import ExitCodes (
exit_no_feed_hosts,
exit_no_password,
- exit_no_username )
+ exit_no_username,
+ exit_pidfile_exists )
import Logging (
init_logging,
log_debug,
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
--
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."
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 </message>
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
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"
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
recv_prompt = recv_chars 10
-connect_and_loop :: Configuration -> String -> IO ()
-connect_and_loop cfg host = do
+-- | 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 ()
--
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 []
-- | The entry point of the program.
+--
main :: IO ()
main = do
rc_cfg <- OC.from_rc
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
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)
projects / dead / htsn.git / blobdiff