易栈网-膘叔

dd

三八节看起来不象是我们男性过的节日，但事实上，在三八节，我真的要感谢很多人。。。
远的就不说了，以前那些老师啥的很多都是女性的。

就从身边吧，感谢我的母亲，感谢我的岳母，感谢我的妻子。这三个人是我最想表达感谢之意的。

母亲生我养我，这是毋庸置疑的，当然得感谢。

岳母和岳父每天辛苦的帮我们照顾小朋友，我父母又不在上海，岳父母承担的压力就大了，几乎是天天在照顾着小孩（几乎每个小孩都是自己爷爷奶奶或者外公外婆带大的吧。），我和妻子回家又晚，她们辛苦极了。

最后感谢我的妻子，除了因为爱情，还有小朋友啊。虽然我更喜欢小姑娘多一点，但小家伙也是个很可爱的人呢。

这是一篇来自Yii官方的文章，写在了1.1.6的new fetures里面，值得一看，最起码，你在看完后，下次被人面试的时候，问到什么 是MVC，你可以有回答的东西了。

不多说，上原文，内容也不复杂，所以我就不翻译了（其实是我翻译不来，将就着看看可以，可是要翻译成人人都能看得懂的内容就难了）。。。

原文来自于：http://www.yiiframework.com/doc/guide/1.1/en/basics.best-practices，目前官方也确实没有中文版。

Although Model-View-Controller (MVC) is known by nearly every Web developer, how to properly use MVC in real application development still eludes many people. The central idea behind MVC is code reusability and separation of concerns. In this section, we describe some general guidelines on how to better follow MVC when developing a Yii application.

To better explain these guidelines, we assume a Web application consists of several sub-applications, such as

• front end: a public-facing website for normal end users;
• back end: a website that exposes administrative functionality for managing the application. This is usually restricted to administrative staff;
• console: an application consisting of console commands to be run in a terminal window or as scheduled jobs to support the whole application;
• Web API: providing interfaces to third parties for integrating with the application.

The sub-applications may be implemented in terms of modules, or as a Yii application that shares some code with other sub-applications.

1. Model 

Models represent the underlying data structure of a Web application. Models are often shared among different sub-applications of a Web application. For example, a LoginForm model may be used by both the front end and the back end of an application; a News model may be used by the console commands, Web APIs, and the front/back end of an application. Therefore, models

• should contain properties to represent specific data;

• should contain business logic (e.g. validation rules) to ensure the represented data fulfills the design requirement;

• may contain code for manipulating data. For example, a SearchForm model, besides representing the search input data, may contain a search method to implement the actual search.

Sometimes, following the last rule above may make a model very fat, containing too much code in a single class. It may also make the model hard to maintain if the code it contains serves different purposes. For example, a News model may contain a method named getLatestNews which is only used by the front end; it may also contain a method named getDeletedNews which is only used by the back end. This may be fine for an application of small to medium size. For large applications, the following strategy may be used to make models more maintainable:

• Define a NewsBase model class which only contains code shared by different sub-applications (e.g. front end, back end);

• In each sub-application, define a News model by extending from NewsBase. Place all of the code that is specific to the sub-application in this News model.

So, if we were to employ this strategy in our above example, we would add a News model in the front end application that contains only the getLatestNews method, and we would add another News model in the back end application, which contains only the getDeletedNews method.

In general, models should not contain logic that deals directly with end users. More specifically, models

• should not use $_GET, $_POST, or other similar variables that are directly tied to the end-user request. Remember that a model may be used by a totally different sub-application (e.g. unit test, Web API) that may not use these variables to represent user requests. These variables pertaining to the user request should be handled by the Controller.

• should avoid embedding HTML or other presentational code. Because presentational code varies according to end user requirements (e.g. front end and back end may show the detail of a news in completely different formats), it is better taken care of by views.

2. View 

Views are responsible for presenting models in the format that end users desire. In general, views

• should mainly contain presentational code, such as HTML, and simple PHP code to traverse, format and render data;

• should avoid containing code that performs explicit DB queries. Such code is better placed in models.

• should avoid direct access to $_GET, $_POST, or other similar variables that represent the end user request. This is the controller's job. The view should be focused on the display and layout of the data provided to it by the controller and/or model, but not attempting to access request variables or the database directly.

• may access properties and methods of controllers and models directly. However, this should be done only for the purpose of presentation.

Views can be reused in different ways:

• Layout: common presentational areas (e.g. page header, footer) can be put in a layout view.

• Partial views: use partial views (views that are not decorated by layouts) to reuse fragments of presentational code. For example, we use _form.php partial view to render the model input form that is used in both model creation and updating pages.

• Widgets: if a lot of logic is needed to present a partial view, the partial view can be turned into a widget whose class file is the best place to contain this logic. For widgets that generate a lot of HTML markup, it is best to use view files specific to the widget to contain the markup.

• Helper classes: in views we often need some code snippets to do tiny tasks such as formatting data or generating HTML tags. Rather than placing this code directly into the view files, a better approach is to place all of these code snippets in a view helper class. Then, just use the helper class in your view files. Yii provides an example of this approach. Yii has a powerful CHtml helper class that can produce commonly used HTML code. Helper classes may be put in an autoloadable directory so that they can be used without explicit class inclusion.

3. Controller 

Controllers are the glue that binds models, views and other components together into a runnable application. Controllers are responsible for dealing directly with end user requests. Therefore, controllers

• may access $_GET, $_POST and other PHP variables that represent user requests;

• may create model instances and manage their life cycles. For example, in a typical model update action, the controller may first create the model instance; then populate the model with the user input from $_POST; after saving the model successfully, the controller may redirect the user browser to the model detail page. Note that the actual implementation of saving a model should be located in the model instead of the controller.

• should avoid containing embedded SQL statements, which are better kept in models.

• should avoid containing any HTML or any other presentational markup. This is better kept in views.

In a well-designed MVC application, controllers are often very thin, containing probably only a few dozen lines of code; while models are very fat, containing most of the code responsible for representing and manipulating the data. This is because the data structure and business logic represented by models is typically very specific to the particular application, and needs to be heavily customized to meet the specific application requirements; while controller logic often follows a similar pattern across applications and therefore may well be simplified by the underlying framework or the base classes.

说起湿疹，实在是让我感觉很烦心，小朋友到现在还是有症状存在着，葯也配过也吃过只是觉得好象还没有恢复好。
这两天正在尝试吃中葯，还好，小朋友居然肯吃中葯，而且没有过多的抗拒，要知道中葯可是很苦的，虽然放了一点糖，但苦是必然的。吃过中葯的都清楚这一点，没吃过的，闻过那个味道也会清楚吧。
小朋友也知道要吃葯才会身体好，虽然吃起来苦一点，但还是肯吃的，好感动。也很伤心，只是现在也不知道他的过敏源到底是什么 ，以后估计还会吃苦头。
希望他早日恢复吧。

做前端的用户都会想过如何做lazyLoad，其实很多时候都有很多想法，比如占位图片，TEXTAREA后处理，根据滚动条的位置显示图片等。
介绍介绍上面的说法，因为这些名词是我自己想出来的。。。和一些标准的前端讲法可能是不一致的。
1、占位图片，这个用的比较多一点，即在页面还没有全部加载完的时候，涉及到图片的地方，先用占位图片（1X1大小的图片进行放大）占好，不影响整个DOM的加载，等全部加载完后，再慢慢加载图片。这样的方式优点在于，不影响DOM加载，代码修改量也最小，缺点是，其实还是加载了所有的图片。。。
2、teatarea后处理，这个，被用的比较明显的应该算是淘宝的trademark的页面上，当时在抢购活动的时候就用上了这个技巧，trademark这个页面全是图片，如果全部读出来并显示，很可能一下子就下载大约3M左右的图片，如果用第一种办法，那么占用的流量就非常夸张。于是淘宝当时的页面源码里就很明显的内容就是第一屏是正常的HTML代码，第二屏开始，把每一层的内容都放在textarea容器里。当滚动条滚动的时候，即当textarea开始出现在页面中时，就把textarea中的HTML代码转化成DOM，显示在页面上。它的优点是，textarea中的内容在初次加载时，不会被当成DOM被页面所加载。因此事实上首次加载的时候，只有第一屏的内容。缺点是需要写很多JS。（和第三点也有关）
3、根据滚动条的位置显示图片，这个其实是现在很多网站采用的技巧了，即滚动条滚动到哪里，图片就开始加载到哪里。和第二点其实有点象，只是处理的结构不一样而已。
介绍完这个，那就好好介绍一下第三点的技术了，原文从这里来：http://www.zhangjingwei.com/archives/jquery-inviewport/。

晚上在微博上“拔赤”写了个lazyload插件，发现其中用到一个很有意思的方法”div.inViewportRegion()”，字面意思就是在可视区域内。

在网上找了找，发现这是YUI提供的一个组件，觉得很有意思。
http://gillserver.com/yui/api/dom-region.js.html

如果jQ里面也包含类似的方法，可以做很多事，于是GG了一下，发现国外的同学写过这种选择器，代码表现上更直观。

代码如下：

来源：http://www.appelsiini.net/projects/viewport

简单测了下，不错，呵呵~

Demo：http://www.zhangjingwei.com/inviewport.zip

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事后测试了一下，加载了这段的JS后，剩下对代码的处理就其实不多了，只需要BIND一个in-viewport就OK了，也算是比较方便。值得推荐，不知道啥时候类似功能可以直接进jQuery类库