PostgreSQL.Binary.Decoder

Documentation

type Decoder = BinaryParser

run :: BinaryParser a -> ByteString -> Either Text a

Apply a parser to bytes.

Primitive

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

float4 :: Decoder Float

float8 :: Decoder Double

bool :: Decoder Bool

bytea_strict :: Decoder ByteString

BYTEA or any other type in its undecoded form.

bytea_lazy :: Decoder LazyByteString

BYTEA or any other type in its undecoded form.

Textual

text_strict :: Decoder Text

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

text_lazy :: Decoder LazyText

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

char :: Decoder Char

A UTF-8-decoded char.

Misc

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

Lifts a custom decoder implementation.

numeric :: Decoder Scientific

uuid :: Decoder UUID

json_ast :: Decoder Value

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

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

jsonb_ast :: Decoder Value

jsonb_bytes :: (ByteString -> Either Text a) -> Decoder 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 :: Decoder Day

DATE values decoding.

time_int :: Decoder TimeOfDay

TIME values decoding for servers, which have integer_datetimes enabled.

time_float :: Decoder TimeOfDay

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

timetz_int :: Decoder (TimeOfDay, TimeZone)

TIMETZ values decoding for servers, which have integer_datetimes enabled.

timetz_float :: Decoder (TimeOfDay, TimeZone)

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

timestamp_int :: Decoder LocalTime

TIMESTAMP values decoding for servers, which have integer_datetimes enabled.

timestamp_float :: Decoder LocalTime

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

timestamptz_int :: Decoder UTCTime

TIMESTAMP values decoding for servers, which have integer_datetimes enabled.

timestamptz_float :: Decoder UTCTime

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

interval_int :: Decoder DiffTime

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

interval_float :: Decoder DiffTime

INTERVAL values decoding for servers, which have integer_datetimes enabled.

Exotic

Array

data ArrayDecoder 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 :: Decoder [ [ Text ] ]
x =
  array (arrayDimension replicateM (fmap catMaybes (arrayDimension replicateM (arrayValue text))))

Instances

Functor ArrayDecoder

Methods

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

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

array :: ArrayDecoder a -> Decoder a

Unlift an ArrayDecoder to a value Decoder.

arrayDimension :: (forall m. Monad m => Int -> m a -> m b) -> ArrayDecoder a -> ArrayDecoder 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 arrayDimension or arrayValue.

arrayValue :: Decoder a -> ArrayDecoder (Maybe a)

Lift a value Decoder into ArrayDecoder for parsing of nullable leaf values.

arrayNonNullValue :: Decoder a -> ArrayDecoder a

Lift a value Decoder into ArrayDecoder for parsing of non-nullable leaf values.

Composite

data CompositeDecoder a

Instances

Monad CompositeDecoder

Methods

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

(>>) :: CompositeDecoder a -> CompositeDecoder b -> CompositeDecoder b

return :: a -> CompositeDecoder a

fail :: String -> CompositeDecoder a

Functor CompositeDecoder

Methods

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

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

Applicative CompositeDecoder

Methods

pure :: a -> CompositeDecoder a

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

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

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

composite :: CompositeDecoder a -> Decoder a

Unlift a CompositeDecoder to a value Decoder.

compositeValue :: Decoder a -> CompositeDecoder (Maybe a)

Lift a value Decoder into CompositeDecoder.

compositeNonNullValue :: Decoder a -> CompositeDecoder a

Lift a non-nullable value Decoder into CompositeDecoder.

HStore

hstore :: (forall m. Monad m => Int -> m (k, Maybe v) -> m r) -> Decoder k -> Decoder v -> Decoder 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 :: Decoder [ ( Text , Maybe Text ) ]
hstoreAsList =
  hstore replicateM text text

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

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