterval && interval < settings.minimalInterval ) {
                interval = settings.minimalInterval;
            }

            window.clearTimeout( settings.beatTimer );

            if ( delta < interval ) {
                settings.beatTimer = window.setTimeout(
                    function() {
                        connect();
                    },
                    interval - delta
                );
            } else {
                connect();
            }
        }

        /**
         * Set the internal state when the browser window becomes hidden or loses focus
         *
         * @access private
         *
         * @return void
         */
        function blurred() {
            settings.hasFocus = false;
        }

        /**
         * Set the internal state when the browser window becomes visible or is in focus
         *
         * @access private
         *
         * @return void
         */
        function focused() {
            settings.userActivity = time();

            // Resume if suspended
            settings.suspend = false;

            if ( ! settings.hasFocus ) {
                settings.hasFocus = true;
                scheduleNextTick();
            }
        }

        /**
         * Runs when the user becomes active after a period of inactivity
         *
         * @access private
         *
         * @return void
         */
        function userIsActive() {
            settings.userActivityEvents = false;
            $document.off( '.wp-heartbeat-active' );

            $('iframe').each( function( i, frame ) {
                if ( isLocalFrame( frame ) ) {
                    $( frame.contentWindow ).off( '.wp-heartbeat-active' );
                }
            });

            focused();
        }

        /**
         * Check for user activity
         *
         * Runs every 30 sec.
         * Sets 'hasFocus = true' if user is active and the window is in the background.
         * Set 'hasFocus = false' if the user has been inactive (no mouse or keyboard activity)
         * for 5 min. even when the window has focus.
         *
         * @access private
         *
         * @return void
         */
        function checkUserActivity() {
            var lastActive = settings.userActivity ? time() - settings.userActivity : 0;

            // Throttle down when no mouse or keyboard activity for 5 min.
            if ( lastActive > 300000 && settings.hasFocus ) {
                blurred();
            }

            // Suspend after 10 min. of inactivity when suspending is enabled.
            // Always suspend after 60 min. of inactivity. This will release the post lock, etc.
            if ( ( settings.suspendEnabled && lastActive > 600000 ) || lastActive > 3600000 ) {
                settings.suspend = true;
            }

            if ( ! settings.userActivityEvents ) {
                $document.on( 'mouseover.wp-heartbeat-active keyup.wp-heartbeat-active touchend.wp-heartbeat-active', function() {
                    userIsActive();
                });

                $('iframe').each( function( i, frame ) {
                    if ( isLocalFrame( frame ) ) {
                        $( frame.contentWindow ).on( 'mouseover.wp-heartbeat-active keyup.wp-heartbeat-active touchend.wp-heartbeat-active', function() {
                            userIsActive();
                        });
                    }
                });

                settings.userActivityEvents = true;
            }
        }

        // Public methods

        /**
         * Whether the window (or any local iframe in it) has focus, or the user is active
         *
         * @return bool
         */
        function hasFocus() {
            return settings.hasFocus;
        }

        /**
         * Whether there is a connection error
         *
         * @return bool
         */
        function hasConnectionError() {
            return settings.connectionError;
        }

        /**
         * Connect asap regardless of 'hasFocus'
         *
         * Will not open two concurrent connections. If a connection is in progress,
         * will connect again immediately after the current connection completes.
         *
         * @return void
         */
        function connectNow() {
            settings.lastTick = 0;
            scheduleNextTick();
        }

        /**
         * Disable suspending
         *
         * Should be used only when Heartbeat is performing critical tasks like autosave, post-locking, etc.
         * Using this on many screens may overload the user's hosting account if several
         * browser windows/tabs are left open for a long time.
         *
         * @return void
         */
        function disableSuspend() {
            settings.suspendEnabled = false;
        }

        /**
         * Get/Set the interval
         *
         * When setting to 'fast' or 5, by default interval is 5 sec. for the next 30 ticks (for 2 min and 30 sec).
         * In this case the number of 'ticks' can be passed as second argument.
         * If the window doesn't have focus, the interval slows down to 2 min.
         *
         * @param mixed speed Interval: 'fast' or 5, 15, 30, 60, 120
         * @param string ticks Used with speed = 'fast' or 5, how many ticks before the interval reverts back
         * @return int Current interval in seconds
         */
        function interval( speed, ticks ) {
            var newInterval,
                oldInterval = settings.tempInterval ? settings.tempInterval : settings.mainInterval;

            if ( speed ) {
                switch ( speed ) {
                    case 'fast':
                    case 5:
                        newInterval = 5000;
                        break;
                    case 15:
                        newInterval = 15000;
                        break;
                    case 30:
                        newInterval = 30000;
                        break;
                    case 60:
                        newInterval = 60000;
                        break;
                    case 120:
                        newInterval = 120000;
                        break;
                    case 'long-polling':
                        // Allow long polling, (experimental)
                        settings.mainInterval = 0;
                        return 0;
                    default:
                        newInterval = settings.originalInterval;
                }

                if ( settings.minimalInterval && newInterval < settings.minimalInterval ) {
                    newInterval = settings.minimalInterval;
                }

                if ( 5000 === newInterval ) {
                    ticks = parseInt( ticks, 10 ) || 30;
                    ticks = ticks < 1 || ticks > 30 ? 30 : ticks;

                    settings.countdown = ticks;
                    settings.tempInterval = newInterval;
                } else {
                    settings.countdown = 0;
                    settings.tempInterval = 0;
                    settings.mainInterval = newInterval;
                }

                // Change the next connection time if new interval has been set.
                // Will connect immediately if the time since the last connection
                // is greater than the new interval.
                if ( newInterval !== oldInterval ) {
                    scheduleNextTick();
                }
            }

            return settings.tempInterval ? settings.tempInterval / 1000 : settings.mainInterval / 1000;
        }

        /**
         * Enqueue data to send with the next XHR
         *
         * As the data is send asynchronously, this function doesn't return the XHR response.
         * To see the response, use the custom jQuery event 'heartbeat-tick' on the document, example:
         *        $(document).on( 'heartbeat-tick.myname', function( event, data, textStatus, jqXHR ) {
         *            // code
         *        });
         * If the same 'handle' is used more than once, the data is not overwritten when the third argument is 'true'.
         * Use wp.heartbeat.isQueued('handle') to see if any data is already queued for that handle.
         *
         * $param string handle Unique handle for the data. The handle is used in PHP to receive the data.
         * $param mixed data The data to send.
         * $param bool noOverwrite Whether to overwrite existing data in the queue.
         * $return bool Whether the data was queued or not.
         */
        function enqueue( handle, data, noOverwrite ) {
            if ( handle ) {
                if ( noOverwrite && this.isQueued( handle ) ) {
                    return false;
                }

                settings.queue[handle] = data;
                return true;
            }
            return false;
        }

        /**
         * Check if data with a particular handle is queued
         *
         * $param string handle The handle for the data
         * $return bool Whether some data is queued with this handle
         */
        function isQueued( handle ) {
            if ( handle ) {
                return settings.queue.hasOwnProperty( handle );
            }
        }

        /**
         * Remove data with a particular handle from the queue
         *
         * $param string handle The handle for the data
         * $return void
         */
        function dequeue( handle ) {
            if ( handle ) {
                delete settings.queue[handle];
            }
        }

        /**
         * Get data that was enqueued with a particular handle
         *
         * $param string handle The handle for the data
         * $return mixed The data or undefined
         */
        function getQueuedItem( handle ) {
            if ( handle ) {
                return this.isQueued( handle ) ? settings.queue[handle] : undefined;
            }
        }

        initialize();

        // Expose public methods
        return {
            hasFocus: hasFocus,
            connectNow: connectNow,
            disableSuspend: disableSuspend,
            interval: interval,
            hasConnectionError: hasConnectionError,
            enqueue: enqueue,
            dequeue: dequeue,
            isQueued: isQueued,
            getQueuedItem: getQueuedItem
        };
    };

    /**
     * Ensure the global `wp` object exists.
     *
     * @namespace wp
     */
    window.wp = window.wp || {};
    window.wp.heartbeat = new Heartbeat();

}( jQuery, window ));