module Main
where
-import Control.Concurrent (threadDelay)
-import Control.Exception.Base (bracket)
-import Control.Monad (forever, when)
-import Data.List (isPrefixOf)
-import Data.Maybe (isNothing)
-import Data.Monoid ((<>))
+import Control.Concurrent ( threadDelay )
+import Control.Exception ( bracket, throw )
+import Control.Monad ( when )
+import Data.List ( isPrefixOf )
+import Data.Maybe ( isNothing )
+import Data.Monoid ( (<>) )
import Network (
connectTo,
PortID (PortNumber) )
-import System.Console.CmdArgs (def)
-import System.Directory (doesFileExist)
-import System.Exit (ExitCode(..), exitWith)
-import System.FilePath ((</>))
+import System.Console.CmdArgs ( def )
+import System.Directory ( doesFileExist )
+import System.Exit ( ExitCode(..), exitWith )
+import System.FilePath ( (</>) )
import System.IO (
BufferMode (NoBuffering),
Handle,
hSetBuffering,
stderr,
stdout )
-import System.IO.Error (catchIOError)
+import System.IO.Error ( catchIOError )
+import System.Timeout ( timeout )
-import CommandLine (get_args)
-import Configuration (Configuration(..), merge_optional)
+import CommandLine ( get_args )
+import Configuration ( Configuration(..), merge_optional )
import ExitCodes (
exit_no_feed_hosts,
exit_no_password,
- exit_no_username )
-import FeedHosts (FeedHosts(..))
+ exit_no_username,
+ exit_pidfile_exists )
+import FeedHosts ( FeedHosts(..) )
+import Network.Services.TSN.Logging ( init_logging )
import qualified OptionalConfiguration as OC (
OptionalConfiguration(..),
from_rc )
-import Terminal (hPutRedLn, putGreenLn)
-import TSN.Xml (parse_xmlfid, xml_prologue)
-
-
-report_error :: String -> IO ()
-report_error = hPutRedLn stderr
+import Network.Services.TSN.Report (
+ report_debug,
+ report_info,
+ report_warning,
+ report_error )
+import Network.Services.TSN.Terminal ( display_sent )
+import Xml ( parse_xmlfid )
+import Unix ( full_daemonize )
+-- | Receive a single line of text from a Handle, and send it to the
+-- debug log.
+--
recv_line :: Handle -> IO String
recv_line h = do
line <- hGetLine h
- putStrLn line
+ report_debug (line ++ "\n")
return line
+-- | Takes a Configuration, and an XML document (as a String). The XML
+-- document is written to the output directory, as specified by the
+-- Configuration.
+--
+-- This can fail, but we don't purposefully throw any exceptions. If
+-- something goes wrong, we would rather log it and keep going.
+--
save_document :: Configuration -> String -> IO ()
-save_document cfg doc = do
- case maybe_path of
- Nothing ->
- report_error "ERROR: document missing XML_File_ID element."
- Just path -> do
+save_document cfg doc =
+ case either_path of
+ Left err -> report_error err
+ Right path -> do
already_exists <- doesFileExist path
when already_exists $ do
- let msg = "WARNING: file " ++ path ++ " already exists. Overwriting."
- report_error msg
+ let msg = "File " ++ path ++ " already exists, overwriting."
+ report_warning msg
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 new XML
--- prologue is seen.
+
+-- | Loop forever, writing the buffer to file whenever a </message>
+-- tag is seen. This is the low-level "loop forever" function that
+-- we stay in as long as we are connected to one feed.
+--
+-- The documentation at
+-- <http://www.sportsnetworkdata.com/feeds/xml-levels.asp> states
+-- that \<message\> will always be the root element of the XML
+-- documents, and \</message\> will be the final line transmitted
+-- for a given document. We therefore rely on this to simplify
+-- processing.
+--
loop :: Configuration -> Handle -> [String] -> IO ()
loop !cfg !h !buffer = do
line <- recv_line h
+ let new_buffer = line : buffer
- if (xml_prologue `isPrefixOf` line && not (null buffer))
+ -- Use isPrefixOf to avoid line-ending issues. Hopefully they won't
+ -- send invalid junk (on the same line) after closing the root
+ -- element.
+ if "</message>" `isPrefixOf` line
then do
- -- This is the beginning of a new document, and we have an "old"
- -- one to save. The buffer is in reverse (newest first) order,
- -- though, so we have to reverse it first. We then concatenate all
- -- of its lines into one big string.
- let document = concat $ reverse buffer
+ -- The buffer is in reverse (newest first) order, though, so we
+ -- have to reverse it first. We then concatenate all of its lines
+ -- into one big string.
+ let document = concat $ reverse new_buffer
save_document cfg document
- loop cfg h [line] -- empty the buffer before looping again
+ loop cfg h [] -- Empty the buffer before looping again.
else
- loop cfg h (line : buffer) -- append line to the head of the buffer and loop
+ -- Append line to the head of the buffer and loop.
+ 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 "ERROR: didn't receive username prompt."
+ 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 "ERROR: didn't receive password prompt."
+ 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
- hPutStr h' (s ++ "\r\n")
- putGreenLn s
+ 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 -- Don't log the username/password!
recv_chars :: Int -> Handle -> IO String
recv_chars n h' = do
s <- sequence [ hGetChar h' | _ <- [1..n] ]
- putStr s
+ report_debug s
return s
recv_prompt :: Handle -> IO String
recv_prompt = recv_chars 10
-connect_and_loop :: Configuration -> IO ()
-connect_and_loop cfg =
+
+-- | 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
- --acquire_handle = connectTo "feed1.sportsnetwork.com" (PortNumber 4500)
- acquire_handle = connectTo "feed2.sportsnetwork.com" (PortNumber 4500)
- --acquire_handle = connectTo "127.0.0.1" (PortNumber 13337)
+ five_seconds :: Int
+ five_seconds = 5000000
+
+ acquire_handle = connectTo host (PortNumber 4500)
release_handle = hClose
action h = do
-- No buffering anywhere.
hSetBuffering h NoBuffering
- log_in cfg h
- loop cfg h []
+
+ -- The feed is often unresponsive after we send out username. It
+ -- happens in a telnet session, too (albeit less frequently?),
+ -- so there might be a bug on their end.
+ --
+ -- If we dump the packets with tcpdump, it looks like their
+ -- software is getting confused: they send us some XML in
+ -- the middle of the log-in procedure.
+ --
+ -- On the other hand, the documentation at
+ -- <http://www.sportsnetworkdata.com/feeds/xml-levels.asp>
+ -- states that you can only make one connection per username to
+ -- a given host. So maybe they're simply rejecting the username
+ -- in an unfriendly fashion. In any case, the easiest fix is to
+ -- disconnect and try again.
+ --
+ login_worked <- timeout five_seconds $ log_in cfg h
+ case login_worked of
+ Nothing -> report_info $ "Login timed out (5 seconds). "
+ ++ "Waiting 5 seconds to reconnect."
+ Just _ -> loop cfg h []
-- | 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))
threadDelay microseconds
+-- | The entry point of the program.
+--
main :: IO ()
main = do
rc_cfg <- OC.from_rc
-- prefering the command-line ones.
let opt_config = rc_cfg <> cmd_cfg
+ -- Update a default config with any options that have been set in
+ -- either the config file or on the command-line. We initialize
+ -- logging before the missing parameter checks below so that we can
+ -- log the errors.
+ let cfg = (def :: Configuration) `merge_optional` opt_config
+ init_logging (log_level cfg) (log_file cfg) (syslog cfg)
+
+ -- Check the optional config for missing required options. This is
+ -- necessary because if the user specifies an empty list of
+ -- hostnames in e.g. the config file, we want to bail rather than
+ -- fall back on the default list (which was merged from a default
+ -- Configuration above).
when (null $ get_feed_hosts (OC.feed_hosts opt_config)) $ do
- report_error "ERROR: no feed hosts supplied."
+ report_error "No feed hosts supplied."
exitWith (ExitFailure exit_no_feed_hosts)
when (isNothing (OC.password opt_config)) $ do
- report_error "ERROR: no password supplied."
+ report_error "No password supplied."
exitWith (ExitFailure exit_no_password)
when (isNothing (OC.username opt_config)) $ do
- report_error "ERROR: no username supplied."
+ report_error "No username supplied."
exitWith (ExitFailure exit_no_username)
- -- Finally, update a default config with any options that have been
- -- set in either the config file or on the command-line.
- let cfg = (def :: Configuration) `merge_optional` opt_config
+ 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
- forever $ do
- catchIOError (connect_and_loop cfg) (report_error . show)
- thread_sleep 10 -- Wait 10s before attempting to reconnect.
+ -- 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 try_daemonize cfg run_program
+ else run_program
+
+ where
+ -- | This is the top-level "loop forever" function. If an
+ -- exception is thrown, it will propagate up to this point, where
+ -- it will be logged and ignored in style.
+ --
+ -- Afterwards, we recurse (call ourself) again to loop more forevers.
+ --
+ round_robin :: Configuration -> Int -> IO ()
+ round_robin cfg feed_host_idx = do
+ let hosts = get_feed_hosts $ feed_hosts cfg
+ let host = hosts !! feed_host_idx
+ 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)
+
+
+ -- | 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 :: Configuration -> IO () -> IO ()
+ try_daemonize cfg program =
+ catchIOError
+ (full_daemonize cfg program)
+ (\e -> do
+ report_error (show e)
+ throw e)
projects / dead / htsn.git / blobdiff