Comment Thread Subscriptions

* Add ability to (un)subscribe from comment threads on Forums and Photos.
* Creating a forum post, replying to a post or adding a comment to a photo
  automatically subscribes you to be notified when somebody else adds a
  comment to the thing later.
* At the top of each comment thread is a link to disable or re-enable your
  subscription. You can join a subscription without even needing to comment.
  If you click to disable notifications, they stay disabled even if you
  add another comment later.

README.md

@@ -56,6 +56,10 @@ Run `nonshy --help` for its documentation.
 
 Run `nonshy web` to start the web server.
 
+```bash
+nonshy web --host 0.0.0.0 --port 8080 --debug
+```
+
 ## Create Admin User Accounts
 
 Use the `nonshy user add` command like so:
@@ -70,6 +74,44 @@ $ nonshy user add --admin \
 Shorthand options `-e`, `-p` and `-u` can work in place of the longer
 options `--email`, `--password` and `--username` respectively.
 
+After the first admin user is created, you may promote other users thru
+the web app by using the admin controls on their profile page.
+
+## A Brief Tour of the Code
+
+* `cmd/nonshy/main.go`: the entry point for the Go program.
+* `pkg/webserver.go`: the entry point for the web server.
+* `pkg/config`: mostly hard-coded configuration values - all of the page
+  sizes and business logic controls are in here, set at compile time. For
+  ease of local development you may want to toggle SkipEmailValidation in
+  here - the signup form will then directly allow full signup with a user
+  and password.
+* `pkg/controller`: the various web endpoint controllers are here,
+  categorized into subpackages (account, forum, inbox, photo, etc.)
+* `pkg/log`: the logging to terminal functions.
+* `pkg/mail`: functions for delivering HTML email messages.
+* `pkg/markdown`: functions to render GitHub Flavored Markdown.
+* `pkg/middleware`: HTTP middleware functions, for things such as:
+    * Session cookies
+    * Authentication (LoginRequired, AdminRequired)
+    * CSRF protection
+    * Logging HTTP requests
+    * Panic recovery for unhandled server errors
+* `pkg/models`: the SQL database models and query functions are here.
+    * `pkg/models/deletion`: the code to fully scrub wipe data for
+      user deletion (GDPR/CCPA compliance).
+* `pkg/photo`: photo management functions: handle uploads, scale and
+  crop, generate URLs and deletion.
+* `pkg/ratelimit`: rate limiter for login attempts etc.
+* `pkg/redis`: Redis cache functions - get/set JSON values for things like
+  session cookie storage and temporary rate limits.
+* `pkg/router`: the HTTP route URLs for the controllers are here.
+* `pkg/session`: functions to read/write the user's session cookie
+  (log in/out, get current user, flash messages)
+* `pkg/templates`: functions to handle HTTP responses - render HTML
+  templates, issue redirects, error pages, ...
+* `pkg/utility`: miscellaneous useful functions for the app.
+
 ## License
 
 GPLv3.

pkg/controller/comment/post_comment.go

@@ -178,6 +178,39 @@ func PostComment() http.HandlerFunc {
 							log.Error("Couldn't create Comment notification: %s", err)
 						}
 					}
+
+					// Notify subscribers to this comment thread.
+					for _, userID := range models.GetSubscribers(comment.TableName, comment.TableID) {
+						if notifyUser != nil && userID == notifyUser.ID {
+							// Don't notify the recipient twice.
+							continue
+						} else if userID == currentUser.ID {
+							// Don't notify the poster of the comment.
+							continue
+						}
+
+						notif := &models.Notification{
+							UserID:    userID,
+							AboutUser: *currentUser,
+							Type:      models.NotificationAlsoCommented,
+							TableName: comment.TableName,
+							TableID:   comment.TableID,
+							Message:   message,
+							Link:      fromURL,
+						}
+						if err := models.CreateNotification(notif); err != nil {
+							log.Error("Couldn't create Comment notification for subscriber %d: %s", userID, err)
+						}
+					}
+
+					// Subscribe the current user to this comment thread, so they are
+					// notified if other users add followup comments.
+					if _, err := models.SubscribeTo(currentUser, comment.TableName, comment.TableID); err != nil {
+						log.Error("Couldn't subscribe user %d to comment thread %s/%d: %s",
+							currentUser.ID, comment.TableName, comment.TableID, err,
+						)
+					}
+
 					return
 				}
 			}

pkg/controller/comment/subscription.go

@@ -0,0 +1,91 @@
+package comment
+
+import (
+	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
+
+	"code.nonshy.com/nonshy/website/pkg/models"
+	"code.nonshy.com/nonshy/website/pkg/session"
+	"code.nonshy.com/nonshy/website/pkg/templates"
+)
+
+// Subscription endpoint - to opt in or out of comment thread subscriptions.
+func Subscription() http.HandlerFunc {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// Query params.
+		var (
+			tableName = r.FormValue("table_name")
+			tableID   uint64
+			subscribe = r.FormValue("subscribe") == "true"
+			fromURL   = r.FormValue("next") // what page to send back to
+		)
+
+		// Parse the table ID param.
+		if idStr := r.FormValue("table_id"); idStr == "" {
+			session.FlashError(w, r, "Comment table ID required.")
+			templates.Redirect(w, "/")
+			return
+		} else {
+			if idInt, err := strconv.Atoi(idStr); err != nil {
+				session.FlashError(w, r, "Comment table ID invalid.")
+				templates.Redirect(w, "/")
+				return
+			} else {
+				tableID = uint64(idInt)
+			}
+		}
+
+		// Redirect URL must be relative.
+		if !strings.HasPrefix(fromURL, "/") {
+			// Maybe it's URL encoded?
+			fromURL, _ = url.QueryUnescape(fromURL)
+			if !strings.HasPrefix(fromURL, "/") {
+				fromURL = "/"
+			}
+		}
+
+		// Validate everything else.
+		if _, ok := models.CommentableTables[tableName]; !ok {
+			session.FlashError(w, r, "You can not comment on that.")
+			templates.Redirect(w, "/")
+			return
+		}
+
+		// Get the current user.
+		currentUser, err := session.CurrentUser(r)
+		if err != nil {
+			session.FlashError(w, r, "Couldn't get current user: %s", err)
+			templates.Redirect(w, "/")
+			return
+		}
+
+		// Get their subscription.
+		sub, err := models.GetSubscription(currentUser, tableName, tableID)
+		if err != nil {
+			// If they want to subscribe, insert their row.
+			if subscribe {
+				if _, err := models.SubscribeTo(currentUser, tableName, tableID); err != nil {
+					session.FlashError(w, r, "Couldn't create subscription: %s", err)
+				} else {
+					session.Flash(w, r, "You will now be notified about comments on this page.")
+				}
+			}
+		} else {
+			// Toggle it.
+			sub.Subscribed = subscribe
+			if err := sub.Save(); err != nil {
+				session.FlashError(w, r, "Couldn't save your subscription settings: %s", err)
+			} else {
+				if subscribe {
+					session.Flash(w, r, "You will now be notified about comments on this page.")
+				} else {
+					session.Flash(w, r, "You will no longer be notified about new comments on this page.")
+				}
+			}
+		}
+
+		templates.Redirect(w, fromURL)
+	})
+}

pkg/controller/forum/new_post.go

@@ -5,6 +5,7 @@ import (
 	"net/http"
 	"strconv"
 
+	"code.nonshy.com/nonshy/website/pkg/log"
 	"code.nonshy.com/nonshy/website/pkg/markdown"
 	"code.nonshy.com/nonshy/website/pkg/models"
 	"code.nonshy.com/nonshy/website/pkg/session"
@@ -160,6 +161,31 @@ func NewPost() http.HandlerFunc {
 						session.FlashError(w, r, "Couldn't add reply to thread: %s", err)
 					} else {
 						session.Flash(w, r, "Reply added to the thread!")
+
+						// Notify watchers about this new post.
+						for _, userID := range models.GetSubscribers("threads", thread.ID) {
+							if userID == currentUser.ID {
+								continue
+							}
+
+							notif := &models.Notification{
+								UserID:    userID,
+								AboutUser: *currentUser,
+								Type:      models.NotificationAlsoPosted,
+								TableName: "threads",
+								TableID:   thread.ID,
+								Message:   message,
+								Link:      fmt.Sprintf("/forum/thread/%d", thread.ID),
+							}
+							if err := models.CreateNotification(notif); err != nil {
+								log.Error("Couldn't create thread reply notification for subscriber %d: %s", userID, err)
+							}
+						}
+
+						// Subscribe the current user to further responses on this thread.
+						if _, err := models.SubscribeTo(currentUser, "threads", thread.ID); err != nil {
+							log.Error("Couldn't subscribe user %d to forum thread %d: %s", currentUser.ID, thread.ID, err)
+						}
 					}
 					templates.Redirect(w, fmt.Sprintf("/forum/thread/%d", thread.ID))
 					return
@@ -178,6 +204,12 @@ func NewPost() http.HandlerFunc {
 					session.FlashError(w, r, "Couldn't create thread: %s", err)
 				} else {
 					session.Flash(w, r, "Thread created!")
+
+					// Subscribe the current user to responses on this thread.
+					if _, err := models.SubscribeTo(currentUser, "threads", thread.ID); err != nil {
+						log.Error("Couldn't subscribe user %d to forum thread %d: %s", currentUser.ID, thread.ID, err)
+					}
+
 					templates.Redirect(w, fmt.Sprintf("/forum/thread/%d", thread.ID))
 					return
 				}

pkg/controller/forum/thread.go

@@ -74,11 +74,15 @@ func Thread() http.HandlerFunc {
 			return
 		}
 
+		// Is the current user subscribed to notifications on this thread?
+		_, isSubscribed := models.IsSubscribed(currentUser, "threads", thread.ID)
+
 		var vars = map[string]interface{}{
-			"Forum":    forum,
-			"Thread":   thread,
-			"Comments": comments,
-			"Pager":    pager,
+			"Forum":        forum,
+			"Thread":       thread,
+			"Comments":     comments,
+			"Pager":        pager,
+			"IsSubscribed": isSubscribed,
 		}
 		if err := tmpl.Execute(w, r, vars); err != nil {
 			http.Error(w, err.Error(), http.StatusInternalServerError)

pkg/controller/photo/view.go

@@ -76,13 +76,17 @@ func View() http.HandlerFunc {
 			log.Error("Couldn't list comments for photo %d: %s", photo.ID, err)
 		}
 
+		// Is the current user subscribed to notifications on this thread?
+		_, isSubscribed := models.IsSubscribed(currentUser, "photos", photo.ID)
+
 		var vars = map[string]interface{}{
-			"IsOwnPhoto": currentUser.ID == user.ID,
-			"User":       user,
-			"Photo":      photo,
-			"LikeMap":    likeMap,
-			"CommentMap": commentMap,
-			"Comments":   comments,
+			"IsOwnPhoto":   currentUser.ID == user.ID,
+			"User":         user,
+			"Photo":        photo,
+			"LikeMap":      likeMap,
+			"CommentMap":   commentMap,
+			"Comments":     comments,
+			"IsSubscribed": isSubscribed,
 		}
 		if err := tmpl.Execute(w, r, vars); err != nil {
 			http.Error(w, err.Error(), http.StatusInternalServerError)

pkg/models/comment.go

@@ -22,7 +22,8 @@ type Comment struct {
 // CommentableTables are the set of table names that allow comments (via the
 // generic "/comments" URI which accepts a table_name param)
 var CommentableTables = map[string]interface{}{
-	"photos": nil,
+	"photos":  nil,
+	"threads": nil,
 }
 
 // Preload related tables for the forum (classmethod).

pkg/models/deletion/delete_user.go

@@ -23,6 +23,7 @@ func DeleteUser(user *models.User) error {
 		{"Likes", DeleteLikes},
 		{"Threads", DeleteForumThreads},
 		{"Comments", DeleteComments},
+		{"Subscriptions", DeleteSubscriptions},
 		{"Photos", DeleteUserPhotos},
 		{"Certification Photo", DeleteCertification},
 		{"Messages", DeleteUserMessages},
@@ -126,6 +127,16 @@ func DeleteNotifications(userID uint64) error {
 	return result.Error
 }
 
+// DeleteSubscriptions scrubs all notification subscriptions about a user.
+func DeleteSubscriptions(userID uint64) error {
+	log.Error("DeleteUser: DeleteSubscriptions(%d)", userID)
+	result := models.DB.Where(
+		"user_id = ?",
+		userID,
+	).Delete(&models.Subscription{})
+	return result.Error
+}
+
 // DeleteLikes scrubs all Likes about a user.
 func DeleteLikes(userID uint64) error {
 	log.Error("DeleteUser: DeleteLikes(%d)", userID)

pkg/models/models.go

@@ -21,4 +21,5 @@ func AutoMigrate() {
 	DB.AutoMigrate(&Comment{})
 	DB.AutoMigrate(&Like{})
 	DB.AutoMigrate(&Notification{})
+	DB.AutoMigrate(&Subscription{})
 }

pkg/models/notification.go

@@ -34,6 +34,8 @@ const (
 	NotificationLike           NotificationType = "like"
 	NotificationFriendApproved                  = "friendship_approved"
 	NotificationComment                         = "comment"
+	NotificationAlsoCommented                   = "also_comment"
+	NotificationAlsoPosted                      = "also_posted" // forum replies
 	NotificationCertRejected                    = "cert_rejected"
 	NotificationCertApproved                    = "cert_approved"
 	NotificationCustom                          = "custom" // custom message pushed
@@ -104,8 +106,10 @@ func (n *Notification) Save() error {
 
 // NotificationBody can store remote tables mapped.
 type NotificationBody struct {
-	PhotoID uint64
-	Photo   *Photo
+	PhotoID  uint64
+	ThreadID uint64
+	Photo    *Photo
+	Thread   *Thread
 }
 
 type NotificationMap map[uint64]*NotificationBody
@@ -131,6 +135,14 @@ func MapNotifications(ns []*Notification) NotificationMap {
 		result[row.ID] = &NotificationBody{}
 	}
 
+	result.mapNotificationPhotos(IDs)
+	result.mapNotificationThreads(IDs)
+
+	return result
+}
+
+// Helper function of MapNotifications to eager load Photo attachments.
+func (nm NotificationMap) mapNotificationPhotos(IDs []uint64) {
 	type scanner struct {
 		PhotoID        uint64
 		NotificationID uint64
@@ -157,7 +169,7 @@ func MapNotifications(ns []*Notification) NotificationMap {
 	var photoIDs = []uint64{}
 	for _, row := range scan {
 		// Store the photo ID in the result now.
-		result[row.NotificationID].PhotoID = row.PhotoID
+		nm[row.NotificationID].PhotoID = row.PhotoID
 		photoIDs = append(photoIDs, row.PhotoID)
 	}
 
@@ -167,13 +179,58 @@ func MapNotifications(ns []*Notification) NotificationMap {
 			log.Error("Couldn't load photo IDs for notifications: %s", err)
 		} else {
 			// Marry them to their notification IDs.
-			for _, body := range result {
+			for _, body := range nm {
 				if photo, ok := photos[body.PhotoID]; ok {
 					body.Photo = photo
 				}
 			}
 		}
 	}
-
-	return result
+}
+
+// Helper function of MapNotifications to eager load Thread attachments.
+func (nm NotificationMap) mapNotificationThreads(IDs []uint64) {
+	type scanner struct {
+		ThreadID       uint64
+		NotificationID uint64
+	}
+	var scan []scanner
+
+	// Load all of these that have threads.
+	err := DB.Table(
+		"notifications",
+	).Joins(
+		"JOIN threads ON (notifications.table_name='threads' AND notifications.table_id=threads.id)",
+	).Select(
+		"threads.id AS thread_id",
+		"notifications.id AS notification_id",
+	).Where(
+		"notifications.id IN ?",
+		IDs,
+	).Scan(&scan)
+	if err.Error != nil {
+		log.Error("Couldn't select thread IDs for notifications: %s", err.Error)
+	}
+
+	// Collect and load all the threads by ID.
+	var threadIDs = []uint64{}
+	for _, row := range scan {
+		// Store the thread ID in the result now.
+		nm[row.NotificationID].ThreadID = row.ThreadID
+		threadIDs = append(threadIDs, row.ThreadID)
+	}
+
+	// Load the threads.
+	if len(threadIDs) > 0 {
+		if threads, err := GetThreads(threadIDs); err != nil {
+			log.Error("Couldn't load thread IDs for notifications: %s", err)
+		} else {
+			// Marry them to their notification IDs.
+			for _, body := range nm {
+				if thread, ok := threads[body.ThreadID]; ok {
+					body.Thread = thread
+				}
+			}
+		}
+	}
 }

pkg/models/subscription.go

@@ -0,0 +1,81 @@
+package models
+
+import (
+	"time"
+
+	"code.nonshy.com/nonshy/website/pkg/log"
+)
+
+// Subscription table - for notifications. You comment on someone's post, you get subscribed
+// to other comments added to the post (unless you opt off).
+type Subscription struct {
+	ID         uint64 `gorm:"primaryKey"`
+	UserID     uint64 `gorm:"index"` // who it belongs to
+	Subscribed bool   `gorm:"index"`
+	TableName  string // on which of your tables (photos, comments, ...)
+	TableID    uint64
+	CreatedAt  time.Time
+	UpdatedAt  time.Time
+}
+
+// GetSubscription looks for an existing subscription or returns error if not found.
+func GetSubscription(user *User, tableName string, tableID uint64) (*Subscription, error) {
+	var s *Subscription
+	result := DB.Model(s).Where(
+		"user_id = ? AND table_name = ? AND table_id = ?",
+		user.ID, tableName, tableID,
+	).First(&s)
+	return s, result.Error
+}
+
+// GetSubscribers returns all of the UserIDs that are subscribed to a thread.
+func GetSubscribers(tableName string, tableID uint64) []uint64 {
+	var userIDs = []uint64{}
+	result := DB.Table(
+		"subscriptions",
+	).Select(
+		"user_id",
+	).Where(
+		"table_name = ? AND table_id = ? AND subscribed IS TRUE",
+		tableName, tableID,
+	).Scan(&userIDs)
+
+	if result.Error != nil {
+		log.Error("GetSubscribers(%s, %d): couldn't get user IDs: %s", tableName, tableID)
+	}
+
+	return userIDs
+}
+
+// IsSubscribed checks whether a user is currently subscribed (and notified) to a thing.
+// Returns whether the row exists, and whether the user is to be notified (false if opted out).
+func IsSubscribed(user *User, tableName string, tableID uint64) (exists bool, notified bool) {
+	if sub, err := GetSubscription(user, tableName, tableID); err != nil {
+		return false, false
+	} else {
+		return true, sub.Subscribed
+	}
+}
+
+// SubscribeTo creates a subscription to a thing (comment thread) to be notified of future activity on.
+func SubscribeTo(user *User, tableName string, tableID uint64) (*Subscription, error) {
+	// Is there already a subscription row?
+	if sub, err := GetSubscription(user, tableName, tableID); err == nil {
+		return sub, err
+	}
+
+	// Create the default subscription.
+	sub := &Subscription{
+		UserID:     user.ID,
+		Subscribed: true,
+		TableName:  tableName,
+		TableID:    tableID,
+	}
+	result := DB.Create(sub)
+	return sub, result.Error
+}
+
+// Save a subscription.
+func (n *Subscription) Save() error {
+	return DB.Save(n).Error
+}

pkg/router/router.go

@@ -54,6 +54,7 @@ func New() http.Handler {
 	mux.Handle("/users/block", middleware.LoginRequired(block.BlockUser()))
 	mux.Handle("/users/blocked", middleware.LoginRequired(block.Blocked()))
 	mux.Handle("/comments", middleware.LoginRequired(comment.PostComment()))
+	mux.Handle("/comments/subscription", middleware.LoginRequired(comment.Subscription()))
 	mux.Handle("/admin/unimpersonate", middleware.LoginRequired(admin.Unimpersonate()))
 
 	// Certification Required. Pages that only full (verified) members can access.

web/templates/account/dashboard.html

@@ -218,6 +218,26 @@
                                                         {{end}}
                                                         </a>
                                                     </span>
+                                                {{else if eq .Type "also_comment"}}
+                                                    <span class="icon"><i class="fa fa-comment has-text-success"></i></span>
+                                                    <span>
+                                                        <a href="/u/{{.AboutUser.Username}}"><strong>{{.AboutUser.Username}}</strong></a>
+                                                        also commented on a
+                                                        <a href="{{.Link}}">
+                                                        {{if eq .TableName "photos"}}
+                                                            photo
+                                                        {{else}}
+                                                            {{.TableName}}
+                                                        {{end}}
+                                                        </a>
+                                                        that you replied to:
+                                                    </span>
+                                                {{else if eq .Type "also_posted"}}
+                                                    <span class="icon"><i class="fa fa-comments has-text-success"></i></span>
+                                                    <span>
+                                                        <a href="/u/{{.AboutUser.Username}}"><strong>{{.AboutUser.Username}}</strong></a>
+                                                        replied to <a href="{{.Link}}">a forum thread</a> that you follow:
+                                                    </span>
                                                 {{else if eq .Type "friendship_approved"}}
                                                     <span class="icon"><i class="fa fa-user-group has-text-success"></i></span>
                                                     <span>
@@ -242,7 +262,14 @@
                                                 <!-- Attached message? -->
                                                 {{if .Message}}
                                                 <div class="block content mb-1">
-                                                    {{ToMarkdown .Message}}
+                                                    <blockquote class="p-2 pl-4">{{ToMarkdown (TrimEllipses .Message 256)}}</blockquote>
+                                                </div>
+                                                {{end}}
+
+                                                <!-- Attached forum thread? -->
+                                                {{if $Body.Thread}}
+                                                <div>
+                                                    On thread: <a href="{{.Link}}">{{$Body.Thread.Title}}</a>
                                                 </div>
                                                 {{end}}
 

web/templates/forum/thread.html

@@ -71,11 +71,24 @@
     <em title="{{.Thread.UpdatedAt.Format "2006-01-02 15:04:05"}}">Updated {{SincePrettyCoarse .Thread.UpdatedAt}} ago</em>
 </div>
 
-<p class="block p-4">
+<p class="block p-4 mb-0">
     Found <strong>{{.Pager.Total}}</strong> post{{Pluralize64 .Pager.Total}} on this thread
     (page {{.Pager.Page}} of {{.Pager.Pages}}).
 </p>
 
+<p class="block px-4 mb-4">
+    <a href="/comments/subscription?table_name=threads&table_id={{.Thread.ID}}&next={{UrlEncode .Request.URL.String}}&subscribe={{if not .IsSubscribed}}true{{else}}false{{end}}">
+        <span class="icon"><i class="fa fa-bell{{if not .IsSubscribed}}-slash{{end}}"></i></span>
+        <span>
+            {{if .IsSubscribed}}
+            Disable notifications about this thread
+            {{else}}
+            Enable notifications about this thread
+            {{end}}
+        </span>
+    </a>
+</p>
+
 <div class="block p-2">
     <nav class="pagination" role="navigation" aria-label="pagination">
         <a class="pagination-previous{{if not .Pager.HasPrevious}} is-disabled{{end}}" title="Previous"

web/templates/index.html

@@ -44,19 +44,6 @@
                 </li>
             </ul>
 
-            <h1>Open Beta</h1>
-
-            <p>
-                This website is currently open for beta testing. It's not 100% complete yet, but is basically
-                functional. It currently supports profile pages, photo galleries, friend requests, Direct
-                Messages, a member directory to discover new users, and basic account management features.
-            </p>
-
-            <p>
-                Before the "1.0" launch it will include web forums which will provide a community space to
-                chat with and meet other members.
-            </p>
-
             <h1>Site Rules</h1>
 
             <ul>

web/templates/photo/permalink.html

@@ -183,6 +183,21 @@
 
                 <hr class="is-dark">
 
+                {{if not .IsOwnPhoto}}
+                <p class="mb-4">
+                    <a href="/comments/subscription?table_name=photos&table_id={{.Photo.ID}}&next={{UrlEncode .Request.URL.String}}&subscribe={{if not .IsSubscribed}}true{{else}}false{{end}}">
+                        <span class="icon"><i class="fa fa-bell{{if not .IsSubscribed}}-slash{{end}}"></i></span>
+                        <span>
+                            {{if .IsSubscribed}}
+                            Disable notifications about this comment thread
+                            {{else}}
+                            Enable notifications about this comment thread
+                            {{end}}
+                        </span>
+                    </a>
+                </p>
+                {{end}}
+
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