Centralize campaign From header templating logic.

Author: knadh

cmd/campaigns.go

@@ -663,27 +663,9 @@ func (a *App) sendTestMessage(sub models.Subscriber, camp *models.Campaign) erro
 func (a *App) validateCampaignFields(c campReq) (campReq, error) {
 	if c.FromEmail == "" {
 		c.FromEmail = a.cfg.FromEmail
-	} else {
-		fromEmail := c.FromEmail
-
-		// If the From header contains a template, render it against the
-		// dummy subscriber so the resolved address can be validated.
-		if strings.Contains(fromEmail, "{{") {
-			testCamp := models.Campaign{FromEmail: fromEmail}
-			if err := testCamp.CompileTemplate(a.manager.TemplateFuncs(&testCamp)); err != nil {
-				return c, errors.New(a.i18n.Ts("campaigns.fieldInvalidFromEmail") + ": " + err.Error())
-			}
-			msg, err := a.manager.NewCampaignMessage(&testCamp, dummySubscriber)
-			if err != nil {
-				return c, errors.New(a.i18n.Ts("campaigns.fieldInvalidFromEmail") + ": " + err.Error())
-			}
-			fromEmail = msg.From()
-		}
-
-		if !reFromAddress.Match([]byte(fromEmail)) {
-			if _, err := a.importer.SanitizeEmail(fromEmail); err != nil {
-				return c, errors.New(a.i18n.T("campaigns.fieldInvalidFromEmail"))
-			}
+	} else if !models.HasTplExpr(c.FromEmail) && !reFromAddress.Match([]byte(c.FromEmail)) {
+		if _, err := a.importer.SanitizeEmail(c.FromEmail); err != nil {
+			return c, errors.New(a.i18n.T("campaigns.fieldInvalidFromEmail"))
 		}
 	}
 

internal/manager/message.go

@@ -101,11 +101,6 @@ func (m *CampaignMessage) Subject() string {
 	return m.subject
 }
 
-// From returns the rendered From header.
-func (m *CampaignMessage) From() string {
-	return m.from
-}
-
 // Body returns a copy of the message body.
 func (m *CampaignMessage) Body() []byte {
 	out := make([]byte, len(m.body))

models/campaigns.go

@@ -140,34 +140,15 @@ func (camps Campaigns) LoadStats(stmt *sqlx.Stmt) error {
 // CompileTemplate compiles a campaign body template into its base
 // template and sets the resultant template to Campaign.Tpl.
 func (c *Campaign) CompileTemplate(f template.FuncMap) error {
-	// If the subject line has a template string, compile it.
-	if hasTplExpr(c.Subject) {
-		subj := c.Subject
-		for _, r := range regTplFuncs {
-			subj = r.regExp.ReplaceAllString(subj, r.replace)
-		}
-
-		var txtFuncs map[string]any = f
-		subjTpl, err := txttpl.New(ContentTpl).Funcs(txtFuncs).Parse(subj)
-		if err != nil {
-			return fmt.Errorf("error compiling subject: %v", err)
-		}
-		c.SubjectTpl = subjTpl
+	var err error
+	c.SubjectTpl, err = compileTxtTpl("subject", c.Subject, f)
+	if err != nil {
+		return err
 	}
 
-	// If the From header has a template string, compile it.
-	if hasTplExpr(c.FromEmail) {
-		from := c.FromEmail
-		for _, r := range regTplFuncs {
-			from = r.regExp.ReplaceAllString(from, r.replace)
-		}
-
-		var txtFuncs map[string]any = f
-		fromTpl, err := txttpl.New(ContentTpl).Funcs(txtFuncs).Parse(from)
-		if err != nil {
-			return fmt.Errorf("error compiling from: %v", err)
-		}
-		c.FromEmailTpl = fromTpl
+	c.FromEmailTpl, err = compileTxtTpl("from", c.FromEmail, f)
+	if err != nil {
+		return err
 	}
 
 	// Compile the base template.
@@ -213,7 +194,7 @@ func (c *Campaign) CompileTemplate(f template.FuncMap) error {
 	}
 	c.Tpl = out
 
-	if hasTplExpr(c.AltBody.String) {
+	if HasTplExpr(c.AltBody.String) {
 		b := c.AltBody.String
 		for _, r := range regTplFuncs {
 			b = r.regExp.ReplaceAllString(b, r.replace)
@@ -228,7 +209,7 @@ func (c *Campaign) CompileTemplate(f template.FuncMap) error {
 	// Compile any header values that contain template expressions.
 	for _, set := range c.Headers {
 		for _, val := range set {
-			if hasTplExpr(val) {
+			if HasTplExpr(val) {
 				c.HeaderTpls = make([]map[string]*txttpl.Template, len(c.Headers))
 				break
 			}
@@ -242,25 +223,36 @@ func (c *Campaign) CompileTemplate(f template.FuncMap) error {
 		for i, set := range c.Headers {
 			c.HeaderTpls[i] = make(map[string]*txttpl.Template, len(set))
 			for hdr, val := range set {
-				if !hasTplExpr(val) {
-					continue
-				}
-				tpl, err := txttpl.New(ContentTpl).Funcs(txtFuncs).Parse(val)
+				tpl, err := compileTxtTpl(fmt.Sprintf("header %q", hdr), val, txtFuncs)
 				if err != nil {
-					return fmt.Errorf("error compiling header %q: %v", hdr, err)
+					return err
+				}
+				if tpl != nil {
+					c.HeaderTpls[i][hdr] = tpl
 				}
-				c.HeaderTpls[i][hdr] = tpl
 			}
 		}
 	}
 
 	return nil
 }
 
-// hasTplExpr checks whether a given string has a Go template expression with {{ and  }}.
-func hasTplExpr(s string) bool {
-	_, after, ok := strings.Cut(s, "{{")
-	return ok && strings.Contains(after, "}}")
+func compileTxtTpl(label, val string, f template.FuncMap) (*txttpl.Template, error) {
+	if !HasTplExpr(val) {
+		return nil, nil
+	}
+
+	for _, r := range regTplFuncs {
+		val = r.regExp.ReplaceAllString(val, r.replace)
+	}
+
+	var txtFuncs map[string]any = f
+	tpl, err := txttpl.New(ContentTpl).Funcs(txtFuncs).Parse(val)
+	if err != nil {
+		return nil, fmt.Errorf("error compiling %s: %v", label, err)
+	}
+
+	return tpl, nil
 }
 
 // ConvertContent converts a campaign's body from one format to another,
@@ -286,3 +278,9 @@ func (c *Campaign) ConvertContent(from, to string) (string, error) {
 
 	return out, nil
 }
+
+// HasTplExpr checks whether a given string has a Go template expression with {{ and  }}.
+func HasTplExpr(s string) bool {
+	_, after, ok := strings.Cut(s, "{{")
+	return ok && strings.Contains(after, "}}")
+}

models/messages.go

@@ -86,7 +86,7 @@ func (m *TxMessage) Render(sub Subscriber, tpl *Template, funcs txttpl.FuncMap)
 	b.Reset()
 
 	// Render alt body if it has any templating strings.
-	if m.AltBody != "" && hasTplExpr(m.AltBody) {
+	if m.AltBody != "" && HasTplExpr(m.AltBody) {
 		t, err := txttpl.New(BaseTpl).Funcs(funcs).Parse(m.AltBody)
 		if err != nil {
 			return fmt.Errorf("error compiling alt body: %v", err)
@@ -104,7 +104,7 @@ func (m *TxMessage) Render(sub Subscriber, tpl *Template, funcs txttpl.FuncMap)
 		subject = m.Subject
 	)
 	if subject != "" {
-		if hasTplExpr(m.Subject) {
+		if HasTplExpr(m.Subject) {
 			// If the subject has a template string, render that.
 			s, err := txttpl.New(BaseTpl).Funcs(funcs).Parse(m.Subject)
 			if err != nil {

models/templates.go

@@ -44,7 +44,7 @@ func (t *Template) Compile(f template.FuncMap) error {
 	t.Tpl = tpl
 
 	// If the subject line has a template string, compile it.
-	if hasTplExpr(t.Subject) {
+	if HasTplExpr(t.Subject) {
 		subj := t.Subject
 
 		subjTpl, err := txttpl.New(BaseTpl).Funcs(txttpl.FuncMap(f)).Parse(subj)