Module epgsql_wire

Description
Data Types
Function Index
Function Details

Interface to encoder/decoder for postgresql wire-protocol

Description

Interface to encoder/decoder for postgresql wire-protocol

Data Types

copy_row_encoder()

abstract datatype: copy_row_encoder()

packet_type()

packet_type() = byte()

see protocol.hrl -type packet_type(Exact) :: Exact. % TODO: uncomment when OTP-18 is dropped

parameters_encoder()

abstract datatype: parameters_encoder()

row_decoder()

abstract datatype: row_decoder()

Function Index

build_copy_row_encoder/2	Builds "row encoder" that can be used to efficiently encode multiple COPY rows.
build_decoder/2	Build decoder for DataRow.
build_parameters_encoder/2	Builds reusable encoder that can be used to encode BIND parameters.
decode_columns/3	decode RowDescription column information.
decode_complete/1	decode CcommandComplete msg.
decode_data/2	decode row data.
decode_error/1	decode ErrorResponse See `http://www.postgresql.org/docs/current/interactive/protocol-error-fields.html`
decode_message/1	tries to extract single postgresql packet from TCP stream.
decode_parameters/2	decode ParameterDescription.
decode_strings/1	decode multiple null-terminated string.
encode_bind/4	encodes `Bind` packet.
encode_close/2	encodes `Close` packet.
encode_command/1	Encode iodata with size-prefix (used for `StartupMessage` and `SSLRequest` packets).
encode_command/2	Encode PG command with type and size prefix.
encode_copy_done/0	encodes `CopyDone` packet.
encode_copy_header/0	encode binary copy data file header.
encode_copy_row_with_encoder/3	encode binary copy data file row / tuple.
encode_copy_trailer/0	encode binary copy data file header.
encode_describe/2	encodes `Describe` packet.
encode_execute/2	encodes `Execute` packet.
encode_flush/0	encodes `Flush` packet.
encode_formats/1	encode expected result set column formats << NumberOfColumns, ColumnFormat * NumberOfColumns (ColumnFormat: 0 -> text; 1 -> binary) >>
encode_parameters/2	encode parameters for 'Bind' <<NumberOfParameters, ParameterFormat * NumberOfParameters, (ParameterFormat: 0 -> text; 1 -> binary) NumberOfParameters, (ParamLength, ParamValue) * NumberOfparameters>>
encode_parameters_with_encoder/3
encode_parse/3	encodes 'Parse' packet.
encode_query/1	encodes simple 'Query' packet.
encode_standby_status_update/3	encode replication status message.
encode_sync/0	encodes `Sync` packet.
encode_types/2	encode parameter types specification for `Parse` packet.
format/2	Returns 1 if Codec knows how to decode binary format of the type provided and 0 otherwise.

Function Details

build_copy_row_encoder/2

build_copy_row_encoder(Types::[epgsql:epgsql_type()], Codec::epgsql_binary:codec()) -> copy_row_encoder()

Builds "row encoder" that can be used to efficiently encode multiple COPY rows

See also: encode_copy_row_with_encoder/3.

build_decoder/2

build_decoder(Columns::[epgsql:column()], Codec::epgsql_binary:codec()) -> row_decoder()

Build decoder for DataRow

build_parameters_encoder/2

build_parameters_encoder(Types::[epgsql:epgsql_type()], Codec::epgsql_binary:codec()) -> parameters_encoder()

Builds reusable encoder that can be used to encode BIND parameters

In case you need to bind parameters to the same statement multiple times. To be used with encode_parameters_with_encoder/2

decode_columns/3

decode_columns(Count::non_neg_integer(), Bin::binary(), Codec::epgsql_binary:codec()) -> [epgsql:column()]

decode RowDescription column information

decode_complete/1

decode_complete(Bin) -> any()

decode CcommandComplete msg

decode_data/2

decode_data(Bin::binary(), X2::row_decoder()) -> tuple()

decode row data

decode_error/1

decode_error(Bin::binary()) -> epgsql:query_error()

decode ErrorResponse See http://www.postgresql.org/docs/current/interactive/protocol-error-fields.html

decode_message/1

decode_message(Bin::binary()) -> {packet_type(), binary(), binary()} | binary()

tries to extract single postgresql packet from TCP stream

decode_parameters/2

decode_parameters(X1::binary(), Codec::epgsql_binary:codec()) -> [epgsql_oid_db:type_info() | {unknown_oid, epgsql_oid_db:oid()}]

decode ParameterDescription

decode_strings/1

decode_strings(Bin::binary()) -> [binary(), ...]

decode multiple null-terminated string

encode_bind/4

encode_bind(PortalName::iodata(), StmtName::iodata(), BinParams::iodata(), BinFormats::iodata()) -> {packet_type(), iodata()}

BinParams: see encode_parameters/2.
BinFormats: see encode_formats/1

encodes Bind packet.

encode_close/2

encode_close(What::byte() | statement | portal, Name::iodata()) -> {packet_type(), iodata()}

What: see encode_describe/2

encodes Close packet.

Results in CloseComplete response

encode_command/1

encode_command(Data) -> any()

Encode iodata with size-prefix (used for StartupMessage and SSLRequest packets)

encode_command/2

encode_command(Type::packet_type(), Data::iodata()) -> iodata()

Encode PG command with type and size prefix

encode_copy_done/0

encode_copy_done() -> {packet_type(), iodata()}

encodes CopyDone packet.

encode_copy_header/0

encode_copy_header() -> any()

encode binary copy data file header

See https://www.postgresql.org/docs/current/sql-copy.html#id-1.9.3.55.9.4.5

encode_copy_row_with_encoder/3

encode_copy_row_with_encoder(ValuesTuple::[epgsql:bind_param()] | tuple(), Encoder::copy_row_encoder(), Codec::epgsql_binary:codec()) -> iodata()

encode binary copy data file row / tuple

It uses pre-built copy_row_encoder() for eficiency See https://www.postgresql.org/docs/current/sql-copy.html#id-1.9.3.55.9.4.6

encode_copy_trailer/0

encode_copy_trailer() -> any()

encode binary copy data file header

See https://www.postgresql.org/docs/current/sql-copy.html#id-1.9.3.55.9.4.7

encode_describe/2

encode_describe(What::byte() | statement | portal, Name::iodata()) -> {packet_type(), iodata()}

What: might be ?PORTAL (results in RowDescription response) or ?PREPARED_STATEMENT (results in ParameterDescription followed by RowDescription or NoData response)

encodes Describe packet.

encode_execute/2

encode_execute(PortalName::iodata(), MaxRows::non_neg_integer()) -> {packet_type(), iodata()}

PortalName: might be an empty string (anonymous portal) or name of the named portal
MaxRows: how many rows server should send (0 means all of them)

encodes Execute packet.

Results in 0 or up to MaxRows packets of DataRow type followed by CommandComplete (when no more rows are available) or PortalSuspend (repeated Execute will return more rows)

encode_flush/0

encode_flush() -> {packet_type(), iodata()}

encodes Flush packet.

It doesn't cause any specific response packet, but tells PostgreSQL server to flush it's send network buffers

encode_formats/1

encode_formats(Columns::[epgsql:column()]) -> binary()

encode expected result set column formats

  <<
   NumberOfColumns,
   ColumnFormat * NumberOfColumns (ColumnFormat: 0 -> text; 1 -> binary)
  >>

encode_parameters/2

encode_parameters(TypedParameters::[{epgsql:epgsql_type(), epgsql:bind_param()}], Codec::epgsql_binary:codec()) -> iolist()

encode parameters for 'Bind'

  <<NumberOfParameters,
    ParameterFormat * NumberOfParameters, (ParameterFormat: 0 -> text; 1 -> binary)
    NumberOfParameters,
    (ParamLength, ParamValue) * NumberOfparameters>>

encode_parameters_with_encoder/3

encode_parameters_with_encoder(Parameters::[epgsql:bind_param()], X2::parameters_encoder(), Codec::epgsql_binary:codec()) -> iodata()

encode_parse/3

encode_parse(Name::iodata(), SQL::iodata(), ColumnEncoding::iodata()) -> {packet_type(), iodata()}

ColumnEncoding: see encode_types/2

encodes 'Parse' packet.

Results in ParseComplete response.

Results in ReadyForQuery response

encode_types/2

encode_types(Types::[epgsql:type_name() | {array, epgsql:type_name()}], Codec::epgsql_binary:codec()) -> binary()

encode parameter types specification for Parse packet

format/2

format(Column::epgsql:column(), Codec::epgsql_binary:codec()) -> 0 | 1

Returns 1 if Codec knows how to decode binary format of the type provided and 0 otherwise

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