"Boom!"

1 files changed, 78 insertions, 0 deletions

diff --git a/news.hs b/news.hs
new file mode 100644
index 0000000..ce48ccc
--- /dev/null
+++ b/news.hs
@@ -0,0 +1,78 @@
+{-# LANGUAGE OverloadedStrings #-}
+import Data.Monoid
+import Prelude hiding (elem)
+import Network.Wreq
+import Control.Lens
+import Text.Feed.Import
+import qualified Text.Atom.Feed as Atom
+import qualified Data.ByteString.Lazy.Char8 as LBS8
+import qualified Data.ByteString.Char8 as BS8
+import qualified Data.ByteString as BS
+import Text.RSS.Syntax
+import qualified Text.Feed.Types as Feed
+import qualified Data.BloomFilter as Bloom
+import qualified Data.BloomFilter.Easy as Bloom
+import Control.Concurrent
+import System.Environment
+import System.IO
+import Control.Exception
+
+
+data Item = Item
+    { ni_title :: BS.ByteString
+    , ni_link :: BS.ByteString
+    }
+  deriving Show
+
+
+atomEntryToItems :: Atom.Entry -> [Item]
+atomEntryToItems entry =
+    map (Item title) links
+  where
+    title = BS8.pack $ Atom.txtToString (Atom.entryTitle entry)
+    links = map (BS8.pack . Atom.linkHref) (Atom.entryLinks entry)
+
+rssItemToItems :: RSSItem -> [Item]
+rssItemToItems item =
+    map (Item title) links
+  where
+    title = maybe "untitled" BS8.pack (rssItemTitle item)
+    links = maybe [] ((:[]) . BS8.pack) (rssItemLink item)
+
+
+main :: IO ()
+main = do
+    hSetBuffering stdout LineBuffering
+    [url, delayString] <- getArgs
+    let delay = read delayString :: Int
+    rec url delay (Bloom.easyList 0.000001 ([] :: [BS.ByteString]))
+    return ()
+  where
+    rec url delay bloom =
+      ( do
+        r <- get url
+        let f = parseFeedString $ LBS8.unpack $ r ^. responseBody
+            items =
+              case f of
+                Just (Feed.RSSFeed rss) ->
+                    concatMap rssItemToItems (rssItems (rssChannel rss))
+                Just (Feed.AtomFeed atom) ->
+                    concatMap atomEntryToItems (Atom.feedEntries atom)
+                _ -> []
+
+            bloom' = Bloom.insertList (map ni_link items) bloom
+            newLinkItems = filter (\item ->
+                    let link = ni_link item in
+                    link `Bloom.notElem` bloom
+                ) items
+        mapM_ print (map (\item ->
+                let title = ni_title item
+                    link = ni_link item
+                in title <> " " <> link
+            ) newLinkItems)
+        threadDelay (delay * 10^6)
+        rec url delay bloom'
+      )
+        `catch` \e -> putStrLn ("Caught " ++ show (e :: SomeException)) >> rec url delay bloom
+
+