24 | Network.N2O.Web defines adjoin interfaces to underlying 33 | transports: HTTP for static file serving and WebSocket for N2O protocols.
34 | 35 |This module may refer to: 54 | TYPES, 55 | PROTOCOLS, 56 | CORE 57 |
58 | 59 |
24 | The Network.N2O.Internal module contains request and context definition, state and N2O monad.
31 |
35 | type Header = (BS.ByteString, BS.ByteString)
36 | data Req = Req
37 | { reqPath :: BS.ByteString
38 | , reqMeth :: BS.ByteString
39 | , reqVers :: BS.ByteString
40 | , reqHead :: [Header]
41 | }
42 |
44 | data Resp = Resp
45 | { respCode :: Int
46 | , respHead :: [Header]
47 | , respBody :: BS.ByteString
48 | } deriving (Show)
49 |
54 | data Event a
55 | = Init
56 | | Message a
57 | | Terminate
58 | deriving Show
59 |
61 | data Result a
62 | = Reply a
63 | | Ok
64 | | Unknown
65 | | Empty
66 | deriving (Show, Eq)
67 |
69 | data Context (f :: * -> *) a where Context ::
70 | { cxHandler :: Event a -> N2O f a (Result a)
71 | , cxReq :: Req
72 | , cxMiddleware :: [Context f a -> Context f a]
73 | , cxProtos :: [Proto f a]
74 | , cxActions :: BS.ByteString
75 | , cxDict :: M.Map BS.ByteString BS.ByteString
76 | } -> Context f a
77 |
79 | mkCx = Context
80 | { cxReq = undefined
81 | , cxHandler = undefined
82 | , cxMiddleware = []
83 | , cxProtos = []
84 | , cxActions = ""
85 | , cxDict = M.empty
86 | }
87 |
93 | type Proto (f :: * -> *) a
94 | = (f a) -> N2O f a (Result (f a))
95 |
96 | type N2O f a
97 | = ReaderT (IORef (Context f a)) IO
98 |
24 | N2O defines a way we scale protocols, database schema, applications and 65 | services across companies, formatters, views and presentation layers. 66 | At the core N2O folds a list of protocols and their handlers providing 67 | a minimal type-level specification for general purpose application protocol tract.
68 | 69 |As example this Haskell version of N2O is shipped with Nitro protocol 70 | implementation, that listens the tract and push prerendered JavaScript 71 | events back to the channel. This smart and simple reactive way 72 | of client-server interaction first was used by Rusty Klophaus in 73 | his Nitrogen web framework, that was pushed forward since then in 74 | N2O by Andy Melnikov and Marat Khafizov.
75 | 76 |The philosophy behind N2O is a simplicity, cleanness, and purity. 77 | The core of N2O should be no more than 500 LOC.
78 | 79 |
82 | data Example = Greet deriving (Show, Eq, Read)
83 |
84 | main = runServer "localhost" 3000 cx
85 | cx = createCx router
86 | router cx@Cx{cxReq=Req{reqPath=path}} =
87 | let handler = case path of
88 | "/ws/samples/static/index.html" -> index
89 | "/ws/samples/static/about.html" -> about
90 | _ -> index
91 | in traceShow path cx{cxHandler=handler}
92 | The idea to send prerendered JavaScript events over the 95 | wire belongs to Rusty Klophaus who made Nitrogen Erlang web framework. 96 | Later this was refined by N2O team and now is available 97 | in its purity of Haskell.
98 | 99 |
102 | index Init = do
103 | updateText "system" "What is your name?"
104 | wireEl button{id="send", postback=Just Greet, source=["name"]}
105 |
106 | index (Message Greet) = do
107 | Just name <- get "name" -- wf:q/1
108 | updateText "system" ("Hello, " <> jsEscape name <> "!")
109 |
110 | about Init =
111 | updateText "app" "This is the N2O Hello World App"
112 | The N2O does not limit in developing only web applications. 115 | N2O stack of protocols covers bus, storage, process interfaces. 116 | Subscribe to follow Haskell implementations.
117 |