client [NET-992]: pre-compiled JSON schema validator (#1642)

## Summary

Compile JSON schema validator functions at build time instead of run
time as described here https://ajv.js.org/standalone.html to avoid
having to rely on `eval` during run time. Another added benefit is that
we don't need to include `ajv` in our webpack build, reducing the
browser bundle size slightly.

## Changes
- Mark packages `ajv` and `ajv-format` as dev dependencies.
- Add script `bin/generate-config-validator.js` that generates the
pre-built JSON schema validator function.
- Call above script in `prebuild` phase, ensuring it gets called every
time the client package is built.
- Add folder `src/generated` for generated code that gets ignored by
eslint.

packages/client/.eslintignore

@@ -8,3 +8,4 @@ test/benchmarks/**
 test/memory/*
 docs/**
 .idea/**
+src/generated/**

packages/client/bin/generate-config-validator.js

@@ -0,0 +1,30 @@
+/**
+ * This script generates a client config AJV validation function to avoid
+ * having to compile it during run time which requires the use of `eval`.
+ * Use of `eval` is not allowed e.g. in Chrome plugins.
+ */
+/* eslint-disable @typescript-eslint/no-require-imports */
+
+const fs = require('fs')
+const path = require('path')
+const Ajv = require('ajv')
+const standaloneCode = require('ajv/dist/standalone').default
+const { fastFormats, fullFormats } = require('ajv-formats/dist/formats')
+const CONFIG_SCHEMA = require('../src/config.schema.json')
+
+const ajv = new Ajv({
+    useDefaults: true,
+    code: {
+        source: true
+    }
+})
+// addFormats(ajv) does not work properly when generating stand-alone code
+// (https://github.com/ajv-validator/ajv-formats/issues/68) so adding formats one-by-one
+ajv.addFormat('uri', fastFormats['uri'])
+ajv.addFormat('ipv4', fullFormats['ipv4'])
+ajv.addFormat('ethereum-address', /^0x[a-zA-Z0-9]{40}$/)
+ajv.addFormat('ethereum-private-key', /^(0x)?[a-zA-Z0-9]{64}$/)
+
+const validate = ajv.compile(CONFIG_SCHEMA)
+const moduleCode = standaloneCode(ajv, validate)
+fs.writeFileSync(path.join(__dirname, "../src/generated/validateConfig.js"), moduleCode)

packages/client/package.json

@@ -19,7 +19,7 @@
     }
   },
   "scripts": {
-    "prebuild": "bash vendor-hack.sh",
+    "prebuild": "node bin/generate-config-validator.js && bash vendor-hack.sh",
     "postbuild": "bash copy-package.sh && bash fix-esm.sh",
     "build": "tsc --build ./tsconfig.node.json",
     "build-production": "npm run clean; NODE_ENV=production npm run build && npm run build-browser-production",
@@ -53,6 +53,8 @@
     "@types/secp256k1": "^4.0.3",
     "@types/split2": "^4.2.0",
     "@types/uuid": "^9.0.2",
+    "ajv": "^8.8.2",
+    "ajv-formats": "^2.1.1",
     "babel-loader": "^9.1.2",
     "babel-plugin-add-module-exports": "^1.0.4",
     "babel-plugin-lodash": "^3.3.4",
@@ -100,8 +102,6 @@
     "@streamr/network-node": "8.5.4",
     "@streamr/protocol": "8.5.4",
     "@streamr/utils": "8.5.4",
-    "ajv": "^8.8.2",
-    "ajv-formats": "^2.1.1",
     "core-js": "^3.31.0",
     "env-paths": "^2.2.1",
     "eventemitter3": "^5.0.0",

packages/client/src/Config.ts

@@ -1,18 +1,16 @@
 import 'reflect-metadata'
 import type { Overrides } from '@ethersproject/contracts'
 import cloneDeep from 'lodash/cloneDeep'
-import Ajv, { ErrorObject } from 'ajv'
-import addFormats from 'ajv-formats'
 import type { ExternalProvider } from '@ethersproject/providers'
 import { MarkOptional, DeepRequired } from 'ts-essentials'
 
-import CONFIG_SCHEMA from './config.schema.json'
 import { TrackerRegistryRecord } from '@streamr/protocol'
 import { LogLevel } from '@streamr/utils'
 
 import { IceServer, Location, WebRtcPortRange, ExternalIP } from '@streamr/network-node'
 import type { ConnectionInfo } from '@ethersproject/web'
 import { generateClientId } from './utils/utils'
+import validate from './generated/validateConfig'
 
 export interface ProviderAuthConfig {
     ethereum: ExternalProvider
@@ -377,23 +375,16 @@ export const createStrictConfig = (input: StreamrClientConfig = {}): StrictStrea
 }
 
 export const validateConfig = (data: unknown): StrictStreamrClientConfig | never => {
-    const ajv = new Ajv({
-        useDefaults: true
-    })
-    addFormats(ajv)
-    ajv.addFormat('ethereum-address', /^0x[a-zA-Z0-9]{40}$/)
-    ajv.addFormat('ethereum-private-key', /^(0x)?[a-zA-Z0-9]{64}$/)
-    const validate = ajv.compile<StrictStreamrClientConfig>(CONFIG_SCHEMA)
     if (!validate(data)) {
-        throw new Error(validate.errors!.map((e: ErrorObject) => {
-            let text = ajv.errorsText([e], { dataVar: '' }).trim()
+        throw new Error((validate as any).errors!.map((e: any) => {
+            let text = e.instancePath + " " + e.message
             if (e.params.additionalProperty) {
                 text += `: ${e.params.additionalProperty}`
             }
             return text
         }).join('\n'))
     }
-    return data
+    return data as any
 }
 
 export const redactConfig = (config: StrictStreamrClientConfig): void => {