The async-refresh package

[ Tags: bsd3, control, library ] [ Propose Tags ]

This package can be used for refreshing of expiring data according to a user-provided action. Using callbacks, the user can decide how she or he would like to be informed about data refreshing.


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Properties

Versions 0.1.7, 0.2.0, 0.2.0.2
Dependencies base (>=4.7 && <5), formatting, lifted-async, microlens, microlens-th, monad-control, monad-logger, safe-exceptions, stm, text [details]
License BSD3
Copyright (c) 2017 Moritz Schulte
Author Moritz Schulte
Maintainer mtesseract@silverratio.net
Category Control
Home page https://github.com/mtesseract/async-refresh
Source repository head: git clone https://github.com/mtesseract/async-refresh
Uploaded Thu Jun 29 17:37:56 UTC 2017 by mtesseract
Distributions LTSHaskell:0.2.0.2, NixOS:0.2.0.2, Stackage:0.2.0.2, Tumbleweed:0.2.0.2
Downloads 251 total (23 in the last 30 days)
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Status Docs available [build log]
Last success reported on 2017-06-29 [all 1 reports]
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Readme for async-refresh-0.2.0.2

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async-refresh Hackage version Stackage version Build Status

About

This is Haskell library implementing the logic for refreshing of expiring data according to user-provided actions.

Usage

  • Create a new configuration using newAsyncRefreshConf, providing the action to be used for data refreshing.

  • Adjust the configuration using the asyncRefreshConfSet* functions, in particular using asyncRefreshConfSetCallback.

  • Use newAsyncRefresh to initiate a new thread managing the asynchronous refreshing.

Example

The following IO action produces a TVar which is updated every ten seconds to contain the current time (wrapped in an Either SomeException, because refreshing may fail).

periodicTimeUpdater :: IO (TVar (Either SomeException UTCTime))
periodicTimeUpdater = runStderrLoggingT $ do
  timeStore <- liftIO $ newTVarIO (Left (toException NotFound))
  let conf = newAsyncRefreshConf (RefreshResult <$> liftIO getCurrentTime <*> pure Nothing)
        & asyncRefreshConfSetLabel "CurrentTime updated every 10 seconds"
        & asyncRefreshConfSetDefaultInterval (10 * 10^3)
        & asyncRefreshConfSetCallback (liftIO . atomically . writeTVar timeStore . fmap refreshResult)
  _ <- newAsyncRefresh conf
  return timeStore