如何在一段时间后自动化jQuery BBQ缓存的到期?

时间:2014-03-04 16:32:35

标签: javascript jquery html ajax caching

我正在使用此代码:

$(function () {

            // For each .bbq widget, keep a data object containing a mapping of
            // url-to-container for caching purposes.
            $('.bbq').each(function () {
                $(this).data('bbq', {
                    cache: {
                        // If url is '' (no fragment), display this div's content.
                        '': $(this).find('.bbq-default')
                    }
                });
            });

            // For all links inside a .bbq widget, push the appropriate state onto the
            // history when clicked.
            $('.bbq a[href^=#]').live('click', function (e) {
                var state = {},

                  // Get the id of this .bbq widget.
                  id = $(this).closest('.bbq').attr('id'),

                  // Get the url from the link's href attribute, stripping any leading #.
                  url = $(this).attr('href').replace(/^#/, '');

                // Set the state!
                state[id] = url;
                $.bbq.pushState(state);

                // And finally, prevent the default link click behavior by returning false.
                return false;
            });

            // Bind an event to window.onhashchange that, when the history state changes,
            // iterates over all .bbq widgets, getting their appropriate url from the
            // current state. If that .bbq widget's url has changed, display either our
            // cached content or fetch new content to be displayed.
            $(window).bind('hashchange', function (e) {

                // Iterate over all .bbq widgets.
                $('.bbq').each(function () {
                    var that = $(this),

                      // Get the stored data for this .bbq widget.
                      data = that.data('bbq'),

                      // Get the url for this .bbq widget from the hash, based on the
                      // appropriate id property. In jQuery 1.4, you should use e.getState()
                      // instead of $.bbq.getState().
                      url = $.bbq.getState(that.attr('id')) || '';

                    // If the url hasn't changed, do nothing and skip to the next .bbq widget.
                    if (data.url === url) { return; }

                    // Store the url for the next time around.
                    data.url = url;

                    // Remove .bbq-current class from any previously "current" link(s).
                    that.find('a.bbq-current').removeClass('bbq-current');

                    // Hide any visible ajax content.
                    that.find('.bbq-content').children(':visible').hide();

                    // Add .bbq-current class to "current" nav link(s), only if url isn't empty.
                    url && that.find('a[href="#' + url + '"]').addClass('bbq-current');

                    if (data.cache[url]) {
                        // Since the widget is already in the cache, it doesn't need to be
                        // created, so instead of creating it again, let's just show it!
                        data.cache[url].show();


                    } else {
                        // Show "loading" content while AJAX content loads.
                        that.find('.bbq-loading').show();

                        // Create container for this url's content and store a reference to it in
                        // the cache.
                        data.cache[url] = $('<div class="bbq-item"/>')

                          // Append the content container to the parent container.
                          .appendTo(that.find('.bbq-content'))

                          // Load external content via AJAX. Note that in order to keep this
                          // example streamlined, only the content in .infobox is shown. You'll
                          // want to change this based on your needs.
                          .load(url, function () {
                              // Content loaded, hide "loading" content.
                              that.find('.bbq-loading').hide();
                          });
                    }
                });
            })

            // Since the event is only triggered when the hash changes, we need to trigger
            // the event now, to handle the hash the page may have loaded with.
            $(window).trigger('hashchange');

        });

从这里开始:http://benalman.com/code/projects/jquery-bbq/examples/fragment-advanced/

它正在缓存动态加载的内容。我想在每10秒后使此缓存失效。我不是那么专业的JQuery。我怎样才能做到这一点?请帮忙!

更新

我试过这段代码:

<script type="text/javascript" src="jquery.timer.js"></script>
<script type="text/javascript">
        var timer = $.timer(function () {
        $('.bbq').removeData('.bbq-content');
        });

        timer.set({ time: 5000, autostart: true });
</script>

代码每5秒到达$('.bbq').removeData('.bbq-content');行,但不清除缓存。无法显示更新的结果。请帮忙!

1 个答案:

答案 0 :(得分:1)

您不需要每10秒清除一次缓存数据;您只需要在显示之前检查缓存数据是否超过10秒。

首先,我们需要一个地方来为每个缓存数据保存时间戳。用以下代码替换第一块代码:

            $('.bbq').each(function () {
                $(this).data('bbq', {
                    cache: {
                        // If url is '' (no fragment), display this div's content.
                        '': $(this).find('.bbq-default')
                    },
                    cacheTimes: {} // <-- this line is new (plus the comma above)
                });
            });

然后,当hashchange事件发生时,我们需要当前时间:

            // Bind an event to window.onhashchange that, when the history state changes,
            // iterates over all .bbq widgets, getting their appropriate url from the
            // current state. If that .bbq widget's url has changed, display either our
            // cached content or fetch new content to be displayed.
            $(window).bind('hashchange', function (e) {

                var now = (new Date()).getTime(); // <-- this line is new

                // Iterate over all .bbq widgets.
                $('.bbq').each(function () {

对于每个小部件,我们检查是否有足够的时间使缓存失效:

                      // Get the url for this .bbq widget from the hash, based on the
                      // appropriate id property. In jQuery 1.4, you should use e.getState()
                      // instead of $.bbq.getState().
                      url = $.bbq.getState(that.attr('id')) || '';

                    // this chunk is new
                    if (url !== '' && now - (data.cacheTimes[url] || 0) > 10000) { // 10 seconds
                        data.url = null;
                        if (data.cache[url]) {
                            data.cache[url].remove();
                            data.cache[url] = null;
                        }
                    }

                    // If the url hasn't changed, do nothing and skip to the next .bbq widget.
                    if (data.url === url) { return; }

获取数据时,我们会记住当前时间:

                        // Show "loading" content while AJAX content loads.
                        that.find('.bbq-loading').show();

                        data.cacheTimes[url] = now; // <-- this line is new

                        // Create container for this url's content and store a reference to it in
                        // the cache.
                        data.cache[url] = $('<div class="bbq-item"/>')