fix: proxy code to support both variants of proxy protocol (#1076)

Author: zobo

CHANGELOG.md

@@ -4,6 +4,10 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](http://keepachangelog.com/) and this project adheres to [Semantic Versioning](http://semver.org/).
 
+## [1.38.1]
+
+- Fix proxy protocol to support both variants
+
 ## [1.38.0]
 
 - Implement advanced copy functions

src/proxyConnect.ts

@@ -152,10 +152,28 @@ export class ProxyConnect extends EventEmitter {
         })
     }
 
+    /**
+     * The proxy protocol changed over time and initially the response was just XML.
+     * Later with re-implementation it follows the same spec as DBGp: [data length] [NULL] [xml] [NULL]
+     * @param data Recieved data
+     */
+    private _extractPacket(data: Buffer): string {
+        let packetData = data
+        const nullByteIndex = data.indexOf(0)
+        if (nullByteIndex !== -1) {
+            const lastPiece = data.subarray(0, nullByteIndex)
+            const dataLength = parseInt(decode(lastPiece, ENCODING))
+            if (!!dataLength && dataLength <= data.length - nullByteIndex - 1) {
+                packetData = data.subarray(nullByteIndex + 1, nullByteIndex + 1 + dataLength)
+            }
+        }
+        return decode(packetData, ENCODING)
+    }
+
     /** Parse data from response server and emit the relevant notification. */
     private _responseStrategy(data: Buffer) {
         try {
-            const documentElement = this._parser.parseFromString(decode(data, ENCODING), 'application/xml')
+            const documentElement = this._parser.parseFromString(this._extractPacket(data), 'application/xml')
                 .documentElement!
             const isSuccessful = documentElement.getAttribute('success') === '1'
             const error = documentElement.firstChild

src/test/proxy.ts

@@ -11,6 +11,9 @@ describe('ProxyConnect', () => {
         const err = `<proxy${cmd} success="${success}"><error id="${id}"><message>${msg}</message></error></proxy${cmd}>`
         return encode(`<?xml version="1.0" encoding="UTF-8"?>\n${err}`, ENCODING)
     }
+    function _dbgpWrap(raw: Buffer): Buffer {
+        return Buffer.concat([encode(raw.length.toString() + '\0', ENCODING), raw, Buffer.from([0])])
+    }
 
     const host = 'host'
     const port = 9001
@@ -78,7 +81,7 @@ describe('ProxyConnect', () => {
         })
     })
 
-    it('should be registered', (done: Mocha.Done) => {
+    it('should be registered (new protocol)', (done: Mocha.Done) => {
         conn.on('log_response', (str: string) => {
             assert.equal(str, msgs.registerSuccess)
             done()
@@ -87,7 +90,7 @@ describe('ProxyConnect', () => {
         conn.sendProxyInitCommand().catch((err: Error) => {
             done(err)
         })
-        testSocket.emit('data', _xml('init', 1))
+        testSocket.emit('data', _dbgpWrap(_xml('init', 1)))
         testSocket.emit('close', false)
     })