Django forms allow the creation of HTML forms and validation of submitted data. The document discusses:
1. The Django forms API automatically renders HTML forms, validates data, and converts it to relevant data types.
2. Forms are defined in forms.py using fields like CharField and IntegerField, which have default widgets and validation logic.
3. Forms can be rendered unbound without data or bound with specific data. Validation is triggered by calling is_valid() on a bound form.
4. ModelForms map models to forms and include model field validation. They support creating and editing model instances.
This is the slides I used when I shared my humble insight on Django to the students in University of Taipei in 2016. Please feel free to correct me if there is anything wrong.
If you are using jQuery, you need to understand the Document Object Model and how it accounts for all the elements inside any HTML document or Web page.
This is the slides I used when I shared my humble insight on Django to the students in University of Taipei in 2016. Please feel free to correct me if there is anything wrong.
If you are using jQuery, you need to understand the Document Object Model and how it accounts for all the elements inside any HTML document or Web page.
So you're starting a startup an need best practices for your engineering team. Well, look for:
1. Versionning
2. Branching and Pull Requests (GitHub Flow)
3. Deployment & Continuous Delivery
4. Rollback Strategies
5. Testing
6. Backups
7. Monitoring
8. Communication
9. Issue Tracker / Project Management
This deck talks about the tool used by Le Wagon and startup coached by Le Wagon.
Le Wagon is the French innovating coding school for entrepreneurs. More info on https://www.lewagon.com
What is the DOM?
The DOM is a W3C (World Wide Web Consortium) standard.
The DOM defines a standard for accessing documents:
"The W3C Document Object Model (DOM) is a platform and language-neutral interface that allows programs and scripts to dynamically access and update the content, structure, and style of a document."
The W3C DOM standard is separated into 3 different parts:
Core DOM - standard model for all document types
XML DOM - standard model for XML documents
HTML DOM - standard model for HTML documents
The HTML DOM (Document Object Model)
When a web page is loaded, the browser creates a Document Object Model of the page.
The HTML DOM model is constructed as a tree of Objects.
With the HTML DOM, JavaScript can access and change all the elements of an HTML document.
PHP stands for “PHP: Hypertext Preprocessor”. It is very good for creating dynamic content. PHP is a widely-used, free, and efficient alternative to competitors such as Microsoft's ASP.
JavaScript - An Introduction is a beginner's guide to JavaScript. It starts with very basic level and goes to intermediate level. You'll be introduced with every language constructs, Event handling, Form handling and AJAX which is supported by JavaScript with XMLHttpRequest object. This XHR object is discussed in enough detail so that you can understand how the underlying AJAX functionality works in jQuery. At the end it discusses advance concepts and library build on/around JavaScript.
HTML5 Tutorial For Beginners - Learning HTML 5 in simple and easy steps with examples covering 2D Canvas, Audio, Video, New Semantic Elements, Geolocation, Persistent Local Storage, Web Storage, Forms Elements,Application Cache,Inline SVG,Document
This presentation introduces application developers to the use of XPages in IBM Lotus
Notes and Domino applications for the Web. It is accompanied by a series of exercises. For more information, see http://www-10.lotus.com/ldd/ddwiki.nsf/dx/Tutorial-intro-to-XPages.htm
So you're starting a startup an need best practices for your engineering team. Well, look for:
1. Versionning
2. Branching and Pull Requests (GitHub Flow)
3. Deployment & Continuous Delivery
4. Rollback Strategies
5. Testing
6. Backups
7. Monitoring
8. Communication
9. Issue Tracker / Project Management
This deck talks about the tool used by Le Wagon and startup coached by Le Wagon.
Le Wagon is the French innovating coding school for entrepreneurs. More info on https://www.lewagon.com
What is the DOM?
The DOM is a W3C (World Wide Web Consortium) standard.
The DOM defines a standard for accessing documents:
"The W3C Document Object Model (DOM) is a platform and language-neutral interface that allows programs and scripts to dynamically access and update the content, structure, and style of a document."
The W3C DOM standard is separated into 3 different parts:
Core DOM - standard model for all document types
XML DOM - standard model for XML documents
HTML DOM - standard model for HTML documents
The HTML DOM (Document Object Model)
When a web page is loaded, the browser creates a Document Object Model of the page.
The HTML DOM model is constructed as a tree of Objects.
With the HTML DOM, JavaScript can access and change all the elements of an HTML document.
PHP stands for “PHP: Hypertext Preprocessor”. It is very good for creating dynamic content. PHP is a widely-used, free, and efficient alternative to competitors such as Microsoft's ASP.
JavaScript - An Introduction is a beginner's guide to JavaScript. It starts with very basic level and goes to intermediate level. You'll be introduced with every language constructs, Event handling, Form handling and AJAX which is supported by JavaScript with XMLHttpRequest object. This XHR object is discussed in enough detail so that you can understand how the underlying AJAX functionality works in jQuery. At the end it discusses advance concepts and library build on/around JavaScript.
HTML5 Tutorial For Beginners - Learning HTML 5 in simple and easy steps with examples covering 2D Canvas, Audio, Video, New Semantic Elements, Geolocation, Persistent Local Storage, Web Storage, Forms Elements,Application Cache,Inline SVG,Document
This presentation introduces application developers to the use of XPages in IBM Lotus
Notes and Domino applications for the Web. It is accompanied by a series of exercises. For more information, see http://www-10.lotus.com/ldd/ddwiki.nsf/dx/Tutorial-intro-to-XPages.htm
This presentation is an overview of the "base_import" module in OpenERP. With test driven development and data migration, we need to gather and enter real data owned by users.
Form validation normally used to occur at the server, after the client had entered all the necessary data and then pressed the Submit button. If the data entered by a client was incorrect or was simply missing, the server would have to send all the data back to the client and request that the form be resubmitted with correct information. This was really a lengthy process which used to put a lot of burden on the server.
JavaScript provides a way to validate form's data on the client's computer before sending it to the web server. Form validation generally performs two functions.
Basic Validation − First of all, the form must be checked to make sure all the mandatory fields are filled in. It would require just a loop through each field in the form and check for data.
Data Format Validation − Secondly, the data that is entered must be checked for correct form and value. Your code must include appropriate logic to test correctness of data.
This slideshow details how to create a means of searching a Django model without going outside of Django itself. No need for a full-text search engine, just use the power of Django.
If you don't have knowledge of HTML, CSS & JavaScript than you may face some difficulties in validating a HTML form yet I will make the entire step very easy to understand by you.
2. Objectives
Explore Django forms API
Review the Django forms documentation
Create forms using the Django Forms API
3. Out of the Box
Form handling django library
Automatically displays HTML form elements
Validates submitted data
Displays validation errors
Automatically converts submitted data into relevant data
types.
5. forms.py
Forms are composed of fields
from django import forms
class ContactForm(forms.Form):
name = forms.CharField()
email = forms.EmailField()
age = forms.IntegerField()
6. forms.py - fields
Each field has custom validation logic and other useful hooks.
name = forms.CharField(
label =“Full Name”,
max_length = “50”,
)
email = forms.EmailField(
max_length = “100”,
required = “false”
)
age = forms.IntegerField(
min_value = 18,
)
7. forms.py - widgets
Each field has a default widget which serves to render html.
name = forms.CharField(
label =“Full Name”,
max_length = “50”,
widget = forms.TextInput(
attrs = { „size‟ : ‟50‟, „class‟ = „customClass‟ }
)
)
email = forms.EmailField(
max_length = “100”,
required = “false”,
widget = forms.HiddenInput()
)
age = forms.IntegerField(
min_value = 18,
widget = forms.TextInput()
error_messages={‟invalid': ‟Only numbers please.'}
)
8. Instantiation : Bound vs Unbound
Unbound forms don‟t have data associated with them, but then
can be rendered.
form = ContactForm()
Bound forms have specific data associated, which can be
validated.
form = ContactForm(data = dataDict)
9. Initial Data
Data displayed only in unbound forms, and are not used as
fallback values if a particular value isn‟t provided.
Initial != Default
Can be set two different ways :
1. Set it in the field declaration of your form.
age = forms.IntegerField(initial=18)
2. Set it when you instantiate your form.
form = ContactForm(initial = initialDict)
11. Form Validation Overview
Only bound forms may be validated
Validation is triggered when form.is_valid() is called
Validated, cleaned data is stored in form.cleaned_data
Perform the full validation cycle by calling form.full_clean()
12. Field Validating
Three phases for fields: To Python, Validation, and Cleaning
If validation raises an Error, cleaning is skipped
Validators are callables that can raise a ValidationError
Django inlcludes generic ones for common tasks.
URLS, Min/Max Value, Email, etc.
13. Validators - defining
A callable that takes a value and raises a ValidationError; can
be useful for reusing validation logic.
App/validators.py
from django.core.exceptions import ValidationError
Import re
def validate_full_name(value):
if len(re.findall(r'w+', value)) < 2:
raise ValidationError(u‟%s is not a full name.‟ % value)
14. Validators - using
from django import forms
from projectgroup.project.application.validators import validate_full_name
class ContactForm(forms.Form):
name = forms.CharField(
label =“Full Name”,
max_length = “50”,
validators = [validate_full_name]
)
email = forms.EmailField(
max_length = “100”,
required = “false”
)
age = forms.IntegerField(
min_value = 18,
)
15. Field Cleaning
.clean_fieldname() is called after validators
Input has already been converted to Python objects
Methods can still raise ValidationError
Methods must return the cleaned_value
16. Specific Field Cleaning Example
from django import forms
from projectgroup.project.application.validators import validate_full_name
class ContactForm(forms.Form):
# Everything as before
…
def clean_email(self):
data = self.cleaned_data.get(„email‟, „‟)
if „gmail.com‟ not in data:
raise forms.ValidationError(“Why you no like gmail?”)
# always return the cleaned data, whether you have change
# it or not
return data
17. Form Validation
.clean() perform cross-field validation
Called even if errors were raised by Fields
Must return the cleaned data dictionary
ValidationError‟s raised by .clean() will be grouped in
form.non_field_errors() by default
18. Cross-field Cleaning Example
from django import forms
from projectgroup.project.application.validators import validate_full_name
class ContactForm(forms.Form):
# Everything as before
…
def clean (self):
cleaned_data = super(ContactForm, self).clean()
age = cleaned_data.get(“age”)
email = cleaned_data.get(“email”)
if not age and not email:
raise forms.ValidationError(“Age and email are required.”)
return cleaned_data
22. Dynamically Created
<form id=“contact” action=“” method=“get”>
{{ form.as_p }}
<input type=“submit” name=“save”/>
</form>
<form id=“contact” action=“” method=“get”>
{{ field.non_form_errors }}
{% for field in form %}
<div class=“fieldWrapper”>
{{ field.errors }}
{{ field.label_tag }}: {{ field }}
</div>
{% endfor %}
<input type=“submit” name=“save”/>
</form>
23. Model Forms
modelForms map a model to a form
validation includes model validators
Supports creating and editing instances
Key differences from forms
There will be a field for a primary key (id)
New save() method
New instance attribute
24. Model Form Example
app/models.py
from django import models
class Contact(models.Model):
name = models.CharField(max_length=50)
email = models.EmailField()
age = models.IntegerField()
app/forms.py
from django import forms
from grp.prj.app.models import Contact
class ContactForm(forms.Modelform):
class Meta:
model = Contact
25. Limiting Fields
Specify fields to expose, or fields to exclude
app/forms.py
from django import forms
from grp.prj.app.models import Contact
class ContactForm(forms.ModelForm):
class Meta:
model = Contact
fields = ('name', 'email',)
class ContactForm(forms.ModelForm):
class Meta:
model = Contact
exclude = (‟age',)
26. Instantiating Model Forms
Like before, we may have bound and unbound Model Forms
Unbound
mform = ContactForm()
Bound
mform = ContactForm(instance=Contact.objects.get(id=2) )
27. Handling forms in views.py
1. Import your form(s)
2. Within your view function
1. Check for submission(GET or POST).
1. If submitted
1. bind the form to the data.
2. Validate.
1. If its valid, do stuff.
2. Otherwise let it remain unbound.
3. Pass form to the context
4. Render your page.
28. views.py example
from grp.prj.app.forms import ContactForm
…
def contactView(request):
context = {}
contactPDA = Dpdpcntc()
…
initials = {
‘age' : ’18'
}
#instantiate
if request.GET.get(„submit‟):
form = ContactForm(data = request.GET)
if form.is_valid():
….
else:
form = ContactForm(initial=initials)
context[„form‟] = form
return render_to_response(…)
Import Form
Check for submission
Bind Form
Form Validation
Unbound Form
Render HTML
Form in Context
29. views.py – other examples
if request.GET.get(„submit‟):
form = ContactForm(request.GET)
if form.is_valid():
….
else:
form = ContactForm(initial=initials)
if request.GET:
form = ContactForm(request.GET)
if form.is_valid():
….
else:
form = ContactForm(initial=initials)
form = ContactForm(data=request.GET or None, initial=initials)
if form.is_valid():
….