一个非常好的问题，我很惊讶，因为我认为这是一个非常普遍的任务，现在我会有足够的资源来解决这个问题，然而事实并非如此。

我的想法如下: -创建一些在API控制器和HTML控制器之间具有公共逻辑的模块，而不返回json或呈现HTML，并将此模块包含在HTML控制器和API控制器中，然后做任何你想做的事情，例如:

module WebAndAPICommon
    module Products

        def index
            @products = # do some logic here that will set @products variable
        end

    end
end


class ProductsController < ApplicationController
    # default products controlelr, for rendering HMTL pages 
    include WebAndAPICommon

    def index
        super
    end

end



module API
    class ProductsController
        include WebAndAPICommon

        def index
            super
            render json: @products
        end

    end
end

我更倾向于选择第二条和第三条。主要是因为第一条违反了关注点的分离，并且混合了各种各样的东西。最终，你会发现需要有一个没有匹配HTML页面的API端点/等等，你会在同一个代码库中遇到HTML和JSON端点混合的麻烦。它变得一团糟，即使它是MVP，你最终也不得不重写它，因为它太混乱了，甚至不值得挽救。

Going with #2 or #3 allows you to completely have a API that acts the same (for the most part) regardless. This provides great flexibility. I'm not 100% sold on Backbone/ember/whatever/etc.js just yet. I think its great, but as we're seeing with twitter this is not optimal. BUT... Twitter is also a huge beast of a company and has hundreds of millions of users. So any improvement can have a huge impact to bottom line on various areas of various business units. I think there is more to the decision than speed alone and they're not letting us in on that. But thats just my opinion. However, I do not discount backbone and its competitors. These apps are great to use and are very clean and are very responsive (for the most part).

第三种选择也有一定的吸引力。这就是我遵循帕累托原则(80/20规则)的地方，让20%的主标记(反之亦然)在服务器上呈现，然后让一个漂亮的JS客户端(backbone/etc)运行剩下的部分。你可能不会通过JS客户端与REST api进行100%的通信，但如果有必要的话，你会做一些工作来让suer体验更好。

我认为这是一个“视情况而定”的问题，答案是“这取决于”你在做什么，你在为谁服务，以及你希望他们得到什么样的体验。我认为你可以选择2个或3个或者它们的混合。

在Boundless，我们已经深入研究了第2个选项，并将其推广给了数千名学生。我们的服务器是一个JSON REST API (Scala + MongoDB)，我们所有的客户端代码都是直接从CloudFront提供的(即:www.boundless.com只是CloudFront的别名)。

优点:

尖端的/令人兴奋 好处多多:API为你自己的web客户端、移动客户端、第三方访问等提供了基础。 非常快的网站加载/页面转换

缺点:

不SEO友好/准备没有更多的工作。 需要一流的web前端人员，他们准备好应对网站体验的现实，70%是javascript和这意味着什么。

我认为这是所有网络应用程序的未来。

对web前端人员的一些想法(这是这个架构所具有的所有新事物/挑战):

CoffeeScript。更容易生成高质量的代码。 骨干。组织逻辑和活跃社区的好方法。 HAMLC。Haml + CoffeeScript模板=> JS。 萨斯

我们已经为我们的前端开发构建了一个名为“Spar”(单页应用Rocketship)的工具，它实际上是Rails为单页应用开发调整的资产管道。我们将在接下来的几周内在我们的github页面上开放源代码，同时还有一篇博客文章解释如何使用它和更详细的整体架构。

更新:

With respect to people's concerns with Backbone, I think they are over-rated. Backbone is far more an organizational principle than it is a deep framework. Twitter's site itself is a giant beast of Javascript covering every corner-case across millions of users & legacy browsers, while loading tweets real-time, garbage collect, display lots of multimedia, etc. Of all the 'pure' js sites I've seen, Twitter is the odd one out. There have been many impressively complicated apps delivered via JS that fare very well.

体系结构的选择完全取决于您的目标。如果您正在寻找支持多个客户端的最快方式，并有机会接触到优秀的前端人才，那么投资一个独立的API是一个很好的方法。

问得好。+ 1。当然，这对我将来是一个有用的参考。此外，@Aaron和其他人也为讨论提供了价值。 和Ruby一样，这个问题同样适用于其他编程环境。

我使用了前两个选项。第一个用于许多应用程序，第二个用于我的开源项目Cowoop

选项1 这无疑是最受欢迎的一个。但我发现实现是非常http的。每个API的初始代码都用于处理请求对象。所以API代码不仅仅是纯粹的ruby/python/其他语言代码。

Option 2 I always loved this. This option also implies that HTML is not runtime generated on server. This is how option 2 is different from option 3. But are build as static html using a build script. When loaded on client side these HTML would call API server as JS API client. Separation of concerns is great advantage. And very much to your liking (and mine) backend experts implement backend APIs, test them easily like usual language code without worrying about framework/ http request code. This really is not as difficult as it sounds on frontend side. Do API calls and resulting data (mostly json) is available to your client side template or MVC. Less server side processing. It means you may go for commodity hardware/ less expensive server. Easier to test layers independently, easier to generate API docs. It does have some downsides. Many developers find this over engineered and hard to understand. So chances are that architecture may get criticized. i18n/l10n is hard. Since HTML is essentially generated build time are static, one needs multiple builds per supported language (which isn't necessarily a bad thing). But even with that you may have corner cases around l10n/i18n and need to be careful.

Option 3 Backend coding in this case must be same as second option. Most points for option 2 are applicable here as well. Web pages are rendered runtime using server side templates. This makes i18n/l10n much easier with more established/accepted techniques. May be one less http call for some essential context needed for page rendering like user, language, currency etc. So server side processing is increased with rendering but possibly compensated by less http calls to API server. Now that pages are server rendered on server, frontend is now more tied with programming environment. This might not be even a consideration for many applications.

Twitter的情况下

据我所知，Twitter可能会在服务器上进行初始页面渲染，但对于页面更新，它仍然有一些API调用和客户端模板来操作DOM。所以在这种情况下，你需要维护两个模板，这增加了一些开销和复杂性。不是每个人都能负担得起这个选项，不像Twitter。

我们的项目Stack

我碰巧使用Python。我使用JsonRPC 2.0代替REST。我建议使用REST，尽管出于各种原因我喜欢JsonRPC的想法。我使用下面的库。考虑选项2/3的人可能会觉得有用。

一个快速的web微框架- Flask 前端服务器:Nginx 客户端MVC: Knockout.js 其他相关工具/库: Jquery js代表货币 Webshim:跨浏览器填充 director:客户端路由 生成HTML

我的结论和建议

选项3 !

总之，我已经成功地使用了选项2，但现在为了简单起见，我倾向于选项3。使用构建脚本生成静态HTML页面，并使用专门提供静态页面的超高速服务器提供这些页面是非常诱人的(选项2)。

在创建gauge .es时，我们选择了#2。我负责API (ruby, sinatra等)，我的业务伙伴Steve Smith负责前端(javascript客户端)。

优点:

Move quickly in parallel. If I worked ahead of Steve, I could keep creating APIs for new features. If he worked ahead of me, he could fake out the API very easily and build the UI. API for free. Having open access to the data in your app is quickly becoming a standard feature. If you start with an API from the ground up, you get this for free. Clean separation. It is better to think of your app as an API with clients. Sure, the first and most important client may be a web one, but it sets you up for easily creating other clients (iPhone, Android).

缺点:

向后兼容性。这与API的关系比你直接的问题更大，但一旦你的API出来了，你就不能破坏它，也不能破坏所有的客户端。这并不意味着你要放慢速度，但它确实意味着你必须经常同时做两件事。添加到API或新字段是可以的，但是在没有版本控制的情况下不应该进行更改/删除。

我现在想不出什么骗局了。

结论:如果你计划发布一个API, API + JS客户端是正确的选择。

另外，我还建议在发布API之前完整地记录它。编写gage .es API的过程确实帮助了我们进行imp操作

http://get.gaug.es/documentation/api/

一个非常好的问题，我很惊讶，因为我认为这是一个非常普遍的任务，现在我会有足够的资源来解决这个问题，然而事实并非如此。

我的想法如下: -创建一些在API控制器和HTML控制器之间具有公共逻辑的模块，而不返回json或呈现HTML，并将此模块包含在HTML控制器和API控制器中，然后做任何你想做的事情，例如:

module WebAndAPICommon
    module Products

        def index
            @products = # do some logic here that will set @products variable
        end

    end
end


class ProductsController < ApplicationController
    # default products controlelr, for rendering HMTL pages 
    include WebAndAPICommon

    def index
        super
    end

end



module API
    class ProductsController
        include WebAndAPICommon

        def index
            super
            render json: @products
        end

    end
end