Add (optional) validation for minimum anonymous torrent size (#342)

MINIMUM_ANONYMOUS_TORRENT_SIZE can be used to require a minimum total
size of torrents uploaded by anonymous users (ie. without accounts).

Sets up a "framework" for post-WTForm torrent validation as well;
this can easily be extended into filename blacklists and such.

config.example.py

@@ -46,6 +46,9 @@ ENFORCE_MAIN_ANNOUNCE_URL = False
 MAIN_ANNOUNCE_URL = 'http://127.0.0.1:6881/announce'
 TRACKER_API_URL = 'http://127.0.0.1:6881/api'
 TRACKER_API_AUTH = 'topsecret'
+# Torrents uploaded without an account must be at least this big in total (bytes)
+# Set to 0 to disable
+MINIMUM_ANONYMOUS_TORRENT_SIZE = 1 * 1024 * 1024
 
 BACKUP_TORRENT_FOLDER = 'torrents'
 

nyaa/api_handler.py

@@ -99,6 +99,7 @@ def v2_api_upload():
     upload_form.category.choices = _create_upload_category_choices()
 
     if upload_form.validate():
+        try:
             torrent = backend.handle_torrent_upload(upload_form, flask.g.user)
 
             # Create a response dict with relevant data
@@ -111,7 +112,9 @@ def v2_api_upload():
             }
 
             return flask.jsonify(torrent_metadata)
-    else:
+        except backend.TorrentExtraValidationException:
+            pass
+
     # Map errors back from form fields into the api keys
     mapped_errors = {UPLOAD_API_FORM_KEYMAP.get(k, k): v for k, v in upload_form.errors.items()}
     return flask.jsonify({'errors': mapped_errors}), 400

nyaa/backend.py

@@ -15,6 +15,11 @@ from nyaa.extensions import db
 app = flask.current_app
 
 
+class TorrentExtraValidationException(Exception):
+    def __init__(self, errors):
+        self.errors = errors
+
+
 @utils.cached_function
 def get_category_id_map():
     ''' Reads database for categories and turns them into a dict with
@@ -44,7 +49,37 @@ def _replace_utf8_values(dict_or_list):
     return did_change
 
 
+def validate_torrent_post_upload(torrent, upload_form=None):
+    ''' Validates a Torrent instance before it's saved to the database.
+        Enforcing user-and-such-based validations is more flexible here vs WTForm context '''
+    errors = {
+        'torrent_file': []
+    }
+
+    # Encorce minimum size for userless uploads
+    minimum_anonymous_torrent_size = app.config['MINIMUM_ANONYMOUS_TORRENT_SIZE']
+    if torrent.user is None and torrent.filesize < minimum_anonymous_torrent_size:
+        errors['torrent_file'].append('Torrent too small for an anonymous uploader')
+
+    print(errors)
+    # Remove keys with empty lists
+    errors = {k: v for k, v in errors.items() if v}
+    if errors:
+        if upload_form:
+            # Add error messages to the form fields
+            for field_name, field_errors in errors.items():
+                getattr(upload_form, field_name).errors.extend(field_errors)
+            # Clear out the wtforms dict to force a regeneration
+            upload_form._errors = None
+
+        raise TorrentExtraValidationException(errors)
+
+
 def handle_torrent_upload(upload_form, uploading_user=None, fromAPI=False):
+    ''' Stores a torrent to the database.
+        May throw TorrentExtraValidationException if the form/torrent fails
+        post-WTForm validation! Exception messages will also be added to their
+        relevant fields on the given form. '''
     torrent_data = upload_form.torrent_file.parsed_data
 
     # Delete exisiting torrent which is marked as deleted
@@ -197,6 +232,9 @@ def handle_torrent_upload(upload_form, uploading_user=None, fromAPI=False):
                                                  tracker_id=tracker.id, order=order)
         db.session.add(torrent_tracker)
 
+    # Before final commit, validate the torrent again
+    validate_torrent_post_upload(torrent, upload_form)
+
     db.session.commit()
 
     # Store the actual torrent file as well

nyaa/views/torrents.py

@@ -307,10 +307,13 @@ def upload():
     upload_form.category.choices = _create_upload_category_choices()
 
     if flask.request.method == 'POST' and upload_form.validate():
+        try:
             torrent = backend.handle_torrent_upload(upload_form, flask.g.user)
 
             return flask.redirect(flask.url_for('torrents.view', torrent_id=torrent.id))
-    else:
+        except backend.TorrentExtraValidationException:
+            pass
+
     # If we get here with a POST, it means the form data was invalid: return a non-okay status
     status_code = 400 if flask.request.method == 'POST' else 200
     return flask.render_template('upload.html', upload_form=upload_form), status_code