EventStore Haskell TCP client ============================= [Talk and exchange ideas in our dedicated Discord Server] That driver supports 100% of EventStore features ! More information about the GetEventStore database can be found there: https://eventstore.com/ Requirements ============ * 64bits system * GHC >= 8.0.3 * Cabal >= 1.18 * EventStore >= 4 (Doesn't support EventStore 2020 Preview yet, previously named version 6). *Note: If you use this client version >= to `1.1`, it will only supports EventStore >= 4.0.0.* Install ======= * Using [Hackage](https://hackage.haskell.org/package/eventstore) ``` $ cabal update $ cabal install eventstore ``` * From source ``` $ git clone https://github.com/YoEight/eventstore.git $ cd eventstore $ cabal install ``` How to test =========== Tests are available. Those assume a server is running on `127.0.0.1` and `1113` port. ``` $ cabal test ``` How to use ========== ```haskell {-# LANGUAGE OverloadedStrings #-} -- That library uses `Text` pervasively. This pragma permits to use -- String literal when a Text is needed. module Main where import Control.Concurrent.Async (wait) import Data.Aeson -- It requires to have `aeson` package installed. Note that EventStore doesn't constraint you to JSON -- format but putting common use aside, by doing so you'll be able to use some interesting EventStore -- features like its Complex Event Processing (CEP) capabality. import Database.EventStore -- Note that imports 'NonEmpty' data constructor and 'nonEmpty' function from -- 'Data.List.NonEmpty'. main :: IO () main = do -- A common pattern with an EventStore connection is to create a single instance only and pass it -- wherever you need it (it's threadsafe). It's very important to not consider an EventStore connection like -- its regular SQL counterpart. An EventStore connection will try its best to reconnect -- automatically to the server if the connection dropped. Of course that behavior can be tuned -- through some settings. conn <- connect defaultSettings (Static "127.0.0.1" 1113) let js = object ["isHaskellTheBest" .= True] -- (.=) comes from Data.Aeson module. evt = createEvent "programming" Nothing (withJson js) -- Appends an event to a stream named `languages`. as <- sendEvent conn (StreamName "languages") anyVersion evt Nothing -- EventStore interactions are fundamentally asynchronous. Nothing requires you to wait -- for the completion of an operation, but it's good to know if something went wrong. _ <- wait as -- Again, if you decide to `shutdown` an EventStore connection, it means your application is -- about to terminate. shutdown conn -- Make sure the EventStore connection completes every ongoing operation. For instance, if -- at the moment we call `shutdown` and some operations (or subscriptions) were still pending, -- the connection aborted all of them. waitTillClosed conn ``` Notes ===== That library was tested on Linux and OSX. Contributions and bug reports are welcome! BSD3 License -Yorick Laupa [Talk and exchange ideas in our dedicated Discord Server]: https://discord.gg/x7q37jJ