Use the Form class to publish new posts

Reference: Django builds personal blogs: Use the Form class to publish new posts

Forms the form class

Working with forms can be complicated. Django’s forms functionality simplifies most tasks, and is much safer than most programmers writing their own code.

The central component of Djangos forms system is the Form class.

In the same way that fields of a model class map to database fields, fields of a form class map to elements of an HTML form. ModelForm maps the fields of the model class through the Form to the element of the HTML Form on which Django Admin is based.

Building a form

Create the forms.py file in article/ and write:

article/forms.py

# Introduce form classes
from django import forms
# Introduce the article model
from .models import ArticlePost

# form class for writing articles
class ArticlePostForm(forms.ModelForm) :
    class Meta:
        Specify the source of the data model
        model = ArticlePost
        Define the fields that the form contains
        fields = ('title'.'body')
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In the codeArticlePostFormClass inherits from Djangos form classesforms.ModelFormAnd defines inner classes in the classclass MetaIndicate where the data model comes from and which fields of the data model should be included in the form.

inArticlePostIn the model.createdandupdatedThe field is automatically generated and does not need to be filled in;authorField temporarily fixed toid=1Administrator user, also do not need to fill; The rest of thetitleandbodyThat’s what the form needs to fill in.

Next, rewrite article/views.py and add a view function to handle article requests:

article/views.py

...

# introduce the Redirect redirect module
from django.shortcuts import render, redirect
# introduction HttpResponse
from django.http import HttpResponse
# Import the ArticlePostForm form class you just defined
from .forms import ArticlePostForm
# Introduce the User model
from django.contrib.auth.models import User

...

# View for writing articles
def article_create(request) :
    Determine whether the user submits data
    if request.method == "POST" :       
        Assign the submitted data to the form instance
        article_post_form = ArticlePostForm (request.POST) 
        
        Determine whether the submitted data meets the requirements of the model
        if article_post_form.is_valid():
            
            Save the data, but do not commit to the database for the time being
            new_article = article_post_form.save(commit=False)

            Select * from user where id = 1 as author
            new_article.author = User.objects.get(pk=1)

            Save the new article to the database
            new_article.save()

            Return to the list of articles
            return redirect("article:article_list")
        
        If the data is invalid, return an error message
        else:
            return HttpResponse("The content of the form is wrong, please fill it out again.")
    
    If the user requests the data
    else:
        Create a form class instance
        article_post_form = ArticlePostForm()

        # Assign context
        context = {'article_post_form' : article_post_form }

        # return template
        return render(request,'article/create.html',context)
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When a view function receives a request from a client, it first determines whether the user wants to POST or GET data based on request.method:

If the user isSubmit dataAssigns the form data posted to the server toarticle_post_formInstance.

Then use Django’s built-in methods.is_valid()Determine whether the submitted data meets the requirements of the model.

ifMeet the requirementsSave the data in the form (butcommit=FalseDo not commit to the database for now becauseauthorNot yet specified) and specifyThe author of id = 1Is the administrator user of. It then commits to the database and passesredirectReturns a list of articles.redirectYou can use the name of the URL to reverse lookup to the corresponding URL.

If the requirements are not met, the user is returned with the string “The form content is wrong, please fill it out again” to tell the user what the problem is.

If the user is retrieving data, an empty form-like object is returned for the user to fill in.

Once you’ve written the view, you need to write the template file. Create create.html in templates/article/ :

templates/article/create.html

<! --extends indicates that the page extends from the base.html file -->
{% extends 'base.html' %}

<! -- Write the title defined in base -->{% endblock title %}<! -- Write the content file defined in base -->
{% block content %}

<! Write an article form -->
<div class="container">
    <div class="row">
        <div class="col-12">
            <br />
            <! -- Form for submitting articles -->
            <form method="post" action=".">
                <! -- Django POST must have cSRF_token -->
                {% csrf_token %}

                <! -- Article title -->
                <div class="form-group">
                    <! - label - >
                    <label for="title">The article title</label>
                    <! -- Textbox -->
                    <input
                        type="text"
                        class="form-control"
                        id="title"
                        name="title"
                    />
                </div>
                <! -- Text -->
                <div class="form-group">
                    <label for="body">The article body</label>
                    <! -- Text area -->
                    <textarea
                        type="text"
                        class="form-control"
                        id="body"
                        name="body"
                        rows="12"
                    ></textarea>
                </div>
                <! -- Submit button -->

                <button type="submit" class="btn btn-primary">complete</button>
            </form>
        </div>
    </div>
</div>

{% endblock content %}
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<form>.. </form>The content of the tag is the form that needs to be submitted.method="post"Specifies form submission as POST (with view functions)request.methodBe connected withaction="."Specifies that the address for the form submission is the default current URL.

about{% csrf_token %}, which is a network security-related middleware validation in Django. We won’t go into the implementation for now, just know that it must be included in the form or you’ll get a 403 error.

<input>and<textarea>In the tagname=''Property specifies the name of the data submitted by the current textbox, whichMust correspond to the field name in the form classOtherwise, the server will not be able to properly match the fields to the data.

Or:

{% csrf_token %} 
{% for f in form %}
<div class="col-12 my-2">{{f.label_tag}}</div>
<div class="col-12 my-2">{{f}}</div>
{% endfor %}
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Finally, add an article/urls.py URL:

article/urls.py

urlpatterns = [
    ...
    
    # to write the article
    path('article-create/', views.article_create, name='article_create'),]Copy the code

Optimize entry for writing articles

As before, we need a post entry in the navigation bar to optimize the experience. Add the following code to templates/header.html:

<li class="nav-item">
    <a class="nav-link" href="{% url 'article:article_create' %}">Write an article</a>
</li>
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Save the changes, and run the server entry in the address bar: http://127.0.0.1:8000/article/article-create/, see the following industry:

Use the Form class to publish new posts

Forms the form class

Building a form

Optimize entry for writing articles

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