Add temporary bans (manual)

This enables me to set a ban expiry time for a user (manually, in the
database). By doing so:

* The user's page will say that they're temporarily banned, and show the
  date their ban will be lifted.
* If the user tries to log in, it will say they're temporarily banned,
  and give a specific datetime that the ban will be lifted by.
* An hourly cronjob will lift any bans that have expired.

salt/salt/cronjobs.sls

@@ -1,5 +1,12 @@
 {% from 'common.jinja2' import app_dir, app_username, bin_dir %}
 
+lift-expired-temp-bans-cronjob:
+  cron.present:
+    - name: {{ bin_dir }}/python -c "from scripts.lift_expired_temporary_bans import lift_expired_temporary_bans; lift_expired_temporary_bans('{{ app_dir }}/{{ pillar['ini_file'] }}')"
+    - user: {{ app_username }}
+    - hour: '*'
+    - minute: 1
+
 close-voting-cronjob:
   cron.present:
     - name: {{ bin_dir }}/python -c "from scripts.close_voting_on_old_posts import close_voting_on_old_posts; close_voting_on_old_posts('{{ app_dir }}/{{ pillar['ini_file'] }}')"

tildes/alembic/versions/4d86b372a8db_user_add_ban_expiry_time.py

@@ -0,0 +1,27 @@
+"""User: add ban_expiry_time
+
+Revision ID: 4d86b372a8db
+Revises: 9148909b78e9
+Create Date: 2020-05-09 20:05:30.503634
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = "4d86b372a8db"
+down_revision = "9148909b78e9"
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    op.add_column(
+        "users",
+        sa.Column("ban_expiry_time", sa.TIMESTAMP(timezone=True), nullable=True),
+    )
+
+
+def downgrade():
+    op.drop_column("users", "ban_expiry_time")

tildes/scripts/lift_expired_temporary_bans.py

@@ -0,0 +1,23 @@
+# Copyright (c) 2020 Tildes contributors <code@tildes.net>
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+"""Simple script to lift any temporary bans that have expired.
+
+This script should be set up to run regularly (such as every hour).
+"""
+
+from tildes.lib.database import get_session_from_config
+from tildes.lib.datetime import utc_now
+from tildes.models.user import User
+
+
+def lift_expired_temporary_bans(config_path: str) -> None:
+    """Lift temporary bans that have expired."""
+    db_session = get_session_from_config(config_path)
+
+    db_session.query(User).filter(
+        User.ban_expiry_time < utc_now(),  # type: ignore
+        User.is_banned == True,  # noqa
+    ).update({"is_banned": False, "ban_expiry_time": None}, synchronize_session=False)
+
+    db_session.commit()

tildes/tildes/models/user/user.py

@@ -126,6 +126,7 @@ class User(DatabaseModel):
     deleted_time: Optional[datetime] = Column(TIMESTAMP(timezone=True))
     is_banned: bool = Column(Boolean, nullable=False, server_default="false")
     banned_time: Optional[datetime] = Column(TIMESTAMP(timezone=True))
+    ban_expiry_time: Optional[datetime] = Column(TIMESTAMP(timezone=True))
     home_default_order: Optional[TopicSortOption] = Column(ENUM(TopicSortOption))
     home_default_period: Optional[str] = Column(Text)
     filtered_topic_tags: List[str] = Column(

tildes/tildes/templates/user.jinja2

@@ -31,7 +31,12 @@
 {% if user.is_deleted or user.is_banned %}
   <div class="empty">
     {% if user.is_banned %}
-      <h2 class="empty-title">This user is banned</h2>
+      {% if user.ban_expiry_time %}
+        <h2 class="empty-title">This user is temporarily banned</h2>
+        <p class="empty-subtitle">The ban will be lifted on {{ user.ban_expiry_time.strftime("%B %-d, %Y") }}</p>
+      {% else %}
+        <h2 class="empty-title">This user is banned</h2>
+      {% endif %}
     {% elif user.is_deleted %}
       <h2 class="empty-title">This user has deleted their account</h2>
     {% endif %}

tildes/tildes/views/login.py

@@ -3,6 +3,7 @@
 
 """Views related to logging in/out."""
 
+from datetime import timedelta
 from typing import NoReturn
 from urllib.parse import unquote_plus
 
@@ -115,7 +116,17 @@ def post_login(
 
     # Don't allow banned users to log in
     if user.is_banned:
-        raise HTTPUnprocessableEntity("This account has been banned")
+        if user.ban_expiry_time:
+            # add an hour to the ban's expiry time since the cronjob runs hourly
+            unban_time = user.ban_expiry_time + timedelta(hours=1)
+            unban_time = unban_time.strftime("%Y-%m-%d %H:%M (UTC)")
+
+            raise HTTPUnprocessableEntity(
+                "That account is temporarily banned. "
+                f"The ban will be lifted at {unban_time}"
+            )
+
+        raise HTTPUnprocessableEntity("That account has been banned")
 
     # If 2FA is enabled, save username to session and make user enter code
     if user.two_factor_enabled: