Module backend 

Backend (server-to-client) messages.

This module parses messages sent from the Hyper server to the client. Each message variant is discriminated by a single-byte tag; see the *_TAG constants and the Message enum for the full catalog.

Authentication Flow

The server initiates authentication with an Authentication* message. Supported methods:

Method	Tag subtype	Flow
Trust	R(0)	Server sends AuthenticationOk immediately
Cleartext	R(3)	Server requests password; client sends PasswordMessage
MD5	R(5) + 4-byte salt	Client hashes md5(md5(password + user) + salt)
SCRAM-SHA-256	R(10)	Multi-step challenge-response via SASLInitialResponse / SASLResponse

After successful authentication the server sends AuthenticationOk, followed by ParameterStatus messages, BackendKeyData, and finally ReadyForQuery.

Attribution

Portions of this module were adapted from postgres-protocol’s message/backend.rs (Copyright (c) 2016 Steven Fackler, MIT or Apache-2.0). Adapted material includes the message-tag constants (PARSE_COMPLETE_TAG = b'1', BIND_COMPLETE_TAG = b'2', …, AUTHENTICATION_TAG = b'R', etc.), the Header struct shape, and message-framing logic. Hyper-specific changes added on top include the HyperBinary COPY format and Hyper-specific message variants. See the NOTICE file at the repo root for the full upstream copyright and reproduced license text.

Structs

AuthenticationMd5PasswordBody

MD5 password authentication body.

AuthenticationSaslBody

SASL authentication body.

AuthenticationSaslContinueBody

SASL continue authentication body.

AuthenticationSaslFinalBody

SASL final authentication body.

BackendKeyDataBody

Backend key data body.

CommandCompleteBody

Command complete body.

CopyDataBody

COPY data body.

CopyInResponseBody

COPY IN response body.

CopyOutResponseBody

COPY OUT response body.

DataRowBody

Data row body.

DataRowRanges

Iterator over data row column ranges.

ErrorField

A single error or notice field.

ErrorFields

Iterator over error fields in an ErrorResponse or NoticeResponse.

ErrorResponseBody

Error response body.

Field

A field description in a RowDescription.

Fields

Iterator over field descriptions in a RowDescription.

Header

Message header information.

NoticeResponseBody

Notice response body (same format as error).

NotificationResponseBody

Notification response body.

ParameterDescriptionBody

Parameter description body.

ParameterStatusBody

Parameter status body.

Parameters

Iterator over parameter OIDs in a ParameterDescription.

ReadyForQueryBody

Ready for query body.

RowDescriptionBody

Row description body.

SaslMechanisms

Iterator over SASL mechanism names in an authentication message.

Enums

Message

An enum representing backend messages from Hyper server.

Constants

AUTHENTICATION_TAG

Message tag for Authentication (‘R’).

BACKEND_KEY_DATA_TAG

Message tag for BackendKeyData (‘K’).

BIND_COMPLETE_TAG

Message tag for BindComplete (‘2’).

CLOSE_COMPLETE_TAG

Message tag for CloseComplete (‘3’).

COMMAND_COMPLETE_TAG

Message tag for CommandComplete (‘C’).

COPY_DATA_TAG

Message tag for CopyData (‘d’).

COPY_DONE_TAG

Message tag for CopyDone (‘c’).

COPY_IN_RESPONSE_TAG

Message tag for CopyInResponse (‘G’).

COPY_OUT_RESPONSE_TAG

Message tag for CopyOutResponse (‘H’).

DATA_ROW_TAG

Message tag for DataRow (‘D’).

EMPTY_QUERY_RESPONSE_TAG

Message tag for EmptyQueryResponse (‘I’).

ERROR_RESPONSE_TAG

Message tag for ErrorResponse (‘E’).

NOTICE_RESPONSE_TAG

Message tag for NoticeResponse (‘N’).

NOTIFICATION_RESPONSE_TAG

Message tag for NotificationResponse (‘A’).

NO_DATA_TAG

Message tag for NoData (‘n’).

PARAMETER_DESCRIPTION_TAG

Message tag for ParameterDescription (‘t’).

PARAMETER_STATUS_TAG

Message tag for ParameterStatus (‘S’).

PARSE_COMPLETE_TAG

Message tag for ParseComplete (‘1’).

PORTAL_SUSPENDED_TAG

Message tag for PortalSuspended (‘s’).

READY_FOR_QUERY_TAG

Message tag for ReadyForQuery (‘Z’).

ROW_DESCRIPTION_TAG

Message tag for RowDescription (‘T’).