@@ -1,18 +1,14 @@
1−{-# LANGUAGE DeriveDataTypeable #-}
2−{-# LANGUAGE NamedFieldPuns #-}
3−{-# LANGUAGE OverloadedStrings #-}
4−{-# LANGUAGE PatternGuards #-}
5−{-# LANGUAGE RecordWildCards #-}
6−{-# LANGUAGE ViewPatterns #-}
1+{-# LANGUAGE DeriveDataTypeable, RecordWildCards, NamedFieldPuns #-}
72
83------------------------------------------------------------------------------
94-- |
105-- Module: Database.PostgreSQL.Simple
116-- Copyright: (c) 2011 MailRank, Inc.
12−-- (c) 2011-2012 Leon P Smith
7+-- (c) 2011 Leon P Smith
138-- License: BSD3
149-- Maintainer: Leon P Smith <leon@melding-monads.com>
1510-- Stability: experimental
11+-- Portability: portable
1612--
1713-- A mid-level client library for the PostgreSQL database, aimed at ease of
1814-- use and high performance.
@@ -42,9 +38,6 @@ module Database.PostgreSQL.Simple
4238 -- ** Modifying multiple rows at once
4339 -- $many
4440
45− -- ** @RETURNING@: modifications that return results
46− -- $returning
47−
4841 -- * Extracting results
4942 -- $result
5043
@@ -55,35 +48,26 @@ module Database.PostgreSQL.Simple
5548 -- $types
5649
5750 -- * Types
58− Connection
51+ Base.ConnectInfo(..)
52+ , Connection
5953 , Query
60− , ToRow
61− , FromRow
6254 , In(..)
6355 , Binary(..)
6456 , Only(..)
65− , (:.)(..)
6657 -- ** Exceptions
67− , SomePostgreSqlException(..)
6858 , SqlError(..)
69− , PQ.ExecStatus(..)
70− , FormatError(..)
71− , QueryError(..)
72− , ResultError(..)
59+ , FormatError(fmtMessage, fmtQuery, fmtParams)
60+ , QueryError(qeMessage, qeQuery)
61+ , ResultError(errSQLType, errHaskellType, errMessage)
7362 -- * Connection management
74− , Base.connectPostgreSQL
75− , Base.close
7663 , Base.connect
77− , Base.withConnect
78− , Base.ConnectInfo(..)
79− , Base.defaultConnectInfo
64+ , Base.connectPostgreSQL
8065 , Base.postgreSQLConnectionString
66+ , Base.defaultConnectInfo
67+ , Base.close
8168 -- * Queries that return results
8269 , query
8370 , query_
84− -- ** Queries taking parser as argument
85− , queryWith
86− , queryWith_
8771 -- * Queries that stream results
8872 , FoldOptions(..)
8973 , FetchQuantity(..)
@@ -94,15 +78,6 @@ module Database.PostgreSQL.Simple
9478 , foldWithOptions_
9579 , forEach
9680 , forEach_
97− , returning
98− -- ** Queries that stream results taking a parser as an argument
99− , foldWith
100− , foldWithOptionsAndParser
101− , foldWith_
102− , foldWithOptionsAndParser_
103− , forEachWith
104− , forEachWith_
105− , returningWith
10681 -- * Statements that do not return results
10782 , execute
10883 , execute_
@@ -110,9 +85,18 @@ module Database.PostgreSQL.Simple
11085-- , Base.insertID
11186 -- * Transaction handling
11287 , withTransaction
113− , withSavepoint
88+ , TransactionMode(..)
89+ , IsolationLevel(..)
90+ , ReadWriteMode(..)
91+ , defaultTransactionMode
92+ , defaultIsolationLevel
93+ , defaultReadWriteMode
94+ , withTransactionLevel
95+ , withTransactionMode
11496-- , Base.autocommit
11597 , begin
98+ , beginLevel
99+ , beginMode
116100 , commit
117101 , rollback
118102 -- * Helper functions
@@ -120,27 +104,58 @@ module Database.PostgreSQL.Simple
120104 , formatQuery
121105 ) where
122106
123−import Data.ByteString.Builder (Builder, byteString, char8)
124−import Control.Applicative ((<$>))
125−import Control.Exception as E
107+import Blaze.ByteString.Builder
108+ ( Builder, fromByteString, toByteString )
109+import Blaze.ByteString.Builder.Char8 (fromChar)
110+import Control.Applicative ((<$>), pure)
111+import Control.Concurrent.MVar
112+import Control.Exception
113+ ( Exception, bracket, onException, throw, throwIO, finally )
114+import Control.Monad (foldM)
126115import Data.ByteString (ByteString)
116+import Data.Char(ord)
127117import Data.Int (Int64)
118+import qualified Data.IntMap as IntMap
128119import Data.List (intersperse)
129−import Data.Monoid (mconcat)
130−import Database.PostgreSQL.Simple.Compat ((<>), toByteString)
131−import Database.PostgreSQL.Simple.Cursor
120+import Data.Monoid (mappend, mconcat)
121+import Data.Typeable (Typeable)
122+import Database.PostgreSQL.Simple.BuiltinTypes
123+ ( oid2builtin, builtin2typname )
132124import Database.PostgreSQL.Simple.FromField (ResultError(..))
133125import Database.PostgreSQL.Simple.FromRow (FromRow(..))
134−import Database.PostgreSQL.Simple.ToField (Action(..))
135−import Database.PostgreSQL.Simple.ToRow (ToRow(..))
126+import Database.PostgreSQL.Simple.Ok
127+import Database.PostgreSQL.Simple.Param (Action(..), inQuotes)
128+import Database.PostgreSQL.Simple.QueryParams (QueryParams(..))
136129import Database.PostgreSQL.Simple.Types
137− ( Binary(..), In(..), Only(..), Query(..), (:.)(..) )
130+ ( Binary(..), In(..), Only(..), Query(..) )
138131import Database.PostgreSQL.Simple.Internal as Base
139−import Database.PostgreSQL.Simple.Internal.PQResultUtils
140−import Database.PostgreSQL.Simple.Transaction
141132import qualified Database.PostgreSQL.LibPQ as PQ
133+import Text.Regex.PCRE.Light (compile, caseless, match)
142134import qualified Data.ByteString.Char8 as B
143−
135+import qualified Data.Vector as V
136+import Control.Exception
137+import Control.Monad.Trans.Reader
138+import Control.Monad.Trans.State.Strict
139+
140+-- | Exception thrown if a 'Query' could not be formatted correctly.
141+-- This may occur if the number of \'@?@\' characters in the query
142+-- string does not match the number of parameters provided.
143+data FormatError = FormatError {
144+ fmtMessage :: String
145+ , fmtQuery :: Query
146+ , fmtParams :: [ByteString]
147+ } deriving (Eq, Show, Typeable)
148+
149+instance Exception FormatError
150+
151+-- | Exception thrown if 'query' is used to perform an @INSERT@-like
152+-- operation, or 'execute' is used to perform a @SELECT@-like operation.
153+data QueryError = QueryError {
154+ qeMessage :: String
155+ , qeQuery :: Query
156+ } deriving (Eq, Show, Typeable)
157+
158+instance Exception QueryError
144159
145160-- | Format a query string.
146161--
@@ -152,11 +167,11 @@ import qualified Data.ByteString.Char8 as B
152167--
153168-- Throws 'FormatError' if the query string could not be formatted
154169-- correctly.
155−formatQuery :: ToRow q => Connection -> Query -> q -> IO ByteString
170+formatQuery :: QueryParams q => Connection -> Query -> q -> IO ByteString
156171formatQuery conn q@(Query template) qs
157172 | null xs && '?' `B.notElem` template = return template
158173 | otherwise = toByteString <$> buildQuery conn q template xs
159− where xs = toRow qs
174+ where xs = renderParams qs
160175
161176-- | Format a query string with a variable number of rows.
162177--
@@ -171,208 +186,106 @@ formatQuery conn q@(Query template) qs
171186--
172187-- Throws 'FormatError' if the query string could not be formatted
173188-- correctly.
174−formatMany :: (ToRow q) => Connection -> Query -> [q] -> IO ByteString
189+formatMany :: (QueryParams q) => Connection -> Query -> [q] -> IO ByteString
175190formatMany _ q [] = fmtError "no rows supplied" q []
176191formatMany conn q@(Query template) qs = do
177− case parseTemplate template of
178− Just (before, qbits, after) -> do
179− bs <- mapM (buildQuery conn q qbits . toRow) qs
180− return . toByteString . mconcat $ byteString before :
181− intersperse (char8 ',') bs ++
182− [byteString after]
183− Nothing -> fmtError "syntax error in multi-row template" q []
184−
185−-- Split the input string into three pieces, @before@, @qbits@, and @after@,
186−-- following this grammar:
187−--
188−-- start: ^ before qbits after $
189−-- before: ([^?]* [^?\w])? 'VALUES' \s*
190−-- qbits: '(' \s* '?' \s* (',' \s* '?' \s*)* ')'
191−-- after: [^?]*
192−--
193−-- \s: [ \t\n\r\f]
194−-- \w: [A-Z] | [a-z] | [\x80-\xFF] | '_' | '$' | [0-9]
195−--
196−-- This would be much more concise with some sort of regex engine.
197−-- 'formatMany' used to use pcre-light instead of this hand-written parser,
198−-- but pcre is a hassle to install on Windows.
199−parseTemplate :: ByteString -> Maybe (ByteString, ByteString, ByteString)
200−parseTemplate template =
201− -- Convert input string to uppercase, to facilitate searching.
202− search $ B.map toUpper_ascii template
192+ case match re template [] of
193+ Just [_,before,qbits,after] -> do
194+ bs <- mapM (buildQuery conn q qbits . renderParams) qs
195+ return . toByteString . mconcat $ fromByteString before :
196+ intersperse (fromChar ',') bs ++
197+ [fromByteString after]
198+ _ -> error "foo"
203199 where
204− -- Search for the next occurrence of "VALUES"
205− search bs =
206− case B.breakSubstring "VALUES" bs of
207− (x, y)
208− -- If "VALUES" is not present in the string, or any '?' characters
209− -- were encountered prior to it, fail.
210− | B.null y || ('?' `B.elem` x)
211− -> Nothing
212−
213− -- If "VALUES" is preceded by an identifier character (a.k.a. \w),
214− -- try the next occurrence.
215− | not (B.null x) && isIdent (B.last x)
216− -> search $ B.drop 6 y
217−
218− -- Otherwise, we have a legitimate "VALUES" token.
219− | otherwise
220− -> parseQueryBits $ skipSpace $ B.drop 6 y
221−
222− -- Parse '(' \s* '?' \s* . If this doesn't match
223− -- (and we don't consume a '?'), look for another "VALUES".
224− --
225− -- qb points to the open paren (if present), meaning it points to the
226− -- beginning of the "qbits" production described above. This is why we
227− -- pass it down to finishQueryBits.
228− parseQueryBits qb
229− | Just ('(', skipSpace -> bs1) <- B.uncons qb
230− , Just ('?', skipSpace -> bs2) <- B.uncons bs1
231− = finishQueryBits qb bs2
232− | otherwise
233− = search qb
234−
235− -- Parse (',' \s* '?' \s*)* ')' [^?]* .
236− --
237− -- Since we've already consumed at least one '?', there's no turning back.
238− -- The parse has to succeed here, or the whole thing fails
239− -- (because we don't allow '?' to appear outside of the VALUES list).
240− finishQueryBits qb bs0
241− | Just (')', bs1) <- B.uncons bs0
242− = if '?' `B.elem` bs1
243− then Nothing
244− else Just $ slice3 template qb bs1
245− | Just (',', skipSpace -> bs1) <- B.uncons bs0
246− , Just ('?', skipSpace -> bs2) <- B.uncons bs1
247− = finishQueryBits qb bs2
248− | otherwise
249− = Nothing
250−
251− -- Slice a string into three pieces, given the start offset of the second
252− -- and third pieces. Each "offset" is actually a tail of the uppercase
253− -- version of the template string. Its length is used to infer the offset.
254− --
255− -- It is important to note that we only slice the original template.
256− -- We don't want our all-caps trick messing up the actual query string.
257− slice3 source p1 p2 =
258− (s1, s2, source'')
259− where
260− (s1, source') = B.splitAt (B.length source - B.length p1) source
261− (s2, source'') = B.splitAt (B.length p1 - B.length p2) source'
262−
263− toUpper_ascii c | c >= 'a' && c <= 'z' = toEnum (fromEnum c - 32)
264− | otherwise = c
265−
266− -- Based on the definition of {ident_cont} in src/backend/parser/scan.l
267− -- in the PostgreSQL source. No need to check [a-z], since we converted
268− -- the whole string to uppercase.
269− isIdent c = (c >= '0' && c <= '9')
270− || (c >= 'A' && c <= 'Z')
271− || (c >= '\x80' && c <= '\xFF')
272− || c == '_'
273− || c == '$'
274−
275− -- Based on {space} in scan.l
276− isSpace_ascii c = (c == ' ') || (c >= '\t' && c <= '\r')
277−
278− skipSpace = B.dropWhile isSpace_ascii
200+ re = compile "^([^?]+\\bvalues\\s*)\
201+ \(\\(\\s*[?](?:\\s*,\\s*[?])*\\s*\\))\
202+ \([^?]*)$"
203+ [caseless]
279204
205+escapeStringConn :: Connection -> ByteString -> IO (Maybe ByteString)
206+escapeStringConn conn s = withConnection conn $ \c -> do
207+ PQ.escapeStringConn c s
280208
281209buildQuery :: Connection -> Query -> ByteString -> [Action] -> IO Builder
282−buildQuery conn q template xs =
283− zipParams (split template) <$> mapM (buildAction conn q xs) xs
284− where split s =
285− -- This part escapes double '??'s to make literal '?'s possible
286− -- in PostgreSQL queries using the JSON operators: @?@, @?|@ and @?&@
287− let (h,t) = breakOnSingleQuestionMark s
288− in byteString h
289− : if B.null t
290− then []
291− else split (B.tail t)
292− zipParams (t:ts) (p:ps) = t <> p <> zipParams ts ps
210+buildQuery conn q template xs = zipParams (split template) <$> mapM sub xs
211+ where quote = inQuotes . fromByteString . maybe undefined id
212+ sub (Plain b) = pure b
213+ sub (Escape s) = quote <$> escapeStringConn conn s
214+ sub (Many ys) = mconcat <$> mapM sub ys
215+ split s = fromByteString h : if B.null t then [] else split (B.tail t)
216+ where (h,t) = B.break (=='?') s
217+ zipParams (t:ts) (p:ps) = t `mappend` p `mappend` zipParams ts ps
293218 zipParams [t] [] = t
294− zipParams _ _ = fmtError (show countSingleQs ++
295− " single '?' characters, but " ++
219+ zipParams _ _ = fmtError (show (B.count '?' template) ++
220+ " '?' characters, but " ++
296221 show (length xs) ++ " parameters") q xs
297− countSingleQs = go 0 template
298− where go i "" = (i :: Int)
299− go i bs = case qms of
300− ("?","?") -> go i nextQMBS
301− ("?",_) -> go (i+1) nextQMBS
302− _ -> i
303− where qms = B.splitAt 1 qmBS
304− (qmBS,nextQMBS) = B.splitAt 2 qmBS'
305− qmBS' = B.dropWhile (/= '?') bs
306222
307223-- | Execute an @INSERT@, @UPDATE@, or other SQL query that is not
308224-- expected to return results.
309225--
310226-- Returns the number of rows affected.
311227--
312−-- Throws 'FormatError' if the query could not be formatted correctly, or
313−-- a 'SqlError' exception if the backend returns an error.
314−execute :: (ToRow q) => Connection -> Query -> q -> IO Int64
228+-- Throws 'FormatError' if the query could not be formatted correctly.
229+execute :: (QueryParams q) => Connection -> Query -> q -> IO Int64
315230execute conn template qs = do
316231 result <- exec conn =<< formatQuery conn template qs
317232 finishExecute conn template result
318233
234+-- | A version of 'execute' that does not perform query substitution.
235+execute_ :: Connection -> Query -> IO Int64
236+execute_ conn q@(Query stmt) = do
237+ result <- exec conn stmt
238+ finishExecute conn q result
239+
319240-- | Execute a multi-row @INSERT@, @UPDATE@, or other SQL query that is not
320241-- expected to return results.
321242--
322−-- Returns the number of rows affected. If the list of parameters is empty,
323−-- this function will simply return 0 without issuing the query to the backend.
324−-- If this is not desired, consider using the 'Values' constructor instead.
325−--
326−-- Throws 'FormatError' if the query could not be formatted correctly, or
327−-- a 'SqlError' exception if the backend returns an error.
328−--
329−-- For example, here's a command that inserts two rows into a table
330−-- with two columns:
331−--
332−-- @
333−-- executeMany c [sql|
334−-- INSERT INTO sometable VALUES (?,?)
335−-- |] [(1, \"hello\"),(2, \"world\")]
336−-- @
337−--
338−-- Here's an canonical example of a multi-row update command:
243+-- Returns the number of rows affected.
339244--
340−-- @
341−-- executeMany c [sql|
342−-- UPDATE sometable
343−-- SET y = upd.y
344−-- FROM (VALUES (?,?)) as upd(x,y)
345−-- WHERE sometable.x = upd.x
346−-- |] [(1, \"hello\"),(2, \"world\")]
347−-- @
348−
349−executeMany :: (ToRow q) => Connection -> Query -> [q] -> IO Int64
245+-- Throws 'FormatError' if the query could not be formatted correctly.
246+executeMany :: (QueryParams q) => Connection -> Query -> [q] -> IO Int64
350247executeMany _ _ [] = return 0
351248executeMany conn q qs = do
352249 result <- exec conn =<< formatMany conn q qs
353250 finishExecute conn q result
354251
355−-- | Execute @INSERT ... RETURNING@, @UPDATE ... RETURNING@, or other SQL
356−-- query that accepts multi-row input and is expected to return results.
357−-- Note that it is possible to write
358−-- @'query' conn "INSERT ... RETURNING ..." ...@
359−-- in cases where you are only inserting a single row, and do not need
360−-- functionality analogous to 'executeMany'.
361−--
362−-- If the list of parameters is empty, this function will simply return @[]@
363−-- without issuing the query to the backend. If this is not desired,
364−-- consider using the 'Values' constructor instead.
365−--
366−-- Throws 'FormatError' if the query could not be formatted correctly.
367−returning :: (ToRow q, FromRow r) => Connection -> Query -> [q] -> IO [r]
368−returning = returningWith fromRow
252+finishExecute :: Connection -> Query -> PQ.Result -> IO Int64
253+finishExecute _conn q result = do
254+ status <- PQ.resultStatus result
255+ case status of
256+ PQ.CommandOk -> do
257+ ncols <- PQ.nfields result
258+ if ncols /= 0
259+ then throwIO $ QueryError ("execute resulted in " ++ show ncols ++
260+ "-column result") q
261+ else do
262+ nstr <- PQ.cmdTuples result
263+ return $ case nstr of
264+ Nothing -> 0 -- is this appropriate?
265+ Just str -> toInteger str
266+ PQ.TuplesOk -> do
267+ ncols <- PQ.nfields result
268+ throwIO $ QueryError ("execute resulted in " ++ show ncols ++
269+ "-column result") q
270+ PQ.CopyIn -> fail "FIXME: postgresql-simple does not currently support COPY IN"
271+ PQ.CopyOut -> fail "FIXME: postgresql-simple does not currently support COPY OUT"
272+ _ -> do
273+ errormsg <- maybe "" id <$> PQ.resultErrorMessage result
274+ statusmsg <- PQ.resStatus status
275+ state <- maybe "" id <$> PQ.resultErrorField result PQ.DiagSqlstate
276+ throwIO $ SqlError { sqlState = state
277+ , sqlNativeError = fromEnum status
278+ , sqlErrorMsg = B.concat [ "execute: ", statusmsg
279+ , ": ", errormsg ]}
280+ where
281+ toInteger str = B.foldl' delta 0 str
282+ where
283+ delta acc c =
284+ if '0' <= c && c <= '9'
285+ then 10 * acc + fromIntegral (ord c - ord '0')
286+ else error ("finishExecute: not an int: " ++ B.unpack str)
287+
369288
370−-- | A version of 'returning' taking parser as argument
371−returningWith :: (ToRow q) => RowParser r -> Connection -> Query -> [q] -> IO [r]
372−returningWith _ _ _ [] = return []
373−returningWith parser conn q qs = do
374− result <- exec conn =<< formatMany conn q qs
375− finishQueryWith parser conn q result
376289
377290-- | Perform a @SELECT@ or other SQL query that is expected to return
378291-- results. All results are retrieved and converted before this
@@ -389,27 +302,17 @@ returningWith parser conn q qs = do
389302-- using 'execute' instead of 'query').
390303--
391304-- * 'ResultError': result conversion failed.
392−--
393−-- * 'SqlError': the postgresql backend returned an error, e.g.
394−-- a syntax or type error, or an incorrect table or column name.
395−query :: (ToRow q, FromRow r) => Connection -> Query -> q -> IO [r]
396−query = queryWith fromRow
305+query :: (QueryParams q, FromRow r)
306+ => Connection -> Query -> q -> IO [r]
307+query conn template qs = do
308+ result <- exec conn =<< formatQuery conn template qs
309+ finishQuery conn template result
397310
398311-- | A version of 'query' that does not perform query substitution.
399312query_ :: (FromRow r) => Connection -> Query -> IO [r]
400−query_ = queryWith_ fromRow
401−
402−-- | A version of 'query' taking parser as argument
403−queryWith :: ToRow q => RowParser r -> Connection -> Query -> q -> IO [r]
404−queryWith parser conn template qs = do
405− result <- exec conn =<< formatQuery conn template qs
406− finishQueryWith parser conn template result
407−
408−-- | A version of 'query_' taking parser as argument
409−queryWith_ :: RowParser r -> Connection -> Query -> IO [r]
410−queryWith_ parser conn q@(Query que) = do
313+query_ conn q@(Query que) = do
411314 result <- exec conn que
412− finishQueryWith parser conn q result
315+ finishQuery conn q result
413316
414317-- | Perform a @SELECT@ or other SQL query that is expected to return
415318-- results. Results are streamed incrementally from the server, and
@@ -421,12 +324,6 @@ queryWith_ parser conn q@(Query que) = do
421324-- This fold is /not/ strict. The stream consumer is responsible for
422325-- forcing the evaluation of its result to avoid space leaks.
423326--
424−-- This is implemented using a database cursor. As such, this requires
425−-- a transaction. This function will detect whether or not there is a
426−-- transaction in progress, and will create a 'ReadCommitted' 'ReadOnly'
427−-- transaction if needed. The cursor is given a unique temporary name,
428−-- so the consumer may itself call fold.
429−--
430327-- Exceptions that may be thrown:
431328--
432329-- * 'FormatError': the query string could not be formatted correctly.
@@ -435,10 +332,8 @@ queryWith_ parser conn q@(Query que) = do
435332-- using 'execute' instead of 'query').
436333--
437334-- * 'ResultError': result conversion failed.
438−--
439−-- * 'SqlError': the postgresql backend returned an error, e.g.
440−-- a syntax or type error, or an incorrect table or column name.
441−fold :: ( FromRow row, ToRow params )
335+
336+fold :: ( FromRow row, QueryParams params )
442337 => Connection
443338 -> Query
444339 -> params
@@ -447,20 +342,6 @@ fold :: ( FromRow row, ToRow params )
447342 -> IO a
448343fold = foldWithOptions defaultFoldOptions
449344
450−-- | A version of 'fold' taking a parser as an argument
451−foldWith :: ( ToRow params )
452− => RowParser row
453− -> Connection
454− -> Query
455− -> params
456− -> a
457− -> (a -> row -> IO a)
458− -> IO a
459−foldWith = foldWithOptionsAndParser defaultFoldOptions
460−
461−-- | Number of rows to fetch at a time. 'Automatic' currently defaults
462−-- to 256 rows, although it might be nice to make this more intelligent
463−-- based on e.g. the average size of the rows.
464345data FetchQuantity
465346 = Automatic
466347 | Fixed !Int
@@ -471,20 +352,13 @@ data FoldOptions
471352 transactionMode :: !TransactionMode
472353 }
473354
474−-- | defaults to 'Automatic', and 'TransactionMode' 'ReadCommitted' 'ReadOnly'
475355defaultFoldOptions :: FoldOptions
476356defaultFoldOptions = FoldOptions {
477357 fetchQuantity = Automatic,
478358 transactionMode = TransactionMode ReadCommitted ReadOnly
479359 }
480360
481−-- | The same as 'fold', but this provides a bit more control over
482−-- lower-level details. Currently, the number of rows fetched per
483−-- round-trip to the server and the transaction mode may be adjusted
484−-- accordingly. If the connection is already in a transaction,
485−-- then the existing transaction is used and thus the 'transactionMode'
486−-- option is ignored.
487−foldWithOptions :: ( FromRow row, ToRow params )
361+foldWithOptions :: ( FromRow row, QueryParams params )
488362 => FoldOptions
489363 -> Connection
490364 -> Query
@@ -492,21 +366,9 @@ foldWithOptions :: ( FromRow row, ToRow params )
492366 -> a
493367 -> (a -> row -> IO a)
494368 -> IO a
495−foldWithOptions opts = foldWithOptionsAndParser opts fromRow
496−
497−-- | A version of 'foldWithOptions' taking a parser as an argument
498−foldWithOptionsAndParser :: (ToRow params)
499− => FoldOptions
500− -> RowParser row
501− -> Connection
502− -> Query
503− -> params
504− -> a
505− -> (a -> row -> IO a)
506− -> IO a
507−foldWithOptionsAndParser opts parser conn template qs a f = do
369+foldWithOptions opts conn template qs a f = do
508370 q <- formatQuery conn template qs
509− doFold opts parser conn template (Query q) a f
371+ doFold opts conn template (Query q) a f
510372
511373-- | A version of 'fold' that does not perform query substitution.
512374fold_ :: (FromRow r) =>
@@ -517,14 +379,6 @@ fold_ :: (FromRow r) =>
517379 -> IO a
518380fold_ = foldWithOptions_ defaultFoldOptions
519381
520−-- | A version of 'fold_' taking a parser as an argument
521−foldWith_ :: RowParser r
522− -> Connection
523− -> Query
524− -> a
525− -> (a -> r -> IO a)
526− -> IO a
527−foldWith_ = foldWithOptionsAndParser_ defaultFoldOptions
528382
529383foldWithOptions_ :: (FromRow r) =>
530384 FoldOptions
@@ -533,27 +387,18 @@ foldWithOptions_ :: (FromRow r) =>
533387 -> a -- ^ Initial state for result consumer.
534388 -> (a -> r -> IO a) -- ^ Result consumer.
535389 -> IO a
536−foldWithOptions_ opts conn query' a f = doFold opts fromRow conn query' query' a f
537−
538−-- | A version of 'foldWithOptions_' taking a parser as an argument
539−foldWithOptionsAndParser_ :: FoldOptions
540− -> RowParser r
541− -> Connection
542− -> Query -- ^ Query.
543− -> a -- ^ Initial state for result consumer.
544− -> (a -> r -> IO a) -- ^ Result consumer.
545− -> IO a
546−foldWithOptionsAndParser_ opts parser conn query' a f = doFold opts parser conn query' query' a f
547−
548−doFold :: FoldOptions
549− -> RowParser row
390+foldWithOptions_ opts conn query a f = doFold opts conn query query a f
391+
392+
393+doFold :: ( FromRow row )
394+ => FoldOptions
550395 -> Connection
551396 -> Query
552397 -> Query
553398 -> a
554399 -> (a -> row -> IO a)
555400 -> IO a
556−doFold FoldOptions{..} parser conn _template q a0 f = do
401+doFold FoldOptions{..} conn _template q a f = do
557402 stat <- withConnection conn PQ.transactionStatus
558403 case stat of
559404 PQ.TransIdle -> withTransactionMode transactionMode conn go
@@ -571,17 +416,11 @@ doFold FoldOptions{..} parser conn _template q a0 f = do
571416 PQ.TransUnknown -> fail "foldWithOpts FIXME: PQ.TransUnknown"
572417 -- Not sure what this means.
573418 where
574− declare =
575− declareCursor conn q
576− fetch cursor a =
577− foldForwardWithParser cursor parser chunkSize f a
578−
579− go = bracket declare closeCursor $ \cursor ->
580− let loop a = fetch cursor a >>=
581− \r -> case r of
582− Left x -> return x
583− Right x -> loop x
584− in loop a0
419+ go = do
420+ -- FIXME: what about name clashes with already-declared cursors?
421+ _ <- execute_ conn ("DECLARE fold NO SCROLL CURSOR FOR "
422+ `mappend` q)
423+ loop a `finally` execute_ conn "CLOSE fold"
585424
586425-- FIXME: choose the Automatic chunkSize more intelligently
587426-- One possibility is to use the type of the results, although this
@@ -592,45 +431,200 @@ doFold FoldOptions{..} parser conn _template q a0 f = do
592431 chunkSize = case fetchQuantity of
593432 Automatic -> 256
594433 Fixed n -> n
434+ loop a = do
435+ rs <- query conn "FETCH FORWARD ? FROM fold" (Only chunkSize)
436+ if null rs then return a else foldM f a rs >>= loop
595437
596438-- | A version of 'fold' that does not transform a state value.
597−forEach :: (ToRow q, FromRow r) =>
439+forEach :: (QueryParams q, FromRow r) =>
598440 Connection
599441 -> Query -- ^ Query template.
600442 -> q -- ^ Query parameters.
601443 -> (r -> IO ()) -- ^ Result consumer.
602444 -> IO ()
603−forEach = forEachWith fromRow
445+forEach conn template qs = fold conn template qs () . const
604446{-# INLINE forEach #-}
605447
606−-- | A version of 'forEach' taking a parser as an argument
607−forEachWith :: ( ToRow q )
608− => RowParser r
609− -> Connection
610− -> Query
611− -> q
612− -> (r -> IO ())
613− -> IO ()
614−forEachWith parser conn template qs = foldWith parser conn template qs () . const
615−{-# INLINE forEachWith #-}
616−
617448-- | A version of 'forEach' that does not perform query substitution.
618449forEach_ :: (FromRow r) =>
619450 Connection
620451 -> Query -- ^ Query template.
621452 -> (r -> IO ()) -- ^ Result consumer.
622453 -> IO ()
623−forEach_ = forEachWith_ fromRow
454+forEach_ conn template = fold_ conn template () . const
624455{-# INLINE forEach_ #-}
625456
626−forEachWith_ :: RowParser r
627− -> Connection
628− -> Query
629− -> (r -> IO ())
630− -> IO ()
631−forEachWith_ parser conn template = foldWith_ parser conn template () . const
632−{-# INLINE forEachWith_ #-}
633−
457+forM' :: (Ord n, Num n) => n -> n -> (n -> IO a) -> IO [a]
458+forM' lo hi m = loop hi []
459+ where
460+ loop !n !as
461+ | n < lo = return as
462+ | otherwise = do
463+ a <- m n
464+ loop (n-1) (a:as)
465+
466+finishQuery :: (FromRow r) => Connection -> Query -> PQ.Result -> IO [r]
467+finishQuery conn q result = do
468+ status <- PQ.resultStatus result
469+ case status of
470+ PQ.CommandOk -> do
471+ throwIO $ QueryError "query resulted in a command response" q
472+ PQ.TuplesOk -> do
473+ ncols <- PQ.nfields result
474+ let unCol (PQ.Col x) = fromIntegral x
475+ typenames <- V.generateM (unCol ncols)
476+ (\(PQ.Col . fromIntegral -> col) -> do
477+ getTypename conn =<< PQ.ftype result col)
478+ nrows <- PQ.ntuples result
479+ ncols <- PQ.nfields result
480+ forM' 0 (nrows-1) $ \row -> do
481+ let rw = Row row typenames result
482+ case runStateT (runReaderT (unRP fromRow) rw) 0 of
483+ Ok (val,col) | col == ncols -> return val
484+ | otherwise -> do
485+ vals <- forM' 0 (ncols-1) $ \c -> do
486+ v <- PQ.getvalue result row c
487+ return ( typenames V.! unCol c
488+ , fmap ellipsis v )
489+ throw (ConversionFailed
490+ (show (unCol ncols) ++ " values: " ++ show vals)
491+ (show (unCol col) ++ " slots in target type")
492+ "mismatch between number of columns to \
493+ \convert and number in target type")
494+ Errors [] -> throwIO $ ConversionFailed "" "" "unknown error"
495+ Errors [x] -> throwIO x
496+ Errors xs -> throwIO $ ManyErrors xs
497+
498+ellipsis :: ByteString -> ByteString
499+ellipsis bs
500+ | B.length bs > 15 = B.take 10 bs `B.append` "[...]"
501+ | otherwise = bs
502+
503+-- | Throw a 'ConversionFailed' exception, indicating a mismatch
504+-- between the number of columns in the 'Field' and row, and the
505+-- number in the collection to be converted to.
506+convertError :: [Field]
507+ -- ^ Descriptors of fields to be converted.
508+ -> [Maybe ByteString]
509+ -- ^ Contents of the row to be converted.
510+ -> Int
511+ -- ^ Number of columns expected for conversion. For
512+ -- instance, if converting to a 3-tuple, the number to
513+ -- provide here would be 3.
514+ -> Either SomeException a
515+convertError fs vs n = Left . SomeException $ ConversionFailed
516+ (show (length fs) ++ " values: " ++ show (zip (map typename fs)
517+ (map (fmap ellipsis) vs)))
518+ (show n ++ " slots in target type")
519+ "mismatch between number of columns to convert and number in target type"
520+
521+
522+-- | Of the four isolation levels defined by the SQL standard,
523+-- these are the three levels distinguished by PostgreSQL as of version 9.0.
524+-- See <http://www.postgresql.org/docs/9.1/static/transaction-iso.html>
525+-- for more information.
526+
527+data IsolationLevel
528+ = DefaultIsolationLevel
529+ | ReadCommitted
530+ | RepeatableRead
531+ | Serializable
532+ deriving (Show, Eq, Ord, Enum, Bounded)
533+
534+data ReadWriteMode
535+ = ReadWrite
536+ | ReadOnly
537+ deriving (Show, Eq, Ord, Enum, Bounded)
538+
539+data TransactionMode = TransactionMode {
540+ isolationLevel :: !IsolationLevel,
541+ readWriteMode :: !ReadWriteMode
542+ } deriving (Show, Eq)
543+
544+defaultTransactionMode :: TransactionMode
545+defaultTransactionMode = TransactionMode DefaultIsolationLevel ReadWrite
546+
547+defaultIsolationLevel :: IsolationLevel
548+defaultIsolationLevel = ReadCommitted
549+
550+defaultReadWriteMode :: ReadWriteMode
551+defaultReadWriteMode = ReadWrite
552+
553+-- | Execute an action inside a SQL transaction.
554+--
555+-- This function initiates a transaction with a \"@begin
556+-- transaction@\" statement, then executes the supplied action. If
557+-- the action succeeds, the transaction will be completed with
558+-- 'Base.commit' before this function returns.
559+--
560+-- If the action throws /any/ kind of exception (not just a
561+-- PostgreSQL-related exception), the transaction will be rolled back using
562+-- 'rollback', then the exception will be rethrown.
563+withTransaction :: Connection -> IO a -> IO a
564+withTransaction = withTransactionMode defaultTransactionMode
565+
566+-- | Execute an action inside a SQL transaction with a given isolation level.
567+withTransactionLevel :: IsolationLevel -> Connection -> IO a -> IO a
568+withTransactionLevel lvl
569+ = withTransactionMode defaultTransactionMode { isolationLevel = lvl }
570+
571+-- | Execute an action inside a SQL transaction with a given transaction mode.
572+withTransactionMode :: TransactionMode -> Connection -> IO a -> IO a
573+withTransactionMode mode conn act =
574+ mask $ \restore -> do
575+ beginMode mode conn
576+ r <- restore act `onException` rollback conn
577+ commit conn
578+ return r
579+
580+-- | Rollback a transaction.
581+rollback :: Connection -> IO ()
582+rollback conn = execute_ conn "ABORT" >> return ()
583+
584+-- | Commit a transaction.
585+commit :: Connection -> IO ()
586+commit conn = execute_ conn "COMMIT" >> return ()
587+
588+-- | Begin a transaction.
589+begin :: Connection -> IO ()
590+begin = beginMode defaultTransactionMode
591+
592+-- | Begin a transaction with a given isolation level
593+beginLevel :: IsolationLevel -> Connection -> IO ()
594+beginLevel lvl = beginMode defaultTransactionMode { isolationLevel = lvl }
595+
596+-- | Begin a transaction with a given transaction mode
597+beginMode :: TransactionMode -> Connection -> IO ()
598+beginMode mode conn = do
599+ _ <- execute_ conn $!
600+ case mode of
601+ TransactionMode DefaultIsolationLevel ReadWrite ->
602+ "BEGIN"
603+ TransactionMode DefaultIsolationLevel ReadOnly ->
604+ "BEGIN READ ONLY"
605+ TransactionMode ReadCommitted ReadWrite ->
606+ "BEGIN ISOLATION LEVEL READ COMMITTED"
607+ TransactionMode ReadCommitted ReadOnly ->
608+ "BEGIN ISOLATION LEVEL READ COMMITTED READ ONLY"
609+ TransactionMode RepeatableRead ReadWrite ->
610+ "BEGIN ISOLATION LEVEL REPEATABLE READ"
611+ TransactionMode RepeatableRead ReadOnly ->
612+ "BEGIN ISOLATION LEVEL REPEATABLE READ READ ONLY"
613+ TransactionMode Serializable ReadWrite ->
614+ "BEGIN ISOLATION LEVEL SERIALIZABLE"
615+ TransactionMode Serializable ReadOnly ->
616+ "BEGIN ISOLATION LEVEL SERIALIZABLE READ ONLY"
617+ return ()
618+
619+fmtError :: String -> Query -> [Action] -> a
620+fmtError msg q xs = throw FormatError {
621+ fmtMessage = msg
622+ , fmtQuery = q
623+ , fmtParams = map twiddle xs
624+ }
625+ where twiddle (Plain b) = toByteString b
626+ twiddle (Escape s) = s
627+ twiddle (Many ys) = B.concat (map twiddle ys)
634628
635629-- $use
636630--
@@ -658,11 +652,9 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
658652-- >
659653-- > import Database.PostgreSQL.Simple
660654-- >
661−-- > hello :: IO Int
662655-- > hello = do
663−-- > conn <- connectPostgreSQL ""
664−-- > [Only i] <- query_ conn "select 2 + 2"
665−-- > return i
656+-- > conn <- connect defaultConnectInfo
657+-- > query conn "select 2 + 2"
666658--
667659-- A 'Query' value does not represent the actual query that will be
668660-- executed, but is a template for constructing the final query.
@@ -709,7 +701,7 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
709701-- Automated type inference means that you will often be able to avoid
710702-- supplying explicit type signatures for the elements of a tuple.
711703-- However, sometimes the compiler will not be able to infer your
712−-- types. Consider a case where you write a numeric literal in a
704+-- types. Consider a care where you write a numeric literal in a
713705-- parameter tuple:
714706--
715707-- > query conn "select ? + ?" (40,2)
@@ -723,30 +715,15 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
723715-- The same kind of problem can arise with string literals if you have
724716-- the @OverloadedStrings@ language extension enabled. Again, just
725717-- use an explicit type signature if this happens.
726−--
727−-- Finally, remember that the compiler must be able to infer the type
728−-- of a query's /results/ as well as its parameters. We might like
729−-- the following example to work:
730−--
731−-- > print =<< query_ conn "select 2 + 2"
732−--
733−-- Unfortunately, while a quick glance tells us that the result type
734−-- should be a single row containing a single numeric column, the
735−-- compiler has no way to infer what the types are. We can easily fix
736−-- this by providing an explicit type annotation:
737−--
738−-- > xs <- query_ conn "select 2 + 2"
739−-- > print (xs :: [Only Int])
740718
741719-- $only_param
742720--
743721-- Haskell lacks a single-element tuple type, so if you have just one
744−-- value you want substituted into a query or a single-column result,
745−-- what should you do?
722+-- value you want substituted into a query, what should you do?
746723--
747724-- The obvious approach would appear to be something like this:
748725--
749−-- > instance (ToField a) => ToRow a where
726+-- > instance (Param a) => QueryParam a where
750727-- > ...
751728--
752729-- Unfortunately, this wreaks havoc with type inference, so we take a
@@ -757,9 +734,6 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
757734--
758735-- > execute conn "insert into users (first_name) values (?)"
759736-- > ["Nuala"]
760−--
761−-- A row of /n/ query results is represented using an /n/-tuple, so
762−-- you should use 'Only' to represent a single-column result.
763737
764738-- $in
765739--
@@ -777,7 +751,7 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
777751-- Here's an example:
778752--
779753-- > query conn "select * from users where first_name in ?" $
780−-- > Only $ In ["Anna", "Boris", "Carla"]
754+-- > In ["Anna", "Boris", "Carla"]
781755--
782756-- If your 'In'-wrapped list is empty, the string @\"(null)\"@ will be
783757-- substituted instead, to ensure that your clause remains
@@ -805,7 +779,7 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
805779-- * There must be no other \"@?@\" characters anywhere in your
806780-- template.
807781--
808−-- * There must be one or more \"@?@\" in the parentheses.
782+-- * There must one or more \"@?@\" in the parentheses.
809783--
810784-- * Extra white space is fine.
811785--
@@ -826,22 +800,6 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
826800-- > insert into users (first_name,last_name) values
827801-- > ('Boris','Karloff'),('Ed','Wood')
828802
829−-- $returning
830−--
831−-- PostgreSQL supports returning values from data manipulation statements
832−-- such as @INSERT@ and @UPDATE@. You can use these statements by
833−-- using 'query' instead of 'execute'. For multi-tuple inserts,
834−-- use 'returning' instead of 'executeMany'.
835−--
836−-- For example, were there an auto-incrementing @id@ column and
837−-- timestamp column @t@ that defaulted to the present time for the
838−-- @sales@ table, then the following query would insert two new
839−-- sales records and also return their new @id@s and timestamps.
840−--
841−-- > let q = "insert into sales (amount, label) values (?,?) returning id, t"
842−-- > xs :: [(Int, UTCTime)] <- query conn q (15,"Sawdust")
843−-- > ys :: [(Int, UTCTime)] <- returning conn q [(20,"Chips"),(300,"Wood")]
844−
845803-- $result
846804--
847805-- The 'query' and 'query_' functions return a list of values in the
@@ -876,7 +834,7 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
876834--
877835-- Although SQL can accommodate @NULL@ as a value for any of these
878836-- types, Haskell cannot. If your result contains columns that may be
879−-- @NULL@, be sure that you use 'Maybe' in those positions of your
837+-- @NULL@, be sure that you use 'Maybe' in those positions of of your
880838-- tuple.
881839--
882840-- > (Text, Maybe Int, Int)
@@ -902,7 +860,7 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
902860-- all values of the given PostgreSQL type is considered \"compatible\".
903861-- For instance, you can always extract a PostgreSQL 16-bit @SMALLINT@
904862-- column to a Haskell 'Int'. The Haskell 'Float' type can accurately
905−-- represent a @SMALLINT@, so it is considered compatible with those types.
863+-- represent a @SMALLINT@, so it is considered compatble with those types.
906864--
907865-- * A numeric compatibility check is based only on the type of a
908866-- column, /not/ on its values. For instance, a PostgreSQL 64-bit
@@ -916,3 +874,25 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
916874-- UTF-8. If you use some other encoding, decoding may fail or give
917875-- wrong results. In such cases, write a @newtype@ wrapper and a
918876-- custom 'Result' instance to handle your encoding.
877+
878+getTypename :: Connection -> PQ.Oid -> IO ByteString
879+getTypename conn@Connection{..} oid =
880+ case oid2builtin oid of
881+ Just builtin -> return $! builtin2typname builtin
882+ Nothing -> modifyMVar connectionObjects $ \oidmap -> do
883+ case IntMap.lookup (oid2int oid) oidmap of
884+ Just name -> return (oidmap, name)
885+ Nothing -> do
886+ names <- query conn "SELECT typname FROM pg_type WHERE oid=?"
887+ (Only oid)
888+ name <- case names of
889+ [] -> return $ throw SqlError {
890+ sqlNativeError = -1,
891+ sqlErrorMsg = "invalid type oid",
892+ sqlState = ""
893+ }
894+ [Only x] -> return x
895+ _ -> fail "typename query returned more than one result"
896+ -- oid is a primary key, so the query should
897+ -- never return more than one result
898+ return (IntMap.insert (oid2int oid) name oidmap, name)