initial

.gitignore

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+*.lock
+*.cabal

LICENSE

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+Copyright Author name here (c) 2020
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Author name here nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

README.md

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+# simplex-messaging

Setup.hs

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+import Distribution.Simple
+main = defaultMain

package.yaml

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+name: simplex-messaging
+version: 0.1.0.0
+#synopsis:
+#description:
+homepage: https://github.com/githubuser/simplex-messaging#readme
+license: BSD3
+author: Author name here
+maintainer: example@example.com
+copyright: 2020 Author name here
+category: Web
+extra-source-files:
+  - README.md
+
+dependencies:
+  - base >= 4.7 && < 5
+  - bytestring
+  - network
+
+executables:
+  simplex-messaging:
+    source-dirs: src
+    main: Main.hs

src/Main.hs

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+module Main where
+
+import Control.Concurrent
+import qualified Control.Exception as E
+import Control.Monad
+import Network.Socket
+import System.IO
+
+main = do
+  putStrLn $ "Listening on port " ++ port
+  runTCPServer Nothing port talk
+
+port :: String
+port = "5223"
+
+runTCPServer :: Maybe HostName -> ServiceName -> (Handle -> IO ()) -> IO ()
+runTCPServer mhost port server = withSocketsDo $ do
+  let hints = defaultHints {addrFlags = [AI_PASSIVE], addrSocketType = Stream}
+  addr : _ <- getAddrInfo (Just hints) mhost (Just port)
+  E.bracket (open addr) close loop
+  where
+    open addr = do
+      sock <- socket (addrFamily addr) (addrSocketType addr) (addrProtocol addr)
+      setSocketOption sock ReuseAddr 1
+      withFdSocket sock $ setCloseOnExecIfNeeded
+      bind sock $ addrAddress addr
+      listen sock 1024
+      return sock
+    loop sock = forever $ do
+      (conn, peer) <- accept sock
+      putStrLn $ "Accepted connection from " ++ show peer
+      h <- socketToHandle conn ReadWriteMode
+      hSetBinaryMode h True
+      hSetBuffering h LineBuffering
+      hPutStrLn h "Welcome\r"
+      forkFinally (server h) (const $ hClose h)
+
+talk :: Handle -> IO ()
+talk h = do
+  line <- hGetLine h
+  if line == "end"
+    then hPutStrLn h "Bye\r"
+    else do
+      hPutStrLn h (show (2 * (read line :: Integer)) ++ "\r")
+      talk h

src/Transport.hs

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+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE KindSignatures #-}
+
+module Transport where
+
+data Party = Broker | Recipient | Sender
+
+type Transmission (a :: Party) = (Signed a, Signature)
+
+type Signed (a :: Party) = (ConnId, Com a)
+
+data Com (a :: Party) where
+  CREATE :: RecipientKey -> Com Recipient
+  SECURE :: SenderKey -> Com Recipient
+  DELMSG :: MsgId -> Com Recipient
+  SUB :: Com Recipient
+  SUSPEND :: Com Recipient
+  DELETE :: Com Recipient
+  SEND :: MsgBody -> Com Sender
+  MSG :: MsgId -> Timestamp -> MsgBody -> Com Broker
+  CONN :: SenderId -> RecipientId -> Com Broker
+  ERROR :: ErrorType -> Com Broker
+  OK :: Com Broker
+
+type Encoded = String
+
+type Signature = Encoded
+
+type RecipientKey = Encoded
+
+type SenderKey = Encoded
+
+type ConnId = Encoded
+
+type SenderId = Encoded
+
+type RecipientId = Encoded
+
+type MsgId = Encoded
+
+type Timestamp = Encoded
+
+type MsgBody = Encoded
+
+data ErrorType = CMD | SYNTAX | AUTH | INTERNAL

stack.yaml

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+# This file was automatically generated by 'stack init'
+#
+# Some commonly used options have been documented as comments in this file.
+# For advanced use and comprehensive documentation of the format, please see:
+# https://docs.haskellstack.org/en/stable/yaml_configuration/
+
+# Resolver to choose a 'specific' stackage snapshot or a compiler version.
+# A snapshot resolver dictates the compiler version and the set of packages
+# to be used for project dependencies. For example:
+#
+# resolver: lts-3.5
+# resolver: nightly-2015-09-21
+# resolver: ghc-7.10.2
+#
+# The location of a snapshot can be provided as a file or url. Stack assumes
+# a snapshot provided as a file might change, whereas a url resource does not.
+#
+# resolver: ./custom-snapshot.yaml
+# resolver: https://example.com/snapshots/2018-01-01.yaml
+resolver: lts-16.17
+
+# User packages to be built.
+# Various formats can be used as shown in the example below.
+#
+# packages:
+# - some-directory
+# - https://example.com/foo/bar/baz-0.0.2.tar.gz
+#   subdirs:
+#   - auto-update
+#   - wai
+packages:
+  - .
+# Dependency packages to be pulled from upstream that are not in the resolver.
+# These entries can reference officially published versions as well as
+# forks / in-progress versions pinned to a git hash. For example:
+#
+extra-deps:
+# - network-run-0.2.4@sha256:7dbb06def522dab413bce4a46af476820bffdff2071974736b06f52f4ab57c96,885
+# - git: https://github.com/commercialhaskell/stack.git
+#   commit: e7b331f14bcffb8367cd58fbfc8b40ec7642100a
+#
+# extra-deps: []
+
+# Override default flag values for local packages and extra-deps
+# flags: {}
+
+# Extra package databases containing global packages
+# extra-package-dbs: []
+
+# Control whether we use the GHC we find on the path
+# system-ghc: true
+#
+# Require a specific version of stack, using version ranges
+# require-stack-version: -any # Default
+# require-stack-version: ">=2.1"
+#
+# Override the architecture used by stack, especially useful on Windows
+# arch: i386
+# arch: x86_64
+#
+# Extra directories used by stack for building
+# extra-include-dirs: [/path/to/dir]
+# extra-lib-dirs: [/path/to/dir]
+#
+# Allow a newer minor version of GHC than the snapshot specifies
+# compiler-check: newer-minor