Use a single Manager across the whole application

3 files changed, 61 insertions, 40 deletions

diff --git a/src/Xmobar/Plugins/Monitors/Common/Types.hs b/src/Xmobar/Plugins/Monitors/Common/Types.hs
index c36a562..8662ba3 100644
--- a/src/Xmobar/Plugins/Monitors/Common/Types.hs
+++ b/src/Xmobar/Plugins/Monitors/Common/Types.hs
@@ -25,8 +25,9 @@ module Xmobar.Plugins.Monitors.Common.Types ( Monitor
                                             , io
                                             ) where
 
-import Data.IORef
-import Control.Monad.Reader
+import Data.IORef (IORef, modifyIORef, newIORef, readIORef)
+import Control.Monad.Reader (ReaderT, ask, liftIO)
+import Network.HTTP.Conduit (Manager, newManager, tlsManagerSettings)
 
 type Monitor a = ReaderT MConfig IO a
 
@@ -55,6 +56,7 @@ data MConfig =
        , naString :: IORef String
        , maxTotalWidth :: IORef Int
        , maxTotalWidthEllipsis :: IORef String
+       , manager :: IORef Manager
        }
 
 -- | from 'http:\/\/www.haskell.org\/hawiki\/MonadState'
@@ -102,7 +104,8 @@ mkMConfig tmpl exprts =
        na <- newIORef "N/A"
        mt <- newIORef 0
        mtel <- newIORef ""
-       return $ MC nc l lc h hc t e p d mn mx mel pc pr bb bf bw up na mt mtel
+       man <- newIORef =<< newManager tlsManagerSettings
+       return $ MC nc l lc h hc t e p d mn mx mel pc pr bb bf bw up na mt mtel man
 
 data Opts = HighColor String
           | NormalColor String
diff --git a/src/Xmobar/Plugins/Monitors/UVMeter.hs b/src/Xmobar/Plugins/Monitors/UVMeter.hs
index 079177f..3756856 100644
--- a/src/Xmobar/Plugins/Monitors/UVMeter.hs
+++ b/src/Xmobar/Plugins/Monitors/UVMeter.hs
@@ -18,14 +18,14 @@ module Xmobar.Plugins.Monitors.UVMeter where
 import Xmobar.Plugins.Monitors.Common
 
 import qualified Control.Exception as CE
-import Network.HTTP.Conduit
-       (parseRequest, newManager, tlsManagerSettings, httpLbs,
-        responseBody)
+import Network.HTTP.Conduit (httpLbs, parseRequest, responseBody)
 import Data.ByteString.Lazy.Char8 as B
 import Text.Read (readMaybe)
 import Text.Parsec
 import Text.Parsec.String
 import Control.Monad (void)
+import Control.Monad.Reader (asks)
+import Data.IORef (readIORef)
 
 
 uvConfig :: IO MConfig
@@ -40,16 +40,18 @@ newtype UvInfo = UV { index :: String }
 uvURL :: String
 uvURL = "https://uvdata.arpansa.gov.au/xml/uvvalues.xml"
 
-getData :: IO String
-getData =
-  CE.catch (do request <- parseRequest uvURL
-               manager <- newManager tlsManagerSettings
-               res <- httpLbs request manager
-               return $ B.unpack $ responseBody res)
-           errHandler
-  where errHandler
-          :: CE.SomeException -> IO String
-        errHandler _ = return "<Could not retrieve data>"
+-- | Get the UV data from the given url.
+getData :: Monitor String
+getData = do
+    man <- io =<< readIORef <$> asks manager
+    io $ CE.catch
+        (do request <- parseRequest uvURL
+            res <- httpLbs request man
+            return $ B.unpack $ responseBody res)
+        errHandler
+  where
+    errHandler :: CE.SomeException -> IO String
+    errHandler _ = return "<Could not retrieve data>"
 
 textToXMLDocument :: String -> Either ParseError [XML]
 textToXMLDocument = parse document ""
@@ -73,7 +75,7 @@ getUVRating _ [] = Nothing
 runUVMeter :: [String] -> Monitor String
 runUVMeter [] = return "N.A."
 runUVMeter (s:_) = do
-    resp <- io getData
+    resp <- getData
     case textToXMLDocument resp of
         Right doc -> formatUVRating (getUVRating s doc)
         Left _ -> getConfigValue naString
diff --git a/src/Xmobar/Plugins/Monitors/Weather.hs b/src/Xmobar/Plugins/Monitors/Weather.hs
index 07d8cc4..250c258 100644
--- a/src/Xmobar/Plugins/Monitors/Weather.hs
+++ b/src/Xmobar/Plugins/Monitors/Weather.hs
@@ -19,11 +19,13 @@ import Xmobar.Plugins.Monitors.Common
 
 import qualified Control.Exception as CE
 
-import Network.HTTP.Conduit
-import Network.HTTP.Types.Status
-import Network.HTTP.Types.Method
+import Control.Monad.Reader (asks)
 import qualified Data.ByteString.Lazy.Char8 as B
 import Data.Char (toLower)
+import Data.IORef (readIORef)
+import Network.HTTP.Conduit
+import Network.HTTP.Types.Method (methodHead)
+import Network.HTTP.Types.Status
 
 import Text.ParserCombinators.Parsec
 import System.Console.GetOpt (ArgDescr(ReqArg), OptDescr(Option))
@@ -208,15 +210,18 @@ defUrl = "https://tgftp.nws.noaa.gov/data/observations/metar/decoded/"
 stationUrl :: String -> String
 stationUrl station = defUrl ++ station ++ ".TXT"
 
-getData :: String -> IO String
-getData station = CE.catch (do
-    manager <- newManager tlsManagerSettings
-    request <- parseUrlThrow $ stationUrl station
-    res <- httpLbs request manager
-    return $  B.unpack $ responseBody res
-    ) errHandler
-    where errHandler :: CE.SomeException -> IO String
-          errHandler _ = return "<Could not retrieve data>"
+-- | Get the decoded weather data from the given station.
+getData :: String -> Monitor String
+getData station = do
+    man <- io =<< readIORef <$> asks manager
+    io $ CE.catch ( do
+        request <- parseUrlThrow $ stationUrl station
+        res <- httpLbs request man
+        return $ B.unpack $ responseBody res
+        ) errHandler
+  where
+    errHandler :: CE.SomeException -> IO String
+    errHandler _ = return "<Could not retrieve data>"
 
 formatSk :: Eq p => [(p, p)] -> p -> p
 formatSk ((a,b):sks) sk = if a == sk then b else formatSk sks sk
@@ -242,27 +247,38 @@ showWeather :: String -> String -> String
 showWeather "" d = d
 showWeather s  _ = s
 
+-- | Run the 'Weather' monitor.
 runWeather :: [String] -> Monitor String
 runWeather = runWeather' []
 
-runWeather' :: [(String, String)] -> [String] -> Monitor String
+-- | Run the 'WeatherX' monitor.
+runWeather'
+    :: [(String, String)]  -- ^ 'SkyConditionS' replacement strings
+    -> [String]            -- ^ User supplied arguments
+    -> Monitor String
 runWeather' sks args =
-    do d <- io $ getData $ head args
+    do d <- getData $ head args
        o <- io $ parseOptsWith options defaultOpts args
        i <- io $ runP parseData d
        formatWeather o sks i
 
+-- | Test internet connectivity before executing the monitor.
 weatherReady :: [String] -> Monitor Bool
 weatherReady str = do
     initRequest <- parseUrlThrow $ stationUrl $ head str
     let request = initRequest{method = methodHead}
+    man <- io =<< readIORef <$> asks manager
     io $ CE.catch ( do
-        manager <- newManager tlsManagerSettings
-        res     <- httpLbs request manager
-        return $ checkResult $responseStatus res ) errHandler
-    where errHandler :: CE.SomeException -> IO Bool
-          errHandler _ = return False
-          checkResult status
-            | statusIsServerError status = False
-            | statusIsClientError status = False
-            | otherwise = True
+        res  <- httpLbs request man
+        return $ checkResult $ responseStatus res ) errHandler
+  where
+    -- | If any exception occurs, indicate that the monitor is not ready.
+    errHandler :: CE.SomeException -> IO Bool
+    errHandler _ = return False
+
+    -- | Check for and indicate any errors in the http response.
+    checkResult :: Status -> Bool
+    checkResult status
+        | statusIsServerError status = False
+        | statusIsClientError status = False
+        | otherwise = True