Make all connection string parameters optional.

[mailbox-count.git] / src / Main.hs

diff --git a/src/Main.hs b/src/Main.hs
index d6f7c8fdbf0d3656a49d09c59abc7c2886d0289f..633e969fcef69849fd07ed602990e52a0f49d80f 100644 (file)
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -1,6 +1,73 @@
 module Main
 where
 
+import Data.Maybe ( fromMaybe )
+import Data.Monoid ( (<>) )
+import Data.String.Utils ( join )
+import Database.HDBC.PostgreSQL ( connectPostgreSQL )
+import System.Console.CmdArgs ( def )
+
+import CommandLine ( get_args )
+import Configuration ( Configuration(..), merge_optional )
+import qualified OptionalConfiguration as OC ( from_rc )
+import Report ( report )
+
+-- | Construct a connection string (postgres-only, for now) from a
+--   'Configuration'. All of these are optional, at least for
+--   Postgres, and so we want to avoid appending e.g. \"host=\" to the
+--   connection string if @(host cfg)@ is 'Nothing'.
+--
+--   Examples:
+--
+--   >>> let default_cfg = def :: Configuration
+--   >>> let cfg = default_cfg { host = Just "localhost" }
+--   >>> connection_string cfg
+--   "host=localhost"
+--   >>> let cfg2 = cfg { username = Just "postgres" }
+--   >>> connection_string cfg2
+--   "host=localhost user=postgres"
+--
+connection_string :: Configuration -> String
+connection_string cfg =
+  trim $ join " " [host_part, port_part, user_part, pw_part, db_part]
+  where
+    -- | Strip leading/trailing whitespace, and collapse multiple
+    --   consecutive spaces into one.
+    trim :: String -> String
+    trim = unwords . words
+
+    host_part = let h = fmap ("host=" ++) (host cfg) in  fromMaybe "" h
+    port_part = let p = fmap (("port=" ++) . show) (port cfg) in fromMaybe "" p
+    user_part = let u = fmap ("user=" ++) (username cfg) in fromMaybe "" u
+    pw_part = let pw = fmap ("password=" ++) (password cfg) in fromMaybe "" pw
+    db_part = let db = fmap ("dbname=" ++) (database cfg) in fromMaybe "" db
+
+
 main :: IO ()
 main = do
-  putStrLn "Hello, world!"
+  rc_cfg <- OC.from_rc
+  cmd_cfg <- get_args
+
+    -- Merge the config file options with the command-line ones,
+  -- 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
+
+  -- 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)
+
+  --when (isNothing (OC.username opt_config)) $ do
+  --  report_error "No username supplied."
+  --exitWith (ExitFailure exit_no_username)
+
+  conn <- connectPostgreSQL (connection_string cfg)
+  r <- report conn (both cfg) (detail cfg)
+  putStrLn r
+--  disconnect conn