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Unable to change Django default templates

I'm learning Django using W. Vincent's "Django for beginners". I got to the part where we have to customize the password change page (p. 186). According to the author:
"Django already has created the views and URLs for us, we only need to
change the templates."
I created a new template password_change_form.html but when I start a local server and go to the localhost/accounts/password_change, I still see the old default page with the "Django Administration" header. Here is the code:
{% extends "base.html" %}
{% block title %}Password Change{% endblock title %}
{% block content %}
<h1>Password change</h1>
<p>Please enter your old password, for security's sake, and then enter your new password twice so we can verify you typed it in correctly.</p>
<form method="POST">
{% csrf_token %}
{{ form.as_p }}
<input class="btn btn-success" type="submit" value="Change my password">
</form>
{% endblock content %}
I'm surprised because everything worked well up until this point, as I was able to successfully updated the login and signup pages' templates. What do you think might be going wrong? Thanks.

This is happening because in "Django For Beginners" book, the author does not configure static file setting in the settings.py file the css you are seeing in the template is because of bootstrap's cdn.
If you want to clear that problem you have to configure static files settings in settings.py.
This article by the same author can be helpful for you

Failed to get value from html page in Django

I have a problem with trying to get a response from my HTML page using Django (admin).
I have a pretty simple div = contenteditable and need to pass data from this div back after the submit button was clicked.
Everything, including choosing selection and opening the intermediate page works fine. But when I tapped submit button, the condition if "apply" in request.POST failed to work.
Please, tell me, what I'm doing wrong?
This is my Django admin:
class QuestionAdmin(AnnotatesDisplayAdminMixin, admin.ModelAdmin):
def matched_skills(self, question):
return ', '.join(s.name for s in question.skills.all())
def update_skills(self, request, queryset):
if 'apply' in request.POST:
print("something")
skills = []
for question in queryset:
skills.append(self.matched_skills(question))
return render(request,
'admin/order_intermediate.html',
context={'skills': skills})
update_skills.short_description = "Update skills"
This is my order_intermediate.html page:
{% extends "admin/base_site.html" %}
{% block content %}
<form method="post">
{% csrf_token %}
<h1>Adjust skills. </h1>
{% for skill in skills %}
<div>
<div id="title" style="margin-left: 5px" contenteditable="true" > {{ skill }} </div>
</div>
{% endfor %}
<input type="hidden" name="action" value="update_status" />
<input type="submit" name="apply" value="Update skills"/>
</form>
{% endblock %}

Actually, request.POST is an HttpRequest object. For getting available keys in the body of the request, you need to use "request.POST.keys()" method. So, you can simply change your condition to:
if 'apply' in request.POST.keys():
print("something")

In my knowledge, you can not send div content with form submit. However you can use input tag with array in name attribute for this. This will send an array as post variable when submit
First, send skills as a enumerate object from your views
return render(request, 'admin/order_intermediate.html', context={'skills': enumerate(skills)})
Then edit your html to this (Note: if you have css in title id, change it to title class)
{% for i,skill in skills %}
<div>
<input class="title" name="skill[{{ i }}]" value="{{ skill }}" style="margin-left: 5px">
</div>
{% endfor %}
and handle array with any action you want to perform in update_skills()
for skill in request.POST.getlist('skill[]'):
# your code

Flask and WTForms with custom validation

I am creating an online form with Python, to send an online form. The form consists of a mixture of free input fields, and standard options. What it does now is convert the input to a mail, and send it. That's great, but I would like to build in a functionality that checks the input first. I need the length of two different inputfields to be of the size. So if someone enters 4 products and only 3 quantities, I want it to return a warning that these amounts differ.
base.py:
from flask import *
from wtforms import *
import yagmail
yag = yagmail.SMTP('email', 'pass')
# App config.
DEBUG = True
app = Flask(__name__)
app.config.from_object(__name__)
app.config['SECRET_KEY'] = 'key'
class ReusableForm(Form):
naam = TextField('Name:', validators=[validators.required()])
#app.route("/", methods=['GET', 'POST'])
def index():
form = ReusableForm(request.form)
print form.errors
if request.method == 'POST':
# Process all input
naam=request.form['naam']
productcodes=request.form['productcodes']
productquantity=request.form['productquantity']
# Convert SKU & EAN input to list of entries
productcodes = [int(i) for i in productcodes.strip('{}').split('\n')]
productquantity = [int(i) for i in productquantity.strip('{}').split('\n')]
# tried this; didn't work
# if len(productcodes) != len(productquantity):
# flash('Unequal inputs')
if form.validate():
# Comment when form is validates
flash('Order succesvol: ' + naam)
(send mail)
else:
flash('Error: All the form fields are required. ')
return render_template('hello.html', form=form)
if __name__ == "__main__":
app.run()
hello.html:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
<title>Form</title>
<link rel="stylesheet" media="screen" href ="static/css/bootstrap.min.css">
<link rel="stylesheet" href="static/css/bootstrap-theme.min.css">
<meta name="viewport" content = "width=device-width, initial-scale=1.0">
</head>
<body>
<div class="container">
<h2>Form</h2>
<form action="" method="post" role="form">
{{ form.csrf }}
<div class="form-group">
<label for="naam">Naam:</label>
<select name="naam" class="selectpicker form-control">
<option value="Jack">Jack</option>
<option value="John">John</option>
</select>
<br>
<label for="productcodes">SKU-codes:</label>
<textarea class="form-control" id="productcodes" name="productcodes"></textarea>
<br>
<textarea class="form-control" id="productquantity" name="productquantity"></textarea>
<br>
</div>
<button type="submit" class="btn btn-success">Send</button>
</form>
<br>
{% with messages = get_flashed_messages(with_categories=true) %}
{% if messages %}
{% for message in messages %}
{% if "Error" not in message[1]: %}
<div class="alert alert-info">
<strong>Success! </strong> {{ message[1] }}
</div>
{% endif %}
{% if "Error" in message[1]: %}
<div class="alert alert-warning">
{{ message[1] }}
</div>
{% endif %}
{% endfor %}
{% endif %}
{% endwith %}
</div>
<br>
</div>
</div>
</body>
</html>
So what i would like to have is that upon the first click, the check is executed. If the size of the input of productcodes is smaller than the size of productquantity, the user has to edit the inputs. If not, the user has to confirm and is able to send the mail.
The lines that are commented out in base.py didn't work.
Thanks in advance!

Quick and Dirty
Based on the commented-out code, in your original attempt there was nothing stopping the form from validating and submitting. Your if len(productcodes) != len(productquantity) just flashed a message, which only shows on the next page load, but doesn't stop validation of the form. form.validate() can only validate the fields you tell it about.
Change the check to be something like:
if len(productcodes) != len(productquantity) and form.validate():
That way your basic check will bounce to the failed validation code path.
The "Right" Way
Keep in mind, even if that works, you're still basing your check on parsing text from a <textarea>, with little to enforce the format. Any unexpected input is likely to break it.
I'd strongly recommend you rethink your form to be a bit more in line with how WTForms and Flask work. Each form field should map directly to an attribute of your Form subclass. That way you can use the built-in validators, and not have to create your own. You should probably look at using something other than a raw <textarea> as well. It may be a bit more work up-front, but it will make it a lot easier for you and your users down the road.

Flask WTF – Forms always redirect to root

I have created a simple Flask WTF form
class SequenceForm(Form):
sequence = StringField('Please enter a sequence in FASTA format', validators=[Required()])
submit = SubmitField('Submit')
and I have set up a route to make it appear on a page
#main.route('/bioinformatics')
def bioinformatics():
form = SequenceForm()
return render_template('bioinformatics.html', form=form)
It all works great (so far). When I point my browser to foo/bioinformatics, I see a page with a SequenceForm rendered. However, when I hit the Submit button, I am always taken back to the root page defined by #main.route('/').
How can I make the Submit button take me somewhere else? I would like to use validate_on_submit() and do stuff with the data entered in the form.
Thanks!
/Michael Knudsen
UPDATE (Code from bioinformatics.html)
{% extends "base.html" %}
{% import "bootstrap/wtf.html" as wtf %}
{% block title %}Bioinformatics{% endblock %}
{% block page_content %}
<div class="page-header">
<h1>Hello, Bioinformatics!</h1>
</div>
{{ wtf.quick_form(form) }}
{% endblock %}

You need to specify an action in the form in your html.
<form action="/url_which_handles_form_data" method="Post">
your code
</form>
make sure to give the correct path if you are using blueprints
Edit:
From https://github.com/mbr/flask-bootstrap/blob/master/flask_bootstrap/templates/bootstrap/wtf.html I found this part.
{% macro quick_form(form,
action="",
method="post",
extra_classes=None,
role="form",
form_type="basic",
horizontal_columns=('lg', 2, 10),
enctype=None,
button_map={},
id="") %}
So you can probably call
{{ wtf.quick_form(form, action="/fancy_url") }}
or
{{ wtf.quick_form(form, action=url_for("blueprint_name.fancy_url")) }}
Depending on where the view is located.

Thanks to Tim Rijavec and Zyber. I used a combination of your suggestions to come up with the following solution.
I added GET and POST to methods for the route
#main.route('/bioinformatics', methods=['GET', 'POST'])
def bioinformatics():
form = SequenceForm()
return render_template('bioinformatics.html', form=form)
and then I wrapped the wtf.quick_form call inside tags.
<form action="{{ url_for('main.bioinformatics') }}" method="POST">
{{ wtf.quick_form(form) }}
</form>
Now everything works beautifully. Thanks!

How does the {{ form }} tag work in Django-registration app

I downloaded and installed django-registration app. I also downloaded a template that has this strange piece of code
{{ form }}
that magically creates 4 labels and 4 textboxes for the user to enter his registration information. How does it work?
{% extends "registration/registration_base.html" %}
{% block title %}Register for an account{% endblock %}
{% block content %}
<table>
<form method='post' action=''>{% csrf_token %}
{{ form }}
<tr><td></td><td><input type="submit" value="Send activation email" /></td>
</form>
</table>
{% endblock %}

It is part of django forms. See the documentation for more info.
https://docs.djangoproject.com/en/1.3/topics/forms/
If you are really interested check out the source code.
https://code.djangoproject.com/browser/django/trunk/django/forms

A django form (but other objects, too) has a unicode method, which is invoked, when a string representation of the object is requested. As you can see in the code, it just passes the call on to as_table - which in turn uses a generic helper function: _html_output. This basically loops over all the fields and constructs the HTML which then is returned and displayed on the page.