问题描述
我有一个执行一些业务逻辑的 Erlang/OTP 应用程序.它是用 Erlang 编写的，主要是为了容错，因为我可以轻松地重新启动系统崩溃的组件之一(高正常运行时间是最重要的要求).它的每个组件都进行某种特定的并行"计算.
I have an Erlang/OTP application which does some business logic. It is written in Erlang mostly for fault-tolerance, because I can easily restart one of the crashed components of the system (high uptime is the most important requirement).Each of its components does some sort of specific "parallel" computations.
作为一个工作周期的结果，应用程序会生成一个值列表.让我们将此 Erlang/OTP 应用程序称为后端".
As a result of one working cycle the application produces a list of values. Let's call this Erlang/OTP application a "back-end".
这个 Erlang/OTP 应用程序还将使用 PostgreSQL 服务器将结果存储在持久存储中，并存储其计算所需的其他元信息(尚未实现).
This Erlang/OTP application would also use a PostgreSQL server to store the results in the persistent storage and to store additional meta-information needed for its computations (not implemented yet).
接下来我需要为这个 Erlang/OTP 应用程序添加一个前端 - 一个简单的基于 Web 的解决方案，可以为 Web 用户提供服务:接受他/她的计算请求，要求后端执行计算并将结果从后端返回给用户.
Next I need to add a front-end to this Erlang/OTP application - a simple web-based solution which can serve to a web user: accept a request for computations from him/her, ask the back-end to do the computations and give the user back the result from the back-end.
没有可扩展性要求，我认为每天最大用户数不能超过1000.
There is no scalability requirement, I think that the maximum number of users per day can be no more than 1000.
所以我现在的任务是为我的后端 Erlang/OTP 应用程序实现一个通用的前端(通常意味着我有一个典型的用例:访问站点、注册、登录、使用应用程序、获取结果显示在一个漂亮的 ajax'y 网页上，注销).
So my current task now is to implement a common front-end for my back-end Erlang/OTP application (common means I have a typical use case: visit the site, register, log-in, use the app, get the result on a nice ajax'y looking web-page, log-out).
一方面，我知道代码重用可以为我节省很多时间:例如，使用 Ruby on Rails 我可以免费获得用户身份验证、密码存储、ajax 接口和许多其他东西.
On one side, I know that code reuse can save me a lot of time: for example with Ruby on Rails I can get user authentication, password storage, ajax interfaces and a lot of other stuff for free.
另一方面，我对设计包含 Erlang/OTP + PostgreSQL 数据库服务器后端和 Web 框架(RoR、Django 等)作为前端的应用程序一无所知.
On the other side I do not know anything about designing an application which comprises an Erlang/OTP + PostgreSQL db server back-end and a web-framework (RoR, Django, etc) as a front-end.
我的脑海中浮现出很多问题:Erlang/OTP 和网络框架是否应该使用相同的 PostgreSQL 数据库来共享结果?将计算请求从网络框架发送到 Erlang/OTP 应用程序并将其取回的最佳方法是什么?我如何监督 PostgreSQL 服务器 - 它不在 OTP 的容错范围内?
I lot of questions spring in my mind: Should Erlang/OTP and the web-framework use the same PostgreSQL database to share the result? What is the best way to send a computation request from the web-framework to the Erlang/OTP application and get it back? How do I supervise the PostgreSQL server - it is not covered by OTP's fault tolerance?
一般来说，我有一些异构的软件组件，我想用它们构建一个工作系统(主要"组件是 Erlang/OTP 应用程序).
Generally speaking, I have a few heterogeneous software components and I want to build a working system from them (the 'chief' component is the Erlang/OTP application).
我应该从哪里开始这项任务?你能给我任何建议或提示要阅读哪些资源吗?
Where I should start with this task? Can you give me any advice or a hint which resources to read?
附言我曾尝试阅读 this 并按照链接进行操作，但不明白很多.
P.S. I have tried to read this and followed the links, but did not understand much.
UPD:我知道 Chicago Boss 和其他 Erlang 网络框架确实存在，但我怀疑它们中的任何一个都拥有如此成熟的环境、充满活力的社区以及不同插件和库的巨大可变性，例如例如 Ruby on Rails、Django 或任何基于 PHP 的 MVC 框架.对?
UPD: I know that Chicago Boss and other Erlang web-frameworks do exist, but I doubt that any of them have such a mature environment, vibrant community and huge variability of different plugins and libraries like for example Ruby on Rails, Django or any PHP-based MVC framework. Right?
UPD2: 也许我必须更深入地阐述这一点:我还需要前端尽可能可维护.在 Erlang 中做这件事意味着我可能会遇到寻找合适的开发人员来维护它的问题；在 RoR、Django 等中做这件事意味着我可以很容易地找到工作人员来维护前端并发展它.
UPD2: Maybe I have to elaborate on this deeper: I also need the front-end to be as maintainable as possible. Doing it in Erlang means that I might face problems finding the right developers to maintain it; doing it in RoR,Django, etc. means I can easily find work force to maintain the front-end and to grow it.
推荐答案
首先，这里有一个 Erlang PostGreySQL Client:https://github.com/wg/epgsql.另一件事是您可能想要查看 ZOTONIC.它是一个用 Erlang 编写的 CMS，但它也是一个 Web 框架.它的特点之一是它很好地集成了 PostGreySQL 数据库，因此 Zotoniuc 背后的所有 Erlang 应用程序都将从中受益.在开发 MVC 或事件驱动的 Web 应用程序时非常好.
此外，您可能想查看 Nitrogen Web 框架 和 Chicago Boss，它们也是 Erlang Web 应用程序的 Web 框架.我个人使用 Nitrogen、Yaws 和 Mnesia 作为一个完整的集合开发了 Erlang 网络应用程序.一个非常好的优势是您可以在此技术堆栈背后拥有多个 Erlang 应用程序.Yaws 网络服务器及其 Appmods 和 动态内容服务能力(所以RESTFUL 我可以向你保证)，它使我们的 JavaScript 驱动的前端 Web 应用程序具有如此惊人的简单性和美感，提供来自多个 Erlang 应用程序的服务.
First of all, there is an Erlang PostGreySQL Client here: https://github.com/wg/epgsql. Another thing is that you may want to check out ZOTONIC. Its a CMS written in Erlang but it is a Web framework as well. One of its features is that it has integrated PostGreySQL Database very well and so all Erlang applications behind Zotoniuc would benefit from this. It is very good when developing MVC or Event driven Web apps.
Also, you may want to check out Nitrogen Web Framework and Chicago Boss which are also web frameworks for Erlang Web apps. I have personally developed Erlang web apps using Nitrogen, Yaws and Mnesia as a complete set. One very nice advantage is that you can have several many Erlang Applications behind this technology stack. Yaws web Server with its Appmods and dynamic Content Serving ability (so RESTFUL i can assure you that), it has empowered our JavaScript Driven Frontend Web Apps with such amazing simplicity and beauty, providing Services from a bunch of several Erlang Applications.
如果您想拥有一个快速的 Web 前端，具有 Ajaxy/HTML5 之类的功能，那么快点，快点！并使用 Nitrogen Web 框架.既然你已经是一个 Erlang 程序员，这对你来说会很快.使用模板，您可以编写 HTML4.X/HTML5 模板，或使用 Web page Maker/Studio 软件 为您创建模板.然后，您将向 Nitrogen 展示从哪里进入，使用动态生成的 JQuery 由您的 Erlang 代码产生的代码.
您会发现文档非常简单.Nitrogen 只是 Erlang 记录的集合，每条记录代表一个 HTML 标签.其他记录用于定义将 POST 回您的 Erlang 应用程序的效果和事件.在 Nitrogen 中开发 Web 漂亮的界面是如此之快.事实上，使用动态生成的 JQuery 代码，您可以将自己的 JavaScript 写入模板以伴随整个功能说，利用另一个 JavaScript 库，如 EXT JS 或 MooTools 或 原型 js.在模板中，您将指出 Nitrogen 应在何处呈现动态生成的 HTML 元素以及将AJaxically"作用于这些元素的 JQuery.在这种情况下，模板仅表示 HTML 页面.
If you want to have a fast Web Front End , with Ajaxy/HTML5 like features , then hurry, quick! and grab your self the Nitrogen Web Framework. Since you are an Erlang Programmer already, this will be so fast for you. With Templating, you can write HTML4.X / HTML5 Templates, or use a Web page Maker/Studio Software to create template(s) for you. Then later, you will show Nitrogen where to come in, binding your Erlang Backends to those nice Pages using Dynamically Generated JQuery Code arising from your Erlang Code.
You will find the documentation very simple. Nitrogen is just a collection of Erlang Records, with each record standing for an HTML Tag. Other records are used for defining effects and events that will be POST back into your Erlang Application. Developing Web beautiful interfaces in Nitrogen is so fast. Infact, with the dynamically generated JQuery code, you can write your own JavaScript into the Template to accompany the entire functionality say, making use of another JavaScript library like EXT JS, or MooTools or prototype js. Within the template is where you will point out where Nitrogen should render the dynamically generated HTML Elements as well as JQuery which will "AJaxically" act on these elements. A template in this case simply means an HTML Page.
请记住成为其邮件列表的成员以获取更多帮助，并在 StackOverflow 上继续提出更多问题.欢迎来到 Erlang Web 开发的世界.您可能感兴趣的几个链接(
IEEE 关于 Erlang 网络开发的论文，
Erlang 网络框架,
erlydtl - Erlang Django like模板实现、
ErlyWeb 框架
) 成功！
编辑
现在，你说的是真的.寻找开发人员来维护它将是一项任务.但是，正如我之前提到的，Zotonic 是一个成熟的 (Web)CMS 就像 Joomla 或 Word Press 等有了它，您自己就可以实际管理/维护站点/应用程序.
但是，您也可以使用 Django 或 Ruby on Rails 开发 Web 前端，但使用 JSON 格式数据创建安全服务到 Mochiweb 来自您的 Web 前端.然后，使用 Mochijson2.erlmochiweb 附带了它，您可以解析 JSON 并将其转换为 Erlang 后端中的请求或方法和参数.这可以双向完成，即您向 Erlang 应用程序发出请求，获取返回的结果并将它们呈现为 JSON 数据.
Mochiweb 是一个强大的工具，可以将任何 Erlang 后端与任何 Web 技术进行交互前端使用 Service/RESTFul 模型.它的简单和重量轻.它的速度很快，它所需要的只是您将其指向处理 POST、GET、PUT 等 HTTP 请求的方法，它会等待返回的结果.Mochiweb 已经在很多 Erlang 系统中使用，例如Couch DB(最先进的 NoSQL DBMS 之一，改变了我们理解 Web 的方式和 SOA 系统)以及所有其他系统，例如 Membase 单服务器、Big Couch/Cloudant 等你可以看到有人在使用 mochiweb 这里，然后在这里 和 最后在这里.
Django、Twisted、PHP 或 Ruby on Rails 框架发出 JSON 请求并期望来自由 Mochiweb 提供支持的 Erlang 后端的 JSON 响应.Erlang Web 后端的另一个出色的 RESTful 接口是 Misultin，它甚至支持 Web Sockets，有时被认为是最快/或响应最快的 Erlang HTTP 库:)
根据我的经验，我曾与 PHP 专家、JavaScript 专家等合作过.但是当我们将 Web 服务器作为 yaws 和 面向服务的模型，使用来自两个方向的 JSON 请求和响应.在这种情况下，我们不会失去 Erlang 的可用性和容错性，顺便说一句，即使它们隐藏在不同的域子网中，您也可以使用 JSONP，所有 JavaScript 和/或 Front-web 框架都支持.我强烈建议您将 Mochiweb 或 Misultin 放在您的 erlang 后端，并拥有您选择使用 JSON 格式(甚至 XML，您将使用 erlsom ，下载此处).我希望你能明白我的建议.成功！！！
Remember to become a member of its mailing list to find more assistance as well as keep asking any more questions here on StackOverflow. Welcome to the world of Erlang Web Development. Some several links you may be interested in (
IEEE Paper on Web Development in Erlang,
Erlang Web Framework,
erlydtl - Erlang Django like Templating Implementation,
ErlyWeb Framework
) Success !
EDIT
Now, what you say is actually true. Finding Developers to Maintain it would be a task. However, Zotonic as i mentioned earlier is a full fledged (Web) CMS just as Joomla or Word Press e.t.c. With it you, yourself can actually manage/maintain the site/application.
However, you could also develope the Web front using Django, or Ruby on Rails but create Secure Services using JSON Formatted Data to Mochiweb from your Web front. Then, using Mochijson2.erl which comes with mochiweb, you parse the JSON and translate it into requests or methods and arguments in your Erlang Back-end. This would be done in both directions i.e. you make requests to your Erlang applications, get the returned results and render them as JSON data.
Mochiweb is the powerful tool that can interface any Erlang Back End with any Web technology at the front using Service/ RESTFul Model. Its simple and light weight. Its fast and all it needs is you to point it to which methods to handle POST, GET, PUT e.t.c HTTP requests and it would wait for the results for sending back. Mochiweb has been used in very many Erlang systems e.g. Couch DB (one of the most advanced NoSQL DBMS changing the way we understand the Web and SOA Systems) and all those other systems such as Membase Single Server, Big Couch / Cloudant, e.t.c. You could see someone putting mochiweb in action here, then here and lastly here.
Django, Twisted, PHP, or Ruby on Rails frameworks make JSON requests and expect JSON responses from Erlang Back ends powered by Mochiweb. Another great RESTful interface for Erlang Web Back-ends is Misultin, which even supports Web Sockets and is sometimes feared to be the fastest/ or most responsive Erlang HTTP library :)
In my experience, i have worked with PHP gurus, JavaScript gurus e.t.c. but we find development cheaper whenever we put our Web server as yaws with a Service Oriented Model using JSON requests and responses from both Directions. In this case we donot lose on Erlang's availability and fault tolerance and by the way, you can make many requests to as many distributed Erlang Servers even if they are hidden in different Sub nets of Domains by using JSONP which is supported by all JavaScript and/or Front-web frameworks. I strongly advise you to put Mochiweb or Misultin in-front of your erlang Backend and have which ever Web framework you choose to make requests using JSON Format (or even XML, which you would parse using erlsom , download it here). I hope you do get what am suggesting. Success!!!
这篇关于使用 OTP/Erlang 作为 Web 应用程序基于组件的架构的一部分的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！