Merge pull request #2 from iAlex97/master

Check if socket is writeable before sending it data

Author: mfbx9da4

src/smtp/smtp.ts

@@ -15,25 +15,34 @@ export const checkSMTP = async (
 ): Promise<OutputFormat> => {
   const timeout = 1000 * 10 // 10 seconds
   return new Promise(r => {
+    let receivedData: boolean = false;
     const socket = net.createConnection(25, exchange)
     socket.setEncoding('ascii')
     socket.setTimeout(timeout)
     socket.on('error', error => {
       log('error', error)
       socket.emit('fail', error)
     })
-
+    socket.on('close', hadError => {
+      if (!receivedData && !hadError) {
+        socket.emit('fail', 'Mail server closed connection without sending any data.')
+      }
+    })
     socket.on('fail', msg => {
       r(createOutput('smtp', msg))
-      socket.write(`quit\r\n`)
-      socket.end()
-      socket.destroy()
+      if (socket.writable && !socket.destroyed) {
+        socket.write(`quit\r\n`)
+        socket.end()
+        socket.destroy()
+      }
     })
 
     socket.on('success', () => {
-      socket.write(`quit\r\n`)
-      socket.end()
-      socket.destroy()
+      if (socket.writable && !socket.destroyed) {
+        socket.write(`quit\r\n`)
+        socket.end()
+        socket.destroy()
+      }
       r(createOutput())
     })
 
@@ -45,7 +54,11 @@ export const checkSMTP = async (
     let i = 0
     socket.on('next', () => {
       if (i < 3) {
-        socket.write(commands[i++])
+        if (socket.writable) {
+          socket.write(commands[i++])
+        } else {
+          socket.emit('fail', 'SMTP communication unexpectedly closed.')
+        }
       } else {
         socket.emit('success')
       }
@@ -57,6 +70,7 @@ export const checkSMTP = async (
 
     socket.on('connect', () => {
       socket.on('data', msg => {
+        receivedData = true;
         log('data', msg)
         if (hasCode(msg, 220) || hasCode(msg, 250)) {
           socket.emit('next', msg)

test/__snapshots__/index.test.ts.snap

@@ -100,6 +100,31 @@ Object {
 }
 `;
 
+exports[`validation tests fails with bad mailbox 3`] = `
+Object {
+  "reason": "smtp",
+  "valid": false,
+  "validators": Object {
+    "disposable": Object {
+      "valid": true,
+    },
+    "mx": Object {
+      "valid": true,
+    },
+    "regex": Object {
+      "valid": true,
+    },
+    "smtp": Object {
+      "reason": "Mailbox not found.",
+      "valid": false,
+    },
+    "typo": Object {
+      "valid": true,
+    },
+  },
+}
+`;
+
 exports[`validation tests fails with bad regex 1`] = `
 Object {
   "reason": "regex",
@@ -175,6 +200,31 @@ Object {
 }
 `;
 
+exports[`validation tests fails without sending data 1`] = `
+Object {
+  "reason": "smtp",
+  "valid": false,
+  "validators": Object {
+    "disposable": Object {
+      "valid": true,
+    },
+    "mx": Object {
+      "valid": true,
+    },
+    "regex": Object {
+      "valid": true,
+    },
+    "smtp": Object {
+      "reason": "Mail server closed connection without sending any data.",
+      "valid": false,
+    },
+    "typo": Object {
+      "valid": true,
+    },
+  },
+}
+`;
+
 exports[`validation tests passes when valid special char 1`] = `
 Object {
   "valid": true,
@@ -198,6 +248,29 @@ Object {
 }
 `;
 
+exports[`validation tests passes when valid special char 2`] = `
+Object {
+  "valid": true,
+  "validators": Object {
+    "disposable": Object {
+      "valid": true,
+    },
+    "mx": Object {
+      "valid": true,
+    },
+    "regex": Object {
+      "valid": true,
+    },
+    "smtp": Object {
+      "valid": true,
+    },
+    "typo": Object {
+      "valid": true,
+    },
+  },
+}
+`;
+
 exports[`validation tests passes when valid wildcard 1`] = `
 Object {
   "valid": true,

test/index.test.ts

@@ -5,6 +5,18 @@ import { validate } from '../src/index'
 const elevenSeconds = 11 * 1000
 
 describe('validation tests', () => {
+  it('fails without sending data', async () => {
+    const res = await validate({
+      email: '[email protected]',
+      sender: '[email protected]',
+      validateTypo: false,
+      validateDisposable: false,
+    })
+    expect(res.valid).toBe(false)
+    expect(res.reason).toBe('smtp')
+    expect(res.validators.smtp?.valid).toBe(false)
+    expect(res).toMatchSnapshot()
+  })
   it('fails with bad regex', async () => {
     const res = await validate('david.gmail.com')
     expect(res.valid).toBe(false)