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Asked: 2026-06-03T02:23:19+00:00

I keep receiving an internal server error – ‘BadValueError: Property content is required. It

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I keep receiving an internal server error – ‘BadValueError: Property content is required. It seems to happen when I pass blog_table into the template to render. Here’s the code:

main.py:

import os
import webapp2
import jinja2

from google.appengine.ext import db

jinja_env = jinja2.Environment(loader = jinja2.FileSystemLoader(os.path.join(os.path.dirname(__file__),'templates')), autoescape = True)

class Handler(webapp2.RequestHandler):
    def write(self,*a,**kw):
        self.response.out.write(*a,**kw)

    def render_str(self,template,**params):
        t = jinja_env.get_template(template)
        return t.render(params)

    def render(self,template,**kw):
        self.write(self.render_str(template,**kw))

class Blog(db.Model):
    subject = db.StringProperty(required = True)
    content = db.TextProperty(required = True)
    created = db.DateTimeProperty(auto_now_add = True)

class MainPage(Handler):
    def render_front(self, subject="", content="", error=""):
        blog_table = db.GqlQuery("SELECT * FROM Blog ORDER BY created DESC")
        self.render("blog.html",subject = subject,content = content,error = error,blog_table = blog_table)

    def get(self):
        self.render_front()

    def post(self):
        subject = self.request.get("subject")
        content = self.request.get("content")

        if subject and content:
            b = Blog(subject = subject, content = content)
            b.put()
            self.redirect("/")

        else:
            error = "we need both a subject and some content"
            self.render_front(subject,content,error)

app = webapp2.WSGIApplication([('/', MainPage)],debug=True)

HTML:

<!DOCTYPE html>

<html>
    <head>
        <title>Blog</title>
    </head>
    <body>
        <h1>Blog</h1>

        <form method="post">
            <label>
                <div>Subject</div>
                <input type="text" name="subject" value="{{subject}}">
            </label>
            <label>
                <div>Content</div>
                <textarea name="content" value="{{content}}"></textarea>
            </label>
            <div class="error">{{error}}</div>
            <input type="submit">
        </form>

        <hr>
    {% for post in blog_table %}
        <div class="post">
            <div class="subject">{{post.subject}}</div>
            <pre class="content">{{post.content}}</pre>
        </div>
    {% endfor %}

    </body>
</html>

To see the error go to http://udacity-cs253-a31.appspot.com/

Thanks.

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1 Answer

  1. Editorial Team

    This is just a guess – changed your Blog model and added the Content attribute recently.

    There’s some old instances of the Blog model in your datastore that have no Content. If you try to load those, your code fails. If you load a Blog instance with Content, everything is fine.

    You have to go through your datastore and ensure all instances of your Blog have Content.

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