X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FMain.hs;h=de0e28e53ea9dfa48fa4d8cb202216b1e9b67788;hb=c4698230179be17f66dc17339cef379733b89fd1;hp=38dd2e5ad5e8af5c4336c667507a6a87b74c0ccd;hpb=bb74b494c23a737b9c0355148d25f090545b856b;p=dead%2Fhtsn.git diff --git a/src/Main.hs b/src/Main.hs index 38dd2e5..de0e28e 100644 --- a/src/Main.hs +++ b/src/Main.hs @@ -4,6 +4,8 @@ module Main where +-- System imports. +import Control.Applicative ( (<$>) ) import Control.Concurrent ( threadDelay ) import Control.Exception ( bracket, throw ) import Control.Monad ( when ) @@ -13,6 +15,13 @@ import Data.Monoid ( (<>) ) import Network ( connectTo, PortID (PortNumber) ) +import Network.Services.TSN.Logging ( init_logging ) +import Network.Services.TSN.Report ( + report_debug, + report_info, + report_warning, + report_error ) +import Network.Services.TSN.Terminal ( display_sent ) import System.Console.CmdArgs ( def ) import System.Directory ( doesFileExist ) import System.Exit ( ExitCode(..), exitWith ) @@ -30,6 +39,7 @@ import System.IO ( import System.IO.Error ( catchIOError ) import System.Timeout ( timeout ) +-- Local imports. import CommandLine ( get_args ) import Configuration ( Configuration(..), merge_optional ) import ExitCodes ( @@ -38,22 +48,15 @@ import ExitCodes ( 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 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. +-- | Receive a single line of text from a 'Handle', and record it for +-- debugging purposes. -- recv_line :: Handle -> IO String recv_line h = do @@ -62,17 +65,24 @@ recv_line h = do 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. +-- | 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 () +-- And in fact the only \"error\" that can occur is from +-- 'parse_xmlfid' if TSN sends us a non-integer XML File ID. But +-- this is expected from time to time, and is merely unsupported. So +-- we report any failures as info instead of as errors. +-- +save_document :: Configuration + -> String -- ^ String representation of an XML document + -> IO () save_document cfg doc = case either_path of - Left err -> report_error err + Left err -> report_info err -- Can only be non-integer XML File ID Right path -> do already_exists <- doesFileExist path when already_exists $ do @@ -81,15 +91,15 @@ 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 - either_path = fmap ((output_directory cfg) ) filename + -- All the <$> are because we're working inside an Either. + xmlfid = show <$> (parse_xmlfid doc) + filename = (++ ".xml") <$> xmlfid + either_path = ((output_directory cfg) ) <$> filename --- | Loop forever, writing the buffer to file whenever a --- tag is seen. This is the low-level "loop forever" function that --- we stay in as long as we are connected to one feed. +-- | Loop forever, writing the @buffer@ to file whenever a +-- \ 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 -- states @@ -98,25 +108,49 @@ save_document cfg doc = -- for a given document. We therefore rely on this to simplify -- processing. -- -loop :: Configuration -> Handle -> [String] -> IO () +-- The bang pattern at least on @buffer@ is necessary for +-- performance reasons. +-- +-- We specify a timeout of fifteen minutes on the 'recv_line' +-- function, after which we will return to our caller. This should +-- cause the connection to be dropped, and a new one initiated. The +-- timeout is in response to observed behavior where the feed +-- eventually stops transmitting data entirely without closing the +-- connection. +-- +loop :: Configuration + -> Handle -- ^ Handle to the feed (network connection) + -> [String] -- ^ Current XML document buffer, line-by-line, in reverse + -> IO () loop !cfg !h !buffer = do - line <- recv_line h - let new_buffer = line : 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 "" `isPrefixOf` line - then do - -- 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 [] -- Empty the buffer before looping again. - else - -- Append line to the head of the buffer and loop. - loop cfg h new_buffer + line' <- timeout fifteen_minutes $ recv_line h + case line' of + -- If we haven't received anything in fifteen minutes, return back + -- to the calling function. This should only happen in the case of + -- an error, and our caller should be prepared to handle it. + Nothing -> report_warning "No data received for 15 minutes." + + Just line -> do + -- If the recv didn't timeout, proceed normally. + let new_buffer = line : 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 "" `isPrefixOf` line + then do + -- 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 [] -- Empty the buffer before looping again. + else + -- Append line to the head of the buffer and loop. + loop cfg h new_buffer + where + fifteen_minutes :: Int + fifteen_minutes = 15 * 60 * 1000000 -- | Once we're connected to a feed, we need to log in. There's no @@ -124,9 +158,9 @@ loop !cfg !h !buffer = do -- (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: \", 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 +-- 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: @@ -139,8 +173,8 @@ loop !cfg !h !buffer = do -- -- 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. +-- 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 @@ -188,23 +222,29 @@ log_in cfg h = do -- -- Steps: -- --- 1. Connect to the host on the XML port +-- 1. Connect to @host@ on the XML feed port. -- --- 2. Log in +-- 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 ++ "." +connect_and_parse :: Configuration + -> String -- ^ Hostname to connect to + -> IO () +connect_and_parse cfg host = bracket acquire_handle release_handle action - return () where five_seconds :: Int - five_seconds = 5000000 + five_seconds = 5 * 1000000 + + acquire_handle = do + report_info $ "Connecting to " ++ host ++ "." + connectTo host (PortNumber 4500) + + release_handle h = do + report_info $ "Closing connection to " ++ host ++ "." + hClose h - acquire_handle = connectTo host (PortNumber 4500) - release_handle = hClose action h = do -- No buffering anywhere. hSetBuffering h NoBuffering @@ -228,13 +268,18 @@ connect_and_parse cfg host = do case login_worked of Nothing -> report_info $ "Login timed out (5 seconds). " ++ "Waiting 5 seconds to reconnect." + + -- If loop returns (due to its timeout), it will pop out right + -- here and the action will terminate causing 'release_handle' + -- to trigger. Just _ -> loop cfg h [] -- | A wrapper around threadDelay which takes seconds instead of -- microseconds as its argument. -- -thread_sleep :: Int -> IO () +thread_sleep :: Int -- ^ Number of seconds for which to sleep. + -> IO () thread_sleep seconds = do let microseconds = seconds * (10 ^ (6 :: Int)) threadDelay microseconds @@ -258,15 +303,7 @@ main = do 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 "No feed hosts supplied." - exitWith (ExitFailure exit_no_feed_hosts) - + -- Check the optional config for missing required options. when (isNothing (OC.password opt_config)) $ do report_error "No password supplied." exitWith (ExitFailure exit_no_password) @@ -275,6 +312,18 @@ main = do report_error "No username supplied." exitWith (ExitFailure exit_no_username) + -- This should be impossible. We had a choice to make: since the + -- command-line feed_hosts are usually not supplied, we don't want + -- to take the empty list supplied on the command-line and use + -- that. But that means that we need to do the same thing if the + -- user supplies an empty list in the config file. That "same thing" + -- is to use the default list. So, this should never be empty, + -- because if the optional config has no feed hosts, we use the + -- default list. + when (null $ get_feed_hosts (feed_hosts cfg)) $ do + report_error "No feed hosts supplied." + exitWith (ExitFailure exit_no_feed_hosts) + 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. @@ -300,7 +349,7 @@ main = do else run_program where - -- | This is the top-level "loop forever" function. If an + -- | 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. --