Auto-register user on comment

db/sqlite.py

@@ -425,11 +425,21 @@ def register_user(self, username, password, time):
             )
             if c.rowcount > 0:
                 db.commit()
-                return True
-            return False
+                # TODO find a way to get the (autoincremented) user ID without looking
+                # up by name.
+                # ROWID is *probably* not always consistent (race conditions).
+                # Ideally we get the ID immediately on insert.
+                return c.execute('''
+                    select user_id
+                    from users
+                    where name = lower(?)
+                    ''',
+                    (username,)
+                ).fetchone()
+            return None
         except sqlite3.IntegrityError:
             # User already exists, probably
-            return False
+            return None
 
     def add_user(self, username, password, time):
         '''

main.py

@@ -234,34 +234,39 @@ def delete_thread(thread_id):
         # TODO return 403, maybe?
     return redirect(url_for('index'))
 
-@app.route('/thread/<int:thread_id>/comment/', methods = ['POST'])
-def add_comment(thread_id):
+def _add_comment_check_user():
     user_id = session.get('user_id')
-    if user_id is None:
-        return redirect(url_for('login'))
+    if user_id is not None:
+        return user_id
+    if not config.registration_enabled:
+        flash('Registrations are not enabled. Please log in to comment', 'error')
+    if register_user(True):
+        return session['user_id']
 
-    text = trim_text(request.form['text'])
-    if text == '':
-        flash('Text may not be empty', 'error')
-    elif db.add_comment_to_thread(thread_id, user_id, text, time.time_ns()):
-        flash('Added comment', 'success')
-    else:
-        flash('Failed to add comment', 'error')
+@app.route('/thread/<int:thread_id>/comment/', methods = ['POST'])
+def add_comment(thread_id):
+    user_id = _add_comment_check_user()
+    if user_id is not None:
+        text = trim_text(request.form['text'])
+        if text == '':
+            flash('Text may not be empty', 'error')
+        elif db.add_comment_to_thread(thread_id, user_id, text, time.time_ns()):
+            flash('Added comment', 'success')
+        else:
+            flash('Failed to add comment', 'error')
     return redirect(url_for('thread', thread_id = thread_id))
 
 @app.route('/comment/<int:comment_id>/comment/', methods = ['POST'])
 def add_comment_parent(comment_id):
-    user_id = session.get('user_id')
-    if user_id is None:
-        return redirect(url_for('login'))
-
-    text = trim_text(request.form['text'])
-    if text == '':
-        flash('Text may not be empty', 'error')
-    elif db.add_comment_to_comment(comment_id, user_id, text, time.time_ns()):
-        flash('Added comment', 'success')
-    else:
-        flash('Failed to add comment', 'error')
+    user_id = _add_comment_check_user()
+    if user_id is not None:
+        text = trim_text(request.form['text'])
+        if text == '':
+            flash('Text may not be empty', 'error')
+        elif db.add_comment_to_comment(comment_id, user_id, text, time.time_ns()):
+            flash('Added comment', 'success')
+        else:
+            flash('Failed to add comment', 'error')
     return redirect(url_for('comment', comment_id = comment_id))
 
 @app.route('/comment/<int:comment_id>/confirm_delete/')
@@ -358,23 +363,7 @@ def edit_comment(comment_id):
 def register():
     if request.method == 'POST':
         username, passwd = request.form['username'], request.form['password']
-        if any(c in username for c in string.whitespace):
-            # This error is more ergonomic in case someone tries to play tricks again :)
-            flash('Username may not contain whitespace', 'error')
-        elif len(username) < 3:
-            flash('Username must be at least 3 characters long', 'error')
-        elif len(passwd) < 8:
-            flash('Password must be at least 8 characters long', 'error')
-        elif not captcha.verify(
-            config.captcha_key,
-            request.form['captcha'],
-            request.form['answer'],
-        ):
-            flash('CAPTCHA answer is incorrect', 'error')
-        elif not db.register_user(username, password.hash(passwd), time.time_ns()):
-            flash('Failed to create account (username may already be taken)', 'error')
-        else:
-            flash('Account has been created. You can login now.', 'success')
+        if register_user(False):
             return redirect(url_for('index'))
 
     capt, answer = captcha.generate(config.captcha_key)
@@ -715,6 +704,35 @@ def get_user():
         return User(id, name, role, banned_until)
     return None
 
+def register_user(show_password):
+    username, passwd = request.form['username'], request.form['password']
+    if any(c in username for c in string.whitespace):
+        # This error is more ergonomic in case someone tries to play tricks again :)
+        flash('Username may not contain whitespace', 'error')
+    elif len(username) < 3:
+        flash('Username must be at least 3 characters long', 'error')
+    elif len(passwd) < 8:
+        flash('Password must be at least 8 characters long', 'error')
+    elif not captcha.verify(
+        config.captcha_key,
+        request.form['captcha'],
+        request.form['answer'],
+    ):
+        flash('CAPTCHA answer is incorrect', 'error')
+    else:
+        uid = db.register_user(username, password.hash(passwd), time.time_ns())
+        if uid is None:
+            flash('Failed to create account (username may already be taken)', 'error')
+        else:
+            s = 'Account has been created.'
+            if show_password:
+                s += f' Your password is <code class=spoiler>{passwd}</code> (hover to reveal).'
+            flash(s, 'success')
+            uid, = uid
+            session['user_id'] = uid
+            return True
+    return False
+
 
 @app.context_processor
 def utility_processor():
@@ -764,11 +782,26 @@ def format_until(t):
     def format_time(t):
         return datetime.utcfromtimestamp(t / 10 ** 9).replace(microsecond=0)
 
+    def rand_password():
+        '''
+        Generate a random password.
+
+        The current implementation returns 12 random lower- and uppercase alphabet characters.
+        This gives up to `log((26 * 2) ** 12) / log(2) = ~68` bits of entropy, which should be
+        enough for the foreseeable future.
+        '''
+        return ''.join(string.ascii_letters[secrets.randbelow(52)] for _ in range(12))
+
+    def gen_captcha():
+        return captcha.generate(config.captcha_key)
+
     return {
         'format_since': format_since,
         'format_time': format_time,
         'format_until': format_until,
         'minimd': minimd.html,
+        'rand_password': rand_password,
+        'gen_captcha': gen_captcha,
     }
 
 

static/theme.css

@@ -55,17 +55,21 @@ th, td {
 }
 
 textarea {
-	width: 50em;
+	width: min(100%, 500px);
 	height: 15em;
 	font-size: 1em;
 }
 
-input[type=text] {
-	width: 50em;
+input[type=text], input[type=password] {
+	width: min(100%, 20em);
 	font-family: monospace;
 	font-size: 1em;
 }
 
+td > input[type=text], td > input[type=password] {
+	width: min(100%, 500px);
+}
+
 .logo {
 	margin: 0;
 	padding: 5px;
@@ -74,9 +78,13 @@ input[type=text] {
 	font-weight: bold;
 }
 
+form.form {
+	width: 90%;
+}
+
 table.form {
 	border-collapse: unset;
-	width: auto;
+	width: 100%;
 }
 
 table.form > * > tr > td, th {
@@ -103,14 +111,6 @@ table.form > * > tr > td, th {
 	padding: 8px;
 }
 
-.login {
-	width: 50%;
-}
-
-.login input[type=text], .login input[type=password] {
-	width: 90%;
-}
-
 /* Abuse checkboxes to collapse comments */
 .collapse {
 	appearance: none;
@@ -129,3 +129,12 @@ table.form > * > tr > td, th {
 .small {
 	font-size: 85%;
 }
+
+.spoiler {
+	background-color: black;
+	color: black;
+}
+.spoiler:hover {
+	opacity: 1;
+	color: white;
+}

templates/base.html

@@ -34,7 +34,11 @@
 	<main>
 		<h1>{{ title }}</h1>
 		{%- for category, msg in get_flashed_messages(True) -%}
-		<p class="flash {{ category }}">{{ msg }}</p>
+		{#-
+			FIXME ensure all flash() messages are free of XSS vectors.
+			In particular, check places where we flash error messages.
+		-#}
+		<p class="flash {{ category }}">{{ msg | safe }}</p>
 		{%- endfor -%}
 		{%- block content %}{% endblock -%}
 	</main>

templates/comment.html

@@ -57,10 +57,26 @@
 {%- endmacro -%}
 
 {%- macro reply() -%}
-{%- if user is not none and not user.is_banned() -%}
+{%- if user is none -%}
+{%- if config.registration_enabled -%}
 <form method="post" action="comment/">
-	<p><textarea name="text"></textarea></p>
-	<p><input type="submit" value="Post comment"></p>
+<p><textarea name=text></textarea></p>
+{#-
+	Using the password generator for usernames should be sufficient to ensure it is unique.
+	If not, it means the password generator is broken and *must* be fixed.
+-#}
+<input type=text name=username value="{{ rand_password() }}" hidden>
+<input type=password name=password value="{{ rand_password() }}" hidden>
+{% set q, a = gen_captcha() %}
+<p>Captcha: {{ q }} <input type=text name=captcha></p>
+<input type=text name=answer value="{{ a }}" hidden>
+<p><input type=submit value="Register & post comment"> (<a href="{{ url_for('login') }}">I already have an account</a>)</p>
+</form>
+{%- endif -%}
+{%- elif not user.is_banned() -%}
+<form method="post" action="comment/">
+<p><textarea name="text"></textarea></p>
+<p><input type="submit" value="Post comment"></p>
 </form>
 {%- endif -%}
 {%- endmacro -%}

test/all.sh

@@ -21,4 +21,4 @@ cd $base/..
 
 export DB=$db
 export SERVER=dev
-$FLASK --app main --debug run
+$FLASK --app main --debug run $TEST_FLASK_ARGS

test/init_db.txt

@@ -29,3 +29,5 @@ insert into comments (author_id, thread_id, create_time, modify_time, text)
 	values (2, 1, 0, 0, "Hi!");
 insert into comments (author_id, thread_id, create_time, modify_time, text, parent_id)
 	values (3, 1, 0, 0, "Greetings.", 1);
+
+update config set registration_enabled = 1;