Golang : How to parse plain email text and process email header?




Problem :

Your program receive email in plain text and you need to parse email header information. How to that in Golang?

Solution :

First, convert the plain text into proper mail message type( see http://golang.org/pkg/net/mail/#Message ) with mail.ReadMessage() function and then process the email header with the associated methods. See example code below.

 package main

 import (
  "bytes"
  "fmt"
  "net/mail"
 )

 var emailData = `From: Adam <adam@earth.com>
 To: Eve <eve@earth.com>
 Subject: Do not eat the apple from that tree!
 Date: Fri, 21 Nov 0000 09:55:06 -0600
 Message-ID: <1234@garden.earth>

 Don't listen to that snake. Don't eat the apple!
 `

 func main() {

  msg, err := mail.ReadMessage(bytes.NewBuffer([]byte(emailData)))

  if err != nil {
 panic(err)
  }

  fmt.Println(msg.Header)

  // --------------

  header := msg.Header

  key := "From"

  address, err := header.AddressList(key)

  if err != nil {
 panic(err)
  }

  fmt.Println(address[0].String())

  // --------------

  key = "To"

  addresses, err := header.AddressList(key)

  if err != nil {
 panic(err)
  }

  fmt.Println(addresses[0].String())

  // --------------

  dateTime, err := header.Date()

  if err != nil {
 panic(err)
  }

  fmt.Println(dateTime.String())

  // --------------

  getSubject := header.Get("Subject")

  fmt.Println(getSubject)

 }

Output :

map[Message-Id:[1234@garden.earth] From:[Adam adam@earth.com] To:[Eve eve@earth.com] Subject:[Do not eat the apple from that tree!] Date:[Fri,

21 Nov 0000 09:55:06 -0600]]

"Adam" adam@earth.com

"Eve" eve@earth.com

0000-11-21 09:55:06 -0600 -0600

Do not eat the apple from that tree!

References :

http://golang.org/pkg/net/mail/#Message

https://www.socketloop.com/references/golang-net-mail-header-type-date-get-and-addresslist-functions-example





By Adam Ng

IF you gain some knowledge or the information here solved your programming problem. Please consider donating to the less fortunate or some charities that you like. Apart from donation, planting trees, volunteering or reducing your carbon footprint will be great too.


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