handle exceptions properly, use concurrency when getting the urls

Database.hs

@@ -62,7 +62,7 @@ addSingle :: SearchResult -> IO (Response [B.ByteString])
 addSingle track = do
   let trackUrl = url track
   let trackDesc = title track
-  fullUrl <- getUrl trackUrl
+  (Just fullUrl) <- getUrl trackUrl
   newId <- MP.withMPD $ MP.addId (toPath fullUrl) Nothing
   --downUrl trackUrl
   either (const $ changeTitle trackDesc newId)

M3U.hs

@@ -3,6 +3,7 @@ module M3U where
 
 import Types
 import qualified Data.Text as TIO
+import qualified Control.Monad as M (join)
 import Data.Text.Encoding
 import Data.Maybe
 import Control.Applicative
@@ -12,6 +13,7 @@ import qualified Data.Attoparsec.Text as AT
 import Utils
 import Playlists
 import Search
+import Control.Concurrent.Async
 
 m3uHeader = "#EXTM3U"
 trackHeader = "#EXTINF"
@@ -29,15 +31,23 @@ toExtinf track =
           makeHeader (artist `mappend` " - " `mappend` title `mappend` "\n")
         Left trackname -> makeHeader $ TIO.pack (trackname `mappend` "\n")
 
+singleTrack :: SearchResult -> IO (Maybe TIO.Text)
 singleTrack track = do
   let extinf = toExtinf track
-  trackUrl <- TIO.pack <$> (getUrl $ url track)
-  return $ extinf `mappend` trackUrl `mappend` "\n"
+  maybeUrl <- getUrl $ url track
+  case maybeUrl of
+    (Just trackUrl) -> (return $ (Just extinf) `mappend` (Just $ TIO.pack trackUrl) `mappend` (Just "\n"))
+    Nothing -> return Nothing
 
 genm3u :: [SearchResult] -> IO M3U
 genm3u srs = do
-  tracks <- mapM singleTrack srs
+  tracks <- (mapConcurrently singleTrack srs)
   return $
     M3U $ m3uHeader `mappend`
     "\n" `mappend`
-    (mconcat tracks)
+    (mconcat $ catMaybes tracks)
+
+
+searchM3U term = do
+  (M3U m3u) <- M.join (genm3u <$> search term)
+  return m3u

Main.hs

@@ -6,7 +6,7 @@ import Types
 import Database
 import Data.List
 import System.Environment (getArgs)
-import qualified Data.Text.IO as TIO (putStrLn, putStr)
+import qualified Data.Text.IO as TIO (putStrLn, putStr, writeFile)
 import qualified Control.Monad as M
 import M3U
 

Playlists.hs

@@ -2,18 +2,22 @@ module Playlists where
 
 import qualified Data.Text as TIO
 import System.Process (readProcess)
+import Control.Concurrent.Async
+import Control.Exception
 import Utils
+import Control.Monad
 
-getUrl :: TIO.Text -> IO String
+getUrls = mapConcurrently getUrl
+
+getUrl :: TIO.Text -> IO (Maybe String)
 -- Gets a direct url using youtube-dl
 -- (if it is installed, otherwise we might fallback to some shitty code)
 
-getUrl yourl = readProcess "youtube-dl"
-                ["-g",
-                "-f",
-                "bestaudio",
-                TIO.unpack yourl,
-                "--no-cache-dir"] ""
+getUrl yourl =
+  let url = catch (Just <$> (readProcess "youtube-dl"
+              ["-g", "-f", "bestaudio", TIO.unpack yourl, "--no-cache-dir"] "")) ((\e -> return Nothing) :: SomeException -> IO (Maybe String))
+    in url
+
 downUrl yourl = readProcess "youtube-dl"
                   ["-f",
                   "bestaudio",

Search.hs

@@ -17,7 +17,7 @@ import Control.Exception
 import Network.HTTP.Base (urlEncode, urlDecode)
 import Types
 
-maxResults = 10
+maxResults = 50
 
 makeURL :: T.Text -> T.Text
 makeURL vid = "https://youtube.com/watch?v=" `T.append` vid