enmime

ExampleEnvelope demonstrates the relationship between Envelope and Parts.

package main

import (
	"fmt"
	"strings"

	"github.com/jhillyerd/enmime"
)

func main() {
	// Create sample message in memory
	raw := `From: user@inbucket.org
Subject: Example message
Content-Type: multipart/alternative; boundary=Enmime-100

--Enmime-100
Content-Type: text/plain
X-Comment: part1

hello!
--Enmime-100
Content-Type: text/html
X-Comment: part2

<b>hello!</b>
--Enmime-100
Content-Type: text/plain
Content-Disposition: attachment;
filename=hi.txt
X-Comment: part3

hello again!
--Enmime-100--
`

	// Parse message body with enmime.ReadEnvelope
	r := strings.NewReader(raw)
	env, err := enmime.ReadEnvelope(r)
	if err != nil {
		fmt.Print(err)
		return
	}

	// The root Part contains the message header, which is also available via the
	// Envelope.GetHeader() method.
	fmt.Printf("Root Part Subject: %q\n", env.Root.Header.Get("Subject"))
	fmt.Printf("Envelope Subject: %q\n", env.GetHeader("Subject"))
	fmt.Println()

	// The text from part1 is consumed and placed into the Envelope.Text field.
	fmt.Printf("Text Content: %q\n", env.Text)

	// But part1 is also available as a child of the root Part.  Only the headers may be accessed,
	// because the content has been consumed.
	part1 := env.Root.FirstChild
	fmt.Printf("Part 1 X-Comment: %q\n", part1.Header.Get("X-Comment"))
	fmt.Println()

	// The HTML from part2 is consumed and placed into the Envelope.HTML field.
	fmt.Printf("HTML Content: %q\n", env.HTML)

	// And part2 is available as the second child of the root Part. Only the headers may be
	// accessed, because the content has been consumed.
	part2 := env.Root.FirstChild.NextSibling
	fmt.Printf("Part 2 X-Comment: %q\n", part2.Header.Get("X-Comment"))
	fmt.Println()

	// Because part3 has a disposition of attachment, it is added to the Envelope.Attachments
	// slice
	fmt.Printf("Attachment 1 X-Comment: %q\n", env.Attachments[0].Header.Get("X-Comment"))

	// And is still available as the third child of the root Part
	part3 := env.Root.FirstChild.NextSibling.NextSibling
	fmt.Printf("Part 3 X-Comment: %q\n", part3.Header.Get("X-Comment"))

	// The content of Attachments, Inlines and OtherParts are available as a slice of bytes
	fmt.Printf("Part 3 Content: %q\n", part3.Content)

	// part3 contained a malformed header line, enmime has attached an Error to it
	p3error := part3.Errors[0]
	fmt.Println(p3error.String())
	fmt.Println()

	// All Part errors are collected and placed into Envelope.Errors
	fmt.Println("Envelope errors:")
	for _, e := range env.Errors {
		fmt.Println(e.String())
	}

}

Output:

Root Part Subject: "Example message"
Envelope Subject: "Example message"

Text Content: "hello!"
Part 1 X-Comment: "part1"

HTML Content: "<b>hello!</b>"
Part 2 X-Comment: "part2"

Attachment 1 X-Comment: "part3"
Part 3 X-Comment: "part3"
Part 3 Content: "hello again!"
[W] Malformed Header: Continued line "filename=hi.txt" was not indented

Envelope errors:
[W] Malformed Header: Continued line "filename=hi.txt" was not indented