EagleCast

internal/manager/message.go

@@ -0,0 +1,107 @@
+package manager
+
+import (
+	"bytes"
+	"fmt"
+
+	"source.offmarket.win/aleagle/eaglecast/models"
+)
+
+// NewCampaignMessage creates and returns a CampaignMessage that is made available
+// to message templates while they're compiled. It represents a message from
+// a campaign that's bound to a single Subscriber.
+func (m *Manager) NewCampaignMessage(c *models.Campaign, s models.Subscriber) (CampaignMessage, error) {
+	msg := CampaignMessage{
+		Campaign:   c,
+		Subscriber: s,
+
+		subject:  c.Subject,
+		from:     c.FromEmail,
+		to:       s.Email,
+		unsubURL: fmt.Sprintf(m.cfg.UnsubURL, c.UUID, s.UUID),
+	}
+
+	if err := msg.render(); err != nil {
+		return msg, err
+	}
+
+	return msg, nil
+}
+
+// render takes a Message, executes its pre-compiled Campaign.Tpl
+// and applies the resultant bytes to Message.body to be used in messages.
+func (m *CampaignMessage) render() error {
+	out := bytes.Buffer{}
+
+	// Render the subject if it's a template.
+	if m.Campaign.SubjectTpl != nil {
+		if err := m.Campaign.SubjectTpl.ExecuteTemplate(&out, models.ContentTpl, m); err != nil {
+			return err
+		}
+		m.subject = out.String()
+		out.Reset()
+	}
+
+	// Compile the main template.
+	if err := m.Campaign.Tpl.ExecuteTemplate(&out, models.BaseTpl, m); err != nil {
+		return err
+	}
+	m.body = out.Bytes()
+
+	// Is there an alt body?
+	if m.Campaign.ContentType != models.CampaignContentTypePlain && m.Campaign.AltBody.Valid {
+		if m.Campaign.AltBodyTpl != nil {
+			b := bytes.Buffer{}
+			if err := m.Campaign.AltBodyTpl.ExecuteTemplate(&b, models.ContentTpl, m); err != nil {
+				return err
+			}
+			m.altBody = b.Bytes()
+		} else {
+			m.altBody = []byte(m.Campaign.AltBody.String)
+		}
+	}
+
+	// If there are templated headers, compile them.
+	if m.Campaign.HeaderTpls == nil {
+		m.headers = m.Campaign.Headers
+	} else {
+		hdrOut := bytes.Buffer{}
+		m.headers = make(models.Headers, len(m.Campaign.Headers))
+		for i, set := range m.Campaign.Headers {
+			m.headers[i] = make(map[string]string, len(set))
+			for hdr, val := range set {
+				tpl := m.Campaign.HeaderTpls[i][hdr]
+				if tpl == nil {
+					m.headers[i][hdr] = val
+					continue
+				}
+				hdrOut.Reset()
+				if err := tpl.ExecuteTemplate(&hdrOut, models.ContentTpl, m); err != nil {
+					return fmt.Errorf("error rendering header %q: %v", hdr, err)
+				}
+				m.headers[i][hdr] = hdrOut.String()
+			}
+		}
+	}
+
+	return nil
+}
+
+// Subject returns a copy of the message subject
+func (m *CampaignMessage) Subject() string {
+	return m.subject
+}
+
+// Body returns a copy of the message body.
+func (m *CampaignMessage) Body() []byte {
+	out := make([]byte, len(m.body))
+	copy(out, m.body)
+	return out
+}
+
+// AltBody returns a copy of the message's alt body.
+func (m *CampaignMessage) AltBody() []byte {
+	out := make([]byte, len(m.altBody))
+	copy(out, m.altBody)
+	return out
+}