![祭代码 状态机抽象
data Stream a = EOF
| Chunks [a]
data Iteratee a b =
Continue (Stream a → Step a b)
| Yield b (Stream a)
| Error String
data Enumerator a b =
Iteratee a b → Iteratee a b](https://image.slidesharecdn.com/haskell-web-110921132224-phpapp01/85/Haskell-Web-16-320.jpg)
![URL Route
mkYesod "Simple" [parseRoutes|
/ HomeR GET
/static StaticR GET
/article ArticleR GET POST
/article/#Int ArticleDetailR GET
|]](https://image.slidesharecdn.com/haskell-web-110921132224-phpapp01/85/Haskell-Web-21-320.jpg)
![Templating
[|hamlet|
<div .section >
<h3>#{title}
<p>#{content}
|]](https://image.slidesharecdn.com/haskell-web-110921132224-phpapp01/85/Haskell-Web-22-320.jpg)
![Widgets （ EDSL ）
dateTimeField name = do
addScriptRemote “...”
addDateTimeCss “...”
toWidget [hamlet|<input ... |]
autoCompleteField name = do
addScriptRemote “...”
addDateTimeCss “...”
toWidget [hamlet|<input ... |]
myForm = do
[hamlet|<form ...|]
DateTimeField “date”
autoCompleteField “tag”](https://image.slidesharecdn.com/haskell-web-110921132224-phpapp01/85/Haskell-Web-23-320.jpg)
走马观花— Haskell Web 开发
- 1. 走马观花—— Haskell Web 开发 黄毅 http://www.yi-programmer.com/ [email protected]
- 2. About me ● CPP( 静 ) → Python( 动 ) → Haskell( 静 ) ● 专业 Python ● 业余 Haskell
- 3. 前情提要 你将会了解到： ● 一门 20 多年依然冷门的语言的简单介绍 ● 微线程模型并发处理的示例程序 ● 一种对“流式处理”的强大抽象 ● 一个常数内存占用的 HTTP 代理服务器的实现 ● 一种类型安全的“宏”，并用它创建 DSL 的例子
- 4. So ， Why Haskell ？
- 5. Quest for Certain Knowledge of Programming
- 6. 虚的部分 • 纯，函数式（抽象！抽象！抽象！） • 命令式（显式的副作用管理） • 强大的静态类型系统（避免逻辑矛盾！）
- 7. 实在一点， 针对 Web 开发， Haskell 能提供什么？
- 8. 一、微线程和高并发
- 9. server <- listenOn (PortNumber 3000) forever $ do (client, h, p) <- accept server hSetBuffering client NoBuffering forkIO $ forever $ do request <- hGetLine client hPrintf client "%s from %s: %dn" request h (toInteger p)
- 11. 二、 Iteratee 针对流式数据处理的抽象 http://www.haskell.org/haskellwiki/Enumerator_and_iteratee
- 12. 示例： A http proxy server runs in constant memory http://github.com/yihuang/webproxy-yesod
- 14. 状态机
- 15. 状态机组合！ requestLine :: Parser Request requestLine = do method <- P.takeWhile1 isToken <* char8 ' ' uri <- P.takeWhile1 (/=32) <* char8 ' ' version <- httpVersion <* endOfLine ...
- 16. 祭代码 状态机抽象 data Stream a = EOF | Chunks [a] data Iteratee a b = Continue (Stream a → Step a b) | Yield b (Stream a) | Error String data Enumerator a b = Iteratee a b → Iteratee a b
- 17. 祭代码 Proxy Application fetch :: Request IO -> (Status -> Headers -> Iteratee..) -> IO a fetch req f = withManager $ m -> run_ $ http req f m getIndexR = do req <- liftIO $ parseUrl url sendWaiResponse $ ResponseEnumerator $ fetch req
- 18. 简单 benchmark ● 300M 数据文件， 100 并发，恒定 25M RES
- 20. Template Haskell ● Run haskell at compile time ● Imagine type safe lisp macro
- 21. URL Route mkYesod "Simple" [parseRoutes| / HomeR GET /static StaticR GET /article ArticleR GET POST /article/#Int ArticleDetailR GET |]
- 22. Templating [|hamlet| <div .section > <h3>#{title} <p>#{content} |]
- 23. Widgets （ EDSL ） dateTimeField name = do addScriptRemote “...” addDateTimeCss “...” toWidget [hamlet|<input ... |] autoCompleteField name = do addScriptRemote “...” addDateTimeCss “...” toWidget [hamlet|<input ... |] myForm = do [hamlet|<form ...|] DateTimeField “date” autoCompleteField “tag”
- 24. Widgets result <script datetime.js <script autocomplete.js … <link datetime.css <link autocomplete.css … <input ...
- 25. Thanks ！