@@ -1,18 +1,14 @@
1−{-# LANGUAGE DeriveDataTypeable #-}
1+{-# LANGUAGE BangPatterns, DeriveDataTypeable, OverloadedStrings #-}
2−{-# LANGUAGE NamedFieldPuns #-}
3−{-# LANGUAGE OverloadedStrings #-}
4−{-# LANGUAGE PatternGuards #-}
5−{-# LANGUAGE RecordWildCards #-}
2+{-# LANGUAGE DoAndIfThenElse, RecordWildCards, NamedFieldPuns #-}
6−{-# LANGUAGE ViewPatterns #-}
8------------------------------------------------------------------------------
3------------------------------------------------------------------------------
10-- Module: Database.PostgreSQL.Simple
5-- Module: Database.PostgreSQL.Simple
11-- Copyright: (c) 2011 MailRank, Inc.
6-- Copyright: (c) 2011 MailRank, Inc.
12−-- (c) 2011-2012 Leon P Smith
7+-- (c) 2011 Leon P Smith
13-- License: BSD3
8-- License: BSD3
14-- Maintainer: Leon P Smith <leon@melding-monads.com>
9-- Maintainer: Leon P Smith <leon@melding-monads.com>
15-- Stability: experimental
10-- Stability: experimental
11+-- Portability: portable
17-- A mid-level client library for the PostgreSQL database, aimed at ease of
13-- A mid-level client library for the PostgreSQL database, aimed at ease of
18-- use and high performance.
14-- use and high performance.
@@ -42,9 +38,6 @@ module Database.PostgreSQL.Simple
42 -- ** Modifying multiple rows at once
38 -- ** Modifying multiple rows at once
45− -- ** @RETURNING@: modifications that return results
48 -- * Extracting results
41 -- * Extracting results
49 -- $result
42 -- $result
@@ -55,54 +48,32 @@ module Database.PostgreSQL.Simple
57 -- * Types
50 -- * Types
58− Connection
52+ , Connection
63 , Binary(..)
55 , Binary(..)
64 , Only(..)
56 , Only(..)
66 -- ** Exceptions
57 -- ** Exceptions
67− , SomePostgreSqlException(..)
70− , FormatError(..)
58+ , FormatError(fmtMessage, fmtQuery, fmtParams)
71− , QueryError(..)
59+ , QueryError(qeMessage, qeQuery)
72− , ResultError(..)
60+ , ResultError(errSQLType, errHaskellType, errMessage)
73 -- * Connection management
61 -- * Connection management
74− , Base.connectPostgreSQL
76 , Base.connect
62 , Base.connect
77− , Base.withConnect
63+ , Base.connectPostgreSQL
78− , Base.ConnectInfo(..)
79− , Base.defaultConnectInfo
80 , Base.postgreSQLConnectionString
64 , Base.postgreSQLConnectionString
65+ , Base.defaultConnectInfo
81 -- * Queries that return results
67 -- * Queries that return results
84− -- ** Queries taking parser as argument
70+{--
87 -- * Queries that stream results
71 -- * Queries that stream results
96 , forEach_
75 , forEach_
98− -- ** Queries that stream results taking a parser as an argument
100− , foldWithOptionsAndParser
102− , foldWithOptionsAndParser_
106 -- * Statements that do not return results
77 -- * Statements that do not return results
107 , execute
78 , execute
108 , execute_
79 , execute_
@@ -110,7 +81,6 @@ module Database.PostgreSQL.Simple
110-- , Base.insertID
81-- , Base.insertID
111 -- * Transaction handling
82 -- * Transaction handling
112 , withTransaction
83 , withTransaction
114-- , Base.autocommit
84-- , Base.autocommit
@@ -120,27 +90,55 @@ module Database.PostgreSQL.Simple
120 , formatQuery
90 , formatQuery
123−import Data.ByteString.Builder (Builder, byteString, char8)
93+import Blaze.ByteString.Builder (Builder, fromByteString, toByteString)
94+import Blaze.ByteString.Builder.Char8 (fromChar)
124−import Control.Applicative ((<$>))
95+import Control.Applicative ((<$>), pure)
125−import Control.Exception as E
96+import Control.Concurrent.MVar
97+import Control.Exception (Exception, bracket, onException, throw, throwIO)
98+import Control.Monad (forM)
99+import Control.Monad.Fix (fix)
126−import Data.ByteString (ByteString)
100+import Data.ByteString (ByteString)
101+-- import qualified Data.ByteString as B (unpack)
102+import Data.Char(ord)
127−import Data.Int (Int64)
103+import Data.Int (Int64)
104+import qualified Data.IntMap as IntMap
128−import Data.List (intersperse)
105+import Data.List (intersperse)
129−import Data.Monoid (mconcat)
106+import Data.Monoid (mappend, mconcat)
130−import Database.PostgreSQL.Simple.Compat ((<>), toByteString)
107+import Data.Typeable (Typeable)
131−import Database.PostgreSQL.Simple.Cursor
108+--import Database.MySQL.Base (Connection, Result)
132−import Database.PostgreSQL.Simple.FromField (ResultError(..))
109+--import Database.MySQL.Base.Types (Field)
133−import Database.PostgreSQL.Simple.FromRow (FromRow(..))
110+import Database.PostgreSQL.Simple.BuiltinTypes (oid2builtin, builtin2typname)
134−import Database.PostgreSQL.Simple.ToField (Action(..))
111+import Database.PostgreSQL.Simple.Param (Action(..), inQuotes)
135−import Database.PostgreSQL.Simple.ToRow (ToRow(..))
112+import Database.PostgreSQL.Simple.QueryParams (QueryParams(..))
136−import Database.PostgreSQL.Simple.Types
113+import Database.PostgreSQL.Simple.Result (ResultError(..))
114+import Database.PostgreSQL.Simple.QueryResults (QueryResults(..))
115+-- import Database.PostgreSQL.Simple.Result (ResultError(..))
137− ( Binary(..), In(..), Only(..), Query(..), (:.)(..) )
116+import Database.PostgreSQL.Simple.Types (Binary(..), In(..), Only(..), Query(..))
138−import Database.PostgreSQL.Simple.Internal as Base
117+import Database.PostgreSQL.Simple.Internal as Base
139−import Database.PostgreSQL.Simple.Internal.PQResultUtils
140−import Database.PostgreSQL.Simple.Transaction
141import qualified Database.PostgreSQL.LibPQ as PQ
118import qualified Database.PostgreSQL.LibPQ as PQ
119+import Text.Regex.PCRE.Light (compile, caseless, match)
142import qualified Data.ByteString.Char8 as B
120import qualified Data.ByteString.Char8 as B
121+--import qualified Database.MySQL.Base as Base
123+-- | Exception thrown if a 'Query' could not be formatted correctly.
124+-- This may occur if the number of \'@?@\' characters in the query
125+-- string does not match the number of parameters provided.
126+data FormatError = FormatError {
127+ fmtMessage :: String
129+ , fmtParams :: [ByteString]
130+ } deriving (Eq, Show, Typeable)
132+instance Exception FormatError
134+-- | Exception thrown if 'query' is used to perform an @INSERT@-like
135+-- operation, or 'execute' is used to perform a @SELECT@-like operation.
136+data QueryError = QueryError {
139+ } deriving (Eq, Show, Typeable)
141+instance Exception QueryError
145-- | Format a query string.
143-- | Format a query string.
@@ -152,11 +150,11 @@ import qualified Data.ByteString.Char8 as B
153-- Throws 'FormatError' if the query string could not be formatted
151-- Throws 'FormatError' if the query string could not be formatted
154-- correctly.
152-- correctly.
155−formatQuery :: ToRow q => Connection -> Query -> q -> IO ByteString
153+formatQuery :: QueryParams q => Connection -> Query -> q -> IO ByteString
156formatQuery conn q@(Query template) qs
154formatQuery conn q@(Query template) qs
157 | null xs && '?' `B.notElem` template = return template
155 | null xs && '?' `B.notElem` template = return template
158 | otherwise = toByteString <$> buildQuery conn q template xs
156 | otherwise = toByteString <$> buildQuery conn q template xs
159− where xs = toRow qs
157+ where xs = renderParams qs
161-- | Format a query string with a variable number of rows.
159-- | Format a query string with a variable number of rows.
@@ -171,208 +169,106 @@ formatQuery conn q@(Query template) qs
172-- Throws 'FormatError' if the query string could not be formatted
170-- Throws 'FormatError' if the query string could not be formatted
173-- correctly.
171-- correctly.
174−formatMany :: (ToRow q) => Connection -> Query -> [q] -> IO ByteString
172+formatMany :: (QueryParams q) => Connection -> Query -> [q] -> IO ByteString
175formatMany _ q [] = fmtError "no rows supplied" q []
173formatMany _ q [] = fmtError "no rows supplied" q []
176formatMany conn q@(Query template) qs = do
174formatMany conn q@(Query template) qs = do
177− case parseTemplate template of
175+ case match re template [] of
178− Just (before, qbits, after) -> do
176+ Just [_,before,qbits,after] -> do
179− bs <- mapM (buildQuery conn q qbits . toRow) qs
177+ bs <- mapM (buildQuery conn q qbits . renderParams) qs
180− return . toByteString . mconcat $ byteString before :
178+ return . toByteString . mconcat $ fromByteString before :
181− intersperse (char8 ',') bs ++
179+ intersperse (fromChar ',') bs ++
182− [byteString after]
180+ [fromByteString after]
183− Nothing -> fmtError "syntax error in multi-row template" q []
181+ _ -> error "foo"
185−-- Split the input string into three pieces, @before@, @qbits@, and @after@,
186−-- following this grammar:
188−-- start: ^ before qbits after $
189−-- before: ([^?]* [^?\w])? 'VALUES' \s*
190−-- qbits: '(' \s* '?' \s* (',' \s* '?' \s*)* ')'
194−-- \w: [A-Z] | [a-z] | [\x80-\xFF] | '_' | '$' | [0-9]
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
204− -- Search for the next occurrence of "VALUES"
183+ re = compile "^([^?]+\\bvalues\\s*)\
205− search bs =
184+ \(\\(\\s*[?](?:\\s*,\\s*[?])*\\s*\\))\
206− case B.breakSubstring "VALUES" bs of
185+ \([^?]*)$"
207− (x, y)
186+ [caseless]
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)
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
218− -- Otherwise, we have a legitimate "VALUES" token.
220− -> parseQueryBits $ skipSpace $ B.drop 6 y
222− -- Parse '(' \s* '?' \s* . If this doesn't match
223− -- (and we don't consume a '?'), look for another "VALUES".
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.
229− | Just ('(', skipSpace -> bs1) <- B.uncons qb
230− , Just ('?', skipSpace -> bs2) <- B.uncons bs1
231− = finishQueryBits qb bs2
235− -- Parse (',' \s* '?' \s*)* ')' [^?]* .
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
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
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.
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 =
260− (s1, source') = B.splitAt (B.length source - B.length p1) source
261− (s2, source'') = B.splitAt (B.length p1 - B.length p2) source'
263− toUpper_ascii c | c >= 'a' && c <= 'z' = toEnum (fromEnum c - 32)
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')
275− -- Based on {space} in scan.l
276− isSpace_ascii c = (c == ' ') || (c >= '\t' && c <= '\r')
278− skipSpace = B.dropWhile isSpace_ascii
188+escapeStringConn conn s = withConnection conn $ \c -> do
189+ PQ.escapeStringConn c s
281buildQuery :: Connection -> Query -> ByteString -> [Action] -> IO Builder
191buildQuery :: Connection -> Query -> ByteString -> [Action] -> IO Builder
282−buildQuery conn q template xs =
192+buildQuery conn q template xs = zipParams (split template) <$> mapM sub xs
283− zipParams (split template) <$> mapM (buildAction conn q xs) xs
193+ where quote = inQuotes . fromByteString . maybe undefined id
284− where split s =
194+ sub (Plain b) = pure b
285− -- This part escapes double '??'s to make literal '?'s possible
195+ sub (Escape s) = quote <$> escapeStringConn conn s
286− -- in PostgreSQL queries using the JSON operators: @?@, @?|@ and @?&@
196+ sub (Many ys) = mconcat <$> mapM sub ys
287− let (h,t) = breakOnSingleQuestionMark s
291− else split (B.tail t)
197+ split s = fromByteString h : if B.null t then [] else split (B.tail t)
198+ where (h,t) = B.break (=='?') s
292− zipParams (t:ts) (p:ps) = t <> p <> zipParams ts ps
199+ zipParams (t:ts) (p:ps) = t `mappend` p `mappend` zipParams ts ps
293 zipParams [t] [] = t
200 zipParams [t] [] = t
294− zipParams _ _ = fmtError (show countSingleQs ++
201+ zipParams _ _ = fmtError (show (B.count '?' template) ++
295− " single '?' characters, but " ++
202+ " '?' characters, but " ++
296 show (length xs) ++ " parameters") q xs
203 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
303− where qms = B.splitAt 1 qmBS
304− (qmBS,nextQMBS) = B.splitAt 2 qmBS'
305− qmBS' = B.dropWhile (/= '?') bs
307-- | Execute an @INSERT@, @UPDATE@, or other SQL query that is not
205-- | Execute an @INSERT@, @UPDATE@, or other SQL query that is not
308-- expected to return results.
206-- expected to return results.
310-- Returns the number of rows affected.
208-- Returns the number of rows affected.
312−-- Throws 'FormatError' if the query could not be formatted correctly, or
210+-- Throws 'FormatError' if the query could not be formatted correctly.
313−-- a 'SqlError' exception if the backend returns an error.
314−execute :: (ToRow q) => Connection -> Query -> q -> IO Int64
211+execute :: (QueryParams q) => Connection -> Query -> q -> IO Int64
315execute conn template qs = do
212execute conn template qs = do
316 result <- exec conn =<< formatQuery conn template qs
213 result <- exec conn =<< formatQuery conn template qs
317 finishExecute conn template result
214 finishExecute conn template result
216+-- | A version of 'execute' that does not perform query substitution.
217+execute_ :: Connection -> Query -> IO Int64
218+execute_ conn q@(Query stmt) = do
219+ result <- exec conn stmt
220+ finishExecute conn q result
319-- | Execute a multi-row @INSERT@, @UPDATE@, or other SQL query that is not
222-- | Execute a multi-row @INSERT@, @UPDATE@, or other SQL query that is not
320-- expected to return results.
223-- expected to return results.
322−-- Returns the number of rows affected. If the list of parameters is empty,
225+-- Returns the number of rows affected.
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.
326−-- Throws 'FormatError' if the query could not be formatted correctly, or
327−-- a 'SqlError' exception if the backend returns an error.
329−-- For example, here's a command that inserts two rows into a table
333−-- executeMany c [sql|
334−-- INSERT INTO sometable VALUES (?,?)
335−-- |] [(1, \"hello\"),(2, \"world\")]
338−-- Here's an canonical example of a multi-row update command:
340−-- @
227+-- Throws 'FormatError' if the query could not be formatted correctly.
341−-- executeMany c [sql|
344−-- FROM (VALUES (?,?)) as upd(x,y)
345−-- WHERE sometable.x = upd.x
346−-- |] [(1, \"hello\"),(2, \"world\")]
349−executeMany :: (ToRow q) => Connection -> Query -> [q] -> IO Int64
228+executeMany :: (QueryParams q) => Connection -> Query -> [q] -> IO Int64
350executeMany _ _ [] = return 0
229executeMany _ _ [] = return 0
351executeMany conn q qs = do
230executeMany conn q qs = do
352 result <- exec conn =<< formatMany conn q qs
231 result <- exec conn =<< formatMany conn q qs
353 finishExecute conn q result
232 finishExecute conn q result
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'.
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.
366−-- Throws 'FormatError' if the query could not be formatted correctly.
367−returning :: (ToRow q, FromRow r) => Connection -> Query -> [q] -> IO [r]
234+finishExecute :: Connection -> Query -> PQ.Result -> IO Int64
368−returning = returningWith fromRow
235+finishExecute conn q result = do
236+ status <- PQ.resultStatus result
238+ PQ.EmptyQuery -> fail "empty query" -- FIXME: error message
240+ ncols <- PQ.nfields result
242+ then throwIO $ QueryError ("execute resulted in " ++ show ncols ++
245+ nstr <- PQ.cmdTuples result
246+ return $ case nstr of
247+ Nothing -> 0 -- is this appropriate?
248+ Just str -> toInteger str
250+ ncols <- PQ.nfields result
251+ throwIO $ QueryError ("execute resulted in " ++ show ncols ++
253+ PQ.CopyIn -> fail "FIXME: postgresql-simple does not currently support COPY IN"
254+ PQ.CopyOut -> fail "FIXME: postgresql-simple does not currently support COPY OUT"
256+ errormsg <- maybe "" id <$> PQ.resultErrorMessage result
257+ statusmsg <- PQ.resStatus status
258+ state <- maybe "" id <$> PQ.resultErrorField result PQ.DiagSqlstate
259+ throw $ SqlError { sqlState = state
260+ , sqlNativeError = 0 -- FIXME
261+ , sqlErrorMsg = B.concat [ "execute: ", statusmsg
264+ toInteger str = B.foldl' delta 0 str
267+ if '0' <= c && c <= '9'
268+ then 10 * acc + fromIntegral (ord c - ord '0')
269+ else error ("finishExecute: not an int: " ++ B.unpack str)
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
377-- | Perform a @SELECT@ or other SQL query that is expected to return
273-- | Perform a @SELECT@ or other SQL query that is expected to return
378-- results. All results are retrieved and converted before this
274-- results. All results are retrieved and converted before this
@@ -389,44 +285,33 @@ returningWith parser conn q qs = do
389-- using 'execute' instead of 'query').
285-- using 'execute' instead of 'query').
391-- * 'ResultError': result conversion failed.
287-- * 'ResultError': result conversion failed.
392−--
288+query :: (QueryParams q, QueryResults r)
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
398−-- | A version of 'query' that does not perform query substitution.
399−query_ :: (FromRow r) => Connection -> Query -> IO [r]
400−query_ = queryWith_ fromRow
402−-- | A version of 'query' taking parser as argument
403−queryWith :: ToRow q => RowParser r -> Connection -> Query -> q -> IO [r]
289+ => Connection -> Query -> q -> IO [r]
404−queryWith parser conn template qs = do
290+query conn template qs = do
405 result <- exec conn =<< formatQuery conn template qs
291 result <- exec conn =<< formatQuery conn template qs
406− finishQueryWith parser conn template result
292+ finishQuery conn template result
408−-- | A version of 'query_' taking parser as argument
294+-- | A version of 'query' that does not perform query substitution.
409−queryWith_ :: RowParser r -> Connection -> Query -> IO [r]
295+query_ :: (QueryResults r) => Connection -> Query -> IO [r]
410−queryWith_ parser conn q@(Query que) = do
296+query_ conn q@(Query que) = do
411 result <- exec conn que
297 result <- exec conn que
412− finishQueryWith parser conn q result
298+ finishQuery conn q result
414-- | Perform a @SELECT@ or other SQL query that is expected to return
300-- | Perform a @SELECT@ or other SQL query that is expected to return
415-- results. Results are streamed incrementally from the server, and
301-- results. Results are streamed incrementally from the server, and
416-- consumed via a left fold.
302-- consumed via a left fold.
304+-- The result consumer must be carefully written to execute
305+-- quickly. If the consumer is slow, server resources will be tied up,
306+-- and other clients may not be able to update the tables from which
307+-- the results are being streamed.
418-- When dealing with small results, it may be simpler (and perhaps
309-- When dealing with small results, it may be simpler (and perhaps
419-- faster) to use 'query' instead.
310-- faster) to use 'query' instead.
421-- This fold is /not/ strict. The stream consumer is responsible for
312-- This fold is /not/ strict. The stream consumer is responsible for
422-- forcing the evaluation of its result to avoid space leaks.
313-- forcing the evaluation of its result to avoid space leaks.
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.
430-- Exceptions that may be thrown:
315-- Exceptions that may be thrown:
432-- * 'FormatError': the query string could not be formatted correctly.
317-- * 'FormatError': the query string could not be formatted correctly.
@@ -435,202 +320,164 @@ queryWith_ parser conn q@(Query que) = do
435-- using 'execute' instead of 'query').
320-- using 'execute' instead of 'query').
437-- * 'ResultError': result conversion failed.
322-- * 'ResultError': result conversion failed.
438−--
323+fold :: (QueryParams q, QueryResults r) =>
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 )
446− -> (a -> row -> IO a)
448−fold = foldWithOptions defaultFoldOptions
450−-- | A version of 'fold' taking a parser as an argument
451−foldWith :: ( ToRow params )
457− -> (a -> row -> IO a)
459−foldWith = foldWithOptionsAndParser defaultFoldOptions
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.
470− fetchQuantity :: !FetchQuantity,
471− transactionMode :: !TransactionMode
474−-- | defaults to 'Automatic', and 'TransactionMode' 'ReadCommitted' 'ReadOnly'
475−defaultFoldOptions :: FoldOptions
476−defaultFoldOptions = FoldOptions {
477− fetchQuantity = Automatic,
478− transactionMode = TransactionMode ReadCommitted ReadOnly
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 )
489− -> Connection
324+ Connection
490− -> Query
325+ -> Query -- ^ Query template.
491− -> params
326+ -> q -- ^ Query parameters.
492− -> a
327+ -> a -- ^ Initial state for result consumer.
493− -> (a -> row -> IO a)
328+ -> (a -> r -> IO a) -- ^ Result consumer.
495−foldWithOptions opts = foldWithOptionsAndParser opts fromRow
497−-- | A version of 'foldWithOptions' taking a parser as an argument
498−foldWithOptionsAndParser :: (ToRow params)
505− -> (a -> row -> IO a)
507−foldWithOptionsAndParser opts parser conn template qs a f = do
330+fold conn template qs z f = do
508− q <- formatQuery conn template qs
331+ Base.query conn =<< formatQuery conn template qs
509− doFold opts parser conn template (Query q) a f
332+ finishFold conn template z f
511-- | A version of 'fold' that does not perform query substitution.
335-- | A version of 'fold' that does not perform query substitution.
512−fold_ :: (FromRow r) =>
336+fold_ :: (QueryResults r) =>
513 Connection
337 Connection
514 -> Query -- ^ Query.
338 -> Query -- ^ Query.
515 -> a -- ^ Initial state for result consumer.
339 -> a -- ^ Initial state for result consumer.
516 -> (a -> r -> IO a) -- ^ Result consumer.
340 -> (a -> r -> IO a) -- ^ Result consumer.
518−fold_ = foldWithOptions_ defaultFoldOptions
342+fold_ conn q@(Query que) z f = do
519−
343+ Base.query conn que
520−-- | A version of 'fold_' taking a parser as an argument
344+ finishFold conn q z f
521−foldWith_ :: RowParser r
345+--}
522− -> Connection
346+{--
527−foldWith_ = foldWithOptionsAndParser_ defaultFoldOptions
529−foldWithOptions_ :: (FromRow r) =>
532− -> Query -- ^ Query.
533− -> a -- ^ Initial state for result consumer.
534− -> (a -> r -> IO a) -- ^ Result consumer.
536−foldWithOptions_ opts conn query' a f = doFold opts fromRow conn query' query' a f
538−-- | A version of 'foldWithOptions_' taking a parser as an argument
539−foldWithOptionsAndParser_ :: FoldOptions
542− -> Query -- ^ Query.
543− -> a -- ^ Initial state for result consumer.
544− -> (a -> r -> IO a) -- ^ Result consumer.
546−foldWithOptionsAndParser_ opts parser conn query' a f = doFold opts parser conn query' query' a f
548−doFold :: FoldOptions
554− -> (a -> row -> IO a)
556−doFold FoldOptions{..} parser conn _template q a0 f = do
557− stat <- withConnection conn PQ.transactionStatus
559− PQ.TransIdle -> withTransactionMode transactionMode conn go
560− PQ.TransInTrans -> go
561− PQ.TransActive -> fail "foldWithOpts FIXME: PQ.TransActive"
562− -- This _shouldn't_ occur in the current incarnation of
563− -- the library, as we aren't using libpq asynchronously.
564− -- However, it could occur in future incarnations of
565− -- this library or if client code uses the Internal module
566− -- to use raw libpq commands on postgresql-simple connections.
567− PQ.TransInError -> fail "foldWithOpts FIXME: PQ.TransInError"
568− -- This should be turned into a better error message.
569− -- It is probably a bad idea to automatically roll
570− -- back the transaction and start another.
571− PQ.TransUnknown -> fail "foldWithOpts FIXME: PQ.TransUnknown"
572− -- Not sure what this means.
575− declareCursor conn q
577− foldForwardWithParser cursor parser chunkSize f a
579− go = bracket declare closeCursor $ \cursor ->
580− let loop a = fetch cursor a >>=
586−-- FIXME: choose the Automatic chunkSize more intelligently
587−-- One possibility is to use the type of the results, although this
588−-- still isn't a perfect solution, given that common types (e.g. text)
589−-- are of highly variable size.
590−-- A refinement of this technique is to pick this number adaptively
591−-- as results are read in from the database.
592− chunkSize = case fetchQuantity of
596-- | A version of 'fold' that does not transform a state value.
347-- | A version of 'fold' that does not transform a state value.
597−forEach :: (ToRow q, FromRow r) =>
348+forEach :: (QueryParams q, QueryResults r) =>
598 Connection
349 Connection
599 -> Query -- ^ Query template.
350 -> Query -- ^ Query template.
600 -> q -- ^ Query parameters.
351 -> q -- ^ Query parameters.
601 -> (r -> IO ()) -- ^ Result consumer.
352 -> (r -> IO ()) -- ^ Result consumer.
603−forEach = forEachWith fromRow
354+forEach conn template qs = fold conn template qs () . const
604{-# INLINE forEach #-}
355{-# INLINE forEach #-}
606−-- | A version of 'forEach' taking a parser as an argument
607−forEachWith :: ( ToRow q )
614−forEachWith parser conn template qs = foldWith parser conn template qs () . const
615−{-# INLINE forEachWith #-}
617-- | A version of 'forEach' that does not perform query substitution.
357-- | A version of 'forEach' that does not perform query substitution.
618−forEach_ :: (FromRow r) =>
358+forEach_ :: (QueryResults r) =>
619 Connection
359 Connection
620 -> Query -- ^ Query template.
360 -> Query -- ^ Query template.
621 -> (r -> IO ()) -- ^ Result consumer.
361 -> (r -> IO ()) -- ^ Result consumer.
623−forEach_ = forEachWith_ fromRow
363+forEach_ conn template = fold_ conn template () . const
624{-# INLINE forEach_ #-}
364{-# INLINE forEach_ #-}
626−forEachWith_ :: RowParser r
367+forM' :: (Ord n, Num n) => n -> n -> (n -> IO a) -> IO [a]
627− -> Connection
368+forM' lo hi m = loop hi []
629− -> (r -> IO ())
370+ loop !n !as
630− -> IO ()
371+ | n < lo = return as
631−forEachWith_ parser conn template = foldWith_ parser conn template () . const
372+ | otherwise = do
632−{-# INLINE forEachWith_ #-}
373+ a <- m n
633−
374+ loop (n-1) (a:as)
376+finishQuery :: (QueryResults r) => Connection -> Query -> PQ.Result -> IO [r]
377+finishQuery conn q result = do
378+ status <- PQ.resultStatus result
380+ PQ.EmptyQuery -> fail "empty query" -- FIXME: error message
382+ throwIO $ QueryError "query resulted in a command response" q
384+ ncols <- PQ.nfields result
385+ fields <- forM' 0 (ncols-1) $ \column -> do
386+ type_oid <- PQ.ftype result column
387+ typename <- getTypename conn type_oid
389+ nrows <- PQ.ntuples result
390+ forM' 0 (nrows-1) $ \row -> do
391+ values <- forM' 0 (ncols-1) (\col -> PQ.getvalue' result row col)
392+ case convertResults fields values of
393+ Left err -> throwIO err
395+ PQ.CopyIn -> fail "FIXME: postgresql-simple does not currently support COPY IN"
396+ PQ.CopyOut -> fail "FIXME: postgresql-simple does not currently support COPY OUT"
398+ errormsg <- maybe "" id <$> PQ.resultErrorMessage result
399+ statusmsg <- PQ.resStatus status
400+ state <- maybe "" id <$> PQ.resultErrorField result PQ.DiagSqlstate
401+ throw $ SqlError { sqlState = state
402+ , sqlNativeError = 0 -- FIXME
403+ , sqlErrorMsg = B.concat [ "execute: ", statusmsg
407+withResult (Base.storeResult conn) q $ \r fs -> do
409+/ flip fix [] $ \loop acc -> do
410+ row <- Base.fetchRow r
412+ [] -> return (reverse acc)
413+ _ -> let !c = convertResults fs row
417+finishFold :: (QueryResults r) =>
418+ Connection -> Query -> a -> (a -> r -> IO a) -> IO a
419+finishFold conn q z0 f = withResult (Base.useResult conn) q $ \r fs ->
420+ flip fix z0 $ \loop z -> do
421+ row <- Base.fetchRow r
424+ _ -> (f z $! convertResults fs row) >>= loop
427+withResult :: (IO Result) -> Query -> (Result -> [Field] -> IO a) -> IO a
428+withResult fetchResult q act = bracket fetchResult Base.freeResult $ \r -> do
429+ ncols <- Base.fieldCount (Right r)
431+ then throwIO $ QueryError "query resulted in zero-column result" q
432+ else act r =<< Base.fetchFields r
434+-- | Execute an action inside a SQL transaction.
436+-- This function initiates a transaction with a \"@begin
437+-- transaction@\" statement, then executes the supplied action. If
438+-- the action succeeds, the transaction will be completed with
439+-- 'Base.commit' before this function returns.
441+-- If the action throws /any/ kind of exception (not just a
442+-- PostgreSQL-related exception), the transaction will be rolled back using
443+-- 'rollback', then the exception will be rethrown.
444+withTransaction :: Connection -> IO a -> IO a
445+withTransaction conn act = do
447+ r <- act `onException` rollback conn
451+-- | Rollback a transaction.
452+-- rollback :: (MonadCatchIO m,MonadIO m) => Connection -> m ()
453+rollback :: Connection -> IO ()
455+ _ <- execute_ conn "ABORT"
458+-- | Commit a transaction.
459+-- commit :: (MonadCatchIO m,MonadIO m) => Connection -> m ()
460+commit :: Connection -> IO ()
462+ _ <- execute_ conn "COMMIT"
465+-- | Begin a transaction.
466+-- begin :: (MonadCatchIO m,MonadIO m) => Connection -> m ()
467+begin :: Connection -> IO ()
469+ _ <- execute_ conn "BEGIN"
472+fmtError :: String -> Query -> [Action] -> a
473+fmtError msg q xs = throw FormatError {
476+ , fmtParams = map twiddle xs
478+ where twiddle (Plain b) = toByteString b
479+ twiddle (Escape s) = s
480+ twiddle (Many ys) = B.concat (map twiddle ys)
@@ -658,11 +505,9 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
659-- > import Database.PostgreSQL.Simple
506-- > import Database.PostgreSQL.Simple
662-- > hello = do
508-- > hello = do
663−-- > conn <- connectPostgreSQL ""
509+-- > conn <- connect defaultConnectInfo
664−-- > [Only i] <- query_ conn "select 2 + 2"
510+-- > query conn "select 2 + 2"
667-- A 'Query' value does not represent the actual query that will be
512-- A 'Query' value does not represent the actual query that will be
668-- executed, but is a template for constructing the final query.
513-- executed, but is a template for constructing the final query.
@@ -709,7 +554,7 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
709-- Automated type inference means that you will often be able to avoid
554-- Automated type inference means that you will often be able to avoid
710-- supplying explicit type signatures for the elements of a tuple.
555-- supplying explicit type signatures for the elements of a tuple.
711-- However, sometimes the compiler will not be able to infer your
556-- However, sometimes the compiler will not be able to infer your
712−-- types. Consider a case where you write a numeric literal in a
557+-- types. Consider a care where you write a numeric literal in a
713-- parameter tuple:
558-- parameter tuple:
715-- > query conn "select ? + ?" (40,2)
560-- > query conn "select ? + ?" (40,2)
@@ -723,30 +568,15 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
723-- The same kind of problem can arise with string literals if you have
568-- The same kind of problem can arise with string literals if you have
724-- the @OverloadedStrings@ language extension enabled. Again, just
569-- the @OverloadedStrings@ language extension enabled. Again, just
725-- use an explicit type signature if this happens.
570-- use an explicit type signature if this happens.
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:
731−-- > print =<< query_ conn "select 2 + 2"
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:
738−-- > xs <- query_ conn "select 2 + 2"
739−-- > print (xs :: [Only Int])
741-- $only_param
572-- $only_param
743-- Haskell lacks a single-element tuple type, so if you have just one
574-- 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,
575+-- value you want substituted into a query, what should you do?
745−-- what should you do?
747-- The obvious approach would appear to be something like this:
577-- The obvious approach would appear to be something like this:
749−-- > instance (ToField a) => ToRow a where
579+-- > instance (Param a) => QueryParam a where
752-- Unfortunately, this wreaks havoc with type inference, so we take a
582-- Unfortunately, this wreaks havoc with type inference, so we take a
@@ -757,9 +587,6 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
758-- > execute conn "insert into users (first_name) values (?)"
588-- > execute conn "insert into users (first_name) values (?)"
759-- > ["Nuala"]
589-- > ["Nuala"]
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.
@@ -777,7 +604,7 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
777-- Here's an example:
604-- Here's an example:
779-- > query conn "select * from users where first_name in ?" $
606-- > query conn "select * from users where first_name in ?" $
780−-- > Only $ In ["Anna", "Boris", "Carla"]
607+-- > In ["Anna", "Boris", "Carla"]
782-- If your 'In'-wrapped list is empty, the string @\"(null)\"@ will be
609-- If your 'In'-wrapped list is empty, the string @\"(null)\"@ will be
783-- substituted instead, to ensure that your clause remains
610-- substituted instead, to ensure that your clause remains
@@ -805,7 +632,7 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
805-- * There must be no other \"@?@\" characters anywhere in your
632-- * There must be no other \"@?@\" characters anywhere in your
806-- template.
633-- template.
808−-- * There must be one or more \"@?@\" in the parentheses.
635+-- * There must one or more \"@?@\" in the parentheses.
810-- * Extra white space is fine.
637-- * Extra white space is fine.
@@ -826,26 +653,10 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
826-- > insert into users (first_name,last_name) values
653-- > insert into users (first_name,last_name) values
827-- > ('Boris','Karloff'),('Ed','Wood')
654-- > ('Boris','Karloff'),('Ed','Wood')
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'.
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.
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")]
845-- $result
656-- $result
847-- The 'query' and 'query_' functions return a list of values in the
658-- The 'query' and 'query_' functions return a list of values in the
848−-- 'FromRow' typeclass. This class performs automatic extraction
659+-- 'QueryResults' typeclass. This class performs automatic extraction
849-- and type conversion of rows from a query result.
660-- and type conversion of rows from a query result.
851-- Here is a simple example of how to extract results:
662-- Here is a simple example of how to extract results:
@@ -876,7 +687,7 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
877-- Although SQL can accommodate @NULL@ as a value for any of these
688-- Although SQL can accommodate @NULL@ as a value for any of these
878-- types, Haskell cannot. If your result contains columns that may be
689-- types, Haskell cannot. If your result contains columns that may be
879−-- @NULL@, be sure that you use 'Maybe' in those positions of your
690+-- @NULL@, be sure that you use 'Maybe' in those positions of of your
882-- > (Text, Maybe Int, Int)
693-- > (Text, Maybe Int, Int)
@@ -900,13 +711,13 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
901-- * For numeric types, any Haskell type that can accurately represent
712-- * For numeric types, any Haskell type that can accurately represent
902-- all values of the given PostgreSQL type is considered \"compatible\".
713-- all values of the given PostgreSQL type is considered \"compatible\".
903−-- For instance, you can always extract a PostgreSQL 16-bit @SMALLINT@
714+-- For instance, you can always extract a PostgreSQL 16-bit @SMALLINT@
904-- column to a Haskell 'Int'. The Haskell 'Float' type can accurately
715-- column to a Haskell 'Int'. The Haskell 'Float' type can accurately
905−-- represent a @SMALLINT@, so it is considered compatible with those types.
716+-- represent a @SMALLINT@, so it is considered compatble with those types.
907-- * A numeric compatibility check is based only on the type of a
718-- * A numeric compatibility check is based only on the type of a
908-- column, /not/ on its values. For instance, a PostgreSQL 64-bit
719-- column, /not/ on its values. For instance, a PostgreSQL 64-bit
909−-- @BIGINT@ column will be considered incompatible with a Haskell
720+-- @BIGINT@ column will be considered incompatible with a Haskell
910-- 'Int16', even if it contains the value @1@.
721-- 'Int16', even if it contains the value @1@.
912-- * If a numeric incompatibility is found, 'query' will throw a
723-- * If a numeric incompatibility is found, 'query' will throw a
@@ -916,3 +727,25 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
916-- UTF-8. If you use some other encoding, decoding may fail or give
727-- UTF-8. If you use some other encoding, decoding may fail or give
917-- wrong results. In such cases, write a @newtype@ wrapper and a
728-- wrong results. In such cases, write a @newtype@ wrapper and a
918-- custom 'Result' instance to handle your encoding.
729-- custom 'Result' instance to handle your encoding.
731+getTypename :: Connection -> PQ.Oid -> IO ByteString
732+getTypename conn@Connection{..} oid =
733+ case oid2builtin oid of
734+ Just builtin -> return $! builtin2typname builtin
735+ Nothing -> modifyMVar connectionObjects $ \oidmap -> do
736+ case IntMap.lookup (oid2int oid) oidmap of
737+ Just name -> return (oidmap, name)
739+ names <- query conn "SELECT typname FROM pg_type WHERE oid=?"
741+ name <- case names of
742+ [] -> return $ throw SqlError {
743+ sqlNativeError = -1,
744+ sqlErrorMsg = "invalid type oid",
747+ [Only x] -> return x
748+ _ -> fail "typename query returned more than one result"
749+ -- oid is a primary key, so the query should
750+ -- never return more than one result
751+ return (IntMap.insert (oid2int oid) name oidmap, name)