Merge pull request #21 from jeffmendoza/memcache

Copy from appengine-memcache-guestbook-python repo.

appengine/memcache/guestbook/README.md

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+## Memcache Guestbook Sample
+
+This is a sample app for Google App Engine that exercises the [memcache Python API](https://cloud.google.com/appengine/docs/python/memcache/usingmemcache).
+
+See our other [Google Cloud Platform github
+repos](https://github.com/GoogleCloudPlatform) for sample applications and
+scaffolding for other python frameworks and use cases.
+
+## Run Locally
+1. Install the [Google Cloud SDK](https://cloud.google.com/sdk/), including the [gcloud tool](https://cloud.google.com/sdk/gcloud/), and [gcloud app component](https://cloud.google.com/sdk/gcloud-app).
+2. Setup the gcloud tool.
+
+   ```
+   gcloud components update app
+   gcloud auth login
+   gcloud config set project <your-app-id>
+   ```
+   You don't need a valid app-id to run locally, but will need a valid id to deploy below.
+
+1. Clone this repo.
+
+   ```
+   git clone https://github.com/GoogleCloudPlatform/python-docs-samples.git
+   cd appengine/memcache/guestbook/
+   ```
+1. Run this project locally from the command line.
+
+   ```
+   gcloud preview app run ./app.yaml
+   ```
+
+1. Visit the application at [http://localhost:8080](http://localhost:8080).
+
+## Deploying
+
+1. Use the [Cloud Developer Console](https://console.developer.google.com)  to create a project/app id. (App id and project id are identical)
+2. Configure gcloud with your app id.
+
+   ```
+   gcloud config set project <your-app-id>
+   ```
+1. Use the [Admin Console](https://appengine.google.com) to view data, queues, and other App Engine specific administration tasks.
+1. Use gcloud to deploy your app.
+
+   ```
+   gcloud preview app deploy ./app.yaml
+   ```
+
+1. Congratulations!  Your application is now live at your-app-id.appspot.com
+
+## Contributing changes
+
+* See [CONTRIBUTING.md](../../../CONTRIBUTING.md)
+
+## Licensing
+
+* See [LICENSE](../../../LICENSE)

appengine/memcache/guestbook/app.yaml

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+# This file specifies your Python application's runtime configuration
+# including URL routing, versions, static file uploads, etc. See
+# https://developers.google.com/appengine/docs/python/config/appconfig
+# for details.
+
+version: 1
+runtime: python27
+api_version: 1
+threadsafe: yes
+
+# Handlers define how to route requests to your application.
+handlers:
+
+# This handler tells app engine how to route requests to a WSGI application.
+# The script value is in the format <path.to.module>.<wsgi_application>
+# where <wsgi_application> is a WSGI application object.
+- url: .*  # This regex directs all routes to main.app
+  script: main.app
+
+libraries:
+- name: webapp2
+  version: "2.5.2"

appengine/memcache/guestbook/index.yaml

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+indexes:
+
+# AUTOGENERATED
+
+# This index.yaml is automatically updated whenever the dev_appserver
+# detects that a new type of query is run.  If you want to manage the
+# index.yaml file manually, remove the above marker line (the line
+# saying "# AUTOGENERATED").  If you want to manage some indexes
+# manually, move them above the marker line.  The index.yaml file is
+# automatically uploaded to the admin console when you next deploy
+# your application using appcfg.py.
+
+- kind: Greeting
+  ancestor: yes
+  properties:
+  - name: date
+    direction: desc

appengine/memcache/guestbook/main.py

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+# Copyright 2015 Google Inc. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# [START all]
+import cgi
+import cStringIO
+import logging
+import urllib
+import webapp2
+
+from google.appengine.ext import ndb
+from google.appengine.api import memcache
+from google.appengine.api import users
+
+
+class Greeting(ndb.Model):
+    """Models an individual Guestbook entry with author, content, and date."""
+    author = ndb.StringProperty()
+    content = ndb.StringProperty()
+    date = ndb.DateTimeProperty(auto_now_add=True)
+
+
+def guestbook_key(guestbook_name=None):
+    """Constructs a Datastore key for a Guestbook entity with guestbook_name."""
+    return ndb.Key('Guestbook', guestbook_name or 'default_guestbook')
+
+
+class MainPage(webapp2.RequestHandler):
+    def get(self):
+        self.response.out.write('<html><body>')
+        guestbook_name = self.request.get('guestbook_name')
+
+        greetings = self.get_greetings(guestbook_name)
+        stats = memcache.get_stats()
+
+        self.response.write('<b>Cache Hits:{}</b><br>'.format(stats['hits']))
+        self.response.write('<b>Cache Misses:{}</b><br><br>'.format(
+                            stats['misses']))
+        self.response.write(greetings)
+
+        self.response.write("""
+          <form action="/sign?{}" method="post">
+            <div><textarea name="content" rows="3" cols="60"></textarea></div>
+            <div><input type="submit" value="Sign Guestbook"></div>
+          </form>
+          <hr>
+          <form>Guestbook name: <input value="{}" name="guestbook_name">
+          <input type="submit" value="switch"></form>
+        </body>
+      </html>""".format(urllib.urlencode({'guestbook_name': guestbook_name}),
+                        cgi.escape(guestbook_name)))
+
+    # [START check_memcache]
+    def get_greetings(self, guestbook_name):
+        """
+        get_greetings()
+        Checks the cache to see if there are cached greetings.
+        If not, call render_greetings and set the cache
+
+        Args:
+          guestbook_name: Guestbook entity group key (string).
+
+        Returns:
+          A string of HTML containing greetings.
+        """
+        greetings = memcache.get('{}:greetings'.format(guestbook_name))
+        if greetings is None:
+            greetings = self.render_greetings(guestbook_name)
+            if not memcache.add('{}:greetings'.format(guestbook_name),
+                                greetings, 10):
+                logging.error('Memcache set failed.')
+        return greetings
+    # [END check_memcache]
+
+    # [START query_datastore]
+    def render_greetings(self, guestbook_name):
+        """
+        render_greetings()
+        Queries the database for greetings, iterate through the
+        results and create the HTML.
+
+        Args:
+          guestbook_name: Guestbook entity group key (string).
+
+        Returns:
+          A string of HTML containing greetings
+        """
+        greetings = ndb.gql('SELECT * '
+                            'FROM Greeting '
+                            'WHERE ANCESTOR IS :1 '
+                            'ORDER BY date DESC LIMIT 10',
+                            guestbook_key(guestbook_name))
+        output = cStringIO.StringIO()
+        for greeting in greetings:
+            if greeting.author:
+                output.write('<b>{}</b> wrote:'.format(greeting.author))
+            else:
+                output.write('An anonymous person wrote:')
+            output.write('<blockquote>{}</blockquote>'.format(
+                             cgi.escape(greeting.content)))
+        return output.getvalue()
+    # [END query_datastore]
+
+
+class Guestbook(webapp2.RequestHandler):
+    def post(self):
+        # We set the same parent key on the 'Greeting' to ensure each greeting
+        # is in the same entity group. Queries across the single entity group
+        # are strongly consistent. However, the write rate to a single entity
+        # group is limited to ~1/second.
+        guestbook_name = self.request.get('guestbook_name')
+        greeting = Greeting(parent=guestbook_key(guestbook_name))
+
+        if users.get_current_user():
+            greeting.author = users.get_current_user().nickname()
+
+        greeting.content = self.request.get('content')
+        greeting.put()
+        self.redirect('/?' +
+                      urllib.urlencode({'guestbook_name': guestbook_name}))
+
+
+app = webapp2.WSGIApplication([('/', MainPage),
+                               ('/sign', Guestbook)],
+                              debug=True)
+
+# [END all]