Add subscription link support to notification email verification template (#573)

* add subscription link support to notification email verification template

* always show token for email subscription in verification email

* hide SubscribeURL from users

backend/app/cmd/server.go

@@ -766,6 +766,8 @@ func (s *ServerCommand) makeNotify(dataStore *service.DataStore, authenticator *
 				From:                s.Notify.Email.From,
 				VerificationSubject: s.Notify.Email.VerificationSubject,
 				UnsubscribeURL:      s.RemarkURL + "/email/unsubscribe.html",
+				// TODO: uncomment after #560 frontend part is ready and URL is known
+				//SubscribeURL:        s.RemarkURL + "/subscribe.html?token=",
 				TokenGenFn: func(userID, email, site string) (string, error) {
 					claims := token.Claims{
 						Handshake: &token.Handshake{ID: userID + "::" + email},

backend/app/notify/email.go

@@ -23,6 +23,7 @@ type EmailParams struct {
 	MsgTemplate          string // request message template
 	VerificationSubject  string // verification message subject
 	VerificationTemplate string // verification message template
+	SubscribeURL         string // full subscribe handler URL
 	UnsubscribeURL       string // full unsubscribe handler URL
 
 	TokenGenFn func(userID, email, site string) (string, error) // Unsubscribe token generation function
@@ -91,10 +92,11 @@ type msgTmplData struct {
 
 // verifyTmplData store data for verification message template execution
 type verifyTmplData struct {
-	User  string
-	Token string
-	Email string
-	Site  string
+	User         string
+	Token        string
+	Email        string
+	Site         string
+	SubscribeURL string
 }
 
 const (
@@ -178,6 +180,10 @@ const (
 	<div style="text-align: center; font-family: Helvetica, Arial, sans-serif; font-size: 18px;">
 		<h1 style="position: relative; color: #4fbbd6; margin-top: 0.2em;">Remark42</h1>
 		<p style="position: relative; max-width: 20em; margin: 0 auto 1em auto; line-height: 1.4em; color:#000!important;">Confirmation for <b>{{.User}}</b> on site <b>{{.Site}}</b></p>
+		{{if .SubscribeURL}}
+		<p style="position: relative; margin: 0 0 0.5em 0;color:#000!important;"><a href="{{.SubscribeURL}}{{.Token}}">Click here to subscribe to email notifications</a></p>
+		<p style="position: relative; margin: 0 0 0.5em 0;color:#000!important;">Alternatively, you can use code below for subscription.</p>
+		{{ end }}
 		<div style="background-color: #eee; max-width: 20em; margin: 0 auto; border-radius: 0.4em; padding: 0.5em;">
 			<p style="position: relative; margin: 0 0 0.5em 0;color:#000!important;">TOKEN</p>
 			<p style="position: relative; font-size: 0.7em; opacity: 0.8;"><i style="color:#000!important;">Copy and paste this text into “token” field on comments page</i></p>
@@ -273,10 +279,11 @@ func (e *Email) buildVerificationMessage(user, email, token, site string) (strin
 	subject := e.VerificationSubject
 	msg := bytes.Buffer{}
 	err := e.verifyTmpl.Execute(&msg, verifyTmplData{
-		User:  user,
-		Token: token,
-		Email: email,
-		Site:  site,
+		User:         user,
+		Token:        token,
+		Email:        email,
+		Site:         site,
+		SubscribeURL: e.SubscribeURL,
 	})
 	if err != nil {
 		return "", errors.Wrapf(err, "error executing template to build verification message")

backend/app/notify/email_test.go

@@ -189,7 +189,8 @@ func TestEmail_Send(t *testing.T) {
 	req := Request{
 		Comment: store.Comment{ID: "999", User: store.User{ID: "1", Name: "test_user"}, PostTitle: "test_title"},
 		parent:  store.Comment{ID: "1", User: store.User{ID: "999", Name: "parent_user"}},
-		Email:   "test@example.org"}
+		Email:   "test@example.org",
+	}
 	assert.NoError(t, email.Send(context.TODO(), req))
 	assert.Equal(t, "from@example.org", fakeSmtp.readMail())
 	assert.Equal(t, 1, fakeSmtp.readQuitCount())
@@ -208,6 +209,50 @@ List-Unsubscribe: <https://remark42.com/api/v1/email/unsubscribe?site=&tkn=token
 Date: `)
 }
 
+func TestEmail_SendVerification(t *testing.T) {
+	email, err := NewEmail(EmailParams{From: "from@example.org"}, SmtpParams{})
+	assert.NoError(t, err)
+	assert.NotNil(t, email)
+	fakeSmtp := fakeTestSMTP{}
+	email.smtp = &fakeSmtp
+	email.TokenGenFn = TokenGenFn
+	req := Request{
+		Email: "test@example.org",
+		Verification: VerificationMetadata{
+			SiteID: "remark",
+			User:   "test_username",
+			Token:  "secret_",
+		},
+	}
+	assert.NoError(t, email.Send(context.TODO(), req))
+	assert.Equal(t, "from@example.org", fakeSmtp.readMail())
+	assert.Equal(t, 1, fakeSmtp.readQuitCount())
+	assert.Equal(t, "test@example.org", fakeSmtp.readRcpt())
+	// test buildMessageFromRequest separately for message text
+	res, err := email.buildVerificationMessage(req.Verification.User, req.Email, req.Verification.Token, req.Verification.SiteID)
+	assert.NoError(t, err)
+	assert.Contains(t, res, `From: from@example.org
+To: test@example.org
+Subject: Email verification
+Content-Transfer-Encoding: quoted-printable
+MIME-version: 1.0
+Content-Type: text/html; charset="UTF-8"
+Date: `)
+	assert.Contains(t, res, `secret_`)
+	assert.NotContains(t, res, `https://example.org/`)
+	email.SubscribeURL = "https://example.org/subscribe.html?token="
+	res, err = email.buildVerificationMessage(req.Verification.User, req.Email, req.Verification.Token, req.Verification.SiteID)
+	assert.NoError(t, err)
+	assert.Contains(t, res, `From: from@example.org
+To: test@example.org
+Subject: Email verification
+Content-Transfer-Encoding: quoted-printable
+MIME-version: 1.0
+Content-Type: text/html; charset="UTF-8"
+Date: `)
+	assert.Contains(t, res, `https://example.org/subscribe.html?token=3Dsecret_`)
+}
+
 func Test_emailClient_Create(t *testing.T) {
 	creator := emailClient{}
 	client, err := creator.Create(SmtpParams{})