Add ParameterDescription message to pg-protocol

Author: Sven Over

packages/pg-protocol/src/inbound-parser.test.ts

@@ -144,6 +144,35 @@ var expectedTwoRowMessage = {
   ],
 }
 
+var emptyParameterDescriptionBuffer = new BufferList()
+  .addInt16(0) // number of parameters
+  .join(true, 't')
+
+var oneParameterDescBuf = buffers.parameterDescription([1111])
+
+var twoParameterDescBuf = buffers.parameterDescription([2222, 3333])
+
+var expectedEmptyParameterDescriptionMessage = {
+  name: 'parameterDescription',
+  length: 6,
+  parameterCount: 0,
+  dataTypeIDs: [],
+}
+
+var expectedOneParameterMessage = {
+  name: 'parameterDescription',
+  length: 10,
+  parameterCount: 1,
+  dataTypeIDs: [1111],
+}
+
+var expectedTwoParameterMessage = {
+  name: 'parameterDescription',
+  length: 14,
+  parameterCount: 2,
+  dataTypeIDs: [2222, 3333],
+}
+
 var testForMessage = function (buffer: Buffer, expectedMessage: any) {
   it('recieves and parses ' + expectedMessage.name, async () => {
     const messages = await parseBuffers([buffer])
@@ -245,6 +274,12 @@ describe('PgPacketStream', function () {
     testForMessage(twoRowBuf, expectedTwoRowMessage)
   })
 
+  describe('parameterDescription messages', function () {
+    testForMessage(emptyParameterDescriptionBuffer, expectedEmptyParameterDescriptionMessage)
+    testForMessage(oneParameterDescBuf, expectedOneParameterMessage)
+    testForMessage(twoParameterDescBuf, expectedTwoParameterMessage)
+  })
+
   describe('parsing rows', function () {
     describe('parsing empty row', function () {
       testForMessage(emptyRowFieldBuf, {

packages/pg-protocol/src/messages.ts

@@ -11,6 +11,7 @@ export type MessageName =
   | 'copyDone'
   | 'copyData'
   | 'rowDescription'
+  | 'parameterDescription'
   | 'parameterStatus'
   | 'backendKeyData'
   | 'notification'
@@ -152,6 +153,14 @@ export class RowDescriptionMessage {
   }
 }
 
+export class ParameterDescriptionMessage {
+  public readonly name: MessageName = MessageName.parameterDescription
+  public readonly dataTypeIDs: number[]
+  constructor(public readonly length: number, public readonly parameterCount: number) {
+    this.dataTypeIDs = new Array(this.parameterCount)
+  }
+}
+
 export class ParameterStatusMessage {
   public readonly name: MessageName = 'parameterStatus'
   constructor(

packages/pg-protocol/src/parser.ts

@@ -15,6 +15,7 @@ import {
   CopyResponse,
   NotificationResponseMessage,
   RowDescriptionMessage,
+  ParameterDescriptionMessage,
   Field,
   DataRowMessage,
   ParameterStatusMessage,
@@ -62,6 +63,7 @@ const enum MessageCodes {
   ErrorMessage = 0x45, // E
   NoticeMessage = 0x4e, // N
   RowDescriptionMessage = 0x54, // T
+  ParameterDescriptionMessage = 0x74, // t
   PortalSuspended = 0x73, // s
   ReplicationStart = 0x57, // W
   EmptyQuery = 0x49, // I
@@ -188,6 +190,8 @@ export class Parser {
         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:
@@ -264,6 +268,16 @@ export class Parser {
     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()

packages/pg-protocol/src/testing/test-buffers.ts

@@ -62,6 +62,16 @@ const buffers = {
     return buf.join(true, 'T')
   },
 
+  parameterDescription: function (dataTypeIDs: number[]) {
+    dataTypeIDs = dataTypeIDs || []
+    var buf = new BufferList()
+    buf.addInt16(dataTypeIDs.length)
+    dataTypeIDs.forEach(function (dataTypeID) {
+      buf.addInt32(dataTypeID)
+    })
+    return buf.join(true, 't')
+  },
+
   dataRow: function (columns: any[]) {
     columns = columns || []
     var buf = new BufferList()