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+{-# LANGUAGE OverloadedStrings #-}
+-----------------------------------------------------------------------------
+-- |
+-- Module : Plugins.Monitors.UVMeter
+-- Copyright : (c) Róman Joost
+-- License : BSD-style (see LICENSE)
+--
+-- Maintainer : Róman Joost
+-- Stability : unstable
+-- Portability : unportable
+--
+-- An australian uv monitor for Xmobar
+--
+-----------------------------------------------------------------------------
+
+module Plugins.Monitors.UVMeter where
+
+import Plugins.Monitors.Common
+
+import qualified Control.Exception as CE
+import Control.Applicative hiding ((<|>),many)
+import Network.HTTP
+import Text.Read (readMaybe)
+import Text.Parsec
+import Text.Parsec.String
+
+
+uvConfig :: IO MConfig
+uvConfig = mkMConfig
+ "<station>" -- template
+ ["station" -- available replacements
+ ]
+
+data UvInfo = UV { index :: String }
+ deriving (Show)
+
+uvURL :: String
+uvURL = "http://www.arpansa.gov.au/uvindex/realtime/xml/uvvalues.xml"
+
+getData :: IO String
+getData = do
+ let request = getRequest uvURL
+ CE.catch (simpleHTTP request >>= getResponseBody) errHandler
+ where errHandler :: CE.IOException -> IO String
+ errHandler _ = return "<Could not retrieve data>"
+
+textToXMLDocument :: String -> Either ParseError [XML]
+textToXMLDocument = parse document ""
+
+formatUVRating :: Maybe Float -> Monitor String
+formatUVRating Nothing = getConfigValue naString
+formatUVRating (Just x) = do
+ uv <- showWithColors show x
+ parseTemplate [uv]
+
+getUVRating :: String -> [XML] -> Maybe Float
+getUVRating locID (Element "stations" _ y:_) = getUVRating locID y
+getUVRating locID (Element "location" [Attribute attr] ys:xs)
+ | locID == snd attr = getUVRating locID ys
+ | otherwise = getUVRating locID xs
+getUVRating _ (Element "index" [] [Body rate]:_) = readMaybe rate
+getUVRating locID (_:xs) = getUVRating locID xs
+getUVRating _ [] = Nothing
+
+
+runUVMeter :: [String] -> Monitor String
+runUVMeter [] = return "N.A."
+runUVMeter (s:_) = do
+ resp <- io getData
+ case textToXMLDocument resp of
+ Right doc -> formatUVRating (getUVRating s doc)
+ Left _ -> getConfigValue naString
+
+-- | XML Parsing code comes here.
+-- This is a very simple XML parser to just deal with the uvvalues.xml
+-- provided by ARPANSA. If you work on a new plugin which needs an XML
+-- parser perhaps consider using a real XML parser and refactor this
+-- plug-in to us it as well.
+--
+-- Note: This parser can not deal with short tags.
+--
+-- Kudos to: Charlie Harvey for his article about writing an XML Parser
+-- with Parsec.
+--
+
+type AttrName = String
+type AttrValue = String
+
+data Attribute = Attribute (AttrName, AttrValue)
+ deriving (Show)
+
+data XML = Element String [Attribute] [XML]
+ | Decl String
+ | Body String
+ deriving (Show)
+
+-- | parse the document
+--
+document :: Parser [XML]
+document = do
+ spaces
+ y <- try xmlDecl <|> tag
+ spaces
+ x <- many tag
+ spaces
+ return (y : x)
+
+-- | parse any tags
+--
+tag :: Parser XML
+tag = do
+ char '<'
+ spaces
+ name <- many (letter <|> digit)
+ spaces
+ attr <- many attribute
+ spaces
+ string ">"
+ eBody <- many elementBody
+ endTag name
+ spaces
+ return (Element name attr eBody)
+
+xmlDecl :: Parser XML
+xmlDecl = do
+ string "<?xml"
+ decl <- many (noneOf "?>")
+ string "?>"
+ return (Decl decl)
+
+elementBody :: Parser XML
+elementBody = spaces *> try tag <|> text
+
+endTag :: String -> Parser String
+endTag str = string "</" *> string str <* char '>'
+
+text :: Parser XML
+text = Body <$> many1 (noneOf "><")
+
+attribute :: Parser Attribute
+attribute = do
+ name <- many (noneOf "= />")
+ spaces
+ char '='
+ spaces
+ char '"'
+ value <- many (noneOf "\"")
+ char '"'
+ spaces
+ return (Attribute (name, value))