[enh] add quick answer functionality with an example answerer

searx/answerers/__init__.py

@@ -0,0 +1,46 @@
+from os import listdir
+from os.path import realpath, dirname, join, isdir
+from searx.utils import load_module
+from collections import defaultdict
+
+
+answerers_dir = dirname(realpath(__file__))
+
+
+def load_answerers():
+    answerers = []
+    for filename in listdir(answerers_dir):
+        if not isdir(join(answerers_dir, filename)):
+            continue
+        module = load_module('answerer.py', join(answerers_dir, filename))
+        if not hasattr(module, 'keywords') or not isinstance(module.keywords, tuple) or not len(module.keywords):
+            exit(2)
+        answerers.append(module)
+    return answerers
+
+
+def get_answerers_by_keywords(answerers):
+    by_keyword = defaultdict(list)
+    for answerer in answerers:
+        for keyword in answerer.keywords:
+            for keyword in answerer.keywords:
+                by_keyword[keyword].append(answerer.answer)
+    return by_keyword
+
+
+def ask(query):
+    results = []
+    query_parts = filter(None, query.query.split())
+
+    if query_parts[0] not in answerers_by_keywords:
+        return results
+
+    for answerer in answerers_by_keywords[query_parts[0]]:
+        result = answerer(query)
+        if result:
+            results.append(result)
+    return results
+
+
+answerers = load_answerers()
+answerers_by_keywords = get_answerers_by_keywords(answerers)

searx/answerers/random/answerer.py

@@ -0,0 +1,50 @@
+import random
+import string
+from flask_babel import gettext
+
+# required answerer attribute
+# specifies which search query keywords triggers this answerer
+keywords = ('random',)
+
+random_int_max = 2**31
+
+random_string_letters = string.lowercase + string.digits + string.uppercase
+
+
+def random_string():
+    return u''.join(random.choice(random_string_letters)
+                    for _ in range(random.randint(8, 32)))
+
+
+def random_float():
+    return unicode(random.random())
+
+
+def random_int():
+    return unicode(random.randint(-random_int_max, random_int_max))
+
+
+random_types = {u'string': random_string,
+                u'int': random_int,
+                u'float': random_float}
+
+
+# required answerer function
+# can return a list of results (any result type) for a given query
+def answer(query):
+    parts = query.query.split()
+    if len(parts) != 2:
+        return []
+
+    if parts[1] not in random_types:
+        return []
+
+    return [{'answer': random_types[parts[1]]()}]
+
+
+# required answerer function
+# returns information about the answerer
+def self_info():
+    return {'name': gettext('Random value generator'),
+            'description': gettext('Generate different random values'),
+            'examples': [u'random {}'.format(x) for x in random_types]}