X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FMain.hs;h=2b0b5b920db4acefd161c2c069ec127695f6483d;hb=fdd40277556133bd14cf0a3f13749f4663b5f3ba;hp=0182e38196db034cb52b070e61ac8042c2d2e210;hpb=8c69c28e5ab5ef5a5ed64411e1213e504a6a309e;p=dead%2Fhtsn.git diff --git a/src/Main.hs b/src/Main.hs index 0182e38..2b0b5b9 100644 --- a/src/Main.hs +++ b/src/Main.hs @@ -35,7 +35,8 @@ import Configuration ( Configuration(..), merge_optional ) import ExitCodes ( exit_no_feed_hosts, exit_no_password, - exit_no_username ) + exit_no_username, + exit_pidfile_exists ) import Logging ( init_logging, log_debug, @@ -53,31 +54,39 @@ import Terminal ( display_warning ) import TSN.FeedHosts ( FeedHosts(..) ) import TSN.Xml ( parse_xmlfid ) +import Unix ( full_daemonize ) - --- | Warning! This does not automatically append a newline. The output --- is displayed/logged as-is, for, you know, debug purposes. +-- | Display and log debug information. WARNING! This does not +-- automatically append a newline. The output is displayed/logged +-- as-is, for, you know, debug purposes. report_debug :: String -> IO () report_debug s = do display_debug s log_debug s + +-- | Display and log an error condition. This will prefix the error +-- with "ERROR: " when displaying (but not logging) it so that it +-- stands out. +-- report_error :: String -> IO () report_error s = do display_error $ "ERROR: " ++ s log_error s + +-- | Display and log an informational (status) message. +-- report_info :: String -> IO () report_info s = do display_info s log_info s --- | Warning! This does not automatically append a newline. -report_sent :: String -> IO () -report_sent s = do - display_sent s - log_debug s +-- | Display and log a warning. This will prefix the warning with +-- "WARNING: " when displaying (but not logging) it so that it +-- stands out. +-- report_warning :: String -> IO () report_warning s = do display_warning $ "WARNING: " ++ s @@ -103,10 +112,9 @@ recv_line h = do -- save_document :: Configuration -> String -> IO () save_document cfg doc = - case maybe_path of - Nothing -> - report_error "Document missing XML_File_ID element." - Just path -> do + case either_path of + Left err -> report_error err + Right path -> do already_exists <- doesFileExist path when already_exists $ do let msg = "File " ++ path ++ " already exists, overwriting." @@ -114,9 +122,10 @@ save_document cfg doc = writeFile path doc report_info $ "Wrote file: " ++ path ++ "." where + -- All the fmaps are because we're working inside a Maybe. xmlfid = fmap show (parse_xmlfid doc) filename = fmap (++ ".xml") xmlfid - maybe_path = fmap ((output_directory cfg) ) filename + either_path = fmap ((output_directory cfg) ) filename -- | Loop forever, writing the buffer to file whenever a @@ -151,6 +160,29 @@ loop !cfg !h !buffer = do loop cfg h new_buffer +-- | Once we're connected to a feed, we need to log in. There's no +-- protocol for this (the docs don't mention one), but we have +-- (apparently) successfully guessed it. +-- +-- The first thing TSN sends once we've connected is the string +-- "Username: ", containing 10 ASCII characters. We then send a +-- username, followed by a newline. If TSN likes the username, the +-- second they'll send is the string "Password: ", also containing +-- 10 ASCII characters, to which we reply in kind. +-- +-- Assuming the above will always hold, it is implemented as follows: +-- +-- 1. Receive 10 chars +-- +-- 2. Send username if we got the username prompt +-- +-- 3. Receive 10 chars +-- +-- 4. Send password if we got the password prompt +-- +-- If TSN likes the password as well, they send the string "The +-- Sports Network" before finally beginning to stream the feed. +-- log_in :: Configuration -> Handle -> IO () log_in cfg h = do prompt1 <- recv_prompt h @@ -158,24 +190,26 @@ log_in cfg h = do if prompt1 /= username_prompt then report_error "Didn't receive username prompt." else do - send_line h (username cfg) + send_cred h (username cfg) prompt2 <- recv_prompt h if prompt2 /= password_prompt then report_error "Didn't receive password prompt." else do - send_line h (password cfg) + send_cred h (password cfg) _ <- recv_line h -- "The Sports Network" + report_info $ "Logged in as " ++ (username cfg) ++ "." return () where username_prompt = "Username: " password_prompt = "Password: " - send_line :: Handle -> String -> IO () - send_line h' s = do + send_cred :: Handle -> String -> IO () + send_cred h' s = do + -- The carriage return is super important! let line = s ++ "\r\n" hPutStr h' line - display_sent line + display_sent line -- Don't log the username/password! recv_chars :: Int -> Handle -> IO String recv_chars n h' = do @@ -187,9 +221,23 @@ log_in cfg h = do recv_prompt = recv_chars 10 -connect_and_loop :: Configuration -> String -> IO () -connect_and_loop cfg host = do - report_info $ "Connecting to " ++ host ++ "..." +-- | Connect to @host@ and attempt to parse the feed. As long as we +-- stay connected and nothing bad happens, the program will remain in +-- this function. If anything goes wrong, then the current invocation +-- of connect_and_parse will return, and get called again later +-- (probably with a different @host@). +-- +-- Steps: +-- +-- 1. Connect to the host on the XML port +-- +-- 2. Log in +-- +-- 3. Go into the eternal read/save loop. +-- +connect_and_parse :: Configuration -> String -> IO () +connect_and_parse cfg host = do + report_info $ "Connecting to " ++ host ++ "." bracket acquire_handle release_handle action return () where @@ -219,7 +267,8 @@ connect_and_loop cfg host = do -- login_worked <- timeout five_seconds $ log_in cfg h case login_worked of - Nothing -> report_info "Login timed out (5s)." + Nothing -> report_info $ "Login timed out (5 seconds). " + ++ "Waiting 5 seconds to reconnect." Just _ -> loop cfg h [] @@ -233,6 +282,7 @@ thread_sleep seconds = do -- | The entry point of the program. +-- main :: IO () main = do rc_cfg <- OC.from_rc @@ -266,13 +316,29 @@ main = do report_error "No username supplied." exitWith (ExitFailure exit_no_username) + 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 + report_error $ "PID file " ++ (pidfile cfg) ++ " already exists. " + ++ "Refusing to start." + exitWith (ExitFailure exit_pidfile_exists) + -- This may be superstition (and I believe stderr is unbuffered), -- but it can't hurt. hSetBuffering stderr NoBuffering hSetBuffering stdout NoBuffering - -- Begin connecting to our feed hosts, starting with the first one. - round_robin cfg 0 + -- The rest of the program is kicked off by the following line which + -- begins connecting to our feed hosts, starting with the first one, + -- and proceeds in a round-robin fashion. + let run_program = round_robin cfg 0 + + -- If we were asked to daemonize, do that; otherwise just run the thing. + if (daemonize cfg) + then full_daemonize cfg run_program + else run_program where -- | This is the top-level "loop forever" function. If an @@ -285,6 +351,6 @@ main = do round_robin cfg feed_host_idx = do let hosts = get_feed_hosts $ feed_hosts cfg let host = hosts !! feed_host_idx - catchIOError (connect_and_loop cfg host) (report_error . show) + catchIOError (connect_and_parse cfg host) (report_error . show) thread_sleep 5 -- Wait 5s before attempting to reconnect. round_robin cfg $ (feed_host_idx + 1) `mod` (length hosts)