Add badge quantity and rarity to /badges. (#238)

Implements feature request to know how many of each badge exists and
to have a 'rarity', a la Steam or PSN badges, relative to number of
non-lurker users.

Because Postgres `COUNT()`s are notoriously costly, /badges has been
memoized for 1hr to avoid a DOS target.

files/routes/static.py

@@ -496,10 +496,19 @@ def robots_txt():
 
 @app.get("/badges")
 @auth_required
+@cache.memoize(timeout=3600)
 def badges(v):
-	badges = g.db.query(BadgeDef).order_by(BadgeDef.id).all()
+	nonlurk_truecoins = 100
 
-	return render_template("badges.html", v=v, badges=badges)
+	badges = g.db.query(BadgeDef).order_by(BadgeDef.id).all()
+	counts_raw = g.db.query(Badge.badge_id, func.count()).group_by(Badge.badge_id).all()
+	users_nonlurk = g.db.query(User.id).filter(User.truecoins >= nonlurk_truecoins).count()
+
+	counts = {}
+	for c in counts_raw:
+		counts[c[0]] = (c[1], float(c[1]) * 100 / max(users_nonlurk, 1))
+
+	return render_template("badges.html", v=v, badges=badges, counts=counts, nonlurk=users_nonlurk, nonlurk_tc=nonlurk_truecoins)
 
 @app.get("/blocks")
 @auth_required

files/templates/badges.html

@@ -6,6 +6,7 @@
 </pre>
 <h1>User Badges</h1>
 <div>This page describes the requirements for obtaining all profile badges.</div>
+<div>Rarity is the ratio of badge quantity to the number of non-lurkers (truescore &geq; <span id="badges-nonlurk-tc">{{ nonlurk_tc }}</span>): <span id="badges-nonlurkers">{{ nonlurk }}</span>.</div>
 <pre>
 
 
@@ -17,6 +18,8 @@
 		<th>Name</th>
 		<th>Image</th>
 		<th>Description</th>
+		<th>#</th>
+		<th>Rarity</th>
 	</tr>
 </thead>
 {% for badge in badges %}
@@ -25,6 +28,9 @@
 		<td>{{badge.name}}</td>
 		<td><img alt="{{badge.name}}" loading="lazy" src="/assets/images/badges/{{badge.id}}.webp?v=1016" width=45.83 height=50>
 		<td>{{badge.description}}</td>
+		{%- set ct = counts[badge.id] if badge.id in counts else (0, 0) %}
+		<td class="badges-rarity-qty">{{ ct[0] }}</td>
+		<td class="badges-rarity-ratio">{{ "{:0.3f}".format(ct[1]) }}%</td>
 	</tr>
 {% endfor %}
 </table>