simplistic implementation of data caching and persistance

getnikola · Jan 4, 2016 · cdc92de · cdc92de
1 parent 8e92f13
commit cdc92de
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diff --git a/CHANGES.txt b/CHANGES.txt
@@ -10,6 +10,7 @@ Features
   if ``GITHUB_COMMIT_SOURCE`` is set to True (Issue #2186)
 * Hugo-like shortcodes (Issue #1707)
 * New Galician translation
+* New facilities for data persistence and data caching (Issues #2209 and #2009)
 
 Bugfixes
 --------

diff --git a/nikola/nikola.py b/nikola/nikola.py
@@ -57,6 +57,7 @@
 from blinker import signal
 
 from .post import Post  # NOQA
+from .state import Persistor
 from . import DEBUG, utils, shortcodes
 from .plugin_categories import (
     Command,
@@ -812,7 +813,15 @@ def __init__(self, **config):
                 self.bad_compilers.add(k)
 
         self._set_global_context()
-
+
+        # Set persistent state facility
+        self.state = Persistor(os.path.join('state_data.json'))
+        self.state.set('foobar', {1:3})
+
+        # Set cache facility
+        self.cache = Persistor(os.path.join(self.config['CACHE_FOLDER'], 'cache_data.json'))
+        self.cache.set('foobar', {1:3})
+
     def init_plugins(self, commands_only=False):
         """Load plugins as needed."""
         self.plugin_manager = PluginManager(categories_filter={

diff --git a/nikola/state.py b/nikola/state.py
@@ -0,0 +1,70 @@
+# -*- coding: utf-8 -*-
+
+# Copyright © 2012-2016 Roberto Alsina and others.
+
+# Permission is hereby granted, free of charge, to any
+# person obtaining a copy of this software and associated
+# documentation files (the "Software"), to deal in the
+# Software without restriction, including without limitation
+# the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the
+# Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice
+# shall be included in all copies or substantial portions of
+# the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
+# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
+# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+# PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS
+# OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+# OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+"""Persistent state implementation."""
+
+import json
+import os
+
+from . import utils
+
+
+class Persistor():
+    """Persist stuff in a place.
+
+    This is an intentionally dumb implementation. It is *not* meant to be
+    fast, or useful for arbitrarily large data. Use lightly.
+
+    Intentionally it has no namespaces, sections, etc. Use as a
+    responsible adult.
+    """
+    def __init__(self, path):
+        """Where do you want it persisted?"""
+        self._path = path
+        utils.makedirs(os.path.dirname(path))
+        self.data = {}
+        if os.path.isfile(path):
+            with open(path) as inf:
+                self.data = json.load(inf)
+
+    def get(self, key):
+        """Get data stored in key."""
+        return self.data.get(key)
+
+    def set(self, key, value):
+        """Store value in key."""
+        self.data[key] = value
+        self._save()
+
+    def delete(self, key):
+        """Delete key and the value it contains."""
+        if key in self.data:
+            self.data.pop(key)
+        self._save()
+
+    def _save(self):
+        with open(self._path, 'w') as outf:
+            json.dump(self.data, outf, sort_keys=True, indent=2)