fix: randomly choose a local address to query from

.gitignore

@@ -11,3 +11,5 @@
 .log
 .purs-repl
 .env
+qed-mail/node_modules/
+qed-mail/dist/

package.json

@@ -14,5 +14,5 @@
   "peerDependencies": {
     "typescript": "^5.0.0"
   },
-  "dependencies": { "qed-mail": "^1.0.2" }
+  "dependencies": { "qed-mail": "./qed-mail/qed-mail-1.0.1@beta-1.tgz" }
 }

qed-mail/.gitignore

@@ -1,130 +0,0 @@
-# Logs
-logs
-*.log
-npm-debug.log*
-yarn-debug.log*
-yarn-error.log*
-lerna-debug.log*
-.pnpm-debug.log*
-
-# Diagnostic reports (https://nodejs.org/api/report.html)
-report.[0-9]*.[0-9]*.[0-9]*.[0-9]*.json
-
-# Runtime data
-pids
-*.pid
-*.seed
-*.pid.lock
-
-# Directory for instrumented libs generated by jscoverage/JSCover
-lib-cov
-
-# Coverage directory used by tools like istanbul
-coverage
-*.lcov
-
-# nyc test coverage
-.nyc_output
-
-# Grunt intermediate storage (https://gruntjs.com/creating-plugins#storing-task-files)
-.grunt
-
-# Bower dependency directory (https://bower.io/)
-bower_components
-
-# node-waf configuration
-.lock-wscript
-
-# Compiled binary addons (https://nodejs.org/api/addons.html)
-build/Release
-
-# Dependency directories
-node_modules/
-jspm_packages/
-
-# Snowpack dependency directory (https://snowpack.dev/)
-web_modules/
-
-# TypeScript cache
-*.tsbuildinfo
-
-# Optional npm cache directory
-.npm
-
-# Optional eslint cache
-.eslintcache
-
-# Optional stylelint cache
-.stylelintcache
-
-# Microbundle cache
-.rpt2_cache/
-.rts2_cache_cjs/
-.rts2_cache_es/
-.rts2_cache_umd/
-
-# Optional REPL history
-.node_repl_history
-
-# Output of 'npm pack'
-*.tgz
-
-# Yarn Integrity file
-.yarn-integrity
-
-# dotenv environment variable files
-.env
-.env.development.local
-.env.test.local
-.env.production.local
-.env.local
-
-# parcel-bundler cache (https://parceljs.org/)
-.cache
-.parcel-cache
-
-# Next.js build output
-.next
-out
-
-# Nuxt.js build / generate output
-.nuxt
-dist
-
-# Gatsby files
-.cache/
-# Comment in the public line in if your project uses Gatsby and not Next.js
-# https://nextjs.org/blog/next-9-1#public-directory-support
-# public
-
-# vuepress build output
-.vuepress/dist
-
-# vuepress v2.x temp and cache directory
-.temp
-.cache
-
-# Docusaurus cache and generated files
-.docusaurus
-
-# Serverless directories
-.serverless/
-
-# FuseBox cache
-.fusebox/
-
-# DynamoDB Local files
-.dynamodb/
-
-# TernJS port file
-.tern-port
-
-# Stores VSCode versions used for testing VSCode extensions
-.vscode-test
-
-# yarn v2
-.yarn/cache
-.yarn/unplugged
-.yarn/build-state.yml
-.yarn/install-state.gz
-.pnp.*

qed-mail/package.json

@@ -1,6 +1,6 @@
 {
   "name": "qed-mail",
-  "version": "1.0.1",
+  "version": "1.0.1@beta-1",
   "description": "📮 A NodeJS library for checking if an email address exists without sending any email.",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",

qed-mail/src/index.ts

@@ -11,7 +11,7 @@ const DEFAULT_RESULT = {
   smtp: { valid: false },
 };
 
-async function checkEmail(email: string): Promise<Result> {
+async function checkEmail(email: string, {fromAddr}: {fromAddr?: string} = {}): Promise<Result> {
   const result: Result = { email, ...DEFAULT_RESULT };
 
   const syntax = checkSyntax(email);
@@ -25,7 +25,7 @@ async function checkEmail(email: string): Promise<Result> {
   }
 
   const records = mx.mxRecords.sort((a, b) => a.priority - b.priority);
-  const smtp = await checkSMTP(email, records[0]!.exchange, 25);
+  const smtp = await checkSMTP(email, records[0]!.exchange, 25, {fromAddr});
   if (!smtp.valid) {
     return { ...result, syntax, mx, smtp };
   }

qed-mail/src/smtp/verify.ts

@@ -1,16 +1,18 @@
 import { Client } from "smtp-fetch";
 import { SMTPResult } from "../types";
+import { TcpNetConnectOpts } from "net";
 
 async function checkSMTP(
   to: string,
   host: string,
   port: number,
-  timeout: number = 5000
+  {fromAddr, timeout = 5000}: {timeout?: number, fromAddr?: string} = {},
 ): Promise<SMTPResult> {
   const c = new Client(host, port);
 
   try {
-    await c.connect({ timeout });
+    const options: Omit<TcpNetConnectOpts, 'host' | 'port'> = { timeout, localAddress: fromAddr };
+    await c.connect(options);
 
     await c.mail("");
     await c.rcpt(to);

spago.yaml

@@ -6,11 +6,14 @@ package:
     - bifunctors
     - effect
     - either
+    - filterable
     - foldable-traversable
     - maybe
     - newtype
+    - node-os
     - nullable
     - prelude
+    - random
     - strings
     - tailrec
     - transformers

src/Effect.Email.js

@@ -1,4 +1,4 @@
 import { checkEmail } from 'qed-mail'
 
-/** @type {(_: string) => () => Promise<import('qed-mail/src/types.js').Result>} */
-export const checkEmailImpl = s => () => checkEmail(s)
+/** @type {(email: string) => (addr: string | null) => () => Promise<import('qed-mail/src/types.js').Result>} */
+export const checkEmailImpl = s => addr => () => checkEmail(s, {fromAddr: addr || undefined})

src/Effect.Email.purs

@@ -14,6 +14,8 @@ import Data.Either (Either(..))
 import Data.Email (Email)
 import Data.Email as Email
 import Data.Eq.Generic (genericEq)
+import Data.Filterable (filter)
+import Data.Foldable (fold)
 import Data.Generic.Rep (class Generic)
 import Data.Int as Int
 import Data.Maybe (maybe)
@@ -24,9 +26,12 @@ import Data.Show.Generic (genericShow)
 import Data.Traversable (for_)
 import Effect (Effect)
 import Effect.Aff (Aff, delay)
+import Effect.Class (liftEffect)
+import Effect.Random (randomInt)
+import Node.OS as Node.OS
 import Type.Function (type ($))
 
-foreign import checkEmailImpl :: String -> Effect $ Promise $ QEDResult
+foreign import checkEmailImpl :: String -> Nullable String -> Effect $ Promise $ QEDResult
 
 data EmailError
   = EmailUnreachable Email
@@ -82,8 +87,12 @@ type QEDResult =
 
 deliverableOnce :: Email -> ExceptT EmailError Aff Email
 deliverableOnce email' = do
-  let email = Email.toString email'
-  { reachable, syntax, mx, smtp } <- lift $ Promise.toAffE $ checkEmailImpl email
+  addrs <- liftEffect $ filter (not <<< _.internal) <$> fold <$> Node.OS.networkInterfaces
+  chosen <- liftEffect $ randomInt 0 (Array.length addrs - 1)
+  let
+    addr = _.address <$> Array.index addrs chosen
+    email = Email.toString email'
+  { reachable, syntax, mx, smtp } <- lift $ Promise.toAffE $ checkEmailImpl email (Nullable.toNullable addr)
   when (not syntax.valid) $ throwError $ EmailSyntaxInvalid email'
   when (not mx.valid) $ throwError $ EmailMXInvalid email'
   when (maybe true Array.null $ Nullable.toMaybe $ mx.mxRecords) $ throwError $ EmailMXNoRecords email'