Question

I am trying to make a basic quotation-sharing app using Webapp. Obviously it is crucial to be able to give arbitrary tags to each quote.

So here are the relevant code that I’ve come up with:
(Mostly from the example chat app in the great introductory book ‘Using Google App Engine‘ )

class Quote(db.Model):
  user = db.ReferenceProperty()
  text = db.StringProperty()
  tags = db.StringListProperty()
  created = db.DateTimeProperty(auto_now=True)

And the ‘view’:

class QuoteHandler(webapp.RequestHandler):

  def get(self):
    que = db.Query(Quote).order('-created');
    chat_list = que.fetch(limit=10)
    doRender(
          self,
          'quote.htm',
          { 'quote_list': quote_list })

  def post(self):
    self.session = Session()
    if not 'userkey' in self.session:
      doRender(self, 'quote.htm', {'error' : 'Must be logged in'} )
      return

    msg = self.request.get('message')
    if msg == '':
      doRender(self,'quote.htm',{'error' : 'Blank quote ignored'} )
      return
    tgs = self.request.get('tags') #really not sure of this
    newq = Quote(user = self.session['userkey'], text=msg, tags= tgs)
    newq.put();
    self.get();

And in quote.htm I have:

{% extends "_base.htm" %}
{% block bodycontent %}
      <h1>Quotes</h1>
      <p>
      <form method="post" action="/quote">
        Quote:<input type="text" name="message" size="60"/><br />
        Tags: <input type="text" name="tags" size="30"/>
      <input type="submit" value="Send"/> 
      </form>
      </p>
      {% ifnotequal error None %}
       <p>
       {{ error }}
       </p>
      {% endifnotequal %}
<br />
<h3> The latest quotes </h3>

      {% for quote in quote_list %}
        <p>
           {{ quote.text }}<br />
         ({{quote.user.account}}) <br />
         {{ quote.tags }}

           {{ quote.created|date:"D d M Y" }}
        </p>
      {% endfor %}
{% endblock %}

However, this combo is faulty. I get:

BadValueError: Property tags must be a list

No matter what I enter in the tags filed, and (obviously) I am new to both Python and Webapp. I googled a lot but could not find any guide to implement tags. So I really appreciate your help to fix this error, or rather point me to a a more elegant way to deal with tags.

Answer 1

Try using split() to turn tgs into a list of words before creating your Quote. Tags should be separated by whitespace in your form, otherwise you can add an argument to split if you’d rather separate them by something else.

...
tgs = self.request.get('tags').split()
newq = Quote(user = self.session['userkey'], text=msg, tags= tgs)
...