new preferences handling

Preferences class was introduced in order to handle user preferences. Right now
it parses cookies and the form in preferences. Also it can retrieve settings
based on the name of the setting.

ATTENTION
Please note that engine preferences are handled differently from now on. So it
introduces incompatible changes. Every user who has saved preferences should reset and
save his/her settings again.

This change was needed, because everytime a default disabled engine was
added saved user preferences would broke. Now engine setting tracking is
fixed.

searx/preferences.py

+from searx import settings, autocomplete
+from searx.languages import language_codes as languages
+
+
+COOKIE_MAX_AGE = 60 * 60 * 24 * 365 * 5  # 5 years
+LANGUAGE_CODES = [l[0] for l in languages]
+LANGUAGE_CODES.append('all')
+DISABLED = 0
+ENABLED = 1
+
+
+class MissingArgumentException(Exception):
+    pass
+
+
+class ValidationException(Exception):
+    pass
+
+
+class Setting(object):
+    """Base class of user settings"""
+
+    def __init__(self, default_value, **kwargs):
+        super(Setting, self).__init__()
+        self.value = default_value
+        for key, value in kwargs.iteritems():
+            setattr(self, key, value)
+
+        self._post_init()
+
+    def _post_init(self):
+        pass
+
+    def parse(self, data):
+        self.value = data
+
+    def get_value(self):
+        return self.value
+
+    def save(self, name, resp):
+        resp.set_cookie(name, bytes(self.value), max_age=COOKIE_MAX_AGE)
+
+
+class StringSetting(Setting):
+    """Setting of plain string values"""
+    pass
+
+
+class EnumStringSetting(Setting):
+    """Setting of a value which can only come from the given choices"""
+
+    def _post_init(self):
+        if not hasattr(self, 'choices'):
+            raise MissingArgumentException('Missing argument: choices')
+
+        if self.value != '' and self.value not in self.choices:
+            raise ValidationException('Invalid default value: {0}'.format(self.value))
+
+    def parse(self, data):
+        if data not in self.choices and data != self.value:
+            raise ValidationException('Invalid choice: {0}'.format(data))
+        self.value = data
+
+
+class MultipleChoiceSetting(EnumStringSetting):
+    """Setting of values which can only come from the given choices"""
+
+    def _post_init(self):
+        if not hasattr(self, 'choices'):
+            raise MissingArgumentException('Missing argument: choices')
+        for item in self.value:
+            if item not in self.choices:
+                raise ValidationException('Invalid default value: {0}'.format(self.value))
+
+    def parse(self, data):
+        if data == '':
+            self.value = []
+            return
+
+        elements = data.split(',')
+        for item in elements:
+            if item not in self.choices:
+                raise ValidationException('Invalid choice: {0}'.format(item))
+        self.value = elements
+
+    def parse_form(self, data):
+        self.value = []
+        for choice in data:
+            if choice in self.choices and choice not in self.value:
+                self.value.append(choice)
+
+    def save(self, name, resp):
+        resp.set_cookie(name, ','.join(self.value), max_age=COOKIE_MAX_AGE)
+
+
+class MapSetting(Setting):
+    """Setting of a value that has to be translated in order to be storable"""
+
+    def _post_init(self):
+        if not hasattr(self, 'map'):
+            raise MissingArgumentException('missing argument: map')
+        if self.value not in self.map.values():
+            raise ValidationException('Invalid default value')
+
+    def parse(self, data):
+        if data not in self.map:
+            raise ValidationException('Invalid choice: {0}'.format(data))
+        self.value = self.map[data]
+        self.key = data
+
+    def save(self, name, resp):
+        resp.set_cookie(name, bytes(self.key), max_age=COOKIE_MAX_AGE)
+
+
+class SwitchableSetting(Setting):
+    """ Base class for settings that can be turned on && off"""
+
+    def _post_init(self):
+        self.disabled = set()
+        self.enabled = set()
+        if not hasattr(self, 'choices'):
+            raise MissingArgumentException('missing argument: choices')
+
+    def transform_form_items(self, items):
+        return items
+
+    def transform_values(self, values):
+        return values
+
+    def parse_cookie(self, data):
+        if data[DISABLED] != '':
+            self.disabled = set(data[DISABLED].split(','))
+        if data[ENABLED] != '':
+            self.enabled = set(data[ENABLED].split(','))
+
+    def parse_form(self, items):
+        items = self.transform_form_items(items)
+
+        self.disabled = set()
+        self.enabled = set()
+        for choice in self.choices:
+            if choice['default_on']:
+                if choice['id'] in items:
+                    self.disabled.add(choice['id'])
+            else:
+                if choice['id'] not in items:
+                    self.enabled.add(choice['id'])
+
+    def save(self, resp):
+        resp.set_cookie('disabled_{0}'.format(self.value), ','.join(self.disabled), max_age=COOKIE_MAX_AGE)
+        resp.set_cookie('enabled_{0}'.format(self.value), ','.join(self.enabled), max_age=COOKIE_MAX_AGE)
+
+    def get_disabled(self):
+        disabled = self.disabled
+        for choice in self.choices:
+            if not choice['default_on'] and choice['id'] not in self.enabled:
+                disabled.add(choice['id'])
+        return self.transform_values(disabled)
+
+    def get_enabled(self):
+        enabled = self.enabled
+        for choice in self.choices:
+            if choice['default_on'] and choice['id'] not in self.disabled:
+                enabled.add(choice['id'])
+        return self.transform_values(enabled)
+
+
+class EnginesSetting(SwitchableSetting):
+    def _post_init(self):
+        super(EnginesSetting, self)._post_init()
+        transformed_choices = []
+        for engine_name, engine in self.choices.iteritems():
+            for category in engine.categories:
+                transformed_choice = dict()
+                transformed_choice['default_on'] = not engine.disabled
+                transformed_choice['id'] = '{}__{}'.format(engine_name, category)
+                transformed_choices.append(transformed_choice)
+        self.choices = transformed_choices
+
+    def transform_form_items(self, items):
+        return [item[len('engine_'):].replace('_', ' ').replace('  ', '__') for item in items]
+
+    def transform_values(self, values):
+        if len(values) == 1 and values[0] == '':
+            return list()
+        transformed_values = []
+        for value in values:
+            engine, category = value.split('__')
+            transformed_values.append((engine, category))
+        return transformed_values
+
+
+class PluginsSetting(SwitchableSetting):
+    def _post_init(self):
+        super(PluginsSetting, self)._post_init()
+        transformed_choices = []
+        for plugin in self.choices:
+            transformed_choice = dict()
+            transformed_choice['default_on'] = plugin.default_on
+            transformed_choice['id'] = plugin.id
+            transformed_choices.append(transformed_choice)
+        self.choices = transformed_choices
+
+    def transform_form_items(self, items):
+        return [item[len('plugin_'):] for item in items]
+
+
+class Preferences(object):
+    """Stores, validates and saves preferences to cookies"""
+
+    def __init__(self, themes, categories, engines, plugins):
+        super(Preferences, self).__init__()
+
+        self.key_value_settings = {'categories': MultipleChoiceSetting(['general'], choices=categories),
+                                   'language': EnumStringSetting('all', choices=LANGUAGE_CODES),
+                                   'locale': EnumStringSetting(settings['ui']['default_locale'],
+                                                               choices=settings['locales'].keys()),
+                                   'autocomplete': EnumStringSetting(settings['search']['autocomplete'],
+                                                                     choices=autocomplete.backends.keys()),
+                                   'image_proxy': MapSetting(settings['server']['image_proxy'],
+                                                             map={'': settings['server']['image_proxy'],
+                                                                  '0': False,
+                                                                  '1': True}),
+                                   'method': EnumStringSetting('POST', choices=('GET', 'POST')),
+                                   'safesearch': MapSetting(settings['search']['safe_search'], map={'0': 0,
+                                                                                                    '1': 1,
+                                                                                                    '2': 2}),
+                                   'theme': EnumStringSetting(settings['ui']['default_theme'], choices=themes)}
+
+        self.engines = EnginesSetting('engines', choices=engines)
+        self.plugins = PluginsSetting('plugins', choices=plugins)
+
+    def parse_cookies(self, input_data):
+        for user_setting_name, user_setting in input_data.iteritems():
+            if user_setting_name in self.key_value_settings:
+                self.key_value_settings[user_setting_name].parse(user_setting)
+            elif user_setting_name == 'disabled_engines':
+                self.engines.parse_cookie([input_data['disabled_engines'], input_data['enabled_engines']])
+            elif user_setting_name == 'disabled_plugins':
+                self.plugins.parse_cookie([input_data['disabled_plugins'], input_data['enabled_plugins']])
+
+    def parse_form(self, input_data):
+        disabled_engines = []
+        enabled_categories = []
+        disabled_plugins = []
+        for user_setting_name, user_setting in input_data.iteritems():
+            if user_setting_name in self.key_value_settings:
+                self.key_value_settings[user_setting_name].parse(user_setting)
+            elif user_setting_name.startswith('engine_'):
+                disabled_engines.append(user_setting_name)
+            elif user_setting_name.startswith('category_'):
+                enabled_categories.append(user_setting_name[len('category_'):])
+            elif user_setting_name.startswith('plugin_'):
+                disabled_plugins.append(user_setting_name)
+        self.key_value_settings['categories'].parse_form(enabled_categories)
+        self.engines.parse_form(disabled_engines)
+        self.plugins.parse_form(disabled_plugins)
+
+    # cannot be used in case of engines or plugins
+    def get_value(self, user_setting_name):
+        if user_setting_name in self.key_value_settings:
+            return self.key_value_settings[user_setting_name].get_value()
+
+    def save(self, resp):
+        for user_setting_name, user_setting in self.key_value_settings.iteritems():
+            user_setting.save(user_setting_name, resp)
+        self.engines.save(resp)
+        self.plugins.save(resp)
+        return resp

searx/search.py

     categories, engines
 )
 from searx.languages import language_codes
-from searx.utils import gen_useragent, get_blocked_engines
+from searx.utils import gen_useragent
 from searx.query import Query
 from searx.results import ResultContainer
 from searx import logger
         self.lang = 'all'
 
         # set blocked engines
-        self.blocked_engines = get_blocked_engines(engines, request.cookies)
+        self.blocked_engines = request.preferences.engines.get_disabled()
 
         self.result_container = ResultContainer()
         self.request_data = {}
 
         # set specific language if set
-        if request.cookies.get('language')\
-           and request.cookies['language'] in (x[0] for x in language_codes):
-            self.lang = request.cookies['language']
+        self.lang = request.preferences.get_value('language')
 
         # set request method
         if request.method == 'POST':
             else:
                 request_params['language'] = self.lang
 
-            try:
-                # 0 = None, 1 = Moderate, 2 = Strict
-                request_params['safesearch'] = int(request.cookies.get('safesearch'))
-            except Exception:
-                request_params['safesearch'] = settings['search']['safe_search']
+            # 0 = None, 1 = Moderate, 2 = Strict
+            request_params['safesearch'] = request.preferences.get_value('safesearch')
 
             # update request parameters dependent on
             # search-engine (contained in engines folder)

searx/settings_robot.yml

 
 search:
     safe_search : 0
-    autocomplete : 0
+    autocomplete : ""
 
 server:
     port : 11111

searx/utils.py

         return a_list[index]
     else:
         return default
-
-
-def get_blocked_engines(engines, cookies):
-    if 'blocked_engines' not in cookies:
-        return [(engine_name, category) for engine_name in engines
-                for category in engines[engine_name].categories if engines[engine_name].disabled]
-
-    blocked_engine_strings = cookies.get('blocked_engines', '').split(',')
-    blocked_engines = []
-
-    if not blocked_engine_strings:
-        return blocked_engines
-
-    for engine_string in blocked_engine_strings:
-        if engine_string.find('__') > -1:
-            engine, category = engine_string.split('__', 1)
-            if engine in engines and category in engines[engine].categories:
-                blocked_engines.append((engine, category))
-        elif engine_string in engines:
-            for category in engines[engine_string].categories:
-                blocked_engines.append((engine_string, category))
-
-    return blocked_engines

searx/webapp.py

 from searx.utils import (
     UnicodeWriter, highlight_content, html_to_text, get_themes,
     get_static_files, get_result_templates, gen_useragent, dict_subset,
-    prettify_url, get_blocked_engines
+    prettify_url
 )
 from searx.version import VERSION_STRING
 from searx.languages import language_codes
 from searx.query import Query
 from searx.autocomplete import searx_bang, backends as autocomplete_backends
 from searx.plugins import plugins
+from searx.preferences import Preferences
 
 # check if the pyopenssl, ndg-httpsclient, pyasn1 packages are installed.
 # They are needed for SSL connection without trouble, see #298
     for (dirpath, dirnames, filenames) in os.walk(theme_img_path):
         global_favicons[indice].extend(filenames)
 
-cookie_max_age = 60 * 60 * 24 * 365 * 5  # 5 years
-
 _category_names = (gettext('files'),
                    gettext('general'),
                    gettext('music'),
 
     if override and override in themes:
         return override
-    theme_name = request.args.get('theme',
-                                  request.cookies.get('theme',
-                                                      default_theme))
+    theme_name = request.args.get('theme', request.preferences.get_value('theme'))
     if theme_name not in themes:
         theme_name = default_theme
     return theme_name
 
 
 def render(template_name, override_theme=None, **kwargs):
-    blocked_engines = get_blocked_engines(engines, request.cookies)
-
-    autocomplete = request.cookies.get('autocomplete', settings['search']['autocomplete'])
-
-    if autocomplete not in autocomplete_backends:
-        autocomplete = None
+    blocked_engines = request.preferences.engines.get_disabled()
+    autocomplete = request.preferences.get_value('autocomplete')
 
     nonblocked_categories = set(category for engine_name in engines
                                 for category in engines[engine_name].categories
                     kwargs['selected_categories'].append(c)
 
     if not kwargs['selected_categories']:
-        cookie_categories = request.cookies.get('categories', '').split(',')
+        cookie_categories = request.preferences.get_value('categories')
         for ccateg in cookie_categories:
             if ccateg in categories:
                 kwargs['selected_categories'].append(ccateg)
 
     kwargs['searx_version'] = VERSION_STRING
 
-    kwargs['method'] = request.cookies.get('method', 'POST')
+    kwargs['method'] = request.preferences.get_value('method')
 
-    kwargs['safesearch'] = request.cookies.get('safesearch', str(settings['search']['safe_search']))
+    kwargs['safesearch'] = str(request.preferences.get_value('safesearch'))
 
     # override url_for function in templates
     kwargs['url_for'] = url_for_theme
 @app.before_request
 def pre_request():
     # merge GET, POST vars
+    preferences = Preferences(themes, categories.keys(), engines, plugins)
+    preferences.parse_cookies(request.cookies)
+    request.preferences = preferences
+
     request.form = dict(request.form.items())
     for k, v in request.args.items():
         if k not in request.form:
             request.form[k] = v
 
     request.user_plugins = []
-    allowed_plugins = request.cookies.get('allowed_plugins', '').split(',')
-    disabled_plugins = request.cookies.get('disabled_plugins', '').split(',')
+    allowed_plugins = preferences.plugins.get_enabled()
+    disabled_plugins = preferences.plugins.get_disabled()
     for plugin in plugins:
         if ((plugin.default_on and plugin.id not in disabled_plugins)
                 or plugin.id in allowed_plugins):
         request_data = request.args
 
     # set blocked engines
-    blocked_engines = get_blocked_engines(engines, request.cookies)
+    blocked_engines = request.preferences.engines.get_disabled()
 
     # parse query
     query = Query(request_data.get('q', '').encode('utf-8'), blocked_engines)
     if not query.getSearchQuery():
         return '', 400
 
-    # get autocompleter
-    completer = autocomplete_backends.get(request.cookies.get('autocomplete', settings['search']['autocomplete']))
+    # run autocompleter
+    completer = autocomplete_backends.get(request.preferences.get_value('autocomplete'))
 
     # parse searx specific autocompleter results like !bang
     raw_results = searx_bang(query)
 
 @app.route('/preferences', methods=['GET', 'POST'])
 def preferences():
-    """Render preferences page.
-
-    Settings that are going to be saved as cookies."""
-    lang = None
-    image_proxy = request.cookies.get('image_proxy', settings['server'].get('image_proxy'))
-
-    if request.cookies.get('language')\
-       and request.cookies['language'] in (x[0] for x in language_codes):
-        lang = request.cookies['language']
-
-    blocked_engines = []
-
-    resp = make_response(redirect(urljoin(settings['server']['base_url'], url_for('index'))))
-
-    if request.method == 'GET':
-        blocked_engines = get_blocked_engines(engines, request.cookies)
-    else:  # on save
-        selected_categories = []
-        post_disabled_plugins = []
-        locale = None
-        autocomplete = ''
-        method = 'POST'
-        safesearch = settings['search']['safe_search']
-        for pd_name, pd in request.form.items():
-            if pd_name.startswith('category_'):
-                category = pd_name[9:]
-                if category not in categories:
-                    continue
-                selected_categories.append(category)
-            elif pd_name == 'locale' and pd in settings['locales']:
-                locale = pd
-            elif pd_name == 'image_proxy':
-                image_proxy = pd
-            elif pd_name == 'autocomplete':
-                autocomplete = pd
-            elif pd_name == 'language' and (pd == 'all' or
-                                            pd in (x[0] for
-                                                   x in language_codes)):
-                lang = pd
-            elif pd_name == 'method':
-                method = pd
-            elif pd_name == 'safesearch':
-                safesearch = pd
-            elif pd_name.startswith('engine_'):
-                if pd_name.find('__') > -1:
-                    # TODO fix underscore vs space
-                    engine_name, category = [x.replace('_', ' ') for x in
-                                             pd_name.replace('engine_', '', 1).split('__', 1)]
-                    if engine_name in engines and category in engines[engine_name].categories:
-                        blocked_engines.append((engine_name, category))
-            elif pd_name == 'theme':
-                theme = pd if pd in themes else default_theme
-            elif pd_name.startswith('plugin_'):
-                plugin_id = pd_name.replace('plugin_', '', 1)
-                if not any(plugin.id == plugin_id for plugin in plugins):
-                    continue
-                post_disabled_plugins.append(plugin_id)
-            else:
-                resp.set_cookie(pd_name, pd, max_age=cookie_max_age)
-
-        disabled_plugins = []
-        allowed_plugins = []
-        for plugin in plugins:
-            if plugin.default_on:
-                if plugin.id in post_disabled_plugins:
-                    disabled_plugins.append(plugin.id)
-            elif plugin.id not in post_disabled_plugins:
-                allowed_plugins.append(plugin.id)
-
-        resp.set_cookie('disabled_plugins', ','.join(disabled_plugins), max_age=cookie_max_age)
+    """Render preferences page && save user preferences"""
 
-        resp.set_cookie('allowed_plugins', ','.join(allowed_plugins), max_age=cookie_max_age)
-
-        resp.set_cookie(
-            'blocked_engines', ','.join('__'.join(e) for e in blocked_engines),
-            max_age=cookie_max_age
-        )
-
-        if locale:
-            resp.set_cookie(
-                'locale', locale,
-                max_age=cookie_max_age
-            )
-
-        if lang:
-            resp.set_cookie(
-                'language', lang,
-                max_age=cookie_max_age
-            )
-
-        if selected_categories:
-            # cookie max age: 4 weeks
-            resp.set_cookie(
-                'categories', ','.join(selected_categories),
-                max_age=cookie_max_age
-            )
-
-            resp.set_cookie(
-                'autocomplete', autocomplete,
-                max_age=cookie_max_age
-            )
-
-        resp.set_cookie('method', method, max_age=cookie_max_age)
-
-        resp.set_cookie('safesearch', str(safesearch), max_age=cookie_max_age)
-
-        resp.set_cookie('image_proxy', image_proxy, max_age=cookie_max_age)
-
-        resp.set_cookie('theme', theme, max_age=cookie_max_age)
-
-        return resp
+    # save preferences
+    if request.method == 'POST':
+        resp = make_response(redirect(urljoin(settings['server']['base_url'], url_for('index'))))
+        try:
+            request.preferences.parse_form(request.form)
+        except ValidationException:
+            # TODO use flash feature of flask
+            return resp
+        return request.preferences.save(resp)
+
+    # render preferences
+    image_proxy = request.preferences.get_value('image_proxy')
+    lang = request.preferences.get_value('language')
+    blocked_engines = request.preferences.engines.get_disabled()
+    allowed_plugins = request.preferences.plugins.get_enabled()
 
     # stats for preferences page
     stats = {}
     return render('preferences.html',
                   locales=settings['locales'],
                   current_locale=get_locale(),
-                  current_language=lang or 'all',
+                  current_language=lang,
                   image_proxy=image_proxy,
                   language_codes=language_codes,
                   engines_by_category=categories,
                   shortcuts={y: x for x, y in engine_shortcuts.items()},
                   themes=themes,
                   plugins=plugins,
-                  allowed_plugins=[plugin.id for plugin in request.user_plugins],
+                  allowed_plugins=allowed_plugins,
                   theme=get_current_theme_name())
 
 
 def opensearch():
     method = 'post'
 
-    if request.cookies.get('method', 'POST') == 'GET':
+    if request.preferences.get_value('method') == 'GET':
         method = 'get'
 
     # chrome/chromium only supports HTTP GET....

tests/unit/test_webapp.py

     def setUp(self):
         webapp.app.config['TESTING'] = True  # to get better error messages
         self.app = webapp.app.test_client()
-        webapp.default_theme = 'default'
 
         # set some defaults
         self.test_results = [
 
         webapp.Search.search = search_mock
 
+        def get_current_theme_name_mock(override=None):
+            return 'default'
+
+        webapp.get_current_theme_name = get_current_theme_name_mock
+
         self.maxDiff = None  # to see full diffs
 
     def test_index_empty(self):