@@ -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 -- $result
@@ -55,54 +48,31 @@ module Database.PostgreSQL.Simple
57 -- * Types
50 -- * Types
58− Connection
52+ , Connection
63 , Binary(..)
55 , Binary(..)
64 , Only(..)
56 , Only(..)
66 -- ** Exceptions
57 -- ** Exceptions
67− , SomePostgreSqlException(..)
68 , SqlError(..)
58 , SqlError(..)
70− , FormatError(..)
59+ , FormatError(fmtMessage, fmtQuery, fmtParams)
71− , QueryError(..)
60+ , QueryError(qeMessage, qeQuery)
72− , ResultError(..)
61+ , ResultError(errSQLType, errHaskellType, errMessage)
73 -- * Connection management
62 -- * Connection management
74− , Base.connectPostgreSQL
76 , Base.connect
63 , Base.connect
77− , Base.withConnect
64+ , Base.connectPostgreSQL
78− , Base.ConnectInfo(..)
79− , Base.defaultConnectInfo
80 , Base.postgreSQLConnectionString
65 , Base.postgreSQLConnectionString
66+ , Base.defaultConnectInfo
81 -- * Queries that return results
68 -- * Queries that return results
84− -- ** Queries taking parser as argument
87 -- * Queries that stream results
71 -- * Queries that stream results
96 , forEach_
75 , forEach_
98− -- ** Queries that stream results taking a parser as an argument
100− , foldWithOptionsAndParser
102− , foldWithOptionsAndParser_
106 -- * Statements that do not return results
76 -- * Statements that do not return results
107 , execute
77 , execute
108 , execute_
78 , execute_
@@ -110,7 +80,6 @@ module Database.PostgreSQL.Simple
110-- , Base.insertID
80-- , Base.insertID
111 -- * Transaction handling
81 -- * Transaction handling
112 , withTransaction
82 , withTransaction
114-- , Base.autocommit
83-- , Base.autocommit
@@ -120,27 +89,50 @@ module Database.PostgreSQL.Simple
120 , formatQuery
89 , formatQuery
123−import Data.ByteString.Builder (Builder, byteString, char8)
92+import Blaze.ByteString.Builder (Builder, fromByteString, toByteString)
93+import Blaze.ByteString.Builder.Char8 (fromChar)
124−import Control.Applicative ((<$>))
94+import Control.Applicative ((<$>), pure)
125−import Control.Exception as E
95+import Control.Concurrent.MVar
96+import Control.Exception (Exception, bracket, onException, throw, throwIO)
97+import Control.Monad (foldM)
98+import Control.Monad.Fix (fix)
126−import Data.ByteString (ByteString)
99+import Data.ByteString (ByteString)
100+import Data.Char(ord)
127−import Data.Int (Int64)
101+import Data.Int (Int64)
102+import qualified Data.IntMap as IntMap
128−import Data.List (intersperse)
103+import Data.List (intersperse)
129−import Data.Monoid (mconcat)
104+import Data.Monoid (mappend, mconcat)
105+import Data.Typeable (Typeable)
130−import Database.PostgreSQL.Simple.Compat ((<>), toByteString)
106+import Database.PostgreSQL.Simple.BuiltinTypes (oid2builtin, builtin2typname)
107+import Database.PostgreSQL.Simple.Param (Action(..), inQuotes)
131−import Database.PostgreSQL.Simple.Cursor
108+import Database.PostgreSQL.Simple.QueryParams (QueryParams(..))
132−import Database.PostgreSQL.Simple.FromField (ResultError(..))
109+import Database.PostgreSQL.Simple.Result (ResultError(..))
133−import Database.PostgreSQL.Simple.FromRow (FromRow(..))
134−import Database.PostgreSQL.Simple.ToField (Action(..))
110+import Database.PostgreSQL.Simple.QueryResults (QueryResults(..))
135−import Database.PostgreSQL.Simple.ToRow (ToRow(..))
136−import Database.PostgreSQL.Simple.Types
111+import Database.PostgreSQL.Simple.Types (Binary(..), In(..), Only(..), Query(..))
137− ( Binary(..), In(..), Only(..), Query(..), (:.)(..) )
138−import Database.PostgreSQL.Simple.Internal as Base
112+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
113import qualified Database.PostgreSQL.LibPQ as PQ
114+import Text.Regex.PCRE.Light (compile, caseless, match)
142import qualified Data.ByteString.Char8 as B
115import qualified Data.ByteString.Char8 as B
117+-- | Exception thrown if a 'Query' could not be formatted correctly.
118+-- This may occur if the number of \'@?@\' characters in the query
119+-- string does not match the number of parameters provided.
120+data FormatError = FormatError {
121+ fmtMessage :: String
123+ , fmtParams :: [ByteString]
124+ } deriving (Eq, Show, Typeable)
126+instance Exception FormatError
128+-- | Exception thrown if 'query' is used to perform an @INSERT@-like
129+-- operation, or 'execute' is used to perform a @SELECT@-like operation.
130+data QueryError = QueryError {
133+ } deriving (Eq, Show, Typeable)
135+instance Exception QueryError
145-- | Format a query string.
137-- | Format a query string.
@@ -152,11 +144,11 @@ import qualified Data.ByteString.Char8 as B
153-- Throws 'FormatError' if the query string could not be formatted
145-- Throws 'FormatError' if the query string could not be formatted
154-- correctly.
146-- correctly.
155−formatQuery :: ToRow q => Connection -> Query -> q -> IO ByteString
147+formatQuery :: QueryParams q => Connection -> Query -> q -> IO ByteString
156formatQuery conn q@(Query template) qs
148formatQuery conn q@(Query template) qs
157 | null xs && '?' `B.notElem` template = return template
149 | null xs && '?' `B.notElem` template = return template
158 | otherwise = toByteString <$> buildQuery conn q template xs
150 | otherwise = toByteString <$> buildQuery conn q template xs
159− where xs = toRow qs
151+ where xs = renderParams qs
161-- | Format a query string with a variable number of rows.
153-- | Format a query string with a variable number of rows.
@@ -171,208 +163,105 @@ formatQuery conn q@(Query template) qs
172-- Throws 'FormatError' if the query string could not be formatted
164-- Throws 'FormatError' if the query string could not be formatted
173-- correctly.
165-- correctly.
174−formatMany :: (ToRow q) => Connection -> Query -> [q] -> IO ByteString
166+formatMany :: (QueryParams q) => Connection -> Query -> [q] -> IO ByteString
175formatMany _ q [] = fmtError "no rows supplied" q []
167formatMany _ q [] = fmtError "no rows supplied" q []
176formatMany conn q@(Query template) qs = do
168formatMany conn q@(Query template) qs = do
177− case parseTemplate template of
169+ case match re template [] of
178− Just (before, qbits, after) -> do
170+ Just [_,before,qbits,after] -> do
179− bs <- mapM (buildQuery conn q qbits . toRow) qs
171+ bs <- mapM (buildQuery conn q qbits . renderParams) qs
180− return . toByteString . mconcat $ byteString before :
172+ return . toByteString . mconcat $ fromByteString before :
181− intersperse (char8 ',') bs ++
173+ intersperse (fromChar ',') bs ++
182− [byteString after]
174+ [fromByteString after]
183− Nothing -> fmtError "syntax error in multi-row template" q []
175+ _ -> 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"
177+ re = compile "^([^?]+\\bvalues\\s*)\
205− search bs =
178+ \(\\(\\s*[?](?:\\s*,\\s*[?])*\\s*\\))\
206− case B.breakSubstring "VALUES" bs of
179+ \([^?]*)$"
207− (x, y)
180+ [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
182+escapeStringConn conn s = withConnection conn $ \c -> do
183+ PQ.escapeStringConn c s
281buildQuery :: Connection -> Query -> ByteString -> [Action] -> IO Builder
185buildQuery :: Connection -> Query -> ByteString -> [Action] -> IO Builder
282−buildQuery conn q template xs =
186+buildQuery conn q template xs = zipParams (split template) <$> mapM sub xs
283− zipParams (split template) <$> mapM (buildAction conn q xs) xs
187+ where quote = inQuotes . fromByteString . maybe undefined id
284− where split s =
188+ sub (Plain b) = pure b
285− -- This part escapes double '??'s to make literal '?'s possible
189+ sub (Escape s) = quote <$> escapeStringConn conn s
286− -- in PostgreSQL queries using the JSON operators: @?@, @?|@ and @?&@
190+ sub (Many ys) = mconcat <$> mapM sub ys
287− let (h,t) = breakOnSingleQuestionMark s
291− else split (B.tail t)
191+ split s = fromByteString h : if B.null t then [] else split (B.tail t)
192+ where (h,t) = B.break (=='?') s
292− zipParams (t:ts) (p:ps) = t <> p <> zipParams ts ps
193+ zipParams (t:ts) (p:ps) = t `mappend` p `mappend` zipParams ts ps
293 zipParams [t] [] = t
194 zipParams [t] [] = t
294− zipParams _ _ = fmtError (show countSingleQs ++
195+ zipParams _ _ = fmtError (show (B.count '?' template) ++
295− " single '?' characters, but " ++
196+ " '?' characters, but " ++
296 show (length xs) ++ " parameters") q xs
197 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
199-- | Execute an @INSERT@, @UPDATE@, or other SQL query that is not
308-- expected to return results.
200-- expected to return results.
310-- Returns the number of rows affected.
202-- Returns the number of rows affected.
312−-- Throws 'FormatError' if the query could not be formatted correctly, or
204+-- 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
205+execute :: (QueryParams q) => Connection -> Query -> q -> IO Int64
315execute conn template qs = do
206execute conn template qs = do
316 result <- exec conn =<< formatQuery conn template qs
207 result <- exec conn =<< formatQuery conn template qs
317 finishExecute conn template result
208 finishExecute conn template result
210+-- | A version of 'execute' that does not perform query substitution.
211+execute_ :: Connection -> Query -> IO Int64
212+execute_ conn q@(Query stmt) = do
213+ result <- exec conn stmt
214+ finishExecute conn q result
319-- | Execute a multi-row @INSERT@, @UPDATE@, or other SQL query that is not
216-- | Execute a multi-row @INSERT@, @UPDATE@, or other SQL query that is not
320-- expected to return results.
217-- expected to return results.
322−-- Returns the number of rows affected. If the list of parameters is empty,
219+-- 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−-- @
221+-- 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
222+executeMany :: (QueryParams q) => Connection -> Query -> [q] -> IO Int64
350executeMany _ _ [] = return 0
223executeMany _ _ [] = return 0
351executeMany conn q qs = do
224executeMany conn q qs = do
352 result <- exec conn =<< formatMany conn q qs
225 result <- exec conn =<< formatMany conn q qs
353 finishExecute conn q result
226 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]
228+finishExecute :: Connection -> Query -> PQ.Result -> IO Int64
368−returning = returningWith fromRow
229+finishExecute conn q result = do
230+ status <- PQ.resultStatus result
233+ ncols <- PQ.nfields result
235+ then throwIO $ QueryError ("execute resulted in " ++ show ncols ++
238+ nstr <- PQ.cmdTuples result
239+ return $ case nstr of
240+ Nothing -> 0 -- is this appropriate?
241+ Just str -> toInteger str
243+ ncols <- PQ.nfields result
244+ throwIO $ QueryError ("execute resulted in " ++ show ncols ++
246+ PQ.CopyIn -> fail "FIXME: postgresql-simple does not currently support COPY IN"
247+ PQ.CopyOut -> fail "FIXME: postgresql-simple does not currently support COPY OUT"
249+ errormsg <- maybe "" id <$> PQ.resultErrorMessage result
250+ statusmsg <- PQ.resStatus status
251+ state <- maybe "" id <$> PQ.resultErrorField result PQ.DiagSqlstate
252+ throwIO $ SqlError { sqlState = state
253+ , sqlNativeError = fromEnum status
254+ , sqlErrorMsg = B.concat [ "execute: ", statusmsg
257+ toInteger str = B.foldl' delta 0 str
260+ if '0' <= c && c <= '9'
261+ then 10 * acc + fromIntegral (ord c - ord '0')
262+ 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
266-- | Perform a @SELECT@ or other SQL query that is expected to return
378-- results. All results are retrieved and converted before this
267-- results. All results are retrieved and converted before this
@@ -389,44 +278,33 @@ returningWith parser conn q qs = do
389-- using 'execute' instead of 'query').
278-- using 'execute' instead of 'query').
391-- * 'ResultError': result conversion failed.
280-- * 'ResultError': result conversion failed.
392−--
281+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]
282+ => Connection -> Query -> q -> IO [r]
404−queryWith parser conn template qs = do
283+query conn template qs = do
405 result <- exec conn =<< formatQuery conn template qs
284 result <- exec conn =<< formatQuery conn template qs
406− finishQueryWith parser conn template result
285+ finishQuery conn template result
408−-- | A version of 'query_' taking parser as argument
287+-- | A version of 'query' that does not perform query substitution.
409−queryWith_ :: RowParser r -> Connection -> Query -> IO [r]
288+query_ :: (QueryResults r) => Connection -> Query -> IO [r]
410−queryWith_ parser conn q@(Query que) = do
289+query_ conn q@(Query que) = do
411 result <- exec conn que
290 result <- exec conn que
412− finishQueryWith parser conn q result
291+ finishQuery conn q result
414-- | Perform a @SELECT@ or other SQL query that is expected to return
293-- | Perform a @SELECT@ or other SQL query that is expected to return
415-- results. Results are streamed incrementally from the server, and
294-- results. Results are streamed incrementally from the server, and
416-- consumed via a left fold.
295-- consumed via a left fold.
297+-- The result consumer must be carefully written to execute
298+-- quickly. If the consumer is slow, server resources will be tied up,
299+-- and other clients may not be able to update the tables from which
300+-- the results are being streamed.
418-- When dealing with small results, it may be simpler (and perhaps
302-- When dealing with small results, it may be simpler (and perhaps
419-- faster) to use 'query' instead.
303-- faster) to use 'query' instead.
421-- This fold is /not/ strict. The stream consumer is responsible for
305-- This fold is /not/ strict. The stream consumer is responsible for
422-- forcing the evaluation of its result to avoid space leaks.
306-- 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:
308-- Exceptions that may be thrown:
432-- * 'FormatError': the query string could not be formatted correctly.
310-- * 'FormatError': the query string could not be formatted correctly.
@@ -435,202 +313,191 @@ queryWith_ parser conn q@(Query que) = do
435-- using 'execute' instead of 'query').
313-- using 'execute' instead of 'query').
437-- * 'ResultError': result conversion failed.
315-- * 'ResultError': result conversion failed.
438−--
316+fold :: (QueryParams q, QueryResults r) =>
439−-- * 'SqlError': the postgresql backend returned an error, e.g.
317+ Connection
440−-- a syntax or type error, or an incorrect table or column name.
318+ -> Query -- ^ Query template.
441−fold :: ( FromRow row, ToRow params )
319+ -> q -- ^ Query parameters.
442− => Connection
320+ -> a -- ^ Initial state for result consumer.
443− -> Query
321+ -> (a -> r -> IO a) -- ^ Result consumer.
444− -> params
322+ -> IO a
445− -> a
323+fold conn template qs z f = withConnection conn $ \c -> do
446− -> (a -> row -> IO a)
324+ success <- PQ.sendQuery c =<< formatQuery conn template qs
447− -> IO a
325+ if success
448−fold = foldWithOptions defaultFoldOptions
326+ then finishFold conn c template z f
450−-- | A version of 'fold' taking a parser as an argument
328+ msg <- maybe "fold error" id <$> PQ.errorMessage c
451−foldWith :: ( ToRow params )
329+ throwIO $ SqlError { sqlNativeError = -1
452− => RowParser row
330+ , sqlErrorMsg = msg
453− -> Connection
331+ , sqlState = "" }
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 )
493− -> (a -> row -> IO a)
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
508− q <- formatQuery conn template qs
509− doFold opts parser conn template (Query q) a f
511-- | A version of 'fold' that does not perform query substitution.
333-- | A version of 'fold' that does not perform query substitution.
512−fold_ :: (FromRow r) =>
334+fold_ :: (QueryResults r) =>
513 Connection
335 Connection
514 -> Query -- ^ Query.
336 -> Query -- ^ Query.
515 -> a -- ^ Initial state for result consumer.
337 -> a -- ^ Initial state for result consumer.
516 -> (a -> r -> IO a) -- ^ Result consumer.
338 -> (a -> r -> IO a) -- ^ Result consumer.
518−fold_ = foldWithOptions_ defaultFoldOptions
520−-- | A version of 'fold_' taking a parser as an argument
521−foldWith_ :: RowParser r
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
340+fold_ conn q@(Query que) z f = withConnection conn $ \c -> do
558− case stat of
341+ success <- PQ.sendQuery c que
559− PQ.TransIdle -> withTransactionMode transactionMode conn go
342+ if success
560− PQ.TransInTrans -> go
343+ then finishFold conn c q z f
561− PQ.TransActive -> fail "foldWithOpts FIXME: PQ.TransActive"
344+ else do
562− -- This _shouldn't_ occur in the current incarnation of
345+ msg <- maybe "fold_ error" id <$> PQ.errorMessage c
563− -- the library, as we aren't using libpq asynchronously.
346+ throwIO $ SqlError { sqlNativeError = -1
564− -- However, it could occur in future incarnations of
347+ , sqlErrorMsg = msg
565− -- this library or if client code uses the Internal module
348+ , sqlState = "" }
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.
350-- | A version of 'fold' that does not transform a state value.
597−forEach :: (ToRow q, FromRow r) =>
351+forEach :: (QueryParams q, QueryResults r) =>
598 Connection
352 Connection
599 -> Query -- ^ Query template.
353 -> Query -- ^ Query template.
600 -> q -- ^ Query parameters.
354 -> q -- ^ Query parameters.
601 -> (r -> IO ()) -- ^ Result consumer.
355 -> (r -> IO ()) -- ^ Result consumer.
603−forEach = forEachWith fromRow
357+forEach conn template qs = fold conn template qs () . const
604{-# INLINE forEach #-}
358{-# 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.
360-- | A version of 'forEach' that does not perform query substitution.
618−forEach_ :: (FromRow r) =>
361+forEach_ :: (QueryResults r) =>
619 Connection
362 Connection
620 -> Query -- ^ Query template.
363 -> Query -- ^ Query template.
621 -> (r -> IO ()) -- ^ Result consumer.
364 -> (r -> IO ()) -- ^ Result consumer.
623−forEach_ = forEachWith_ fromRow
366+forEach_ conn template = fold_ conn template () . const
624{-# INLINE forEach_ #-}
367{-# INLINE forEach_ #-}
626−forEachWith_ :: RowParser r
369+forM' :: (Ord n, Num n) => n -> n -> (n -> IO a) -> IO [a]
627− -> Connection
370+forM' lo hi m = loop hi []
629− -> (r -> IO ())
372+ loop !n !as
630− -> IO ()
373+ | n < lo = return as
631−forEachWith_ parser conn template = foldWith_ parser conn template () . const
374+ | otherwise = do
632−{-# INLINE forEachWith_ #-}
375+ a <- m n
633−
376+ loop (n-1) (a:as)
378+finishQuery :: (QueryResults r) => Connection -> Query -> PQ.Result -> IO [r]
379+finishQuery conn q result = do
380+ status <- PQ.resultStatus result
383+ throwIO $ QueryError "query resulted in a command response" q
385+ ncols <- PQ.nfields result
386+ fields <- forM' 0 (ncols-1) $ \column -> do
387+ type_oid <- PQ.ftype result column
388+ typename <- getTypename conn type_oid
390+ nrows <- PQ.ntuples result
391+ forM' 0 (nrows-1) $ \row -> do
392+ values <- forM' 0 (ncols-1) (\col -> PQ.getvalue result row col)
393+ case convertResults fields values of
394+ Left err -> throwIO err
396+ PQ.CopyIn -> fail "FIXME: postgresql-simple does not currently support COPY IN"
397+ PQ.CopyOut -> fail "FIXME: postgresql-simple does not currently support COPY OUT"
399+ errormsg <- maybe "" id <$> PQ.resultErrorMessage result
400+ statusmsg <- PQ.resStatus status
401+ state <- maybe "" id <$> PQ.resultErrorField result PQ.DiagSqlstate
402+ throwIO $ SqlError { sqlState = state
403+ , sqlNativeError = fromEnum status
404+ , sqlErrorMsg = B.concat [ "query: ", statusmsg
408+finishFold :: (QueryResults r) =>
411+ -> Query -- ^ Query.
412+ -> a -- ^ Initial state for result consumer.
413+ -> (a -> r -> IO a) -- ^ Result consumer.
415+finishFold conn c q a_ f = loop a_
418+ mres <- PQ.getResult c
422+ stat <- PQ.resultStatus result
425+ ncols <- PQ.nfields result
426+ fields <- forM' 0 (ncols-1) $ \column -> do
427+ type_oid <- PQ.ftype result column
428+ typename <- getTypename conn type_oid
430+ nrows <- PQ.ntuples result
431+ a' <- foldM (\a row -> do
432+ values <- forM' 0 (ncols-1) (PQ.getvalue result row)
433+ case convertResults fields values of
434+ Left err -> clear c >> throwIO err
439+ errormsg <- maybe "" id <$> PQ.resultErrorMessage result
440+ statusmsg <- PQ.resStatus stat
441+ state <- maybe "" id <$> PQ.resultErrorField result PQ.DiagSqlstate
443+ throwIO $ SqlError {
445+ sqlNativeError = fromEnum stat,
446+ sqlErrorMsg = B.concat [ "fold: ", statusmsg
449+ mres <- PQ.getResult c
451+ Nothing -> return ()
454+-- | Execute an action inside a SQL transaction.
456+-- This function initiates a transaction with a \"@begin
457+-- transaction@\" statement, then executes the supplied action. If
458+-- the action succeeds, the transaction will be completed with
459+-- 'Base.commit' before this function returns.
461+-- If the action throws /any/ kind of exception (not just a
462+-- PostgreSQL-related exception), the transaction will be rolled back using
463+-- 'rollback', then the exception will be rethrown.
464+withTransaction :: Connection -> IO a -> IO a
465+withTransaction conn act = do
467+ r <- act `onException` rollback conn
471+-- | Rollback a transaction.
472+-- rollback :: (MonadCatchIO m,MonadIO m) => Connection -> m ()
473+rollback :: Connection -> IO ()
475+ _ <- execute_ conn "ABORT"
478+-- | Commit a transaction.
479+-- commit :: (MonadCatchIO m,MonadIO m) => Connection -> m ()
480+commit :: Connection -> IO ()
482+ _ <- execute_ conn "COMMIT"
485+-- | Begin a transaction.
486+-- begin :: (MonadCatchIO m,MonadIO m) => Connection -> m ()
487+begin :: Connection -> IO ()
489+ _ <- execute_ conn "BEGIN"
492+fmtError :: String -> Query -> [Action] -> a
493+fmtError msg q xs = throw FormatError {
496+ , fmtParams = map twiddle xs
498+ where twiddle (Plain b) = toByteString b
499+ twiddle (Escape s) = s
500+ twiddle (Many ys) = B.concat (map twiddle ys)
@@ -658,11 +525,9 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
659-- > import Database.PostgreSQL.Simple
526-- > import Database.PostgreSQL.Simple
662-- > hello = do
528-- > hello = do
663−-- > conn <- connectPostgreSQL ""
529+-- > conn <- connect defaultConnectInfo
664−-- > [Only i] <- query_ conn "select 2 + 2"
530+-- > query conn "select 2 + 2"
667-- A 'Query' value does not represent the actual query that will be
532-- A 'Query' value does not represent the actual query that will be
668-- executed, but is a template for constructing the final query.
533-- executed, but is a template for constructing the final query.
@@ -709,7 +574,7 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
709-- Automated type inference means that you will often be able to avoid
574-- Automated type inference means that you will often be able to avoid
710-- supplying explicit type signatures for the elements of a tuple.
575-- supplying explicit type signatures for the elements of a tuple.
711-- However, sometimes the compiler will not be able to infer your
576-- However, sometimes the compiler will not be able to infer your
712−-- types. Consider a case where you write a numeric literal in a
577+-- types. Consider a care where you write a numeric literal in a
713-- parameter tuple:
578-- parameter tuple:
715-- > query conn "select ? + ?" (40,2)
580-- > query conn "select ? + ?" (40,2)
@@ -723,30 +588,15 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
723-- The same kind of problem can arise with string literals if you have
588-- The same kind of problem can arise with string literals if you have
724-- the @OverloadedStrings@ language extension enabled. Again, just
589-- the @OverloadedStrings@ language extension enabled. Again, just
725-- use an explicit type signature if this happens.
590-- 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
592-- $only_param
743-- Haskell lacks a single-element tuple type, so if you have just one
594-- 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,
595+-- 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:
597-- The obvious approach would appear to be something like this:
749−-- > instance (ToField a) => ToRow a where
599+-- > instance (Param a) => QueryParam a where
752-- Unfortunately, this wreaks havoc with type inference, so we take a
602-- Unfortunately, this wreaks havoc with type inference, so we take a
@@ -757,9 +607,6 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
758-- > execute conn "insert into users (first_name) values (?)"
608-- > execute conn "insert into users (first_name) values (?)"
759-- > ["Nuala"]
609-- > ["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 +624,7 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
777-- Here's an example:
624-- Here's an example:
779-- > query conn "select * from users where first_name in ?" $
626-- > query conn "select * from users where first_name in ?" $
780−-- > Only $ In ["Anna", "Boris", "Carla"]
627+-- > In ["Anna", "Boris", "Carla"]
782-- If your 'In'-wrapped list is empty, the string @\"(null)\"@ will be
629-- If your 'In'-wrapped list is empty, the string @\"(null)\"@ will be
783-- substituted instead, to ensure that your clause remains
630-- substituted instead, to ensure that your clause remains
@@ -805,7 +652,7 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
805-- * There must be no other \"@?@\" characters anywhere in your
652-- * There must be no other \"@?@\" characters anywhere in your
806-- template.
653-- template.
808−-- * There must be one or more \"@?@\" in the parentheses.
655+-- * There must one or more \"@?@\" in the parentheses.
810-- * Extra white space is fine.
657-- * Extra white space is fine.
@@ -826,26 +673,10 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
826-- > insert into users (first_name,last_name) values
673-- > insert into users (first_name,last_name) values
827-- > ('Boris','Karloff'),('Ed','Wood')
674-- > ('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
676-- $result
847-- The 'query' and 'query_' functions return a list of values in the
678-- The 'query' and 'query_' functions return a list of values in the
848−-- 'FromRow' typeclass. This class performs automatic extraction
679+-- 'QueryResults' typeclass. This class performs automatic extraction
849-- and type conversion of rows from a query result.
680-- and type conversion of rows from a query result.
851-- Here is a simple example of how to extract results:
682-- Here is a simple example of how to extract results:
@@ -876,7 +707,7 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
877-- Although SQL can accommodate @NULL@ as a value for any of these
708-- Although SQL can accommodate @NULL@ as a value for any of these
878-- types, Haskell cannot. If your result contains columns that may be
709-- types, Haskell cannot. If your result contains columns that may be
879−-- @NULL@, be sure that you use 'Maybe' in those positions of your
710+-- @NULL@, be sure that you use 'Maybe' in those positions of of your
882-- > (Text, Maybe Int, Int)
713-- > (Text, Maybe Int, Int)
@@ -902,7 +733,7 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
902-- all values of the given PostgreSQL type is considered \"compatible\".
733-- all values of the given PostgreSQL type is considered \"compatible\".
903-- For instance, you can always extract a PostgreSQL 16-bit @SMALLINT@
734-- For instance, you can always extract a PostgreSQL 16-bit @SMALLINT@
904-- column to a Haskell 'Int'. The Haskell 'Float' type can accurately
735-- column to a Haskell 'Int'. The Haskell 'Float' type can accurately
905−-- represent a @SMALLINT@, so it is considered compatible with those types.
736+-- represent a @SMALLINT@, so it is considered compatble with those types.
907-- * A numeric compatibility check is based only on the type of a
738-- * A numeric compatibility check is based only on the type of a
908-- column, /not/ on its values. For instance, a PostgreSQL 64-bit
739-- column, /not/ on its values. For instance, a PostgreSQL 64-bit
@@ -916,3 +747,25 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
916-- UTF-8. If you use some other encoding, decoding may fail or give
747-- 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
748-- wrong results. In such cases, write a @newtype@ wrapper and a
918-- custom 'Result' instance to handle your encoding.
749-- custom 'Result' instance to handle your encoding.
751+getTypename :: Connection -> PQ.Oid -> IO ByteString
752+getTypename conn@Connection{..} oid =
753+ case oid2builtin oid of
754+ Just builtin -> return $! builtin2typname builtin
755+ Nothing -> modifyMVar connectionObjects $ \oidmap -> do
756+ case IntMap.lookup (oid2int oid) oidmap of
757+ Just name -> return (oidmap, name)
759+ names <- query conn "SELECT typname FROM pg_type WHERE oid=?"
761+ name <- case names of
762+ [] -> return $ throw SqlError {
763+ sqlNativeError = -1,
764+ sqlErrorMsg = "invalid type oid",
767+ [Only x] -> return x
768+ _ -> fail "typename query returned more than one result"
769+ -- oid is a primary key, so the query should
770+ -- never return more than one result
771+ return (IntMap.insert (oid2int oid) name oidmap, name)