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, in seconds.
-heartbeat :: Int
-heartbeat = 600
-
+-- |A wrapper around threadDelay which takes seconds instead of
+-- microseconds as its argument.
thread_sleep :: Int -> IO ()
-thread_sleep microseconds = do
- let seconds = microseconds * (10 ^ (6 :: Int))
- threadDelay seconds
-
-
-message_from_status :: Message -> Status -> Message
-message_from_status message status =
- message { subject = "Twat: " ++ (screen_name (user status)),
- body = (pretty_print status) }
-
-recurse :: String -> Integer -> (Maybe Message) -> IO ()
-recurse username latest_status_id maybe_message = do
- thread_sleep heartbeat
+thread_sleep seconds = do
+ let microseconds = seconds * (10 ^ (6 :: Int))
+ threadDelay microseconds
+
+
+-- |Given a 'Message', 'Status', and default date, update that
+-- message's body and subject with the information contained in the
+-- status. Adds a /Date: / header, and returns the updated message.
+message_from_status :: Message -> String -> Status -> Message
+message_from_status message default_date status =
+ message { subject = "Twat: " ++ (screen_name (user status)),
+ body = (pretty_print status),
+ headers = ((headers message) ++ ["Date: " ++ date])}
+ where
+ -- Use the Status' created_at date if it can be coerced into
+ -- RFC822 format.
+ date = case (created_at_to_rfc822 $ created_at status) of
+ Nothing -> default_date
+ Just c -> c
+
+-- |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
+ _ <- 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
- let messages = map (message_from_status message) new_statuses
+ default_date <- rfc822_now
+ let messages = map (message_from_status message (default_date)) new_statuses
sendmail_results <- mapM sendmail messages
- mapM print_sendmail_result sendmail_results
- recurse username new_latest_status_id maybe_message
+ _ <- mapM print_sendmail_result sendmail_results
+ recurse delay username new_latest_status_id maybe_message
return ()
-get_latest_status_id :: String -> IO Integer
-get_latest_status_id username = do
+-- |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 :: 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)
-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
+-- |This function wraps two steps. First, we need to find the latest
+-- status id posted by username. Once we have that, we can begin the
+-- 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 :: 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 ()
+-- |The main function just parses the command-line arguments and then
+-- forks off calls to 'run_twat' for each supplied username. After
+-- forking, main loops forever.
main :: IO ()
main = do
errors <- parse_errors
case from_address of
Nothing -> Nothing
Just fromaddr ->
- Just (Message { headers = [],
+ Just (Message { headers = default_headers,
body = "",
subject = "",
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
+ _ <- 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 ()
+
+
+-- |A debugging tool that will parse, print, and email a single status
+-- (given by its id).
+twat_single_status :: Integer -> (Maybe Message) -> IO ()
+twat_single_status the_status_id maybe_message = do
+ xmldata <- get_status the_status_id
+
+ -- Parsing an empty result can blow up. Just pretend there are
+ -- no new statuses in that case.
+ let statuses = case xmldata of
+ Just xml -> parse_status xml
+ Nothing -> []
+
+ case (length statuses) of
+ 0 -> do
+ putStrLn "No statuses returned."
+ return ()
+ _ -> do
+ _ <- mapM (putStrLn . pretty_print) statuses
+
+ case maybe_message of
+ Nothing -> do
+ putStrLn "No message object given."
+ return ()
+ Just message -> do
+ default_date <- rfc822_now
+ let messages = map (message_from_status message (default_date)) statuses
+ sendmail_results <- mapM sendmail messages
+ _ <- mapM print_sendmail_result sendmail_results
+ return ()
projects / dead / halcyon.git / blobdiff