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Python Build a Social Network with Flask Broadcasting Post Form and View

Kyle Barney
Kyle Barney
9,081 Points
Posted by Kyle Barney
Kyle Barney
9,081 Points

Flask BuildError When Including Link

Background: I'm building this app mostly as it appears in the lesson. The only real difference thus far is that I'm using "Entries" rather than "Posts".

I keep getting a BuildError when I include the code to create a link to the new entry page for authenticated users. This is the code that causes the error to appear (it is located in the "layout.html' file):

<a href="{{ url_for('entry') }}">Post New Entry</a>

Whenever I omit this code, the app runs as expected, which is strange because all this code should do is create a link to the "New Entry" page, right?

Thinking that there may be an issue with my route, here is that section of the main app file (fs_app.py as I've named it):

# Create Entry
@app.route('/newentry', methods=('GET', 'POST'))
@login_required
def new_entry():
    form = forms.EntryForm()
    if form.validate_on_submit():
        models.Entry.create(user=g.user._get_current_object(),
                            title=form.title.data.strip(),
                            content=form.content.data.strip())
        flash("Entry posted.", "success")
        return redirect(url_for('index'))
    return render_template('entry.html', form=form)

And here is the error that is being generated:

werkzeug.routing.BuildError
BuildError: ('entry', {}, None)

Traceback (most recent call last)
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1836, in __call__
return self.wsgi_app(environ, start_response)
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1820, in wsgi_app
response = self.make_response(self.handle_exception(e))
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1403, in handle_exception
reraise(exc_type, exc_value, tb)
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1817, in wsgi_app
response = self.full_dispatch_request()
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1477, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1381, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1475, in full_dispatch_request
rv = self.dispatch_request()
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1461, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "/usr/local/lib/python2.7/dist-packages/flask_login.py", line 792, in decorated_view
return func(*args, **kwargs)
File "/home/kylebarney/LEARN/flasksocial/fs_app.py", line 100, in new_entry
return render_template('entry.html', form=form)
File "/usr/local/lib/python2.7/dist-packages/flask/templating.py", line 128, in render_template
context, ctx.app)
File "/usr/local/lib/python2.7/dist-packages/flask/templating.py", line 110, in _render
rv = template.render(context)
File "/usr/local/lib/python2.7/dist-packages/jinja2/environment.py", line 989, in render
return self.environment.handle_exception(exc_info, True)
File "/usr/local/lib/python2.7/dist-packages/jinja2/environment.py", line 754, in handle_exception
reraise(exc_type, exc_value, tb)
File "/home/kylebarney/LEARN/flasksocial/templates/entry.html", line 2, in top-level template code
{% from 'macros.html' import render_field %}
File "/home/kylebarney/LEARN/flasksocial/templates/layout.html", line 70, in top-level template code
<a href="{{ url_for('entry') }}">Post New Entry</a>
File "/usr/local/lib/python2.7/dist-packages/flask/helpers.py", line 312, in url_for
return appctx.app.handle_url_build_error(error, endpoint, values)
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1641, in handle_url_build_error
reraise(exc_type, exc_value, tb)
File "/usr/local/lib/python2.7/dist-packages/flask/helpers.py", line 305, in url_for
force_external=external)
File "/usr/local/lib/python2.7/dist-packages/werkzeug/routing.py", line 1678, in build
raise BuildError(endpoint, values, method)
BuildError: ('entry', {}, None)

Any ideas?

2 Answers

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 68,454 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,454 Points

You are using "{{ url_for('entry') }}" but your function name is "new_entry". Theses need to match

Kyle Barney
Kyle Barney
9,081 Points
Kyle Barney
Kyle Barney
9,081 Points

Ah, so that references the function rather than the template. Thanks!