module Database.Persist.Postgresql
( withPostgresqlPool
, withPostgresqlConn
, createPostgresqlPool
, module Database.Persist.Sql
, ConnectionString
, PostgresConf (..)
, openSimpleConn
) where
import Database.Persist.Sql
import Data.Maybe (mapMaybe)
import Data.Fixed (Pico)
import qualified Database.PostgreSQL.Simple as PG
import qualified Database.PostgreSQL.Simple.BuiltinTypes as PG
import qualified Database.PostgreSQL.Simple.Internal as PG
import qualified Database.PostgreSQL.Simple.ToField as PGTF
import qualified Database.PostgreSQL.Simple.FromField as PGFF
import qualified Database.PostgreSQL.Simple.Types as PG
import Database.PostgreSQL.Simple.Ok (Ok (..))
import qualified Database.PostgreSQL.LibPQ as LibPQ
import Control.Exception (throw)
import Control.Monad.IO.Class (MonadIO (..))
import Data.List (intercalate)
import Data.IORef
import qualified Data.Map as Map
import Data.Either (partitionEithers)
import Control.Arrow
import Data.List (sort, groupBy)
import Data.Function (on)
import Data.Conduit
import qualified Data.Conduit.List as CL
import Data.ByteString (ByteString)
import qualified Data.ByteString.Char8 as B8
import qualified Data.Text as T
import qualified Data.Text.Encoding as T
import qualified Blaze.ByteString.Builder.Char8 as BBB
import Data.Time.LocalTime (localTimeToUTC, utc)
import Data.Text (Text, pack)
import Data.Aeson
import Control.Monad (forM, mzero)
import System.Environment (getEnvironment)
import Data.Int (Int64)
type ConnectionString = ByteString
withPostgresqlPool :: MonadIO m
=> ConnectionString
-> Int
-> (ConnectionPool -> m a)
-> m a
withPostgresqlPool ci = withSqlPool $ open' ci
createPostgresqlPool :: MonadIO m
=> ConnectionString
-> Int
-> m ConnectionPool
createPostgresqlPool ci = createSqlPool $ open' ci
withPostgresqlConn :: (MonadIO m, MonadBaseControl IO m)
=> ConnectionString -> (Connection -> m a) -> m a
withPostgresqlConn = withSqlConn . open'
open' :: ConnectionString -> IO Connection
open' cstr = do
PG.connectPostgreSQL cstr >>= openSimpleConn
openSimpleConn :: PG.Connection -> IO Connection
openSimpleConn conn = do
smap <- newIORef $ Map.empty
return Connection
{ connPrepare = prepare' conn
, connStmtMap = smap
, connInsertSql = insertSql'
, connClose = PG.close conn
, connMigrateSql = migrate'
, connBegin = const $ PG.begin conn
, connCommit = const $ PG.commit conn
, connRollback = const $ PG.rollback conn
, connEscapeName = escape
, connNoLimit = "LIMIT ALL"
, connRDBMS = "postgresql"
}
prepare' :: PG.Connection -> Text -> IO Statement
prepare' conn sql = do
let query = PG.Query (T.encodeUtf8 sql)
return Statement
{ stmtFinalize = return ()
, stmtReset = return ()
, stmtExecute = execute' conn query
, stmtQuery = withStmt' conn query
}
insertSql' :: DBName -> [DBName] -> DBName -> InsertSqlResult
insertSql' t cols id' = ISRSingle $ pack $ concat
[ "INSERT INTO "
, T.unpack $ escape t
, "("
, intercalate "," $ map (T.unpack . escape) cols
, ") VALUES("
, intercalate "," (map (const "?") cols)
, ") RETURNING "
, T.unpack $ escape id'
]
execute' :: PG.Connection -> PG.Query -> [PersistValue] -> IO Int64
execute' conn query vals = PG.execute conn query (map P vals)
withStmt' :: MonadResource m
=> PG.Connection
-> PG.Query
-> [PersistValue]
-> Source m [PersistValue]
withStmt' conn query vals =
bracketP openS closeS pull
where
openS = do
rawquery <- PG.formatQuery conn query (map P vals)
PG.withConnection conn $ \rawconn -> do
mret <- LibPQ.exec rawconn rawquery
case mret of
Nothing -> do
merr <- LibPQ.errorMessage rawconn
fail $ case merr of
Nothing -> "Postgresql.withStmt': unknown error"
Just e -> "Postgresql.withStmt': " ++ B8.unpack e
Just ret -> do
status <- LibPQ.resultStatus ret
case status of
LibPQ.TuplesOk -> return ()
_ -> do
msg <- LibPQ.resStatus status
mmsg <- LibPQ.resultErrorMessage ret
fail $ "Postgresql.withStmt': bad result status " ++
show status ++ " (" ++ (maybe (show msg) (show . (,) msg) mmsg) ++ ")"
cols <- LibPQ.nfields ret
getters <- forM [0..cols1] $ \col -> do
oid <- LibPQ.ftype ret col
case PG.oid2builtin oid of
Nothing -> fail $ "Postgresql.withStmt': could not " ++
"recognize Oid of column " ++
show (let LibPQ.Col i = col in i) ++
" (counting from zero)"
Just bt -> return $ getGetter bt $
PG.Field ret col oid
rowRef <- newIORef (LibPQ.Row 0)
rowCount <- LibPQ.ntuples ret
return (ret, rowRef, rowCount, getters)
closeS (ret, _, _, _) = LibPQ.unsafeFreeResult ret
pull x = do
y <- liftIO $ pullS x
case y of
Nothing -> return ()
Just z -> yield z >> pull x
pullS (ret, rowRef, rowCount, getters) = do
row <- atomicModifyIORef rowRef (\r -> (r+1, r))
if row == rowCount
then return Nothing
else fmap Just $ forM (zip getters [0..]) $ \(getter, col) -> do
mbs <- LibPQ.getvalue' ret row col
case mbs of
Nothing -> return PersistNull
Just bs -> do
ok <- PGFF.runConversion (getter mbs) conn
bs `seq` case ok of
Errors (exc:_) -> throw exc
Errors [] -> error "Got an Errors, but no exceptions"
Ok v -> return v
newtype P = P PersistValue
instance PGTF.ToField P where
toField (P (PersistText t)) = PGTF.toField t
toField (P (PersistByteString bs)) = PGTF.toField (PG.Binary bs)
toField (P (PersistInt64 i)) = PGTF.toField i
toField (P (PersistDouble d)) = PGTF.toField d
toField (P (PersistRational r)) = PGTF.Plain $
BBB.fromString $
show (fromRational r :: Pico)
toField (P (PersistBool b)) = PGTF.toField b
toField (P (PersistDay d)) = PGTF.toField d
toField (P (PersistTimeOfDay t)) = PGTF.toField t
toField (P (PersistUTCTime t)) = PGTF.toField t
toField (P (PersistZonedTime (ZT t))) = PGTF.toField t
toField (P PersistNull) = PGTF.toField PG.Null
toField (P (PersistList l)) = PGTF.toField $ listToJSON l
toField (P (PersistMap m)) = PGTF.toField $ mapToJSON m
toField (P (PersistObjectId _)) =
error "Refusing to serialize a PersistObjectId to a PostgreSQL value"
type Getter a = PGFF.FieldParser a
convertPV :: PGFF.FromField a => (a -> b) -> Getter b
convertPV f = (fmap f .) . PGFF.fromField
getGetter :: PG.BuiltinType -> Getter PersistValue
getGetter PG.Bool = convertPV PersistBool
getGetter PG.ByteA = convertPV (PersistByteString . unBinary)
getGetter PG.Char = convertPV PersistText
getGetter PG.Name = convertPV PersistText
getGetter PG.Int8 = convertPV PersistInt64
getGetter PG.Int2 = convertPV PersistInt64
getGetter PG.Int4 = convertPV PersistInt64
getGetter PG.Text = convertPV PersistText
getGetter PG.Xml = convertPV PersistText
getGetter PG.Float4 = convertPV PersistDouble
getGetter PG.Float8 = convertPV PersistDouble
getGetter PG.AbsTime = convertPV PersistUTCTime
getGetter PG.RelTime = convertPV PersistUTCTime
getGetter PG.Money = convertPV PersistDouble
getGetter PG.BpChar = convertPV PersistText
getGetter PG.VarChar = convertPV PersistText
getGetter PG.Date = convertPV PersistDay
getGetter PG.Time = convertPV PersistTimeOfDay
getGetter PG.Timestamp = convertPV (PersistUTCTime . localTimeToUTC utc)
getGetter PG.TimestampTZ = convertPV (PersistZonedTime . ZT)
getGetter PG.Bit = convertPV PersistInt64
getGetter PG.VarBit = convertPV PersistInt64
getGetter PG.Numeric = convertPV PersistRational
getGetter PG.Void = \_ _ -> return PersistNull
getGetter other = error $ "Postgresql.getGetter: type " ++
show other ++ " not supported."
unBinary :: PG.Binary a -> a
unBinary (PG.Binary x) = x
migrate' :: [EntityDef a]
-> (Text -> IO Statement)
-> EntityDef SqlType
-> IO (Either [Text] [(Bool, Text)])
migrate' allDefs getter val = fmap (fmap $ map showAlterDb) $ do
let name = entityDB val
old <- getColumns getter val
case partitionEithers old of
([], old'') -> do
let old' = partitionEithers old''
let new = first (filter $ not . safeToRemove val . cName)
$ second (map udToPair)
$ mkColumns allDefs val
if null old
then do
let addTable = AddTable $ concat
[ "CREATe TABLE "
, T.unpack $ escape name
, "("
, T.unpack $ escape $ entityID val
, " SERIAL PRIMARY KEY UNIQUE"
, concatMap (\x -> ',' : showColumn x) $ fst new
, ")"
]
let uniques = flip concatMap (snd new) $ \(uname, ucols) ->
[AlterTable name $ AddUniqueConstraint uname ucols]
references = mapMaybe (getAddReference name) $ fst new
return $ Right $ addTable : uniques ++ references
else do
let (acs, ats) = getAlters val new old'
let acs' = map (AlterColumn name) acs
let ats' = map (AlterTable name) ats
return $ Right $ acs' ++ ats'
(errs, _) -> return $ Left errs
type SafeToRemove = Bool
data AlterColumn = Type SqlType | IsNull | NotNull | Add' Column | Drop SafeToRemove
| Default String | NoDefault | Update' String
| AddReference DBName | DropReference DBName
type AlterColumn' = (DBName, AlterColumn)
data AlterTable = AddUniqueConstraint DBName [DBName]
| DropConstraint DBName
data AlterDB = AddTable String
| AlterColumn DBName AlterColumn'
| AlterTable DBName AlterTable
getColumns :: (Text -> IO Statement)
-> EntityDef a
-> IO [Either Text (Either Column (DBName, [DBName]))]
getColumns getter def = do
stmt <- getter "SELECT column_name,is_nullable,udt_name,column_default,numeric_precision,numeric_scale FROM information_schema.columns WHERE table_name=? AND column_name <> ?"
let vals =
[ PersistText $ unDBName $ entityDB def
, PersistText $ unDBName $ entityID def
]
cs <- runResourceT $ stmtQuery stmt vals $$ helper
stmt' <- getter
"SELECT constraint_name, column_name FROM information_schema.constraint_column_usage WHERE table_name=? AND column_name <> ? ORDER BY constraint_name, column_name"
us <- runResourceT $ stmtQuery stmt' vals $$ helperU
return $ cs ++ us
where
getAll front = do
x <- CL.head
case x of
Nothing -> return $ front []
Just [PersistText con, PersistText col] ->
getAll (front . (:) (con, col))
Just _ -> getAll front
helperU = do
rows <- getAll id
return $ map (Right . Right . (DBName . fst . head &&& map (DBName . snd)))
$ groupBy ((==) `on` fst) rows
helper = do
x <- CL.head
case x of
Nothing -> return []
Just x' -> do
col <- liftIO $ getColumn getter (entityDB def) x'
let col' = case col of
Left e -> Left e
Right c -> Right $ Left c
cols <- helper
return $ col' : cols
safeToRemove :: EntityDef a -> DBName -> Bool
safeToRemove def (DBName colName)
= any (elem "SafeToRemove" . fieldAttrs)
$ filter ((== (DBName colName)) . fieldDB)
$ entityFields def
getAlters :: EntityDef a
-> ([Column], [(DBName, [DBName])])
-> ([Column], [(DBName, [DBName])])
-> ([AlterColumn'], [AlterTable])
getAlters def (c1, u1) (c2, u2) =
(getAltersC c1 c2, getAltersU u1 u2)
where
getAltersC [] old = map (\x -> (cName x, Drop $ safeToRemove def $ cName x)) old
getAltersC (new:news) old =
let (alters, old') = findAlters new old
in alters ++ getAltersC news old'
getAltersU :: [(DBName, [DBName])]
-> [(DBName, [DBName])]
-> [AlterTable]
getAltersU [] old = map DropConstraint $ filter (not . isManual) $ map fst old
getAltersU ((name, cols):news) old =
case lookup name old of
Nothing -> AddUniqueConstraint name cols : getAltersU news old
Just ocols ->
let old' = filter (\(x, _) -> x /= name) old
in if sort cols == sort ocols
then getAltersU news old'
else DropConstraint name
: AddUniqueConstraint name cols
: getAltersU news old'
isManual (DBName x) = "__manual_" `T.isPrefixOf` x
getColumn :: (Text -> IO Statement)
-> DBName -> [PersistValue]
-> IO (Either Text Column)
getColumn getter tname [PersistText x, PersistText y, PersistText z, d, npre, nscl] =
case d' of
Left s -> return $ Left s
Right d'' ->
case getType z of
Left s -> return $ Left s
Right t -> do
let cname = DBName x
ref <- getRef cname
return $ Right Column
{ cName = cname
, cNull = y == "YES"
, cSqlType = t
, cDefault = d''
, cMaxLen = Nothing
, cReference = ref
}
where
getRef cname = do
let sql = pack $ concat
[ "SELECT COUNT(*) FROM "
, "information_schema.table_constraints "
, "WHERE table_name=? "
, "AND constraint_type='FOREIGN KEY' "
, "AND constraint_name=?"
]
let ref = refName tname cname
stmt <- getter sql
runResourceT $ stmtQuery stmt
[ PersistText $ unDBName tname
, PersistText $ unDBName ref
] $$ do
Just [PersistInt64 i] <- CL.head
return $ if i == 0 then Nothing else Just (DBName "", ref)
d' = case d of
PersistNull -> Right Nothing
PersistText t -> Right $ Just t
_ -> Left $ pack $ "Invalid default column: " ++ show d
getType "int4" = Right $ SqlInt32
getType "int8" = Right $ SqlInt64
getType "varchar" = Right $ SqlString
getType "date" = Right $ SqlDay
getType "bool" = Right $ SqlBool
getType "timestamp" = Right $ SqlDayTime
getType "timestamptz" = Right $ SqlDayTimeZoned
getType "float4" = Right $ SqlReal
getType "float8" = Right $ SqlReal
getType "bytea" = Right $ SqlBlob
getType "time" = Right $ SqlTime
getType "numeric" = getNumeric npre nscl
getType a = Right $ SqlOther a
getNumeric (PersistInt64 a) (PersistInt64 b) = Right $ SqlNumeric (fromIntegral a) (fromIntegral b)
getNumeric a b = Left $ pack $ "Can not get numeric field precision, got: " ++ show a ++ " and " ++ show b ++ " as precision and scale"
getColumn _ _ x =
return $ Left $ pack $ "Invalid result from information_schema: " ++ show x
findAlters :: Column -> [Column] -> ([AlterColumn'], [Column])
findAlters col@(Column name isNull sqltype def _maxLen ref) cols =
case filter (\c -> cName c == name) cols of
[] -> ([(name, Add' col)], cols)
Column _ isNull' sqltype' def' _maxLen' ref':_ ->
let refDrop Nothing = []
refDrop (Just (_, cname)) = [(name, DropReference cname)]
refAdd Nothing = []
refAdd (Just (tname, _)) = [(name, AddReference tname)]
modRef =
if fmap snd ref == fmap snd ref'
then []
else refDrop ref' ++ refAdd ref
modNull = case (isNull, isNull') of
(True, False) -> [(name, IsNull)]
(False, True) ->
let up = case def of
Nothing -> id
Just s -> (:) (name, Update' $ T.unpack s)
in up [(name, NotNull)]
_ -> []
modType = if sqltype == sqltype' then [] else [(name, Type sqltype)]
modDef =
if def == def'
then []
else case def of
Nothing -> [(name, NoDefault)]
Just s -> [(name, Default $ T.unpack s)]
in (modRef ++ modDef ++ modNull ++ modType,
filter (\c -> cName c /= name) cols)
getAddReference :: DBName -> Column -> Maybe AlterDB
getAddReference table (Column n _nu _ _def _maxLen ref) =
case ref of
Nothing -> Nothing
Just (s, _) -> Just $ AlterColumn table (n, AddReference s)
showColumn :: Column -> String
showColumn (Column n nu sqlType def _maxLen _ref) = concat
[ T.unpack $ escape n
, " "
, showSqlType sqlType
, " "
, if nu then "NULL" else "NOT NULL"
, case def of
Nothing -> ""
Just s -> " DEFAULT " ++ T.unpack s
]
showSqlType :: SqlType -> String
showSqlType SqlString = "VARCHAR"
showSqlType SqlInt32 = "INT4"
showSqlType SqlInt64 = "INT8"
showSqlType SqlReal = "DOUBLE PRECISION"
showSqlType (SqlNumeric s prec) = "NUMERIC(" ++ show s ++ "," ++ show prec ++ ")"
showSqlType SqlDay = "DATE"
showSqlType SqlTime = "TIME"
showSqlType SqlDayTime = "TIMESTAMP"
showSqlType SqlDayTimeZoned = "TIMESTAMP WITH TIME ZONE"
showSqlType SqlBlob = "BYTEA"
showSqlType SqlBool = "BOOLEAN"
showSqlType (SqlOther t) = T.unpack t
showAlterDb :: AlterDB -> (Bool, Text)
showAlterDb (AddTable s) = (False, pack s)
showAlterDb (AlterColumn t (c, ac)) =
(isUnsafe ac, pack $ showAlter t (c, ac))
where
isUnsafe (Drop safeToRemove) = not safeToRemove
isUnsafe _ = False
showAlterDb (AlterTable t at) = (False, pack $ showAlterTable t at)
showAlterTable :: DBName -> AlterTable -> String
showAlterTable table (AddUniqueConstraint cname cols) = concat
[ "ALTER TABLE "
, T.unpack $ escape table
, " ADD CONSTRAINT "
, T.unpack $ escape cname
, " UNIQUE("
, intercalate "," $ map (T.unpack . escape) cols
, ")"
]
showAlterTable table (DropConstraint cname) = concat
[ "ALTER TABLE "
, T.unpack $ escape table
, " DROP CONSTRAINT "
, T.unpack $ escape cname
]
showAlter :: DBName -> AlterColumn' -> String
showAlter table (n, Type t) =
concat
[ "ALTER TABLE "
, T.unpack $ escape table
, " ALTER COLUMN "
, T.unpack $ escape n
, " TYPE "
, showSqlType t
]
showAlter table (n, IsNull) =
concat
[ "ALTER TABLE "
, T.unpack $ escape table
, " ALTER COLUMN "
, T.unpack $ escape n
, " DROP NOT NULL"
]
showAlter table (n, NotNull) =
concat
[ "ALTER TABLE "
, T.unpack $ escape table
, " ALTER COLUMN "
, T.unpack $ escape n
, " SET NOT NULL"
]
showAlter table (_, Add' col) =
concat
[ "ALTER TABLE "
, T.unpack $ escape table
, " ADD COLUMN "
, showColumn col
]
showAlter table (n, Drop _) =
concat
[ "ALTER TABLE "
, T.unpack $ escape table
, " DROP COLUMN "
, T.unpack $ escape n
]
showAlter table (n, Default s) =
concat
[ "ALTER TABLE "
, T.unpack $ escape table
, " ALTER COLUMN "
, T.unpack $ escape n
, " SET DEFAULT "
, s
]
showAlter table (n, NoDefault) = concat
[ "ALTER TABLE "
, T.unpack $ escape table
, " ALTER COLUMN "
, T.unpack $ escape n
, " DROP DEFAULT"
]
showAlter table (n, Update' s) = concat
[ "UPDATE "
, T.unpack $ escape table
, " SET "
, T.unpack $ escape n
, "="
, s
, " WHERE "
, T.unpack $ escape n
, " IS NULL"
]
showAlter table (n, AddReference t2) = concat
[ "ALTER TABLE "
, T.unpack $ escape table
, " ADD CONSTRAINT "
, T.unpack $ escape $ refName table n
, " FOREIGN KEY("
, T.unpack $ escape n
, ") REFERENCES "
, T.unpack $ escape t2
]
showAlter table (_, DropReference cname) = concat
[ "ALTER TABLE "
, T.unpack (escape table)
, " DROP CONSTRAINT "
, T.unpack $ escape cname
]
escape :: DBName -> Text
escape (DBName s) =
T.pack $ '"' : go (T.unpack s) ++ "\""
where
go "" = ""
go ('"':xs) = "\"\"" ++ go xs
go (x:xs) = x : go xs
data PostgresConf = PostgresConf
{ pgConnStr :: ConnectionString
, pgPoolSize :: Int
}
instance PersistConfig PostgresConf where
type PersistConfigBackend PostgresConf = SqlPersistT
type PersistConfigPool PostgresConf = ConnectionPool
createPoolConfig (PostgresConf cs size) = createPostgresqlPool cs size
runPool _ = runSqlPool
loadConfig (Object o) = do
database <- o .: "database"
host <- o .: "host"
port <- o .:? "port" .!= 5432
user <- o .: "user"
password <- o .: "password"
pool <- o .: "poolsize"
let ci = PG.ConnectInfo
{ PG.connectHost = host
, PG.connectPort = port
, PG.connectUser = user
, PG.connectPassword = password
, PG.connectDatabase = database
}
cstr = PG.postgreSQLConnectionString ci
return $ PostgresConf cstr pool
loadConfig _ = mzero
applyEnv c0 = do
env <- getEnvironment
return $ addUser env
$ addPass env
$ addDatabase env
$ addPort env
$ addHost env c0
where
addParam param val c =
c { pgConnStr = B8.concat [pgConnStr c, " ", param, "='", pgescape val, "'"] }
pgescape = B8.pack . go
where
go ('\'':rest) = '\\' : '\'' : go rest
go ('\\':rest) = '\\' : '\\' : go rest
go ( x :rest) = x : go rest
go [] = []
maybeAddParam param envvar env =
maybe id (addParam param) $
lookup envvar env
addHost = maybeAddParam "host" "PGHOST"
addPort = maybeAddParam "port" "PGPORT"
addUser = maybeAddParam "user" "PGUSER"
addPass = maybeAddParam "password" "PGPASS"
addDatabase = maybeAddParam "dbname" "PGDATABASE"
refName :: DBName -> DBName -> DBName
refName (DBName table) (DBName column) =
DBName $ T.concat [table, "_", column, "_fkey"]
udToPair :: UniqueDef -> (DBName, [DBName])
udToPair ud = (uniqueDBName ud, map snd $ uniqueFields ud)