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import { TransformOptions } from 'stream'
import {
Mode,
bindComplete,
parseComplete,
closeComplete,
noData,
portalSuspended,
copyDone,
replicationStart,
emptyQuery,
ReadyForQueryMessage,
CommandCompleteMessage,
CopyDataMessage,
CopyResponse,
NotificationResponseMessage,
RowDescriptionMessage,
ParameterDescriptionMessage,
Field,
DataRowMessage,
ParameterStatusMessage,
BackendKeyDataMessage,
DatabaseError,
BackendMessage,
MessageName,
AuthenticationMD5Password,
NoticeMessage,
} from './messages'
import { BufferReader } from './buffer-reader'
import assert from 'assert'
// every message is prefixed with a single bye
const CODE_LENGTH = 1
// every message has an int32 length which includes itself but does
// NOT include the code in the length
const LEN_LENGTH = 4
const HEADER_LENGTH = CODE_LENGTH + LEN_LENGTH
export type Packet = {
code: number
packet: Buffer
}
const emptyBuffer = Buffer.allocUnsafe(0)
type StreamOptions = TransformOptions & {
mode: Mode
}
const enum MessageCodes {
DataRow = 0x44, // D
ParseComplete = 0x31, // 1
BindComplete = 0x32, // 2
CloseComplete = 0x33, // 3
CommandComplete = 0x43, // C
ReadyForQuery = 0x5a, // Z
NoData = 0x6e, // n
NotificationResponse = 0x41, // A
AuthenticationResponse = 0x52, // R
ParameterStatus = 0x53, // S
BackendKeyData = 0x4b, // K
ErrorMessage = 0x45, // E
NoticeMessage = 0x4e, // N
RowDescriptionMessage = 0x54, // T
ParameterDescriptionMessage = 0x74, // t
PortalSuspended = 0x73, // s
ReplicationStart = 0x57, // W
EmptyQuery = 0x49, // I
CopyIn = 0x47, // G
CopyOut = 0x48, // H
CopyDone = 0x63, // c
CopyData = 0x64, // d
}
export type MessageCallback = (msg: BackendMessage) => void
export class Parser {
private buffer: Buffer = emptyBuffer
private bufferLength: number = 0
private bufferOffset: number = 0
private reader = new BufferReader()
private mode: Mode
constructor(opts?: StreamOptions) {
if (opts?.mode === 'binary') {
throw new Error('Binary mode not supported yet')
}
this.mode = opts?.mode || 'text'
}
public parse(buffer: Buffer, callback: MessageCallback) {
this.mergeBuffer(buffer)
const bufferFullLength = this.bufferOffset + this.bufferLength
let offset = this.bufferOffset
while (offset + HEADER_LENGTH <= bufferFullLength) {
// code is 1 byte long - it identifies the message type
const code = this.buffer[offset]
// length is 1 Uint32BE - it is the length of the message EXCLUDING the code
const length = this.buffer.readUInt32BE(offset + CODE_LENGTH)
const fullMessageLength = CODE_LENGTH + length
if (fullMessageLength + offset <= bufferFullLength) {
const message = this.handlePacket(offset + HEADER_LENGTH, code, length, this.buffer)
callback(message)
offset += fullMessageLength
} else {
break
}
}
if (offset === bufferFullLength) {
// No more use for the buffer
this.buffer = emptyBuffer
this.bufferLength = 0
this.bufferOffset = 0
} else {
// Adjust the cursors of remainingBuffer
this.bufferLength = bufferFullLength - offset
this.bufferOffset = offset
}
}
private mergeBuffer(buffer: Buffer): void {
if (this.bufferLength > 0) {
const newLength = this.bufferLength + buffer.byteLength
const newFullLength = newLength + this.bufferOffset
if (newFullLength > this.buffer.byteLength) {
// We can't concat the new buffer with the remaining one
let newBuffer: Buffer
if (newLength <= this.buffer.byteLength && this.bufferOffset >= this.bufferLength) {
// We can move the relevant part to the beginning of the buffer instead of allocating a new buffer
newBuffer = this.buffer
} else {
// Allocate a new larger buffer
let newBufferLength = this.buffer.byteLength * 2
while (newLength >= newBufferLength) {
newBufferLength *= 2
}
newBuffer = Buffer.allocUnsafe(newBufferLength)
}
// Move the remaining buffer to the new one
this.buffer.copy(newBuffer, 0, this.bufferOffset, this.bufferOffset + this.bufferLength)
this.buffer = newBuffer
this.bufferOffset = 0
}
// Concat the new buffer with the remaining one
buffer.copy(this.buffer, this.bufferOffset + this.bufferLength)
this.bufferLength = newLength
} else {
this.buffer = buffer
this.bufferOffset = 0
this.bufferLength = buffer.byteLength
}
}
private handlePacket(offset: number, code: number, length: number, bytes: Buffer): BackendMessage {
switch (code) {
case MessageCodes.BindComplete:
return bindComplete
case MessageCodes.ParseComplete:
return parseComplete
case MessageCodes.CloseComplete:
return closeComplete
case MessageCodes.NoData:
return noData
case MessageCodes.PortalSuspended:
return portalSuspended
case MessageCodes.CopyDone:
return copyDone
case MessageCodes.ReplicationStart:
return replicationStart
case MessageCodes.EmptyQuery:
return emptyQuery
case MessageCodes.DataRow:
return this.parseDataRowMessage(offset, length, bytes)
case MessageCodes.CommandComplete:
return this.parseCommandCompleteMessage(offset, length, bytes)
case MessageCodes.ReadyForQuery:
return this.parseReadyForQueryMessage(offset, length, bytes)
case MessageCodes.NotificationResponse:
return this.parseNotificationMessage(offset, length, bytes)
case MessageCodes.AuthenticationResponse:
return this.parseAuthenticationResponse(offset, length, bytes)
case MessageCodes.ParameterStatus:
return this.parseParameterStatusMessage(offset, length, bytes)
case MessageCodes.BackendKeyData:
return this.parseBackendKeyData(offset, length, bytes)
case MessageCodes.ErrorMessage:
return this.parseErrorMessage(offset, length, bytes, 'error')
case MessageCodes.NoticeMessage:
return this.parseErrorMessage(offset, length, bytes, 'notice')
case MessageCodes.RowDescriptionMessage:
return this.parseRowDescriptionMessage(offset, length, bytes)
case MessageCodes.ParameterDescriptionMessage:
return this.parseParameterDescriptionMessage(offset, length, bytes)
case MessageCodes.CopyIn:
return this.parseCopyInMessage(offset, length, bytes)
case MessageCodes.CopyOut:
return this.parseCopyOutMessage(offset, length, bytes)
case MessageCodes.CopyData:
return this.parseCopyData(offset, length, bytes)
default:
assert.fail(`unknown message code: ${code.toString(16)}`)
}
}
private parseReadyForQueryMessage(offset: number, length: number, bytes: Buffer) {
this.reader.setBuffer(offset, bytes)
const status = this.reader.string(1)
return new ReadyForQueryMessage(length, status)
}
private parseCommandCompleteMessage(offset: number, length: number, bytes: Buffer) {
this.reader.setBuffer(offset, bytes)
const text = this.reader.cstring()
return new CommandCompleteMessage(length, text)
}
private parseCopyData(offset: number, length: number, bytes: Buffer) {
const chunk = bytes.slice(offset, offset + (length - 4))
return new CopyDataMessage(length, chunk)
}
private parseCopyInMessage(offset: number, length: number, bytes: Buffer) {
return this.parseCopyMessage(offset, length, bytes, 'copyInResponse')
}
private parseCopyOutMessage(offset: number, length: number, bytes: Buffer) {
return this.parseCopyMessage(offset, length, bytes, 'copyOutResponse')
}
private parseCopyMessage(offset: number, length: number, bytes: Buffer, messageName: MessageName) {
this.reader.setBuffer(offset, bytes)
const isBinary = this.reader.byte() !== 0
const columnCount = this.reader.int16()
const message = new CopyResponse(length, messageName, isBinary, columnCount)
for (let i = 0; i < columnCount; i++) {
message.columnTypes[i] = this.reader.int16()
}
return message
}
private parseNotificationMessage(offset: number, length: number, bytes: Buffer) {
this.reader.setBuffer(offset, bytes)
const processId = this.reader.int32()
const channel = this.reader.cstring()
const payload = this.reader.cstring()
return new NotificationResponseMessage(length, processId, channel, payload)
}
private parseRowDescriptionMessage(offset: number, length: number, bytes: Buffer) {
this.reader.setBuffer(offset, bytes)
const fieldCount = this.reader.int16()
const message = new RowDescriptionMessage(length, fieldCount)
for (let i = 0; i < fieldCount; i++) {
message.fields[i] = this.parseField()
}
return message
}
private parseField(): Field {
const name = this.reader.cstring()
const tableID = this.reader.int32()
const columnID = this.reader.int16()
const dataTypeID = this.reader.int32()
const dataTypeSize = this.reader.int16()
const dataTypeModifier = this.reader.int32()
const mode = this.reader.int16() === 0 ? 'text' : 'binary'
return new Field(name, tableID, columnID, dataTypeID, dataTypeSize, dataTypeModifier, mode)
}
private parseParameterDescriptionMessage(offset: number, length: number, bytes: Buffer) {
this.reader.setBuffer(offset, bytes)
const parameterCount = this.reader.int16()
const message = new ParameterDescriptionMessage(length, parameterCount)
for (let i = 0; i < parameterCount; i++) {
message.dataTypeIDs[i] = this.reader.int32()
}
return message
}
private parseDataRowMessage(offset: number, length: number, bytes: Buffer) {
this.reader.setBuffer(offset, bytes)
const fieldCount = this.reader.int16()
const fields: any[] = new Array(fieldCount)
for (let i = 0; i < fieldCount; i++) {
const len = this.reader.int32()
// a -1 for length means the value of the field is null
fields[i] = len === -1 ? null : this.reader.string(len)
}
return new DataRowMessage(length, fields)
}
private parseParameterStatusMessage(offset: number, length: number, bytes: Buffer) {
this.reader.setBuffer(offset, bytes)
const name = this.reader.cstring()
const value = this.reader.cstring()
return new ParameterStatusMessage(length, name, value)
}
private parseBackendKeyData(offset: number, length: number, bytes: Buffer) {
this.reader.setBuffer(offset, bytes)
const processID = this.reader.int32()
const secretKey = this.reader.int32()
return new BackendKeyDataMessage(length, processID, secretKey)
}
public parseAuthenticationResponse(offset: number, length: number, bytes: Buffer) {
this.reader.setBuffer(offset, bytes)
const code = this.reader.int32()
// TODO(bmc): maybe better types here
const message: BackendMessage & any = {
name: 'authenticationOk',
length,
}
switch (code) {
case 0: // AuthenticationOk
break
case 3: // AuthenticationCleartextPassword
if (message.length === 8) {
message.name = 'authenticationCleartextPassword'
}
break
case 5: // AuthenticationMD5Password
if (message.length === 12) {
message.name = 'authenticationMD5Password'
const salt = this.reader.bytes(4)
return new AuthenticationMD5Password(length, salt)
}
break
case 10: // AuthenticationSASL
message.name = 'authenticationSASL'
message.mechanisms = []
let mechanism: string
do {
mechanism = this.reader.cstring()
if (mechanism) {
message.mechanisms.push(mechanism)
}
} while (mechanism)
break
case 11: // AuthenticationSASLContinue
message.name = 'authenticationSASLContinue'
message.data = this.reader.string(length - 8)
break
case 12: // AuthenticationSASLFinal
message.name = 'authenticationSASLFinal'
message.data = this.reader.string(length - 8)
break
default:
throw new Error('Unknown authenticationOk message type ' + code)
}
return message
}
private parseErrorMessage(offset: number, length: number, bytes: Buffer, name: MessageName) {
this.reader.setBuffer(offset, bytes)
const fields: Record<string, string> = {}
let fieldType = this.reader.string(1)
while (fieldType !== '\0') {
fields[fieldType] = this.reader.cstring()
fieldType = this.reader.string(1)
}
const messageValue = fields.M
const message =
name === 'notice' ? new NoticeMessage(length, messageValue) : new DatabaseError(messageValue, length, name)
message.severity = fields.S
message.code = fields.C
message.detail = fields.D
message.hint = fields.H
message.position = fields.P
message.internalPosition = fields.p
message.internalQuery = fields.q
message.where = fields.W
message.schema = fields.s
message.table = fields.t
message.column = fields.c
message.dataType = fields.d
message.constraint = fields.n
message.file = fields.F
message.line = fields.L
message.routine = fields.R
return message
}
}