[enh] plugin support basics ++ self ip plugin

searx/plugins/__init__.py

+from searx.plugins import self_ip
+from searx import logger
+from sys import exit
+
+logger = logger.getChild('plugins')
+
+required_attrs = ('name',
+                  'description',
+                  'default_on')
+
+
+class Plugin():
+    default_on = False
+    name = 'Default plugin'
+
+
+class PluginStore():
+
+    def __init__(self):
+        self.plugins = []
+
+    def __iter__(self):
+        for plugin in plugins:
+            yield plugin
+
+    def register(self, *plugins):
+        for plugin in plugins:
+            for plugin_attr in required_attrs:
+                if not hasattr(plugin, plugin_attr):
+                    logger.critical('missing attribute "{0}", cannot load plugin: {1}'.format(plugin_attr, plugin))
+                    exit(3)
+            self.plugins.append(plugin)
+
+    def call(self, plugin_type, request, *args, **kwargs):
+        ret = True
+        for plugin in self.plugins:
+            if hasattr(plugin, plugin_type):
+                ret = getattr(plugin, plugin_type)(request, *args, **kwargs)
+                if not ret:
+                    break
+
+        return ret
+
+
+plugins = PluginStore()
+plugins.register(self_ip)

searx/plugins/self_ip.py

+
+name = "Self IP"
+description = ""
+default_on = True
+
+
+def pre_search(request, ctx):
+    if ctx['search'].query == 'ip':
+        x_forwarded_for = request.headers.getlist("X-Forwarded-For")
+        if x_forwarded_for:
+            ip = x_forwarded_for[0]
+        else:
+            ip = request.remote_addr
+        ctx['search'].answers.clear()
+        ctx['search'].answers.add(ip)
+        return False
+    return True

searx/webapp.py

 import os
 import hashlib
 
+from searx import logger
+logger = logger.getChild('webapp')
+
+try:
+    from pygments import highlight
+    from pygments.lexers import get_lexer_by_name
+    from pygments.formatters import HtmlFormatter
+except:
+    logger.critical("cannot import dependency: pygments")
+    from sys import exit
+    exit(1)
+
 from datetime import datetime, timedelta
 from urllib import urlencode
 from werkzeug.contrib.fixers import ProxyFix
 from searx.search import Search
 from searx.query import Query
 from searx.autocomplete import searx_bang, backends as autocomplete_backends
-from searx import logger
-try:
-    from pygments import highlight
-    from pygments.lexers import get_lexer_by_name
-    from pygments.formatters import HtmlFormatter
-except:
-    logger.critical("cannot import dependency: pygments")
-    from sys import exit
-    exit(1)
+from searx.plugins import plugins
 
 
-logger = logger.getChild('webapp')
-
 static_path, templates_path, themes =\
     get_themes(settings['themes_path']
                if settings.get('themes_path')
             'index.html',
         )
 
-    search.search(request)
+    if plugins.call('pre_search', request, locals()):
+        search.search(request)
+
+    plugins.call('post_search', request, locals())
 
     for result in search.results: