70 lines
2.1 KiB
Go
70 lines
2.1 KiB
Go
package mail
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import (
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"bytes"
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"fmt"
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htmltmpl "html/template"
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"strings"
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"github.com/yuin/goldmark"
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)
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// Announcement is one product email to one person: a feature launch, a guide,
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// an offer. vantage-admin's announce package builds it per recipient, because
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// the unsubscribe links carry that person's token.
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type Announcement struct {
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CategoryLabel string // "New features"
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Subject string
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BodyMarkdown string
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UnsubscribeURL string // RFC 8058 one-click target for this category
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PreferencesURL string // the no-login preferences page
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PostalAddress string // optional footer line
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}
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type announcementData struct {
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Announcement
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BodyHTML htmltmpl.HTML
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}
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// md renders with goldmark's defaults, which omit raw HTML: a pasted <script>
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// never reaches an inbox.
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var md = goldmark.New()
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func announcementMessage(a Announcement, publicURL string) (message, error) {
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var buf bytes.Buffer
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if err := md.Convert([]byte(a.BodyMarkdown), &buf); err != nil {
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return message{}, fmt.Errorf("mail: markdown: %w", err)
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}
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return render("announcement", announcementData{Announcement: a, BodyHTML: htmltmpl.HTML(buf.String())}, publicURL)
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}
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// RenderAnnouncement is the staff preview: exactly what a recipient gets.
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func RenderAnnouncement(a Announcement, publicURL string) (subject, html, text string, err error) {
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m, err := announcementMessage(a, publicURL)
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if err != nil {
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return "", "", "", err
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}
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return m.Subject, m.HTML, m.Text, nil
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}
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// SendAnnouncement sends one announcement to one address, with the
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// List-Unsubscribe pair Gmail and Yahoo require of bulk senders.
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func (s Sender) SendAnnouncement(to string, a Announcement) error {
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if strings.Contains(to, ",") {
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return fmt.Errorf("mail: an announcement goes to exactly one address")
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}
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if a.UnsubscribeURL == "" {
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return fmt.Errorf("mail: announcement without an unsubscribe URL")
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}
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m, err := announcementMessage(a, s.PublicURL)
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if err != nil {
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return err
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}
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m.To = to
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m.Headers = map[string]string{
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"List-Unsubscribe": "<" + a.UnsubscribeURL + ">",
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"List-Unsubscribe-Post": "List-Unsubscribe=One-Click",
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}
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return s.send(m)
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}
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