Spit and polish

* Show follower counts on forums
* Sort by popularity (follow count)

pkg/config/config.go

@@ -124,7 +124,7 @@ const (
 	ThreadViewDebounceCooldown = 1 * time.Hour
 
 	// Enable user-owned forums (feature flag)
-	UserForumsEnabled = false
+	UserForumsEnabled = true
 )
 
 // User-Owned Forums: Quota settings for how many forums a user can own.

pkg/controller/forum/browse.go

@@ -23,6 +23,7 @@ func Explore() http.HandlerFunc {
 
 		// Special sort handlers.
 		// See PaginateForums for expanded handlers for these.
+		"by_followers",
 		"by_latest",
 		"by_threads",
 		"by_posts",
@@ -99,6 +100,7 @@ func Explore() http.HandlerFunc {
 			"Categories":      categorized,
 			"ForumMap":        forumMap,
 			"FollowMap":       followMap,
+			"FollowersMap":    models.MapForumFollowers(forums),
 
 			// Search filters
 			"SearchTerm": searchTerm,

pkg/controller/forum/forum.go

@@ -83,6 +83,7 @@ func Forum() http.HandlerFunc {
 		var vars = map[string]interface{}{
 			"Forum":                forum,
 			"ForumModerators":      mods,
+			"ForumSubscriberCount": models.CountForumMemberships(forum),
 			"IsForumSubscribed":    models.IsForumSubscribed(currentUser, forum),
 			"Threads":              threads,
 			"ThreadMap":            threadMap,

pkg/controller/forum/forums.go

@@ -80,6 +80,7 @@ func Landing() http.HandlerFunc {
 			"Categories":   categorized,
 			"ForumMap":     forumMap,
 			"FollowMap":    followMap,
+			"FollowersMap": models.MapForumFollowers(forums),
 
 			// Current viewer's forum quota.
 			"ForumQuota": models.ComputeForumQuota(currentUser),

pkg/models/forum.go

@@ -168,6 +168,12 @@ func PaginateForums(user *User, categories []string, search *Search, subscribed
 
 	// Custom SORT parameters.
 	switch pager.Sort {
+	case "by_followers":
+		pager.Sort = `(
+			SELECT count(forum_memberships.id)
+			FROM forum_memberships
+			WHERE forum_memberships.forum_id = forums.id
+		) DESC`
 	case "by_latest":
 		pager.Sort = `(
 			SELECT MAX(threads.updated_at)

pkg/models/forum_membership.go

@@ -166,6 +166,16 @@ func (u *User) HasForumSubscriptions() bool {
 	return count > 0
 }
 
+// CountForumMemberships counts how many subscribers a forum has.
+func CountForumMemberships(forum *Forum) int64 {
+	var count int64
+	DB.Model(&ForumMembership{}).Where(
+		"forum_id = ?",
+		forum.ID,
+	).Count(&count)
+	return count
+}
+
 // Save a forum membership.
 func (f *ForumMembership) Save() error {
 	return DB.Save(f).Error
@@ -233,3 +243,49 @@ func MapForumMemberships(user *User, forums []*Forum) ForumMembershipMap {
 
 	return result
 }
+
+// ForumFollowerMap maps table IDs to counts of memberships.
+type ForumFollowerMap map[uint64]int64
+
+// Get like stats from the map.
+func (fm ForumFollowerMap) Get(id uint64) int64 {
+	return fm[id]
+}
+
+// MapForumFollowers maps out the count of followers for a set of forums.
+func MapForumFollowers(forums []*Forum) ForumFollowerMap {
+	var (
+		result   = ForumFollowerMap{}
+		forumIDs = []uint64{}
+	)
+
+	// Initialize the result set.
+	for _, forum := range forums {
+		forumIDs = append(forumIDs, forum.ID)
+	}
+
+	// Hold the result of the grouped count query.
+	type group struct {
+		ID        uint64
+		Followers int64
+	}
+	var groups = []group{}
+
+	// Map the counts of likes to each of these IDs.
+	if res := DB.Model(
+		&ForumMembership{},
+	).Select(
+		"forum_id AS id, count(id) AS followers",
+	).Where(
+		"forum_id IN ?",
+		forumIDs,
+	).Group("forum_id").Scan(&groups); res.Error != nil {
+		log.Error("MapLikes: count query: %s", res.Error)
+	}
+
+	for _, row := range groups {
+		result[row.ID] = row.Followers
+	}
+
+	return result
+}

web/templates/forum/board_index.html

@@ -200,6 +200,35 @@
         <label class="label"><i class="fa fa-info-circle"></i> Forum Info</label>
         <div class="mb-4">
             Created on: <span title="{{.Forum.CreatedAt}}">{{.Forum.CreatedAt.Format "Jan _2 2006"}}</span>
+
+            {{if .ForumSubscriberCount}}
+            <div class="has-text-info mt-2">
+                <i class="fa fa-book-bookmark mr-1"></i>
+                {{.ForumSubscriberCount}} {{if eq .ForumSubscriberCount 1}}person follows{{else}}people people{{end}} this forum.
+
+                <!-- Follow/Unfollow This Forum -->
+                <form action="/forum/subscribe" method="POST" class="is-inline">
+                    {{InputCSRF}}
+                    <input type="hidden" name="fragment" value="{{.Forum.Fragment}}">
+
+                    {{if .IsForumSubscribed}}
+                        <button type="submit" class="button is-small ml-2"
+                            name="intent" value="unfollow"
+                            onclick="return confirm('Do you want to remove this forum from your list?')">
+                            <span class="icon"><i class="fa fa-bookmark"></i></span>
+                            <span>Unfollow</span>
+                        </button>
+                    {{else}}
+                        <button type="submit" class="button is-small ml-2"
+                            name="intent" value="follow">
+                            <span class="icon"><i class="fa-regular fa-bookmark has-text-success"></i></span>
+                            <span>Follow it too?</span>
+                        </button>
+                    {{end}}
+                </form>
+            </div>
+            {{end}}
+
             <div class="mt-2">
                 {{if .Forum.Explicit}}
                 <span class="tag is-danger is-light">

web/templates/forum/index.html

@@ -91,12 +91,13 @@
                                         <option value="title asc"{{if eq .Sort "title asc"}} selected{{end}}>Title (A-Z)</option>
                                         <option value="title desc"{{if eq .Sort "title desc"}} selected{{end}}>Title (Z-A)</option>
                                         <option value="created_at desc"{{if eq .Sort "created_at desc"}} selected{{end}}>Recently created</option>
+                                        <option value="by_followers"{{if eq .Sort "by_followers"}} selected{{end}}>Popularity (follower count)</option>
                                     </optgroup>
                                     <optgroup label="Contents">
                                         <option value="by_latest"{{if eq .Sort "by_latest"}} selected{{end}}>Latest post</option>
-                                        <option value="by_threads"{{if eq .Sort "by_threads"}} selected{{end}}>Topic count</option>
+                                        <option value="by_threads"{{if eq .Sort "by_threads"}} selected{{end}}>Topics (count of threads)</option>
-                                        <option value="by_posts"{{if eq .Sort "by_posts"}} selected{{end}}>Post count</option>
+                                        <option value="by_posts"{{if eq .Sort "by_posts"}} selected{{end}}>Posts (count of threads and replies)</option>
-                                        <option value="by_users"{{if eq .Sort "by_users"}} selected{{end}}>User count</option>
+                                        <option value="by_users"{{if eq .Sort "by_users"}} selected{{end}}>Users (distinct members who have posted)</option>
                                     </optgroup>
                                 </select>
                             </div>
@@ -204,12 +205,10 @@
                             </div>
 
                             <!-- Owner line -->
+                            <div class="mt-2 has-text-grey" style="font-size: smaller">
                                 {{if .Category}}
-                            <div class="mt-2 has-text-grey" style="font-size: smaller">
                                     by <a href="/f/{{.Fragment}}">{{PrettyTitle}}</a>
-                            </div>
                                 {{else}}
-                            <div class="mt-2 has-text-grey" style="font-size: smaller">
                                     by
                                     {{template "avatar-16x16" .Owner}}
                                     {{if .Owner.Username}}
@@ -219,9 +218,16 @@
                                     {{else}}
                                         [unavailable]
                                     {{end}}
-                            </div>
                                 {{end}}
 
+                                {{$FollowerCount := $Root.FollowersMap.Get .ID}}
+                                {{if $FollowerCount}}
+                                    <span class="has-text-success ml-2" title="This forum is followed by {{$FollowerCount}} member{{Pluralize64 $FollowerCount}}.">
+                                        <i class="fa fa-book-bookmark mr-1"></i> {{$FollowerCount}}
+                                    </span>
+                                {{end}}
+                            </div>
+
                         </div>
                         <div class="column py-1">
                             <div class="box has-background-success-light has-text-dark">