Add double opt-in support.

- Lists can now be marked as single | double optin.
- Insert subscribers to double opt-in lists send out a
  confirmation e-mail to the subscriber with a confirmation link.
- Add `{{ OptinURL }}` to template functions.

This is a breaking change. Adds a new field 'optin' to the lists
table and changes how campaigns behave. Campaigns on double opt-in
lists exclude subscribers who haven't explicitly confirmed subscriptions.

Changes the structure and behaviour of how notification e-mail routines,
including notif email template compilation,  notification callbacks for
campaign and bulk import completions.

email-templates/subscriber-optin.html

@@ -0,0 +1,21 @@
+{{ define "subscriber-optin" }}
+{{ template "header" . }}
+<h2>Confirm subscription</h2>
+<p>Hi {{ .Subscriber.FirstName }},</p>
+<p>You have been added to the following mailing lists:</p>
+<ul>
+    {{ range $i, $l := .Lists }}
+        {{ if eq .Type "public" }}
+            <li>{{ .Name }}</li>
+        {{ else }}
+            <li>Private list</li>
+        {{ end }}
+    {{ end }}
+</ul>
+<p>Confirm your subscription by clicking the below button.</p>
+<p>
+    <a href="{{ .OptinURL }}" class="button">Confirm subscription</a>
+</p>
+
+{{ template "footer" }}
+{{ end }}

frontend/src/Import.js

@@ -446,19 +446,16 @@ class Import extends React.PureComponent {
             <code className="csv-headers">
               <span>email,</span>
               <span>name,</span>
-              <span>status,</span>
               <span>attributes</span>
             </code>
             <code className="csv-row">
               <span>[email protected],</span>
               <span>"User One",</span>
-              <span>enabled,</span>
               <span>{'"{""age"": 32, ""city"": ""Bangalore""}"'}</span>
             </code>
             <code className="csv-row">
               <span>[email protected],</span>
               <span>"User Two",</span>
-              <span>blacklisted,</span>
               <span>
                 {'"{""age"": 25, ""occupation"": ""Time Traveller""}"'}
               </span>

frontend/src/Lists.js

@@ -153,7 +153,8 @@ class CreateFormDef extends React.PureComponent {
               {...formItemLayout}
               name="type"
               label="Type"
-              extra="Public lists are open to the world to subscribe"
+              extra="Public lists are open to the world to subscribe and their
+              names may appear on public pages such as the subscription management page."
             >
               {getFieldDecorator("type", {
                 initialValue: record.type ? record.type : "private",
@@ -165,6 +166,23 @@ class CreateFormDef extends React.PureComponent {
                 </Select>
               )}
             </Form.Item>
+            <Form.Item
+              {...formItemLayout}
+              name="optin"
+              label="Opt-in"
+              extra="Double opt-in sends an e-mail to the subscriber asking for confirmation.
+              On Double opt-in lists, campaigns are only sent to confirmed subscribers."
+            >
+              {getFieldDecorator("optin", {
+                initialValue: record.optin ? record.optin : "single",
+                rules: [{ required: true }]
+              })(
+                <Select style={{ maxWidth: 120 }}>
+                  <Select.Option value="single">Single</Select.Option>
+                  <Select.Option value="double">Double</Select.Option>
+                </Select>
+              )}
+            </Form.Item>
             <Form.Item
               {...formItemLayout}
               label="Tags"
@@ -239,16 +257,32 @@ class Lists extends React.PureComponent {
       {
         title: "Type",
         dataIndex: "type",
-        width: "10%",
-        render: (type, _) => {
+        width: "15%",
+        render: (type, record) => {
           let color = type === "private" ? "orange" : "green"
-          return <Tag color={color}>{type}</Tag>
+          return (
+            <div>
+              <p>
+                <Tag color={color}>{type}</Tag>
+                <Tag>{record.optin}</Tag>
+              </p>
+              {record.optin === cs.ListOptinDouble && (
+                <p className="text-small">
+                  <Tooltip title="Send a campaign to unconfirmed subscribers to opt-in">
+                    <Link to={`/campaigns/new?list_id=${record.id}`}>
+                      <Icon type="rocket" /> Send opt-in campaign
+                    </Link>
+                  </Tooltip>
+                </p>
+              )}
+            </div>
+          )
         }
       },
       {
         title: "Subscribers",
         dataIndex: "subscriber_count",
-        width: "15%",
+        width: "10%",
         align: "center",
         render: (text, record) => {
           return (

frontend/src/constants.js

@@ -50,6 +50,9 @@ export const SubscriptionStatusConfirmed = "confirmed"
 export const SubscriptionStatusUnConfirmed = "unconfirmed"
 export const SubscriptionStatusUnsubscribed = "unsubscribed"
 
+export const ListOptinSingle = "single"
+export const ListOptinDouble = "double"
+
 // API routes.
 export const Routes = {
   GetDashboarcStats: "/api/dashboard/stats",

handlers.go

@@ -98,6 +98,8 @@ func registerHandlers(e *echo.Echo) {
 		"campUUID", "subUUID"))
 	e.POST("/subscription/:campUUID/:subUUID", validateUUID(subscriberExists(handleSubscriptionPage),
 		"campUUID", "subUUID"))
+	e.GET("/subscription/optin/:subUUID", validateUUID(subscriberExists(handleOptinPage), "subUUID"))
+	e.POST("/subscription/optin/:subUUID", validateUUID(subscriberExists(handleOptinPage), "subUUID"))
 	e.POST("/subscription/export/:subUUID", validateUUID(subscriberExists(handleSelfExportSubscriberData),
 		"subUUID"))
 	e.POST("/subscription/wipe/:subUUID", validateUUID(subscriberExists(handleWipeSubscriberData),

install.go

@@ -54,9 +54,10 @@ func install(app *App, qMap goyesql.Queries, prompt bool) {
 		uuid.NewV4().String(),
 		"Default list",
 		models.ListTypePublic,
+		models.ListOptinSingle,
 		pq.StringArray{"test"},
 	); err != nil {
-		logger.Fatalf("Error creating superadmin user: %v", err)
+		logger.Fatalf("Error creating list: %v", err)
 	}
 
 	// Sample subscriber.

lists.go

@@ -92,6 +92,7 @@ func handleCreateList(c echo.Context) error {
 		o.UUID,
 		o.Name,
 		o.Type,
+		o.Optin,
 		pq.StringArray(normalizeTags(o.Tags))); err != nil {
 		return echo.NewHTTPError(http.StatusInternalServerError,
 			fmt.Sprintf("Error creating list: %s", pqErrMsg(err)))
@@ -120,7 +121,7 @@ func handleUpdateList(c echo.Context) error {
 		return err
 	}
 
-	res, err := app.Queries.UpdateList.Exec(id, o.Name, o.Type, pq.StringArray(normalizeTags(o.Tags)))
+	res, err := app.Queries.UpdateList.Exec(id, o.Name, o.Type, o.Optin, pq.StringArray(normalizeTags(o.Tags)))
 	if err != nil {
 		return echo.NewHTTPError(http.StatusBadRequest,
 			fmt.Sprintf("Error updating list: %s", pqErrMsg(err)))

main.go

@@ -30,12 +30,16 @@ import (
 )
 
 type constants struct {
-	RootURL      string         `koanf:"root"`
-	LogoURL      string         `koanf:"logo_url"`
-	FaviconURL   string         `koanf:"favicon_url"`
-	FromEmail    string         `koanf:"from_email"`
-	NotifyEmails []string       `koanf:"notify_emails"`
-	Privacy      privacyOptions `koanf:"privacy"`
+	RootURL        string `koanf:"root"`
+	LogoURL        string `koanf:"logo_url"`
+	FaviconURL     string `koanf:"favicon_url"`
+	UnsubscribeURL string
+	LinkTrackURL   string
+	ViewTrackURL   string
+	OptinURL       string
+	FromEmail      string         `koanf:"from_email"`
+	NotifyEmails   []string       `koanf:"notify_emails"`
+	Privacy        privacyOptions `koanf:"privacy"`
 }
 
 type privacyOptions struct {
@@ -286,8 +290,8 @@ func main() {
 	app.Queries = q
 
 	// Initialize the bulk subscriber importer.
-	importNotifCB := func(subject string, data map[string]interface{}) error {
-		go sendNotification(notifTplImport, subject, data, app)
+	importNotifCB := func(subject string, data interface{}) error {
+		go sendNotification(app.Constants.NotifyEmails, subject, notifTplImport, data, app)
 		return nil
 	}
 	app.Importer = subimporter.New(q.UpsertSubscriber.Stmt,
@@ -296,30 +300,38 @@ func main() {
 		db.DB,
 		importNotifCB)
 
-	// Read system e-mail templates.
-	notifTpls, err := stuffbin.ParseTemplatesGlob(nil, fs, "/email-templates/*.html")
+	// Prepare notification e-mail templates.
+	notifTpls, err := compileNotifTpls("/email-templates/*.html", fs, app)
 	if err != nil {
-		logger.Fatalf("error loading system e-mail templates: %v", err)
+		logger.Fatalf("error loading e-mail notification templates: %v", err)
 	}
 	app.NotifTpls = notifTpls
 
+	// Static URLS.
+	// url.com/subscription/{campaign_uuid}/{subscriber_uuid}
+	c.UnsubscribeURL = fmt.Sprintf("%s/subscription/%%s/%%s", app.Constants.RootURL)
+
+	// url.com/subscription/optin/{subscriber_uuid}
+	c.OptinURL = fmt.Sprintf("%s/subscription/optin/%%s?%%s", app.Constants.RootURL)
+
+	// url.com/link/{campaign_uuid}/{subscriber_uuid}/{link_uuid}
+	c.LinkTrackURL = fmt.Sprintf("%s/link/%%s/%%s/%%s", app.Constants.RootURL)
+
+	// url.com/campaign/{campaign_uuid}/{subscriber_uuid}/px.png
+	c.ViewTrackURL = fmt.Sprintf("%s/campaign/%%s/%%s/px.png", app.Constants.RootURL)
+
 	// Initialize the campaign manager.
-	campNotifCB := func(subject string, data map[string]interface{}) error {
-		return sendNotification(notifTplCampaign, subject, data, app)
+	campNotifCB := func(subject string, data interface{}) error {
+		return sendNotification(app.Constants.NotifyEmails, subject, notifTplCampaign, data, app)
 	}
 	m := manager.New(manager.Config{
 		Concurrency:   ko.Int("app.concurrency"),
 		MaxSendErrors: ko.Int("app.max_send_errors"),
 		FromEmail:     app.Constants.FromEmail,
-
-		// url.com/unsubscribe/{campaign_uuid}/{subscriber_uuid}
-		UnsubURL: fmt.Sprintf("%s/subscription/%%s/%%s", app.Constants.RootURL),
-
-		// url.com/link/{campaign_uuid}/{subscriber_uuid}/{link_uuid}
-		LinkTrackURL: fmt.Sprintf("%s/link/%%s/%%s/%%s", app.Constants.RootURL),
-
-		// url.com/campaign/{campaign_uuid}/{subscriber_uuid}/px.png
-		ViewTrackURL: fmt.Sprintf("%s/campaign/%%s/%%s/px.png", app.Constants.RootURL),
+		UnsubURL:      c.UnsubscribeURL,
+		OptinURL:      c.OptinURL,
+		LinkTrackURL:  c.LinkTrackURL,
+		ViewTrackURL:  c.ViewTrackURL,
 	}, newManagerDB(q), campNotifCB, logger)
 	app.Manager = m
 

manager/manager.go

@@ -63,9 +63,8 @@ type Message struct {
 	Subscriber *models.Subscriber
 	Body       []byte
 
-	unsubURL string
-	from     string
-	to       string
+	from string
+	to   string
 }
 
 // Config has parameters for configuring the manager.
@@ -76,6 +75,7 @@ type Config struct {
 	FromEmail      string
 	LinkTrackURL   string
 	UnsubURL       string
+	OptinURL       string
 	ViewTrackURL   string
 }
 
@@ -108,9 +108,8 @@ func (m *Manager) NewMessage(c *models.Campaign, s *models.Subscriber) *Message
 		Campaign:   c,
 		Subscriber: s,
 
-		from:     c.FromEmail,
-		to:       s.Email,
-		unsubURL: fmt.Sprintf(m.cfg.UnsubURL, c.UUID, s.UUID),
+		from: c.FromEmail,
+		to:   s.Email,
 	}
 }
 
@@ -423,7 +422,12 @@ func (m *Manager) TemplateFuncs(c *models.Campaign) template.FuncMap {
 				fmt.Sprintf(m.cfg.ViewTrackURL, msg.Campaign.UUID, msg.Subscriber.UUID)))
 		},
 		"UnsubscribeURL": func(msg *Message) string {
-			return msg.unsubURL
+			return fmt.Sprintf(m.cfg.UnsubURL, c.UUID, msg.Subscriber.UUID)
+		},
+		"OptinURL": func(msg *Message) string {
+			// Add list IDs.
+			// TODO: Show private lists list on optin e-mail
+			return fmt.Sprintf(m.cfg.OptinURL, msg.Subscriber.UUID, "")
 		},
 		"Date": func(layout string) string {
 			if layout == "" {

models/models.go

@@ -23,6 +23,11 @@ const (
 	SubscriberStatusDisabled    = "disabled"
 	SubscriberStatusBlackListed = "blacklisted"
 
+	// Subscription.
+	SubscriptionStatusUnconfirmed  = "unconfirmed"
+	SubscriptionStatusConfirmed    = "confirmed"
+	SubscriptionStatusUnsubscribed = "unsubscribed"
+
 	// Campaign.
 	CampaignStatusDraft     = "draft"
 	CampaignStatusScheduled = "scheduled"
@@ -34,6 +39,8 @@ const (
 	// List.
 	ListTypePrivate = "private"
 	ListTypePublic  = "public"
+	ListOptinSingle = "single"
+	ListOptinDouble = "double"
 
 	// User.
 	UserTypeSuperadmin = "superadmin"
@@ -72,7 +79,7 @@ var regTplFuncs = []regTplFunc{
 
 // AdminNotifCallback is a callback function that's called
 // when a campaign's status changes.
-type AdminNotifCallback func(subject string, data map[string]interface{}) error
+type AdminNotifCallback func(subject string, data interface{}) error
 
 // Base holds common fields shared across models.
 type Base struct {
@@ -126,6 +133,7 @@ type List struct {
 	UUID            string         `db:"uuid" json:"uuid"`
 	Name            string         `db:"name" json:"name"`
 	Type            string         `db:"type" json:"type"`
+	Optin           string         `db:"optin" json:"optin"`
 	Tags            pq.StringArray `db:"tags" json:"tags"`
 	SubscriberCount int            `db:"subscriber_count" json:"subscriber_count"`
 	SubscriberID    int            `db:"subscriber_id" json:"-"`
@@ -306,7 +314,7 @@ func (c *Campaign) CompileTemplate(f template.FuncMap) error {
 // FirstName splits the name by spaces and returns the first chunk
 // of the name that's greater than 2 characters in length, assuming
 // that it is the subscriber's first name.
-func (s *Subscriber) FirstName() string {
+func (s Subscriber) FirstName() string {
 	for _, s := range strings.Split(s.Name, " ") {
 		if len(s) > 2 {
 			return s
@@ -319,7 +327,7 @@ func (s *Subscriber) FirstName() string {
 // LastName splits the name by spaces and returns the last chunk
 // of the name that's greater than 2 characters in length, assuming
 // that it is the subscriber's last name.
-func (s *Subscriber) LastName() string {
+func (s Subscriber) LastName() string {
 	chunks := strings.Split(s.Name, " ")
 	for i := len(chunks) - 1; i >= 0; i-- {
 		chunk := chunks[i]