listmonk/internal/messenger/messenger.go
Kailash Nadh 68afd61024 Add support for alternate plaintext body for e-mails.
This commit removes the Go html2text lib that would automatically
convert all HTML messages to plaintext and add them as the alt
text body to outgoing e-mails. This lib also had memory leak
issues with certain kinds of HTML templates.

A new UI field for optionally adding an alt plaintext body to
a campaign is added. On enabling, it converts the HTML message in
the campaign editor into plaintext (using the textversionjs lib).

This introduces breaking changes in the campaigns table schema,
model, and template compilation.
2021-01-30 18:49:47 +05:30

56 lines
1.3 KiB
Go

package messenger
import (
"net/textproto"
"github.com/knadh/listmonk/models"
)
// Messenger is an interface for a generic messaging backend,
// for instance, e-mail, SMS etc.
type Messenger interface {
Name() string
Push(Message) error
Flush() error
Close() error
}
// Message is the message pushed to a Messenger.
type Message struct {
From string
To []string
Subject string
ContentType string
Body []byte
AltBody []byte
Headers textproto.MIMEHeader
Attachments []Attachment
Subscriber models.Subscriber
// Campaign is generally the same instance for a large number of subscribers.
Campaign *models.Campaign
}
// Attachment represents a file or blob attachment that can be
// sent along with a message by a Messenger.
type Attachment struct {
Name string
Header textproto.MIMEHeader
Content []byte
}
// MakeAttachmentHeader is a helper function that returns a
// textproto.MIMEHeader tailored for attachments, primarily
// email. If no encoding is given, base64 is assumed.
func MakeAttachmentHeader(filename, encoding string) textproto.MIMEHeader {
if encoding == "" {
encoding = "base64"
}
h := textproto.MIMEHeader{}
h.Set("Content-Disposition", "attachment; filename="+filename)
h.Set("Content-Type", "application/json; name=\""+filename+"\"")
h.Set("Content-Transfer-Encoding", encoding)
return h
}