[enh] add external plugin support

docs/dev/plugins.rst

@@ -30,6 +30,13 @@ Example plugin
        ctx['search'].suggestions.add('example')
        return True
 
+External plugins
+================
+
+External plugins are standard python modules implementing all the requirements of the standard plugins.
+Plugins can be enabled by adding them to :ref:`settings.yml`'s ``plugins`` section.
+Example external plugin can be found `here <https://github.com/asciimoo/searx_external_plugin_example>`_.
+
 Register your plugin
 ====================
 

searx/__init__.py

@@ -30,6 +30,7 @@
 
 searx_dir = abspath(dirname(__file__))
 engine_dir = dirname(realpath(__file__))
+static_path = abspath(join(dirname(__file__), 'static'))
 
 
 def check_settings_yml(file_name):

searx/plugins/__init__.py

@@ -14,8 +14,14 @@
 
 (C) 2015 by Adam Tauber, <asciimoo@gmail.com>
 '''
+
+from importlib import import_module
+from os.path import abspath, basename, dirname, exists, join
+from shutil import copyfile
 from sys import exit, version_info
-from searx import logger
+from traceback import print_exc
+
+from searx import logger, settings, static_path
 
 if version_info[0] == 3:
     unicode = str
@@ -54,7 +60,9 @@ def __iter__(self):
         for plugin in self.plugins:
             yield plugin
 
-    def register(self, *plugins):
+    def register(self, *plugins, external=False):
+        if external:
+            plugins = load_external_plugins(plugins)
         for plugin in plugins:
             for plugin_attr, plugin_attr_type in required_attrs:
                 if not hasattr(plugin, plugin_attr) or not isinstance(getattr(plugin, plugin_attr), plugin_attr_type):
@@ -77,6 +85,54 @@ def call(self, ordered_plugin_list, plugin_type, request, *args, **kwargs):
         return ret
 
 
+def load_external_plugins(plugin_names):
+    plugins = []
+    for name in plugin_names:
+        logger.debug('loading plugin: {0}'.format(name))
+        try:
+            pkg = import_module(name)
+        except Exception as e:
+            logger.critical('failed to load plugin module {0}: {1}'.format(name, e))
+            exit(3)
+
+        pkg.__base_path = dirname(abspath(pkg.__file__))
+
+        fix_package_resources(pkg, name)
+
+        plugins.append(pkg)
+        logger.debug('plugin "{0}" loaded'.format(name))
+    return plugins
+
+
+def check_resource(base_path, resource_path, name, dir_prefix):
+        dep_path = join(base_path, resource_path)
+        file_name = basename(dep_path)
+        resource_name = '{0}_{1}'.format('_'.join(name.split()), file_name)
+        resource_path = join(static_path, 'plugins', dir_prefix, resource_name)
+        if not exists(resource_path):
+            try:
+                copyfile(dep_path, resource_path)
+            except:
+                logger.critical('failed to copy plugin resource {0} for plugin {1}'.format(resource_name, name))
+                exit(3)
+
+        # returning with the web path of the resource
+        return join('plugins', dir_prefix, resource_name)
+
+
+def fix_package_resources(pkg, name):
+    if hasattr(pkg, 'js_dependencies'):
+        pkg.js_dependencies = tuple([
+            check_resource(pkg.__base_path, x, name, 'js')
+            for x in pkg.js_dependencies
+        ])
+    if hasattr(pkg, 'css_dependencies'):
+        pkg.css_dependencies = tuple([
+            check_resource(pkg.__base_path, x, name, 'css')
+            for x in pkg.css_dependencies
+        ])
+
+
 plugins = PluginStore()
 plugins.register(oa_doi_rewrite)
 plugins.register(https_rewrite)
@@ -86,3 +142,6 @@ def call(self, ordered_plugin_list, plugin_type, request, *args, **kwargs):
 plugins.register(search_on_category_select)
 plugins.register(tracker_url_remover)
 plugins.register(vim_hotkeys)
+# load external plugins
+if 'plugins' in settings:
+    plugins.register(*settings['plugins'], external=True)

searx/settings.yml

@@ -57,6 +57,14 @@ outgoing: # communication with search engines
 #        - 1.1.1.1
 #        - 1.1.1.2
 
+# External plugin configuration
+# See http://asciimoo.github.io/searx/dev/plugins.html for more details
+#
+# plugins:
+#   - plugin1
+#   - plugin2
+#   - ...
+
 engines:
   - name: apk mirror
     engine: apkmirror

searx/webapp.py

@@ -58,7 +58,7 @@
 from flask_babel import Babel, gettext, format_date, format_decimal
 from flask.ctx import has_request_context
 from flask.json import jsonify
-from searx import brand
+from searx import brand, static_path
 from searx import settings, searx_dir, searx_debug
 from searx.exceptions import SearxParameterException
 from searx.engines import (