-- It should more or less be a black box, providing Main with only the
-- information it requires.
module CommandLine
-( help_set,
+( heartbeat,
+ help_set,
help_text,
from_email_address,
to_email_address,
-- |A record containing values for all available options.
-data Options = Options { opt_help :: Bool,
+data Options = Options { opt_heartbeat :: Maybe Int,
+ opt_help :: Bool,
opt_from :: Maybe String,
opt_to :: Maybe String }
-- |Constructs an instance of Options, with each of its members set to
-- default values.
default_options :: Options
-default_options = Options { opt_help = False,
+default_options = Options { opt_heartbeat = Just 600,
+ opt_help = False,
opt_from = Nothing,
opt_to = Nothing }
options :: [OptDescr (Options -> IO Options)]
options =
[ Option ['h'][] (NoArg set_help) "Prints this help message.",
+ Option ['n'][] (ReqArg set_heartbeat "heartbeat") "How many seconds to wait between polling.",
Option ['t'][] (ReqArg set_to "email_address") "Send tweets TO email_address.",
Option ['f'][] (ReqArg set_from "email_address") "Send tweets FROM email_address."
]
+-- | Attempt to parse an 'Int' from a 'String'. This is just a 'Maybe'
+-- wrapper around 'reads'.
+parse_int :: String -> Maybe Int
+parse_int s =
+ case (reads s) of
+ [(n,_)] -> Just n
+ _ -> Nothing
+
+set_heartbeat :: String -> Options -> IO Options
+set_heartbeat arg opts = do
+ let new_heartbeat = parse_int arg
+ return opts { opt_heartbeat = new_heartbeat }
+
set_help :: Options -> IO Options
set_help opts = do
return opts { opt_help = True }
-- The usage header.
usage :: String
-usage = "Usage: twat [-t to_address] [-f from_address] <username1> [username2, [username3]...]"
+usage = "Usage: twat [-n heartbeat] [-t to_address] [-f from_address] <username1> [username2, [username3]...]"
-- The usage header, and all available flags (as generated by GetOpt)
return opts
+-- | A list of parse errors relating to the heartbeat.
+heartbeat_errors :: IO [String]
+heartbeat_errors = do
+ hb <- heartbeat
+ if (isNothing hb)
+ then return ["\"heartbeat\" does not appear to be an integer."]
+ else return []
+
-- |Parse errors relating to the list of usernames.
username_errors :: IO [String]
username_errors = do
let (_, usernames, _) = getOpt Permute options argv
if (null usernames)
- then return ["No usernames provided."]
+ then return ["no usernames provided."]
else return []
toaddr <- to_email_address
fromaddr <- from_email_address
if (isNothing toaddr) && (isJust fromaddr)
- then return ["\"From\" address specified without \"To\" address."]
+ then return ["\"from\" address specified without \"to\" address."]
else return []
toaddr <- to_email_address
fromaddr <- from_email_address
if (isJust toaddr) && (isNothing fromaddr)
- then return ["\"To\" address specified without \"From\" address."]
+ then return ["\"to\" address specified without \"from\" address."]
else return []
parse_errors = do
argv <- getArgs
let (_, _, errors) = getOpt Permute options argv
+ errs_heartbeat <- heartbeat_errors
errs_username <- username_errors
errs_to <- to_errors
errs_from <- from_errors
- return $ map format_error (errors ++ errs_username ++ errs_to ++ errs_from)
+ return $ map format_error (errors ++
+ errs_heartbeat ++
+ errs_username ++
+ errs_to ++
+ errs_from)
-- |Was the "help" option passed on the command line?
help_set :: IO Bool
opts <- parse_options
return (opt_help opts)
+-- |What's the heartbeat?
+heartbeat :: IO (Maybe Int)
+heartbeat = do
+ opts <- parse_options
+ return (opt_heartbeat opts)
-- |What "To" address was given on the command line?
to_email_address :: IO (Maybe String)
import Control.Concurrent (forkIO, threadDelay)
import Control.Monad (forever, when)
+import Data.Maybe (fromJust)
import System.Exit (ExitCode(..), exitWith)
import System.IO (hPutStrLn, stderr)
import Twitter.User
--- |The length of all calls to sleep (or threadDelay), in seconds.
-heartbeat :: Int
-heartbeat = 600
-
-- |A wrapper around threadDelay which takes seconds instead of
-- microseconds as its argument.
thread_sleep :: Int -> IO ()
headers = ((headers message) ++ ["Date: " ++ date])}
--- |This is the main recursive loop. It takes a username, a
--- latest_status_id, and optionally a 'Message' as 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 :: String -> Integer -> (Maybe Message) -> IO ()
-recurse username latest_status_id maybe_message = do
- thread_sleep heartbeat
+-- |This is the main recursive loop. It takes a length of time to
+-- delay (in seconds), a username, a latest_status_id, and optionally
+-- a 'Message' as 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 :: Int -> String -> Integer -> (Maybe Message) -> IO ()
+recurse delay username latest_status_id maybe_message = do
+ thread_sleep delay
xmldata <- get_user_new_statuses username latest_status_id
-- Parsing an empty result can blow up. Just pretend there are
case (length new_statuses) of
0 ->
- recurse username latest_status_id maybe_message
+ recurse delay username latest_status_id maybe_message
_ -> do
let new_latest_status_id = get_max_status_id new_statuses
_ <- mapM (putStrLn . pretty_print) new_statuses
case maybe_message of
Nothing -> do
- recurse username new_latest_status_id maybe_message
+ recurse delay username new_latest_status_id maybe_message
return ()
Just message -> do
date_header <- construct_date_header
let messages = map (message_from_status message (date_header)) new_statuses
sendmail_results <- mapM sendmail messages
_ <- mapM print_sendmail_result sendmail_results
- recurse username new_latest_status_id maybe_message
+ recurse delay username new_latest_status_id maybe_message
return ()
-- |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 :: String -> IO Integer
-get_latest_status_id username = do
+get_latest_status_id :: Int -> String -> IO Integer
+get_latest_status_id delay username = do
xmldata <- get_user_timeline username
let initial_statuses = case xmldata of
0 -> do
-- If the HTTP part barfs, try again after a while.
putStrLn ("Couldn't retrieve " ++ username ++ "'s timeline. Retrying...")
- thread_sleep heartbeat
- get_latest_status_id username
+ thread_sleep delay
+ get_latest_status_id delay username
_ -> return (get_max_status_id initial_statuses)
-- 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_twat :: Maybe Message -> String -> IO ()
-run_twat message username = do
- latest_status_id <- get_latest_status_id username
- recurse username latest_status_id message
+run_twat :: Int -> Maybe Message -> String -> IO ()
+run_twat delay message username = do
+ latest_status_id <- get_latest_status_id delay username
+ recurse delay username latest_status_id message
return ()
to = toaddr,
from = fromaddr })
+ -- This should be safe since we checked for parse errors earlier.
+ delay <- fmap fromJust heartbeat
+
-- Execute run_twat on each username in a new thread.
- _ <- mapM (forkIO . (run_twat message)) usernames
+ _ <- mapM (forkIO . (run_twat delay message)) usernames
_ <- forever $ do
-- 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
+ thread_sleep delay
return ()
projects / dead / halcyon.git / commitdiff