Fix a few hlint suggestions.

[dead/halcyon.git] / src / Mail.hs

diff --git a/src/Mail.hs b/src/Mail.hs
index ba605f977673ae3a76694888131767bfd383e255..8c1f25c89874eae68547f8323387b6116223419e 100644 (file)
--- a/src/Mail.hs
+++ b/src/Mail.hs
@@ -4,16 +4,18 @@ module Mail
 where
 
 import Control.Concurrent
-import Control.Concurrent.MVar
 import Control.Exception (evaluate)
 import Data.List (intercalate)
+import Data.Time (formatTime, getZonedTime)
 import System.Exit
+import System.Locale (defaultTimeLocale, rfc822DateFormat)
 import System.Process
-import System.IO
+import System.IO (hClose, hGetContents, hPutStr)
+
 
 type Header = String
 
--- |A crude model of an RFC821 email message.
+-- | A crude model of an RFC821 email message.
 data Message = Message { headers :: [Header],
                          subject :: String,
                          body    :: String,
@@ -21,28 +23,61 @@ data Message = Message { headers :: [Header],
                          to      :: String }
              deriving (Eq)
 
--- |Showing a message will print it in roughly RFC-compliant
--- form. This form is sufficient for handing the message off to
--- sendmail.
-instance Show Message where    
-    show m =
-        concat [ if (length (headers m) == 0) then "" else (intercalate "\n" (headers m)) ++ "\n",
-                 "Subject: " ++ (subject m) ++ "\n",
-                 "From: " ++ (from m) ++ "\n",
-                 "To: " ++ (to m) ++ "\n",
-                 "\n",
-                 (body m) ]
+-- | The default headers attached to each message.  The MIME junk is
+--   needed for UTF-8 to work properly. Note that your mail server
+--   should support the 8BITMIME extension.
+default_headers :: [Header]
+default_headers = ["MIME-Version: 1.0",
+                   "Content-Type: text/plain; charset=UTF-8",
+                   "Content-Transfer-Encoding: 8bit"]
+
+-- | Showing a message will print it in roughly RFC-compliant
+--   form. This form is sufficient for handing the message off to
+--   sendmail (or compatible).
+instance Show Message where
+  show m =
+    concat [ formatted_headers,
+             "Subject: " ++ (subject m) ++ "\n",
+             "From: " ++ (from m) ++ "\n",
+             "To: " ++ (to m) ++ "\n",
+             "\n",
+             (body m) ]
+    where
+      formatted_headers =
+        if null (headers m)
+        then ""
+        else (intercalate "\n" (headers m)) ++ "\n"
+
+
+-- |Pad a string on the left with zeros until the entire string has
+-- length n.
+pad_left :: String -> Int -> String
+pad_left str n
+ | n < (length str) = str
+ | otherwise = (replicate num_zeros '0') ++ str
+   where num_zeros = n - (length str)
+
+
+
+-- | Constructs a 'String' in RFC822 date format for the current
+--   date/time.
+rfc822_now :: IO String
+rfc822_now = do
+  date <- getZonedTime
+  return $ formatTime defaultTimeLocale rfc822DateFormat date
+
 
 
 -- |Takes a message as an argument, and passes it to the system's
--- sendmail binary.
-sendmail :: Message -> IO (String, String, ExitCode)
-sendmail message = do
+-- sendmail (or compatible) binary.
+sendmail :: FilePath -> Message -> IO (String, String, ExitCode)
+sendmail sendmail_path message = do
   let sendmail_args = ["-f",
-                       (from message)]
+                       (from message),
+                       (to message)]
 
   (inh, outh, errh, ph) <-
-      runInteractiveProcess "/usr/bin/sendmail" sendmail_args Nothing Nothing
+      runInteractiveProcess sendmail_path sendmail_args Nothing Nothing
 
   outm <- newEmptyMVar
   outs <- hGetContents outh
@@ -50,9 +85,9 @@ sendmail message = do
   errm <- newEmptyMVar
   errs <- hGetContents errh
 
-  forkIO $ hPutStr inh (show message) >> hClose inh
-  forkIO $ evaluate (length outs) >> putMVar outm ()
-  forkIO $ evaluate (length errs) >> putMVar errm ()
+  _ <- forkIO $ hPutStr inh (show message) >> hClose inh
+  _ <- forkIO $ evaluate (length outs) >> putMVar outm ()
+  _ <- forkIO $ evaluate (length errs) >> putMVar errm ()
 
   readMVar outm
   readMVar errm
@@ -66,8 +101,8 @@ sendmail message = do
 -- three-tuples.
 print_sendmail_result :: (String, String, ExitCode) -> IO ()
 print_sendmail_result (outs, errs, ec) = do
-    case ec of
-      ExitSuccess -> return ()
-      _ -> putStrLn $ concat ["Output: " ++ outs,
-                              "\nErrors: " ++ errs,
-                              "\nExit Code: " ++ (show ec)]
+  case ec of
+    ExitSuccess -> return ()
+    _ -> putStrLn $ concat ["Output: " ++ outs,
+                            "\nErrors: " ++ errs,
+                            "\nExit Code: " ++ (show ec)]