Port that is used to communicate between Cardano-node and Daedalus (e.g 8090)

Message from the server being sent to the client.

Message which is send out from Cardano-node

Read-only handle

Write-only handle

When using pipes, the write doesn't block, but the read blocks! As a consequence, we eiter need to use IDs to keep track of the client/server pair, or (read) block so we know which message pair arrived. This might seems an overkill for this task, but it's actually required if we want to reason about it and test it properly.

>>> (readEnd, writeEnd) <- createPipe

>>> replicateM 100 $ sendMessage (WriteHandle writeEnd) Cardano.Shell.NodeIPC.Ping
[(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),()]

>>> mesg <- replicateM 100 ((readMessage (ReadHandle readEnd)) :: IO MsgIn)

>>> mesg <- (readMessage (ReadHandle readEnd)) :: IO MsgIn

Blocked!

The way the IPC protocol works - it either responds to a single IPC message or it remains in a loop responding to multiple messages.

Start IPC with NodeJS

This only works if NodeJS spawns the Haskell executable as child process (See server.js as an example)

Start IPC with given ReadHandle, WriteHandle and Port

Function for handling the protocol

Client side IPC protocol.

Test startIPC

The set of handles for the server, the halves of one pipe.

The set of handles for the client, the halves of one pipe.

Close the pipe handles.

Creation of a two-way communication between the server and the client. Full-duplex (two-way) communication normally requires two anonymous pipes. TODO(KS): Bracket this!

A bracket function that can be useful.

This is a blocking call that sends the message to the client and returns it's response, after the client response arrives.

Exception thrown from Node IPC protocol

Message that can be used to let the other know the that exception had occured

Exception

Send JSON message with given WriteHandle

Read JSON message with given ReadHandle

Example using file descriptor

Example of an IPC server that is using haskell executable as an server.

This will be the server, the one which sends the message (such as Ping, QueryPort) to get the response from the client. The client is executed via stack exec node-ipc haskell

Create a pipe for interprocess communication and return a (ReadHandle, WriteHandle) Handle pair.

Acquire a Handle that can be used for IPC from Environment

Checks if given NodeIPCError is IPCError

Checks if given NodeIPCError is HandleClosed

Checks if given NodeIPCError is UnreadableHandle

Checks if given NodeIPCError is UnwritableHandle

Checks if given NodeIPCError is NodeChannelNotFound