Bump version

lib/Database/PostgreSQL/Opium.hs

@@ -1,16 +1,19 @@
-{-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE TypeApplications #-}
 
 module Database.PostgreSQL.Opium
+    -- * Connection Management
+  ( Connection
+  , connect
+  , close
     -- * Queries
     --
     -- Functions for performing queries. @fetch@ retrieves rows, @execute@ doesn't.
     -- The 'Connection' parameter comes last to facilitate currying for implicitly passing in the connection, e.g. from some framework's connection pool.
     --
     -- | TODO: Add @newtype Query = Query Text@ with @IsString@ instance to make constructing query strings at run time harder.
-  ( fetch
+  , fetch
   , fetch_
   , execute
   , execute_
@@ -28,18 +31,16 @@ module Database.PostgreSQL.Opium
 
 import Control.Monad (unless, void)
 import Control.Monad.IO.Class (liftIO)
-import Control.Monad.Trans.Except (ExceptT (..), except, runExceptT, throwE)
+import Control.Monad.Trans.Except (ExceptT (..), runExceptT, throwE)
 import Data.Functor.Identity (Identity (..))
 import Data.Proxy (Proxy (..))
 import Data.Text (Text)
-import Database.PostgreSQL.LibPQ
+import Database.PostgreSQL.LibPQ (Result)
-  ( Connection
-  , Result
-  )
 
 import qualified Data.Text.Encoding as Encoding
 import qualified Database.PostgreSQL.LibPQ as LibPQ
 
+import Database.PostgreSQL.Opium.Connection (Connection, connect, close, withRawConnection)
 import Database.PostgreSQL.Opium.Error (Error (..), ErrorPosition (..))
 import Database.PostgreSQL.Opium.FromField (FromField (..), RawField (..))
 import Database.PostgreSQL.Opium.FromRow (FromRow (..), ColumnTable)
@@ -98,14 +99,23 @@ execParams
   -> a
   -> ExceptT Error IO Result
 execParams conn query params = do
-  let queryBytes = Encoding.encodeUtf8 query
+  -- Actually run the query while locking the connection.
-  liftIO (LibPQ.execParams conn queryBytes (toParamList params) LibPQ.Binary) >>= \case
+  mbResult <- ExceptT runQuery
-    Nothing ->
+  -- Check whether the result is valid or nah.
-      except $ Left ErrorNoResult
+  result <- mbResult `orThrow` ErrorNoResult
-    Just result -> do
   status <- liftIO $ LibPQ.resultStatus result
   mbMessage <- liftIO $ LibPQ.resultErrorMessage result
   case mbMessage of
     Just "" -> pure result
     Nothing -> pure result
-        Just message -> except $ Left $ ErrorInvalidResult status $ Encoding.decodeUtf8 message
+    Just message -> throwE $ ErrorInvalidResult status $ Encoding.decodeUtf8 message
+
+  where
+    orThrow (Just x) _ = pure x
+    orThrow Nothing  e = throwE e
+
+    queryBytes = Encoding.encodeUtf8 query
+    runQuery =
+      flip withRawConnection conn $ \mbRawConn -> runExceptT $ do
+        rawConn <- mbRawConn `orThrow` ErrorConnectionClosed
+        liftIO $ LibPQ.execParams rawConn queryBytes (toParamList params) LibPQ.Binary

lib/Database/PostgreSQL/Opium/Connection.hs

@@ -0,0 +1,50 @@
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE OverloadedRecordDot #-}
+
+module Database.PostgreSQL.Opium.Connection
+  ( Connection
+  , unsafeWithRawConnection
+  , withRawConnection
+  , connect
+  , close
+  ) where
+
+import Control.Concurrent.MVar (MVar, newMVar, modifyMVar_, withMVar)
+import Data.ByteString (ByteString)
+import GHC.Stack (HasCallStack)
+
+import qualified Database.PostgreSQL.LibPQ as LibPQ
+
+newtype Connection = Connection
+  { rawConnection :: MVar (Maybe LibPQ.Connection)
+  } 
+
+withRawConnection
+  :: HasCallStack
+  => (Maybe LibPQ.Connection -> IO a)
+  -> Connection
+  -> IO a
+withRawConnection f conn = withMVar conn.rawConnection f
+
+unsafeWithRawConnection
+  :: HasCallStack
+  => (LibPQ.Connection -> IO a)
+  -> Connection
+  -> IO a
+unsafeWithRawConnection f = withRawConnection $ \case
+  Nothing -> error "raw connection is missing! perhaps the connection was already closed."
+  Just rawConn -> f rawConn
+
+connect :: ByteString -> IO Connection
+connect connectionString = do
+  rawConn <- LibPQ.connectdb connectionString
+
+  Connection <$> newMVar (Just rawConn)
+
+close :: Connection -> IO ()
+close conn = modifyMVar_ conn.rawConnection $ \case
+  Just rawConn -> do
+    LibPQ.finish rawConn
+    pure Nothing
+  Nothing ->
+    pure Nothing

lib/Database/PostgreSQL/Opium/Error.hs

@@ -19,6 +19,7 @@ data Error
   | ErrorInvalidField ErrorPosition Oid ByteString String
   | ErrorNotExactlyOneRow
   | ErrorMoreThanOneRow
+  | ErrorConnectionClosed
   deriving (Eq, Show)
 
 instance Exception Error where

opium.cabal

@@ -20,7 +20,7 @@ name:               opium
 -- PVP summary:     +-+------- breaking API changes
 --                  | | +----- non-breaking API additions
 --                  | | | +--- code changes with no API change
-version:            0.1.0.0
+version:            1.0.0.0
 
 -- A short (one-line) description of the package.
 -- synopsis:
@@ -63,6 +63,7 @@ library
         Database.PostgreSQL.Opium,
         Database.PostgreSQL.Opium.FromField,
         Database.PostgreSQL.Opium.FromRow,
+        Database.PostgreSQL.Opium.Connection,
         Database.PostgreSQL.Opium.ToField
 
     -- Modules included in this library but not exported.
@@ -117,7 +118,8 @@ test-suite opium-test
     other-modules:
         SpecHook,
         Database.PostgreSQL.OpiumSpec,
-        Database.PostgreSQL.Opium.FromFieldSpec
+        Database.PostgreSQL.Opium.FromFieldSpec,
+        Database.PostgreSQL.Opium.FromRowSpec
 
     -- Test dependencies.
     build-depends:

test/Database/PostgreSQL/Opium/FromFieldSpec.hs

@@ -14,7 +14,6 @@ import Data.Time
   , timeOfDayToTime
   )
 import Data.Text (Text)
-import Database.PostgreSQL.LibPQ (Connection)
 import Database.PostgreSQL.Opium (FromRow)
 import GHC.Generics (Generic)
 import Test.Hspec (SpecWith, describe, it, shouldBe, shouldSatisfy)
@@ -113,7 +112,7 @@ newtype ARawField = ARawField
 
 instance FromRow ARawField where
 
-shouldFetch :: (Eq a, FromRow a, Show a) => Connection -> Text -> [a] -> IO ()
+shouldFetch :: (Eq a, FromRow a, Show a) => Opium.Connection -> Text -> [a] -> IO ()
 shouldFetch conn query expectedRows = do
   actualRows <- Opium.fetch_ query conn
   actualRows `shouldBe` Right expectedRows
@@ -121,7 +120,7 @@ shouldFetch conn query expectedRows = do
 (/\) :: (a -> Bool) -> (a -> Bool) -> a -> Bool
 p /\ q = \x -> p x && q x
 
-spec :: SpecWith Connection
+spec :: SpecWith Opium.Connection
 spec = do
   describe "FromField Int" $ do
     it "Decodes smallint" $ \conn -> do

test/Database/PostgreSQL/Opium/FromRowSpec.hs

@@ -0,0 +1,92 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE TypeApplications #-}
+
+module Database.PostgreSQL.Opium.FromRowSpec (spec) where
+
+import Data.ByteString (ByteString)
+import Data.Proxy (Proxy (..))
+import Test.Hspec (SpecWith, aroundWith, describe, it, shouldBe)
+
+import qualified Database.PostgreSQL.LibPQ as LibPQ
+
+import Database.PostgreSQL.Opium.Connection (unsafeWithRawConnection)
+import Database.PostgreSQL.OpiumSpec (ManyFields (..), MaybeTest (..), Person (..), Only (..))
+
+import qualified Database.PostgreSQL.Opium as Opium
+import qualified Database.PostgreSQL.Opium.FromRow as Opium.FromRow
+
+shouldHaveColumns
+  :: Opium.FromRow a
+  => Proxy a
+  -> LibPQ.Connection
+  -> ByteString
+  -> [LibPQ.Column]
+  -> IO ()
+shouldHaveColumns proxy conn query expectedColumns = do
+  Just result <- LibPQ.execParams conn query [] LibPQ.Binary
+  columnTable <- Opium.getColumnTable proxy result
+  let actualColumns = fmap (map fst . Opium.FromRow.toListColumnTable) columnTable
+  actualColumns `shouldBe` Right expectedColumns
+
+-- These test the mapping from Result to ColumnTable/FromRow instances.
+  -- They use the raw LibPQ connection for retrieving the Results.
+spec :: SpecWith Opium.Connection
+spec = aroundWith unsafeWithRawConnection $ do
+  describe "getColumnTable" $ do
+    it "Gets the column table for a result" $ \conn -> do
+      shouldHaveColumns @Person Proxy conn
+        "SELECT name, age FROM person"
+        [0, 1]
+
+    it "Gets the numbers right for funky configurations" $ \conn -> do
+      shouldHaveColumns @Person Proxy conn
+        "SELECT age, name FROM person"
+        [1, 0]
+
+      shouldHaveColumns @Person Proxy conn
+        "SELECT 0 AS a, 1 AS b, 2 AS c, age, 4 AS d, name FROM person"
+        [5, 3]
+
+    it "Fails for missing columns" $ \conn -> do
+      Just result <- LibPQ.execParams conn "SELECT 0 AS a FROM person" [] LibPQ.Binary
+      columnTable <- Opium.getColumnTable @Person Proxy result
+      columnTable `shouldBe` Left (Opium.ErrorMissingColumn "name")
+
+  describe "fromRow" $ do
+    it "Decodes rows in a Result" $ \conn -> do
+      Just result <- LibPQ.execParams conn "SELECT * FROM person" [] LibPQ.Binary
+      Right columnTable <- Opium.getColumnTable @Person Proxy result
+
+      row0 <- Opium.fromRow @Person result columnTable 0
+      row0 `shouldBe` Right (Person "paul" 25)
+
+      row1 <- Opium.fromRow @Person result columnTable 1
+      row1 `shouldBe` Right (Person "albus" 103)
+
+    it "Decodes NULL into Nothing for Maybes" $ \conn -> do
+      Just result <- LibPQ.execParams conn "SELECT NULL AS a" [] LibPQ.Binary
+      Right columnTable <- Opium.getColumnTable @MaybeTest Proxy result
+
+      row <- Opium.fromRow result columnTable 0
+      row `shouldBe` Right (MaybeTest Nothing)
+
+    it "Decodes values into Just for Maybes" $ \conn -> do
+      Just result <- LibPQ.execParams conn "SELECT 'abc' AS a" [] LibPQ.Binary
+      Right columnTable <- Opium.getColumnTable @MaybeTest Proxy result
+
+      row <- Opium.fromRow result columnTable 0
+      row `shouldBe` Right (MaybeTest $ Just "abc")
+
+    it "Works for many fields" $ \conn -> do
+      Just result <- LibPQ.execParams conn "SELECT 'abc' AS a, 42 AS b, 1.0::double precision AS c, 'test' AS d, true AS e" [] LibPQ.Binary
+      Right columnTable <- Opium.getColumnTable @ManyFields Proxy result
+
+      row <- Opium.fromRow result columnTable 0
+      row `shouldBe` Right (ManyFields "abc" 42 1.0 "test" True)
+
+    it "Decodes multiple records into a tuple" $ \conn -> do
+      Just result <- LibPQ.execParams conn "SELECT 'albus' AS name, 123 AS age, 42 AS only" [] LibPQ.Binary
+      Right columnTable <- Opium.getColumnTable @(Person, Only Int) Proxy result
+
+      row <- Opium.fromRow @(Person, Only Int) result columnTable 0
+      row `shouldBe` Right (Person "albus" 123, Only 42)

test/Database/PostgreSQL/OpiumSpec.hs

@@ -4,20 +4,16 @@
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE TypeApplications #-}
 
-module Database.PostgreSQL.OpiumSpec (spec) where
+module Database.PostgreSQL.OpiumSpec (ManyFields (..), MaybeTest (..), Person (..), Only (..), spec) where
 
-import Data.ByteString (ByteString)
 import Data.Either (isLeft)
 import Data.Functor.Identity (Identity (..))
-import Data.Proxy (Proxy (..))
 import Data.Text (Text)
-import Database.PostgreSQL.LibPQ (Connection)
 import GHC.Generics (Generic)
 import Test.Hspec (SpecWith, describe, it, shouldBe, shouldSatisfy)
 
 import qualified Database.PostgreSQL.LibPQ as LibPQ
 import qualified Database.PostgreSQL.Opium as Opium
-import qualified Database.PostgreSQL.Opium.FromRow as Opium.FromRow
 
 data Person = Person
   { name :: Text
@@ -55,80 +51,8 @@ newtype Only a = Only
 
 instance Opium.FromField a => Opium.FromRow (Only a) where
 
-shouldHaveColumns
+spec :: SpecWith Opium.Connection
-  :: Opium.FromRow a
-  => Proxy a
-  -> Connection
-  -> ByteString
-  -> [LibPQ.Column]
-  -> IO ()
-shouldHaveColumns proxy conn query expectedColumns = do
-  Just result <- LibPQ.execParams conn query [] LibPQ.Binary
-  columnTable <- Opium.getColumnTable proxy result
-  let actualColumns = fmap (map fst . Opium.FromRow.toListColumnTable) columnTable
-  actualColumns `shouldBe` Right expectedColumns
-
-spec :: SpecWith Connection
 spec = do
-  describe "getColumnTable" $ do
-    it "Gets the column table for a result" $ \conn -> do
-      shouldHaveColumns @Person Proxy conn
-        "SELECT name, age FROM person"
-        [0, 1]
-
-    it "Gets the numbers right for funky configurations" $ \conn -> do
-      shouldHaveColumns @Person Proxy conn
-        "SELECT age, name FROM person"
-        [1, 0]
-
-      shouldHaveColumns @Person Proxy conn
-        "SELECT 0 AS a, 1 AS b, 2 AS c, age, 4 AS d, name FROM person"
-        [5, 3]
-
-    it "Fails for missing columns" $ \conn -> do
-      Just result <- LibPQ.execParams conn "SELECT 0 AS a FROM person" [] LibPQ.Binary
-      columnTable <- Opium.getColumnTable @Person Proxy result
-      columnTable `shouldBe` Left (Opium.ErrorMissingColumn "name")
-
-  describe "fromRow" $ do
-    it "Decodes rows in a Result" $ \conn -> do
-      Just result <- LibPQ.execParams conn "SELECT * FROM person" [] LibPQ.Binary
-      Right columnTable <- Opium.getColumnTable @Person Proxy result
-
-      row0 <- Opium.fromRow @Person result columnTable 0
-      row0 `shouldBe` Right (Person "paul" 25)
-
-      row1 <- Opium.fromRow @Person result columnTable 1
-      row1 `shouldBe` Right (Person "albus" 103)
-
-    it "Decodes NULL into Nothing for Maybes" $ \conn -> do
-      Just result <- LibPQ.execParams conn "SELECT NULL AS a" [] LibPQ.Binary
-      Right columnTable <- Opium.getColumnTable @MaybeTest Proxy result
-
-      row <- Opium.fromRow result columnTable 0
-      row `shouldBe` Right (MaybeTest Nothing)
-
-    it "Decodes values into Just for Maybes" $ \conn -> do
-      Just result <- LibPQ.execParams conn "SELECT 'abc' AS a" [] LibPQ.Binary
-      Right columnTable <- Opium.getColumnTable @MaybeTest Proxy result
-
-      row <- Opium.fromRow result columnTable 0
-      row `shouldBe` Right (MaybeTest $ Just "abc")
-
-    it "Works for many fields" $ \conn -> do
-      Just result <- LibPQ.execParams conn "SELECT 'abc' AS a, 42 AS b, 1.0::double precision AS c, 'test' AS d, true AS e" [] LibPQ.Binary
-      Right columnTable <- Opium.getColumnTable @ManyFields Proxy result
-
-      row <- Opium.fromRow result columnTable 0
-      row `shouldBe` Right (ManyFields "abc" 42 1.0 "test" True)
-
-    it "Decodes multiple records into a tuple" $ \conn -> do
-      Just result <- LibPQ.execParams conn "SELECT 'albus' AS name, 123 AS age, 42 AS only" [] LibPQ.Binary
-      Right columnTable <- Opium.getColumnTable @(Person, Only Int) Proxy result
-
-      row <- Opium.fromRow @(Person, Only Int) result columnTable 0
-      row `shouldBe` Right (Person "albus" 123, Only 42)
-
   describe "fetch" $ do
     it "Passes numbered parameters and retrieves a list of rows" $ \conn -> do
       rows <- Opium.fetch "SELECT ($1 + $2) AS only" (17 :: Int, 25 :: Int) conn
@@ -182,3 +106,8 @@ spec = do
     it "Does not accept two rows when Maybe is the row container type" $ \conn -> do
       row <- Opium.fetch_ @(Only Int) @Maybe "SELECT 17 AS only UNION ALL SELECT 25 AS only" conn
       row `shouldSatisfy` isLeft
+
+  describe "close" $ do
+    it "Does not crash when called twice on the same connection" $ \conn -> do
+      Opium.close conn
+      Opium.close conn

test/SpecHook.hs

@@ -3,16 +3,16 @@
 module SpecHook (hook) where
 
 import Control.Exception (bracket)
-import Database.PostgreSQL.LibPQ (Connection)
 import System.Environment (lookupEnv)
 import Test.Hspec (Spec, SpecWith, around)
 import Text.Printf (printf)
 
 import qualified Data.Text as Text
 import qualified Data.Text.Encoding as Encoding
-import qualified Database.PostgreSQL.LibPQ as LibPQ
 
-setupConnection :: IO Connection
+import qualified Database.PostgreSQL.Opium as Opium
+
+setupConnection :: IO Opium.Connection
 setupConnection = do
   Just dbUser <- lookupEnv "DB_USER"
   Just dbPass <- lookupEnv "DB_PASS"
@@ -20,24 +20,17 @@ setupConnection = do
   Just dbPort <- lookupEnv "DB_PORT"
 
   let dsn = printf "host=localhost user=%s password=%s dbname=%s port=%s" dbUser dbPass dbName dbPort
-  conn <- LibPQ.connectdb $ Encoding.encodeUtf8 $ Text.pack dsn
+  conn <- Opium.connect $ Encoding.encodeUtf8 $ Text.pack dsn
-  _ <- LibPQ.setClientEncoding conn "UTF8"
 
-  _ <- LibPQ.exec conn "CREATE TABLE person (name TEXT NOT NULL, age INT NOT NULL, score DOUBLE PRECISION NOT NULL, motto TEXT)"
+  Right _ <- Opium.execute_ "DROP TABLE IF EXISTS person" conn
-  _ <- LibPQ.exec conn "INSERT INTO person VALUES ('paul', 25, 30), ('albus', 103, 50.42)"
+  Right _ <- Opium.execute_ "CREATE TABLE person (name TEXT NOT NULL, age INT NOT NULL, score DOUBLE PRECISION NOT NULL, motto TEXT)" conn
+  Right _ <- Opium.execute_ "INSERT INTO person VALUES ('paul', 25, 30), ('albus', 103, 50.42)" conn
 
   pure conn
 
-teardownConnection :: Connection -> IO ()
+teardownConnection :: Opium.Connection -> IO ()
 teardownConnection conn = do
-  _ <- LibPQ.exec conn "DROP TABLE person"
+  Opium.close conn
-  LibPQ.finish conn
 
-class SpecInput a where
+hook :: SpecWith Opium.Connection -> Spec
-  hook :: SpecWith a -> Spec
-
-instance SpecInput Connection where
 hook = around $ bracket setupConnection teardownConnection
-
-instance SpecInput () where
-  hook = id