+{-# LANGUAGE DoAndIfThenElse #-}
+
module Main
where
import Control.Concurrent ( forkIO, threadDelay )
+import Control.Exception ( throw )
import Control.Monad ( forever, when )
import Data.Aeson ( decode )
-import Data.List ( (\\) )
import Data.Maybe ( fromMaybe, isNothing )
import Data.Monoid ( (<>) )
import Data.Time.LocalTime ( TimeZone, getCurrentTimeZone )
+import System.Console.CmdArgs.Default ( Default(..) )
+import System.Directory ( doesFileExist )
import System.Exit ( ExitCode(..), exitWith )
import System.IO ( hPutStrLn, stderr )
+import System.IO.Error ( catchIOError )
import CommandLine ( get_args, show_help )
-import Configuration ( Cfg(..), default_config, merge_optional )
-import ExitCodes ( exit_no_usernames )
+import Configuration ( Cfg(..), merge_optional )
+import ExitCodes ( exit_no_usernames, exit_pidfile_exists )
import qualified OptionalConfiguration as OC ( from_rc )
import Mail (
Message(..),
- default_headers,
print_sendmail_result,
rfc822_now,
sendmail )
pretty_print,
utc_time_to_rfc822 )
import Twitter.User ( User(..) )
+import Unix ( full_daemonize )
import Usernames ( Usernames(..) )
+
-- | A wrapper around threadDelay which takes seconds instead of
-- microseconds as its argument.
+--
thread_sleep :: Int -> IO ()
thread_sleep seconds = do
let microseconds = seconds * (10 ^ (6 :: Int))
-- | Given a 'Message', 'Status', and date, update that message's body
--- and subject with the information contained in the status. Adds a
--- /Date: / header, and returns the updated message.
+-- and subject with the information contained in the status. Adds a
+-- /Date: / header, and returns the updated message.
+--
message_from_status :: Maybe TimeZone -> Message -> String -> Status -> Message
message_from_status mtz message default_date status =
message { subject = "Halcyon: " ++ (screen_name (user status)),
body = (pretty_print mtz status),
headers = ((headers message) ++ ["Date: " ++ date])}
where
- date =
- case created_at status of
- Nothing -> default_date
- Just c -> utc_time_to_rfc822 mtz c
+ date = maybe
+ default_date -- default
+ (utc_time_to_rfc822 mtz) -- function to apply if not Nothing
+ (created_at status) -- the Maybe thing
--- | If the given Message is not Nothing, send a copy of it for every
--- Status in the list.
+
+-- | If the given 'Message' is not 'Nothing', send a copy of it for
+-- every 'Status' in the @statuses@ list.
+--
send_messages :: Cfg -> Maybe TimeZone -> Maybe Message -> [Status] -> IO ()
send_messages cfg mtz maybe_message statuses =
case maybe_message of
let mfs = message_from_status mtz message default_date
let messages = map mfs statuses
sendmail_results <- mapM sendmail' messages
- _ <- mapM print_sendmail_result sendmail_results
- return ()
+ mapM_ print_sendmail_result sendmail_results
where
sendmail' = sendmail (sendmail_path cfg)
+
-- | Display the number of skipped replies if ignore_replies is true
-- and verbose is enabled.
+--
mention_replies :: Cfg -> [Status] -> IO ()
mention_replies cfg ss = do
let replies = filter reply ss
-- | Display the number of skipped retweets if ignore_retweets is true
-- and verbose is enabled.
+--
mention_retweets :: Cfg -> [Status] -> IO ()
mention_retweets cfg ss = do
let retweets = filter retweeted ss
-- | Filter out replies/retweets based on the configuration.
+--
filter_statuses :: Cfg -> [Status] -> [Status]
-filter_statuses cfg ss =
- good_statuses
+filter_statuses cfg =
+ reply_filter . retweet_filter
where
- replies = filter reply ss
- retweets = filter retweeted ss
-
- good_statuses' = if (ignore_replies cfg)
- then ss \\ replies
- else ss
-
- good_statuses = if (ignore_retweets cfg)
- then good_statuses' \\ retweets
- else good_statuses'
+ reply_filter = if ignore_replies cfg
+ then filter (not . reply)
+ else id
+ retweet_filter = if ignore_retweets cfg
+ then filter (not . retweeted)
+ else id
-- | This is the main recursive loop. It takes a the configuration, a
-- username, a latest_status_id, and optionally a 'Message' as
--- arguments. The latest_status_id is the last status (that we know
+-- arguments. The @latest_status_id@ is the last status (that we know
-- of) to be posted to username's Twitter account. If we find any
-- newer statuses when we check, they are printed and optionally
-- emailed (if a 'Message' was supplied). Then, the process repeats.
+--
recurse :: Cfg -> String -> Integer -> (Maybe Message) -> IO ()
recurse cfg username latest_status_id maybe_message = do
thread_sleep (heartbeat cfg)
-- | Try continually to download username's timeline, and determine the
-- latest status id to be posted once we have done so.
+--
get_latest_status_id :: Cfg -> String -> IO Integer
get_latest_status_id cfg username = do
let delay = heartbeat cfg
-- recursive loop that checks for updates forever. The message
-- argument is optional and is passed to recurse in case the updates
-- should be emailed.
+--
run :: Cfg -> Maybe Message -> String -> IO ()
run cfg msg username = do
latest_status_id <- get_latest_status_id cfg username
recurse cfg username latest_status_id msg
- return ()
-- | Take advantage of the Maybe monad to only return a message when
--- we have both a "to" and "from" address.
+-- we have both a \"to\" and \"from\" address.
+--
construct_message :: Cfg -> Maybe Message
construct_message cfg = do
to_addr <- to_address cfg
from_addr <- from_address cfg
- return $ make_msg to_addr from_addr
- where
- make_msg t f = Message { headers = default_headers,
- body = "",
- subject = "",
- to = t,
- from = f }
-
--- |The main function just parses the command-line arguments and then
--- forks off calls to 'run' for each supplied username. After
--- forking, main loops forever.
+ return $ def { to = to_addr, from = from_addr }
+
+
+-- | The main function just parses the command-line arguments and then
+-- forks off calls to 'run' for each supplied username. After
+-- forking, main loops forever.
+--
main :: IO ()
main = do
-- And a Cfg object.
-- Finally, update a default config with any options that have been
-- set in either the config file or on the command-line.
- let cfg = merge_optional default_config opt_config
+ let cfg = merge_optional (def :: Cfg) opt_config
when (null $ get_usernames (usernames cfg)) $ do
hPutStrLn stderr "ERROR: no usernames supplied."
_ <- show_help
exitWith (ExitFailure exit_no_usernames)
+
+ when (daemonize cfg) $ do
+ -- Old PID files can be left around after an unclean shutdown. We
+ -- only care if we're running as a daemon.
+ pidfile_exists <- doesFileExist (pidfile cfg)
+ when pidfile_exists $ do
+ hPutStrLn stderr $ "ERROR: PID file " ++ (pidfile cfg) ++
+ " already exists. Refusing to start."
+ exitWith (ExitFailure exit_pidfile_exists)
+
+
-- If we have both a "To" and "From" address, we'll create a
-- message object to be passed to all of our threads.
let message = construct_message cfg
-
- -- Execute run on each username in a new thread.
let run_curried = run cfg message
- _ <- mapM (forkIO . run_curried) (get_usernames (usernames cfg))
- _ <- forever $
- -- This thread (the one executing main) doesn't do anything,
- -- but when it terminates, so do all the threads we forked.
- -- As a result, we need to keep this thread on life support.
- thread_sleep (heartbeat cfg)
+ let run_program = (mapM_ -- Execute run on each username in a new thread.
+ (forkIO . run_curried)
+ (get_usernames (usernames cfg)))
+ >>
+ -- This thread (the one executing main) doesn't do
+ -- anything, but when it terminates, so do all the
+ -- threads we forked. As a result, we need to
+ -- keep this thread on life support. If we were
+ -- asked to daemonize, do that; otherwise just run
+ -- the thing.
+ forever (thread_sleep (heartbeat cfg))
+
+ if (daemonize cfg)
+ then try_daemonize cfg run_program
+ else run_program
- return ()
+ where
+ -- | A exception handler around full_daemonize. If full_daemonize
+ -- doesn't work, we report the error and crash. This is fine; we
+ -- only need the program to be resilient once it actually starts.
+ --
+ try_daemonize :: Cfg -> IO () -> IO ()
+ try_daemonize cfg program =
+ catchIOError
+ (full_daemonize cfg program)
+ (\e -> do
+ hPutStrLn stderr ("ERROR: " ++ (show e))
+ throw e)
projects / dead / halcyon.git / blobdiff