CODEWITHSUNDEEP
pythongoogle-app-enginegoogle-cloud-datastore
EasilyBaffled
EasilyBaffled

Reputation: 3882

Google App Engine datastore model property returns none

I am trying to create a basic use of the Google App Engine's datastore and db model. My model object is 

class Table(db.Model):
    row = db.IntegerProperty()
    col = db.IntegerProperty()
    date = db.DateTimeProperty(auto_now_add=True)

it will be used to just hold a table of rows and columns. User gives input via html, and then I save the table and draw all of the tables in the datastore. I use Table.all() to get all tables from the datastore and then try to access their contents so that I can print the table but for some reason when table.row and table.col is read in for y in range(row): will apparently return a noneType, does anyone know why?

import webapp2
from google.appengine.ext.webapp.util import run_wsgi_app
from google.appengine.ext import db
from logging import error

INITIAL_INPUT = """\
<html>
    <body>
        <form action="/out?%s" method="POST">
            <input type="text" name="row" />
            <input type="text" name="col" />
            <input type="submit" value="Submit" />
        </form>
    </body>
</html>
"""

class Table(db.Model):
    """Models an individual Guestbook entry with author, content, and date."""
    row = db.IntegerProperty()
    col = db.IntegerProperty()
    date = db.DateTimeProperty(auto_now_add=True)

class MainPage(webapp2.RequestHandler):
    def get(self):
        self.response.write(INITIAL_INPUT)

class Out(webapp2.RequestHandler):

    def post(self):
        newRow = self.request.POST['row']
        newCol = self.request.POST['col']
        newTable = Table()
        newTable.row = int(newRow) if newRow else 1
        newTable.col = int(newCol) if newCol else 1 
        newTable.put()
        tables = Table.all()
        for table in tables:
            self.drawTable(table.row, table.col)


    def drawTable(self, row , col):
        write = self.response.write
        write("<html><body><table>")
        for y in range(row):
            write("<tr>")
            for x in range(col):
                cell = "<td bgcolor=\"#00FF00\">" + str(x) + " " + str(y) + "</td>"
                if x % 2 == 0:
                    cell = "<td bgcolor=\"#FF0000\">" + str(x) + " " + str(y) + "</td>"
                write(cell)
            write("</tr>")    
        write("</table></body></html>")  

application = webapp2.WSGIApplication([
    ('/', MainPage),
    ('/out', Out)]
, debug=True)

def main(*args, **kwds):
    run_wsgi_app(application)


if __name__ == "__main__":
    main()

Upvotes: 0

Views: 243

Answers (1)

Brent Washburne
Brent Washburne

Reputation: 13158

Note: the <form action="/out?%s" is incorrect, it only needs to be action="/out".

I'll bet that you have other entities in Table, so your loop picks them up. Use the Datastore Viewer to view By kind: Table and delete the ones with empty row,col values.

Maybe you only want to draw the table that was POSTed? Change these lines:

    tables = Table.all()
    for table in tables:
        self.drawTable(table.row, table.col)

to:

    self.drawTable(newTable.row, newTable.col)

Upvotes: 1

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