扩展Backbone.Router以支持window.history.back

web应用程序重要的功能的URL通过需要达到可访问，可收藏和可分享的需求。Backbone.Router正是检测客户端url变化触发相应动作和事件的实现框架。对于没有实现HTML5 History API的浏览器，Router提供了优雅和透明的兼容实现，通过控制hash的变化。

Route的例子

var Workspace = Backbone.Router.extend({

routes: {

		"help":                 "help",    // #help
		"search/:query":        "search",  // #search/kiwis
		"search/:query/p:page": "search"   // #search/kiwis/p7
  		},

help: function() {

		...
  		},

search: function(query, page) {

		...
  		}

});

Router的问题

Router很好的解决了进入一个url能触发相应的方法的问题，但是如果在离开某个url想触发相应的方法，Router显得无能为力。通常如果想通过window.history.back()退回上一页面是，触发相应的方法，就需要Router支持leave方法。

下面我们介绍如何通过扩展Backbone.Router已支持leave。

扩展Backbone.Router

class BaseRouter extends Backbone.Router
  route: (route, name, callback)->

    fn = callback

    route = this._routeToRegExp(route) unless _.isRegExp route

    if _.isFunction name
      callback = name
      name = ''

    fn = callback = this[name] unless callback

    if typeof callback == 'object'
      before = callback.before
      fn = callback.route
      after = callback.after

    Backbone.history.route(route, (fragment)=>
      args = @_extractParameters(route, fragment)

      if leave
        if leave() is false
          return
        else
          leave = false

      return if before and before.apply(@, args) is false
      fn.apply(@, args) if fn
      return if after and after.apply(@, args) is false

      if typeof callback == 'object'
        leave = ((_this, args)->->callback.leave.apply(_this, args))(@, args)

      @trigger.apply(@, ["route:#{name}"].concat(args))
      @trigger('route', name, args)
      Backbone.history.trigger('route', @, name, args)
    )
    @

编写Router

class extends Base.Router
  routes:
	"bsdn_editor_:uid/writer":    "fullscreen"
  	#catch every url for leave
  	"*splat": ->

  fullscreen: {
  	route: (uid)->
      $("#bsdn_editor_#{uid}").parent().editor('showFullscreen')
  	leave: (uid)->
      $("#bsdn_editor_#{uid}").parent().editor('hideFullscreen')
   	  }

参考阅读

[1] Backbone router before,after,leave