Simple Blog on Google App Engine - no entries being displayed

Question

I have seen similar questions asked on the same topic, which is coding a very simple blog with Python and hosted on GAE. Apologies if I have missed the solution in one of the answers.

I can't see any database entries being displayed at all. Here is my code:

Entity:

class Comment(db.Model):
    name = db.StringProperty(required=True)
    comment = db.TextProperty(required=True)
    created = time.strftime("%d/%m/%Y")

Main Handler:

class MainPage(Handler):
    def render_front(self, name="", comment="", error=""):
        comments = db.GqlQuery("SELECT * FROM Comment ORDER BY created DESC")
        self.render("front.html", name=name, comment=comment, error=error, comments=comments)
    def get(self):
        self.render_front()
    def post(self):
        name = self.request.get("name")
        comment = self.request.get("comment")
        if name and comment:
            c = Comment(name=name, comment=comment)
            c.put()
            time.sleep(0.5)
            self.redirect("/")

So this will be displayed in the HTML:

{% for e in comments %}
    <div class="comment">
        <div class="comment-name">
            {{e.name}}
        </div>
        <pre class="comment-content">
            {{e.comment}}
            <br>
            on {{e.created}}
        </pre>
    </div>
{% endfor %}

The problem is that the program seems to completely ignore the above for block. I managed to make it work for a while but I checked it many times and can't see where the problem is.

Any help will be appreciated. Thanks in advance.

how did you manage to make it work? Also Have you been checking the App Engine log file for errors? That usually at the very least points you in the right direction.. — Totem, Jan 06 '14 at 16:19

Laurence Moroney · Accepted Answer · 2014-01-08T16:28:07.693

3

A few ways to check through this:

Use the admin console to look at your Datastore. Do you have records in there?
Are your datetime properties being stored correctly? For docs on DS and Datetime, see here: https://developers.google.com/appengine/docs/python/datastore/typesandpropertyclasses#DateTimeProperty
Have you made the date a 'dateTimeProperty' type? See the example here: developers.google.com/appengine/docs/python/ndb/queries See also here: stackoverflow.com/questions/9700579/gql-select-by-date
Try removing the ORDER BY clause in your GQL. I'm wondering if there's something funky with the date/time variable
Try running locally using the App Engine SDK, and use the logs in that to see the behavior. When you're happy that everything works you can upload it to GAE.
Don't use the templating engine -- for now just do the loop completely in Python -- and self.response.write stuff out. This will tell you if your query works properly.

Hope it works out for you! :)

edited Jan 08 '14 at 16:28

answered Jan 07 '14 at 01:33

Laurence Moroney

1,263
8
20

1

Thanks Laurence. So there were indeed records in the Datastore. Removing the ORDER BY clause made it work. For whatever reason, when I add it to the query, nothing is displayed. If I change the created to created = db.DateProperty(auto_now_add=True) and replace the GQL by: comments = Comment.all().order('-created'), it still does not work. – David B. Jan 07 '14 at 11:39
Have you made the date a 'dateTimeProperty' type? See the example here: https://developers.google.com/appengine/docs/python/ndb/queries See also here: http://stackoverflow.com/questions/9700579/gql-select-by-date – Laurence Moroney Jan 07 '14 at 16:05
Changing it to 'DateTimeProperty' works indeed. I can now display all the comments in descending order. Thanks again (and for the useful links as well)! – David B. Jan 08 '14 at 16:23
Great! Please mark my answer as the answer. I'm editing it to add the dateTimeProperty stuff. – Laurence Moroney Jan 08 '14 at 16:27

Simple Blog on Google App Engine - no entries being displayed

1 Answers1