PostgreSQL.Binary.Decoding

Documentation

valueParser :: Value a -> ByteString -> Either Text a

type Value = BinaryParser

Primitive

int :: (Integral a, Bits a) => Value a

float4 :: Value Float

float8 :: Value Double

bool :: Value Bool

bytea_strict :: Value ByteString

BYTEA or any other type in its undecoded form.

bytea_lazy :: Value LazyByteString

BYTEA or any other type in its undecoded form.

Textual

text_strict :: Value Text

Any of the variable-length character types: BPCHAR, VARCHAR, NAME and TEXT.

text_lazy :: Value LazyText

Any of the variable-length character types: BPCHAR, VARCHAR, NAME and TEXT.

char :: Value Char

A UTF-8-decoded char.

Misc

fn :: (ByteString -> Either Text a) -> Value a

Lifts a custom decoder implementation.

numeric :: Value Scientific

uuid :: Value UUID

inet :: Value (NetAddr IP)

json_ast :: Value Value

json_bytes :: (ByteString -> Either Text a) -> Value a

Given a function, which parses a plain UTF-8 JSON string encoded as a byte-array, produces a decoder.

jsonb_ast :: Value Value

jsonb_bytes :: (ByteString -> Either Text a) -> Value a

Given a function, which parses a plain UTF-8 JSON string encoded as a byte-array, produces a decoder.

For those wondering, yes, JSONB is encoded as plain JSON string in the binary format of Postgres. Sad, but true.

Time

date :: Value Day

DATE values decoding.

time_int :: Value TimeOfDay

TIME values decoding for servers, which have integer_datetimes enabled.

time_float :: Value TimeOfDay

TIME values decoding for servers, which don't have integer_datetimes enabled.

timetz_int :: Value (TimeOfDay, TimeZone)

TIMETZ values decoding for servers, which have integer_datetimes enabled.

timetz_float :: Value (TimeOfDay, TimeZone)

TIMETZ values decoding for servers, which don't have integer_datetimes enabled.

timestamp_int :: Value LocalTime

TIMESTAMP values decoding for servers, which have integer_datetimes enabled.

timestamp_float :: Value LocalTime

TIMESTAMP values decoding for servers, which don't have integer_datetimes enabled.

timestamptz_int :: Value UTCTime

TIMESTAMP values decoding for servers, which have integer_datetimes enabled.

timestamptz_float :: Value UTCTime

TIMESTAMP values decoding for servers, which don't have integer_datetimes enabled.

interval_int :: Value DiffTime

INTERVAL values decoding for servers, which don't have integer_datetimes enabled.

interval_float :: Value DiffTime

INTERVAL values decoding for servers, which have integer_datetimes enabled.

Exotic

Array

data Array a

An efficient generic array decoder, which constructs the result value in place while parsing.

Here's how you can use it to produce a specific array value decoder:

x :: Value [ [ Text ] ]
x =
  array (dimensionArray replicateM (fmap catMaybes (dimensionArray replicateM (nullableValueArray text))))

Instances

Functor Array

Defined in PostgreSQL.Binary.Decoding

Methods

fmap :: (a -> b) -> Array a -> Array b

(<$) :: a -> Array b -> Array a

array :: Array a -> Value a

Unlift an Array to a value Value.

valueArray :: Value a -> Array a

Lift a value Value into Array for parsing of non-nullable leaf values.

nullableValueArray :: Value a -> Array (Maybe a)

Lift a value Value into Array for parsing of nullable leaf values.

dimensionArray :: (forall m. Monad m => Int -> m a -> m b) -> Array a -> Array b

A function for parsing a dimension of an array. Provides support for multi-dimensional arrays.

Accepts:

• An implementation of the replicateM function (Control.Monad.replicateM, Data.Vector.replicateM), which determines the output value.
• A decoder of its components, which can be either another dimensionArray or nullableValueArray.

Composite

data Composite a

Instances

Monad Composite

Defined in PostgreSQL.Binary.Decoding

Methods

(>>=) :: Composite a -> (a -> Composite b) -> Composite b

(>>) :: Composite a -> Composite b -> Composite b

return :: a -> Composite a

fail :: String -> Composite a

Functor Composite

Defined in PostgreSQL.Binary.Decoding

Methods

fmap :: (a -> b) -> Composite a -> Composite b

(<$) :: a -> Composite b -> Composite a

Applicative Composite

Defined in PostgreSQL.Binary.Decoding

Methods

pure :: a -> Composite a

(<*>) :: Composite (a -> b) -> Composite a -> Composite b

liftA2 :: (a -> b -> c) -> Composite a -> Composite b -> Composite c

(*>) :: Composite a -> Composite b -> Composite b

(<*) :: Composite a -> Composite b -> Composite a

composite :: Composite a -> Value a

Unlift a Composite to a value Value.

valueComposite :: Value a -> Composite a

Lift a non-nullable value Value into Composite.

nullableValueComposite :: Value a -> Composite (Maybe a)

Lift a value Value into Composite.

HStore

hstore :: (forall m. Monad m => Int -> m (k, Maybe v) -> m r) -> Value k -> Value v -> Value r

A function for generic in place parsing of an HStore value.

Accepts:

• An implementation of the replicateM function (Control.Monad.replicateM, Data.Vector.replicateM), which determines how to produce the final datastructure from the rows.
• A decoder for keys.
• A decoder for values.

Here's how you can use it to produce a parser to list:

hstoreAsList :: Value [ ( Text , Maybe Text ) ]
hstoreAsList =
  hstore replicateM text text

enum :: (Text -> Maybe a) -> Value a

Given a partial mapping from text to value, produces a decoder of that value.

refine :: (a -> Either Text b) -> Value a -> Value b

Given additional constraints when using an existing value decoder, produces a decoder of that value.