From 50f4abacb03340a443d014ccca18c23fa6407c98 Mon Sep 17 00:00:00 2001
From: Igor Chubin <igor@chub.in>
Date: Sun, 17 Feb 2019 14:07:02 +0100
Subject: [PATCH] caching separated into cache.py

---
 lib/adapter/adapter.py            |  8 ++++++
 lib/adapter/cmd.py                |  3 +++
 lib/adapter/learnxiny.py          |  3 +++
 lib/adapter/question.py           |  4 ++-
 lib/cache.py                      | 45 +++++++++++++++++++++++++++++++
 lib/fmt/comments.py               | 23 +++++-----------
 lib/{get_answer.py => routing.py} |  1 +
 7 files changed, 70 insertions(+), 17 deletions(-)
 create mode 100644 lib/cache.py
 rename lib/{get_answer.py => routing.py} (99%)

diff --git a/lib/adapter/adapter.py b/lib/adapter/adapter.py
index 8cf6113..259fb2b 100644
--- a/lib/adapter/adapter.py
+++ b/lib/adapter/adapter.py
@@ -4,6 +4,7 @@ class Adapter(object):
 
     _adapter_name = None
     _output_format = 'code'
+    _cache_needed = False
 
     def __init__(self):
         self._list = {None: self._get_list()}
@@ -30,6 +31,13 @@ class Adapter(object):
         """
         return topic in self._list[None]
 
+    def is_cache_needed(self):
+        """
+        Return True if answers should be cached.
+        Return False if answers should not be cached.
+        """
+        return self._cache_needed
+
     @abc.abstractmethod
     def _get_page(self, topic, request_options=None):
         """
diff --git a/lib/adapter/cmd.py b/lib/adapter/cmd.py
index 906e7b3..63c7f70 100644
--- a/lib/adapter/cmd.py
+++ b/lib/adapter/cmd.py
@@ -18,6 +18,7 @@ class Tldr(Adapter):
 
     _adapter_name = "tldr"
     _output_format = "code"
+    _cache_needed = True
 
     def _get_list(self, prefix=None):
         return [filename[:-3]
@@ -47,6 +48,7 @@ class Cheat(Adapter):
 
     _adapter_name = "cheat"
     _output_format = "code"
+    _cache_needed = True
 
     def _get_list(self, prefix=None):
         return _get_filenames(PATH_CHEAT_PAGES)
@@ -75,6 +77,7 @@ class Translation(Adapter):
 
     _adapter_name = "translation"
     _output_format = "text"
+    _cache_needed = True
 
     def _get_list(self, prefix=None):
         return []
diff --git a/lib/adapter/learnxiny.py b/lib/adapter/learnxiny.py
index 94e1113..c34e33c 100644
--- a/lib/adapter/learnxiny.py
+++ b/lib/adapter/learnxiny.py
@@ -794,6 +794,9 @@ _ADAPTERS = {cls.prefix: cls() for cls in vars()['LearnXYAdapter'].__subclasses_
 
 class LearnXinY(Adapter):
 
+    _output_format = 'code'
+    _cache_needed = True
+
     def __init__(self):
         self.adapters = _ADAPTERS
         Adapter.__init__(self)
diff --git a/lib/adapter/question.py b/lib/adapter/question.py
index 22dd84e..c98d0fb 100644
--- a/lib/adapter/question.py
+++ b/lib/adapter/question.py
@@ -13,11 +13,13 @@ sys.path.append(os.path.abspath(os.path.join(os.path.dirname(__file__), '..')))
 from globals import MYDIR
 
 from adapter import Adapter
+from languages_data import SO_NAME
 
 class Question(Adapter):
 
     _adapter_name = "question"
-    _output_format = "code"
+    _output_format = "text+code"
+    _cache_needed = True
 
     def _get_page(self, topic, request_options=None):
         """
diff --git a/lib/cache.py b/lib/cache.py
new file mode 100644
index 0000000..78b339d
--- /dev/null
+++ b/lib/cache.py
@@ -0,0 +1,45 @@
+import os
+import json
+import redis
+from globals import REDISHOST
+
+if os.environ.get('REDIS_HOST', '').lower() != 'none':
+    _REDIS = redis.StrictRedis(host=REDISHOST, port=6379, db=0)
+else:
+    _REDIS = None
+
+if os.environ.get('REDIS_PREFIX', '').lower() != 'none':
+    _REDIS_PREFIX = os.environ.get('REDIS_PREFIX', '') + ':'
+else:
+    _REDIS_PREFIX = ''
+
+def put(key, value):
+    """
+    Save `value` with `key`, and serialize it if needed
+    """
+
+    if _REDIS_PREFIX:
+        key = _REDIS_PREFIX + key
+
+    if _REDIS:
+        if isinstance(value, (dict, list)):
+            value = json.dumps(value)
+
+        _REDIS.set(key, value)
+
+def get(key):
+    """
+    Read `value` by `key`, and deserialize it if needed
+    """
+
+    if _REDIS_PREFIX:
+        key = _REDIS_PREFIX + key
+
+    if _REDIS:
+        value = _REDIS.get(key)
+        try:
+            value = json.loads(value)
+        except (ValueError, TypeError):
+            pass
+        return value
+    return None
diff --git a/lib/fmt/comments.py b/lib/fmt/comments.py
index a6b7dc6..49c766b 100644
--- a/lib/fmt/comments.py
+++ b/lib/fmt/comments.py
@@ -31,19 +31,14 @@ import re
 from itertools import groupby, chain
 from tempfile import NamedTemporaryFile
 
-import redis
+import cache
 
 MYDIR = os.path.abspath(os.path.join(__file__, '..', '..'))
 sys.path.append("%s/lib/" % MYDIR)
 from languages_data import VIM_NAME
-from globals import PATH_VIM_ENVIRONMENT, REDISHOST
+from globals import PATH_VIM_ENVIRONMENT
 # pylint: enable=wrong-import-position,wrong-import-order
 
-if os.environ.get('REDIS_HOST', '').lower() != 'none':
-    REDIS = redis.StrictRedis(host=REDISHOST, port=6379, db=1)
-else:
-    REDIS = None
-
 FNULL = open(os.devnull, 'w')
 TEXT = 0
 CODE = 1
@@ -301,16 +296,12 @@ def beautify(text, lang, options):
         # if mode is unknown, just don't transform the text at all
         return text
 
-    if REDIS:
-        digest = "t:%s:%s:%s" % (hashlib.md5(text).hexdigest(), lang, mode)
-        answer = REDIS.get(digest)
-        if answer:
-            return answer
-
+    digest = "t:%s:%s:%s" % (hashlib.md5(text).hexdigest(), lang, mode)
+    answer = cache.get(digest)
+    if answer:
+        return answer
     answer = _beautify(text, lang, **beauty_options)
-
-    if REDIS:
-        REDIS.set(digest, answer)
+    cache.put(digest, answer)
 
     return answer
 
diff --git a/lib/get_answer.py b/lib/routing.py
similarity index 99%
rename from lib/get_answer.py
rename to lib/routing.py
index 82a0c69..d2028f4 100644
--- a/lib/get_answer.py
+++ b/lib/routing.py
@@ -18,6 +18,7 @@ from languages_data import LANGUAGE_ALIAS, SO_NAME, rewrite_editor_section_name
 
 import fmt.comments
 
+import cache
 import adapter.cheat_sheets
 import adapter.cmd
 import adapter.internal