-{-# LANGUAGE NoMonomorphismRestriction #-}
{-# LANGUAGE DoAndIfThenElse #-}
+{-# LANGUAGE NoMonomorphismRestriction #-}
module Main
where
-import Control.Arrow ( (&&&), arr, returnA )
+import Control.Arrow ( (&&&), (>>^), arr, returnA )
import Control.Concurrent ( threadDelay )
import Control.Exception ( SomeException, catch )
import Control.Monad ( when )
import qualified TSN.XML.Injuries as Injuries ( Listing )
import qualified TSN.XML.InjuriesDetail as InjuriesDetail ( PlayerListing )
import qualified TSN.XML.News as News ( Message )
-import Xml ( parse_opts )
-
-
-
-import_file :: Configuration -> FilePath -> IO Bool
+import Xml ( DtdName(..), parse_opts )
+
+
+-- | This is where most of the work happens. This function is called
+-- on every file that we would like to import. It determines which
+-- importer to use based on the DTD, processes the file, and then
+-- returns whether or not any records were imported. If the file was
+-- processed, the number of records imported is returned (wrapped in
+-- a Just). Otherwise, if the file was not processed, 'Nothing' is
+-- returned.
+--
+-- Since we are already in arrow world with HXT, the
+-- 'import_with_dtd' function is lifted to an 'Arrow' as well with
+-- 'arr'. This prevents us from having to do a bunch of unwrapping
+-- and rewrapping with the associated error checking.
+--
+import_file :: Configuration -- ^ A configuration object needed for the
+ -- 'backend' and 'connection_string'.
+
+ -> FilePath -- ^ The path of the XML file to import.
+
+ -> IO (Maybe Int) -- ^ If we processed the file, Just the number
+ -- of records imported. Otherwise, Nothing.
import_file cfg path = do
results <- parse_and_import `catch` exception_handler
case results of
- -- If results' is empty, one of the arrows return "nothing."
[] -> do
+ -- One of the arrows returned "nothing."
report_error $ "Unable to determine DTD for file " ++ path ++ "."
- return False
- (Err errmsg:_) -> do
+ return Nothing
+ (ImportFailed errmsg:_) -> do
report_error errmsg
- return False
- (Info infomsg:_) -> do
+ return Nothing
+ (ImportSkipped infomsg:_) -> do
+ -- We processed the message but didn't import anything. Return
+ -- "success" so that the XML file is deleted.
report_info infomsg
- return True
- (Succ count:_) -> do
+ return $ Just 0
+ (ImportSucceeded count:_) -> do
report_info $ "Successfully imported " ++ (show count) ++
" records from " ++ path ++ "."
- return True
+ return $ Just count
+ (ImportUnsupported infomsg:_) -> do
+ -- For now we return "success" for these too, since we know we don't
+ -- support a bunch of DTDs and we want them to get deleted.
+ report_info infomsg
+ return $ Just 0
where
+ -- | This will catch *any* exception, even the ones thrown by
+ -- Haskell's 'error' (which should never occur under normal
+ -- circumstances).
exception_handler :: SomeException -> IO [ImportResult]
exception_handler e = do
report_error (show e)
let errdesc = "Failed to import file " ++ path ++ "."
-- Return a nonempty list so we don't claim incorrectly that
-- we couldn't parse the DTD.
- return [Err errdesc]
+ return [ImportFailed errdesc]
-- | An arrow that reads a document into an 'XmlTree'.
readA :: IOStateArrow s a XmlTree
-- | An arrow which parses the doctype "SYSTEM" of an 'XmlTree'.
-- We use these to determine the parser to use.
- doctypeA :: ArrowXml a => a XmlTree String
- doctypeA = getAttrl >>> hasName "doctype-SYSTEM" /> getText
+ doctypeA :: ArrowXml a => a XmlTree DtdName
+ doctypeA = getAttrl >>> hasName "doctype-SYSTEM" /> getText >>^ DtdName
-- | Combine the arrows above as well as the function below
-- (arrowized with 'arr') into an IO action that does everything
>>=
sequence
- -- | Takes a 'Doctype', 'XmlTree' pair and uses the 'Doctype' to
- -- determine which function to call on the 'XmlTree'.
- import_with_dtd :: (String, XmlTree) -> IO ImportResult
- import_with_dtd (dtd,xml)
+ -- | Takes a ('DtdName', 'XmlTree') pair and uses the 'DtdName'
+ -- to determine which function to call on the 'XmlTree'.
+ import_with_dtd :: (DtdName, XmlTree) -> IO ImportResult
+ import_with_dtd (DtdName dtd,xml)
+ -- We special-case the heartbeat so it doesn't have to run in
+ -- the database monad.
| dtd == "Heartbeat.dtd" = Heartbeat.verify xml
| otherwise =
-- We need NoMonomorphismRestriction here.
| otherwise = \_ -> do -- Dummy arg simplifies the other cases.
let infomsg =
"Unrecognized DTD in " ++ path ++ ": " ++ dtd ++ "."
- return $ Info infomsg
+ return $ ImportUnsupported infomsg
+-- | Entry point of the program. It twiddles some knobs for
+-- configuration options and then calls 'import_file' on each XML file
+-- given on the command-line.
+--
+-- Any file successfully processed is then removed, and we're done.
+--
main :: IO ()
main = do
rc_cfg <- OC.from_rc
-- Zip the results with the files list to find out which ones can be
-- deleted.
let result_pairs = zip (OC.xml_files opt_config) results
- let victims = filter (\(_,result) -> result) result_pairs
+ let victims = [ (p,c) | (p, Just c) <- result_pairs ]
+ let imported_count = sum $ map snd victims
+ report_info $ "Imported " ++ (show imported_count) ++ " records total."
mapM_ ((kill True) . fst) victims
where
+ -- | Wrap these two actions into one function so that we don't
+ -- report that the file was removed if the exception handler is
+ -- run.
+ remove_and_report path = do
+ removeFile path
+ report_info $ "Removed processed file " ++ path ++ "."
+
+ -- | Try to remove @path@ and potentially try again.
kill try_again path = do
- removeFile path `catchIOError` exception_handler
- report_info $ "Removed imported file " ++ path ++ "."
+ (remove_and_report path) `catchIOError` exception_handler
where
-- | A wrapper around threadDelay which takes seconds instead of
-- microseconds as its argument.
let microseconds = seconds * (10 ^ (6 :: Int))
threadDelay microseconds
+ -- | If we can't remove the file, report that, and try once
+ -- more after waiting a few seconds.
exception_handler :: IOError -> IO ()
exception_handler e = do
report_error (show e)
projects / dead / htsn-import.git / commitdiff