feat: programmatically set agentVersion for use in identify (#1296)

If no `agentVersion` is provided for the Identify protocol, the default `AGENT_VERSION` will now be set to
* `js-libp2p/<libp2p.version> UserAgent=<process.version>` when running in Node.js
* `js-libp2p/<libp2p.version> UserAgent=<navigator.userAgent>` when running in the browser (also when running in a webworker)

Fixes #686
Supersedes #1240

Co-authored-by: Kevin Westphal <westphal@consider-it.de>
Co-authored-by: Kevin <56823591+6d7a@users.noreply.github.com>

package.json

@@ -80,6 +80,7 @@
     "clean": "aegir clean",
     "lint": "aegir lint",
     "dep-check": "aegir dep-check",
+    "prepublishOnly": "node scripts/update-version.js",
     "build": "aegir build",
     "generate": "run-s generate:proto:*",
     "generate:proto:circuit": "protons ./src/circuit/pb/index.proto",

scripts/update-version.js

@@ -0,0 +1,14 @@
+import { readFile, writeFile } from 'fs/promises'
+
+const pkg = JSON.parse(
+  await readFile(
+    new URL('../package.json', import.meta.url)
+  )
+)
+
+await writeFile(
+  new URL('../src/version.ts', import.meta.url),
+  `export const version = '${pkg.version}'
+export const name = '${pkg.name}'
+`
+)

src/config.ts

@@ -10,6 +10,7 @@ import type { Libp2pInit } from './index.js'
 import { codes, messages } from './errors.js'
 import errCode from 'err-code'
 import type { RecursivePartial } from '@libp2p/interfaces'
+import { isNode, isBrowser, isWebWorker, isElectronMain, isElectronRenderer, isReactNative } from 'wherearewe'
 
 const DefaultConfig: Partial<Libp2pInit> = {
   addresses: {
@@ -116,5 +117,14 @@ export function validateConfig (opts: RecursivePartial<Libp2pInit>): Libp2pInit
     throw errCode(new Error(messages.ERR_PROTECTOR_REQUIRED), codes.ERR_PROTECTOR_REQUIRED)
   }
 
+  // Append user agent version to default AGENT_VERSION depending on the environment
+  if (resultingOptions.identify.host.agentVersion === AGENT_VERSION) {
+    if (isNode || isElectronMain) {
+      resultingOptions.identify.host.agentVersion += ` UserAgent=${globalThis.process.version}`
+    } else if (isBrowser || isWebWorker || isElectronRenderer || isReactNative) {
+      resultingOptions.identify.host.agentVersion += ` UserAgent=${globalThis.navigator.userAgent}`
+    }
+  }
+
   return resultingOptions
 }

src/version.ts

@@ -1,3 +1,2 @@
-
 export const version = '0.0.0'
 export const name = 'libp2p'

test/identify/service.spec.ts

@@ -14,6 +14,7 @@ import { peerIdFromString } from '@libp2p/peer-id'
 import type { PeerId } from '@libp2p/interface-peer-id'
 import type { Libp2pNode } from '../../src/libp2p.js'
 import { pEvent } from 'p-event'
+import { AGENT_VERSION } from '../../src/identify/consts.js'
 
 describe('libp2p.dialer.identifyService', () => {
   let peerId: PeerId
@@ -147,6 +148,29 @@ describe('libp2p.dialer.identifyService', () => {
     await pWaitFor(() => connection.streams.length === 0)
   })
 
+  it('should append UserAgent information to default AGENT_VERSION', async () => {
+    // Stub environment version for testing dynamic AGENT_VERSION
+    sinon.stub(process, 'version').value('vTEST')
+
+    if (typeof globalThis.navigator !== 'undefined') {
+      sinon.stub(navigator, 'userAgent').value('vTEST')
+    }
+
+    libp2p = await createLibp2pNode(createBaseOptions({
+      peerId
+    }))
+
+    await libp2p.start()
+
+    if (libp2p.identifyService == null) {
+      throw new Error('Identity service was not configured')
+    }
+
+    const storedAgentVersion = await libp2p.peerStore.metadataBook.getValue(peerId, 'AgentVersion')
+
+    expect(AGENT_VERSION + ' UserAgent=vTEST').to.equal(uint8ArrayToString(storedAgentVersion ?? new Uint8Array()))
+  })
+
   it('should store host data and protocol version into metadataBook', async () => {
     const agentVersion = 'js-project/1.0.0'