Network.JavaScript

Sending Remote Monads and Packets

send :: Engine -> RemoteMonad a -> IO a

send a remote monad for execution on a JavaScript engine. The monad may be split into several packets for transmission and exection.

sendA :: Engine -> Packet a -> IO a

send an (applicative) Packet. This packet always sent atomically to JavaScript.

sendE :: Engine -> RemoteMonad a -> IO (Either Value a)

send with all JavaScript exceptions caught and returned.

Building Remote Monads and Packets

newtype JavaScript

Constructors

JavaScript Text

Instances

Show JavaScript

Defined in Network.JavaScript.Internal

Methods

showsPrec :: Int -> JavaScript -> ShowS

show :: JavaScript -> String

showList :: [JavaScript] -> ShowS

IsString JavaScript

Defined in Network.JavaScript.Internal

Methods

fromString :: String -> JavaScript

Semigroup JavaScript

Defined in Network.JavaScript.Internal

Methods

(<>) :: JavaScript -> JavaScript -> JavaScript

sconcat :: NonEmpty JavaScript -> JavaScript

stimes :: Integral b => b -> JavaScript -> JavaScript

Monoid JavaScript

Defined in Network.JavaScript.Internal

Methods

mempty :: JavaScript

mappend :: JavaScript -> JavaScript -> JavaScript

mconcat :: [JavaScript] -> JavaScript

command :: Command f => JavaScript -> f ()

command statement to execute in JavaScript. ';' is not needed as a terminator. Should never throw an exception, which may be reported to console.log.

procedure :: forall a f. (Procedure f, FromJSON a) => JavaScript -> f a

procedure expression to execute in JavaScript. ';' is not needed as a terminator. Should never throw an exception, but any exceptions are returned to the send as Haskell exceptions.

Procedures can return Promises. Before completing the transaction, all the values for all the procedures that are promises are fulfilled (using Promises.all).

If a procedure throws an exception, future commands and procedures in the same packet will not be executed. Use promises to allow all commands and procedures to be invoked, if needed.

constructor :: forall a f. Command f => JavaScript -> f (RemoteValue a)

constructor expression to execute in JavaScript. ';' is not needed as a terminator. Should never throw an exception, but any exceptions are returned to the send as Haskell exceptions.

The value returned in not returned to Haskell. Instead, a handle is returned, that can be used to access the remote value. Examples of remote values include objects that can not be serialized, or values that are too large to serialize.

The first type argument is the phantom type of the RemoteValue, so that type application can be used to specify the type.

Remote Applicative and Monads, and classes for building them

data Packet a

The Remote Applicative Packet

Instances

Functor Packet

Defined in Network.JavaScript.Internal

Methods

fmap :: (a -> b) -> Packet a -> Packet b

(<$) :: a -> Packet b -> Packet a

Applicative Packet

Defined in Network.JavaScript.Internal

Methods

pure :: a -> Packet a

(<*>) :: Packet (a -> b) -> Packet a -> Packet b

liftA2 :: (a -> b -> c) -> Packet a -> Packet b -> Packet c

(*>) :: Packet a -> Packet b -> Packet b

(<*) :: Packet a -> Packet b -> Packet a

Procedure Packet

Defined in Network.JavaScript.Internal

Methods

internalProcedure :: FromJSON a => JavaScript -> Packet a

Command Packet

Defined in Network.JavaScript.Internal

Methods

internalCommand :: JavaScript -> Packet ()

internalConstructor :: JavaScript -> Packet (RemoteValue a)

data RemoteMonad a

The Remote Monad

Instances

Monad RemoteMonad

Defined in Network.JavaScript.Internal

Methods

(>>=) :: RemoteMonad a -> (a -> RemoteMonad b) -> RemoteMonad b

(>>) :: RemoteMonad a -> RemoteMonad b -> RemoteMonad b

return :: a -> RemoteMonad a

fail :: String -> RemoteMonad a

Functor RemoteMonad

Defined in Network.JavaScript.Internal

Methods

fmap :: (a -> b) -> RemoteMonad a -> RemoteMonad b

(<$) :: a -> RemoteMonad b -> RemoteMonad a

Applicative RemoteMonad

Defined in Network.JavaScript.Internal

Methods

pure :: a -> RemoteMonad a

(<*>) :: RemoteMonad (a -> b) -> RemoteMonad a -> RemoteMonad b

liftA2 :: (a -> b -> c) -> RemoteMonad a -> RemoteMonad b -> RemoteMonad c

(*>) :: RemoteMonad a -> RemoteMonad b -> RemoteMonad b

(<*) :: RemoteMonad a -> RemoteMonad b -> RemoteMonad a

Procedure RemoteMonad

Defined in Network.JavaScript.Internal

Methods

internalProcedure :: FromJSON a => JavaScript -> RemoteMonad a

Command RemoteMonad

Defined in Network.JavaScript.Internal

Methods

internalCommand :: JavaScript -> RemoteMonad ()

internalConstructor :: JavaScript -> RemoteMonad (RemoteValue a)

class Command f

Minimal complete definition

internalCommand, internalConstructor

Instances

Command RemoteMonad

Defined in Network.JavaScript.Internal

Methods

internalCommand :: JavaScript -> RemoteMonad ()

internalConstructor :: JavaScript -> RemoteMonad (RemoteValue a)

Command Packet

Defined in Network.JavaScript.Internal

Methods

internalCommand :: JavaScript -> Packet ()

internalConstructor :: JavaScript -> Packet (RemoteValue a)

class Procedure f

Minimal complete definition

internalProcedure

Instances

Procedure RemoteMonad

Defined in Network.JavaScript.Internal

Methods

internalProcedure :: FromJSON a => JavaScript -> RemoteMonad a

Procedure Packet

Defined in Network.JavaScript.Internal

Methods

internalProcedure :: FromJSON a => JavaScript -> Packet a

Remote Values

data RemoteValue a

Instances

Eq (RemoteValue a)

Defined in Network.JavaScript.Internal

Methods

(==) :: RemoteValue a -> RemoteValue a -> Bool

(/=) :: RemoteValue a -> RemoteValue a -> Bool

Ord (RemoteValue a)

Defined in Network.JavaScript.Internal

Methods

compare :: RemoteValue a -> RemoteValue a -> Ordering

(<) :: RemoteValue a -> RemoteValue a -> Bool

(<=) :: RemoteValue a -> RemoteValue a -> Bool

(>) :: RemoteValue a -> RemoteValue a -> Bool

(>=) :: RemoteValue a -> RemoteValue a -> Bool

max :: RemoteValue a -> RemoteValue a -> RemoteValue a

min :: RemoteValue a -> RemoteValue a -> RemoteValue a

Show (RemoteValue a)

Defined in Network.JavaScript.Internal

Methods

showsPrec :: Int -> RemoteValue a -> ShowS

show :: RemoteValue a -> String

showList :: [RemoteValue a] -> ShowS

ToJSON (RemoteValue a)

Defined in Network.JavaScript.Internal

Methods

toJSON :: RemoteValue a -> Value

toEncoding :: RemoteValue a -> Encoding

toJSONList :: [RemoteValue a] -> Value

toEncodingList :: [RemoteValue a] -> Encoding

delete :: Command f => RemoteValue a -> f ()

delete a remote value.

localize :: Procedure f => RemoteValue a -> f Value

localize brings a remote value into Haskell.

remote :: Command f => Value -> f (RemoteValue a)

remote sends a local value to JavaScript.

JavaScript builders

var :: RemoteValue a -> JavaScript

generate the text for a RemoteValue. They can be used as assignment targets as well, but exposes the JavaScript scoping semantics.

value :: ToJSON v => v -> JavaScript

Generate a JavaScript value, including for RemoteValue's.

call :: JavaScript -> [JavaScript] -> JavaScript

Generate a function call

number :: Double -> JavaScript

Generate JavaScript number

string :: Text -> JavaScript

Generate (quoted) JavaScript string

Events

data JavaScriptException

Constructors

JavaScriptException Value

Instances

Eq JavaScriptException

Defined in Network.JavaScript

Methods

(==) :: JavaScriptException -> JavaScriptException -> Bool

(/=) :: JavaScriptException -> JavaScriptException -> Bool

Show JavaScriptException

Defined in Network.JavaScript

Methods

showsPrec :: Int -> JavaScriptException -> ShowS

show :: JavaScriptException -> String

showList :: [JavaScriptException] -> ShowS

Exception JavaScriptException

Defined in Network.JavaScript

Methods

toException :: JavaScriptException -> SomeException

fromException :: SomeException -> Maybe JavaScriptException

displayException :: JavaScriptException -> String

event :: ToJSON v => v -> JavaScript

Send an event back to Haskell

addListener :: Engine -> (Value -> IO ()) -> IO ThreadId

Add a listener for events. There can be many. non-blocking.

From JavaScript, you can call event(..) to send values to this listener. Any valid JSON value can be sent.

listen :: Engine -> IO Value

listen for the next event. blocking.

From JavaScript, you can call event(..) to send values to this listener. Any valid JSON value can be sent.

readEventChan :: Engine -> STM (Value, UTCTime)

readEventChan uses STM to read the next event.

From JavaScript, you can call event(..) to send values to this channel. Any valid JSON value can be sent.

Web services

start :: (Engine -> IO ()) -> Application -> Application

This accepts WebSocket requests, calls the callback with an Engine that can be used to access JavaScript.

data Engine

An Engine is a handle to a specific JavaScript engine

type Application = Request -> (Response -> IO ResponseReceived) -> IO ResponseReceived

The WAI application.

Note that, since WAI 3.0, this type is structured in continuation passing style to allow for proper safe resource handling. This was handled in the past via other means (e.g., ResourceT). As a demonstration:

app :: Application
app req respond = bracket_
    (putStrLn "Allocating scarce resource")
    (putStrLn "Cleaning up")
    (respond $ responseLBS status200 [] "Hello World")