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I am trying to build a basic blog model using Google App Engine in Python. However, something's wrong with my code I suppose, and I am getting a 404 error when I try to display all the posted blog entries on a single page. Here's the python code:
import os
import re
import webapp2
import jinja2
from string import letters
from google.appengine.ext import db
template_dir = os.path.join(os.path.dirname(__file__), 'templates')
jinja_env = jinja2.Environment(loader = jinja2.FileSystemLoader(template_dir), 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))
def post_key(name = "dad"):
return db.Key.from_path('blog', name)
class Blogger(db.Model):
name = db.StringProperty()
content = db.TextProperty()
created = db.DateTimeProperty(auto_now_add = True)
def render(self):
self._render_text = self.content.replace('\n', '<br>')
return render_str("post.html", p = self)
class MainPage(Handler):
def get(self):
self.response.write("Visit our blog")
class BlogHandler(Handler):
def get(self):
posts = db.GqlQuery("SELECT * FROM Blogger order by created desc")
self.render("frontblog.html", posts = posts)
class SubmitHandler(Handler):
def get(self):
self.render("temp.html")
def post(self):
name = self.request.get("name")
content = self.request.get("content")
if name and content:
a = Blogger(name = name, content = content, parent = post_key())
a.put()
self.redirect('/blog/%s' % str(a.key().id()))
else:
error = "Fill in both the columns!"
self.render("temp.html", name = name, content = content, error = error)
class DisplayPost(Handler):
def get(self, post_id):
po = Blogger.get_by_id(int(post_id))
if po:
self.render("perma.html", po = po)
else:
self.response.write("404 Error")
app = webapp2.WSGIApplication([('/', MainPage),
('/blog', BlogHandler),
('/blog/submit', SubmitHandler),
('/blog/([0-9]+)', DisplayPost)], debug=True)
After posting my content, it gets redirected to a permalink. However, this is the error I am getting on submitting my post:
404 Not Found
The resource could not be found
Here's the frontblog.html source code, in case that would help:
<!DOCTYPE html>
<html>
<head>
<title>CS 253 Blog</title>
</head>
<body>
<a href="/blog">
CS 253 Blog
</a>
<div id="content">
{% block content %}
{%for post in posts%}
{{post.render() | safe}}
<br></br>
{%endfor%}
{% endblock %}
</div>
</body>
</html>
So basically, I am not being redirected to the permalink page. What seems to be the problem?
When you create your post, you're giving it a parent (not sure why). But when you get it, you do so by the ID only, and don't take into account the parent ID. In the datastore, a key is actually a path consisting of all the parent kinds and IDs/names and then those of the current entity, and to get an object you need to pass the full path.
Possible solutions here:
Blogger.get_by_id(post_id, parent=parent_key())- obviously this only works if the parent is always the same;Blogger.get(key)- you'll also need to change the route regex to accept alphanumeric chars, eg'/blog/(\w+)', and change the redirect to'/blog/%s' % a.key().