（六）backbone - API学习 - Backbone路由

Backbone路由本质

Backbone路由分为两个大块，Router以及History
用户在Router中定义相关规则，然后开启history.start进行路由监控，执行默认的回调
所以，Router本身除了定义路由规则，全部调用的是Backbone.history的方法
Backbone.History的主要关注点事实上是 popstate(hashChange)的回调checkUrl，无论我们触发navigate或者点击浏览器后退
皆是进入此入口，再回调至Router定义的回调，从而实现相关逻辑

 

•创建规则

 1 var App = Backbone.Router.extend({

 2     routes: {

 3       "": "index",    // #index

 4       "index": "index",    // #index

 5       "detail": "detail"    // #detail

 6     },

 7     index: function () {

 8       var index = new Index(this.interface);

 9   

10    },

11    detail: function () {

12      var detail = new Detail(this.interface);

13  

14    },

15    initialize: function () {

16  

17    },

18    interface: {

19      forward: function (url) {

20        window.location.href = ('#' + url).replace(/^#+/, '#');

21      }

22  

23    }

24 });

•开启路由控制

Backbone.history.start();

Backbone.history源码分析

history构造函数

 1 var History = Backbone.History = function () {

 2   this.handlers = [];

 3   _.bindAll(this, 'checkUrl');

 4 

 5   // Ensure that `History` can be used outside of the browser.

 6   if (typeof window !== 'undefined') {

 7     this.location = window.location;

 8     this.history = window.history;

 9   }

10 };

history.start 函数

 1 start: function(options) {

 2       if (History.started) throw new Error("Backbone.history has already been started");

 3       History.started = true;

 4 

 5       // Figure out the initial configuration. Do we need an iframe?

 6       // Is pushState desired ... is it available?

 7       this.options          = _.extend({root: '/'}, this.options, options);

 8       this.root             = this.options.root;

 9       this._wantsHashChange = this.options.hashChange !== false;

10       this._wantsPushState  = !!this.options.pushState;

11       this._hasPushState    = !!(this.options.pushState && this.history && this.history.pushState);

12       var fragment          = this.getFragment();

13       var docMode           = document.documentMode;

14       var oldIE             = (isExplorer.exec(navigator.userAgent.toLowerCase()) && (!docMode || docMode <= 7));

15 

16       // Normalize root to always include a leading and trailing slash.

17       this.root = ('/' + this.root + '/').replace(rootStripper, '/');

18 

19       // 老版本ie以及希望使用hashChange, 使用iframe实现

20       if (oldIE && this._wantsHashChange) {

21         var frame = Backbone.$('<iframe src="javascript:0" tabindex="-1">');

22         this.iframe = frame.hide().appendTo('body')[0].contentWindow;

23         this.navigate(fragment);

24       }

25       

26       // Depending on whether we're using pushState or hashes, and whether

27       // 'onhashchange' is supported, determine how we check the URL state.

28       if (this._hasPushState) {

29         Backbone.$(window).on('popstate', this.checkUrl);

30       } else if (this._wantsHashChange && ('onhashchange' in window) && !oldIE) {

31         Backbone.$(window).on('hashchange', this.checkUrl);

32       } else if (this._wantsHashChange) {

33         this._checkUrlInterval = setInterval(this.checkUrl, this.interval);

34       }   
           /* 取决于选择hash还是pushState 
 　　　　　　如果使用 pushState，调用方法
           Backbone.history.start({ pushState: true });
           */

35 

36       // Determine if we need to change the base url, for a pushState link

37       // opened by a non-pushState browser.

38       this.fragment = fragment;

39       var loc = this.location;

40 

41       // Transition from hashChange to pushState or vice versa if both are

42       // requested.

43       if (this._wantsHashChange && this._wantsPushState) {

44 

45         // If we've started off with a route from a `pushState`-enabled

46         // browser, but we're currently in a browser that doesn't support it...

47         if (!this._hasPushState && !this.atRoot()) {

48           this.fragment = this.getFragment(null, true);

49           this.location.replace(this.root + '#' + this.fragment);

50           // Return immediately as browser will do redirect to new url

51           return true;

52 

53         // Or if we've started out with a hash-based route, but we're currently

54         // in a browser where it could be `pushState`-based instead...

55         } else if (this._hasPushState && this.atRoot() && loc.hash) {

56           this.fragment = this.getHash().replace(routeStripper, '');

57           this.history.replaceState({}, document.title, this.root + this.fragment);

58         }

59 

60       }

61 

62       if (!this.options.silent) return this.loadUrl();

63     }

统一入口 loadUrl

loadUrl: function (fragmentOverride) {

  var fragment = this.fragment = this.getFragment(fragmentOverride);

  var matched = _.any(this.handlers, function (handler) {      // handlers是routes定义的集合，实例化Router时导入

    if (handler.route.test(fragment)) {

      handler.callback(fragment);

      return true;

    }

  });

  return matched;

}