使用python for GAE覆蓋數據存儲區 - 留言簿示例

我想做一些與Python中提供的Guestbook示例類似的東西。使用python for GAE覆蓋數據存儲區 - 留言簿示例

但是，允許一個用戶多次簽名，我希望每個提交覆蓋任何現有用戶預先存在的提交。

我很難搞清楚如何編輯這個例子來完成這項工作。

import cgi 
import datetime 
import urllib 
import wsgiref.handlers 

from google.appengine.ext import db 
from google.appengine.api import users 
from google.appengine.ext import webapp 
from google.appengine.ext.webapp.util import run_wsgi_app 


class Greeting(db.Model): 
"""Models an individual Guestbook entry with an author, content, and date.""" 
author = db.StringProperty() 
content = db.StringProperty(multiline=True) 
date = db.DateTimeProperty(auto_now_add=True) 


def guestbook_key(guestbook_name=None): 
"""Constructs a Datastore key for a Guestbook entity with guestbook_name.""" 
return db.Key.from_path('Guestbook', guestbook_name or 'default_guestbook') 


class MainPage(webapp.RequestHandler): 
def get(self): 
self.response.out.write('<html><body>') 
guestbook_name=self.request.get('guestbook_name') 

# Ancestor Queries, as shown here, are strongly consistent with the High 
# Replication Datastore. Queries that span entity groups are eventually 
# consistent. If we omitted the ancestor from this query there would be a 
# slight chance that Greeting that had just been written would not show up 
# in a query. 
greetings = db.GqlQuery("SELECT * " 
         "FROM Greeting " 
         "WHERE ANCESTOR IS :1 " 
         "ORDER BY date DESC LIMIT 10", 
         guestbook_key(guestbook_name)) 

for greeting in greetings: 
    if greeting.author: 
    self.response.out.write(
     '<b>%s</b> wrote:' % greeting.author) 
    else: 
    self.response.out.write('An anonymous person wrote:') 
    self.response.out.write('<blockquote>%s</blockquote>' % 
          cgi.escape(greeting.content)) 

self.response.out.write(""" 
     <form action="/sign?%s" 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="%s" name="guestbook_name"> 
     <input type="submit" value="switch"></form> 
    </body> 
    </html>""" % (urllib.urlencode({'guestbook_name': guestbook_name}), 
         cgi.escape(guestbook_name))) 


class Guestbook(webapp.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 will be 
# consistent. However, the write rate to a single entity group should 
# be 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})) 


application = webapp.WSGIApplication([ 
('/', MainPage), 
('/sign', Guestbook) 
], debug=True) 


def main(): 
run_wsgi_app(application) 


if __name__ == '__main__': 
main()

來源

2012-08-08 monkey blot

做到這一點，最簡單的方法是修改Guestbook類的post方法，所以它檢查當前用戶和更新其現有的崗位，如果它存在。

class Guestbook(webapp.RequestHandler): 
    def post(self): 
    guestbook_name = self.request.get('guestbook_name') 
    user = users.get_current_user() 
    nickname = None 
    if user: 
     nickname = user.nickname() 
     greeting = Greeting.gql('WHERE author = :1 AND ANCESTOR IS :2', 
      nickname, guestbook_key(guestbook_name)).get() 
    if not greeting: 
     greeting = Greeting(parent=guestbook_key(guestbook_name)) 
     greeting.author = nickname 

    greeting.content = self.request.get('content') 
    greeting.put() 
    self.redirect('/?' + urllib.urlencode({'guestbook_name': guestbook_name}))

來源

2012-08-09 00:29:12

感謝您的回答。這就像我的本地主機上的魅力。但由於某種原因，部署到網絡上，它可以防止附加消息，但不會更新前一個消息。點擊「簽名留言簿」按鈕，頁面重新加載，但仍然看起來一樣。有任何想法嗎？ – 2012-08-09 00:51:37

我在Greeting.gql中省略了祖先查找。再試一次，讓我知道如果這不起作用。 – 2012-08-09 01:03:53

太棒了。謝謝丹！ – 2012-08-09 01:30:56

使用python for GAE覆蓋數據存儲區 - 留言簿示例

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