Try creating a CRUD function
-Creating a simple app with flask -Try to create a Home screen -Try to create an authentication function -Try to handle the database --Try to create CRUD function ← ★ Currently here
What is CRUD
CRUD is an acronym for Create, Read, Update, and Delete. In the blog application created this time, it is as follows.
--Create: New blog creation function (new data creation) --Read: Blog list display function and detailed display function (reading data) --Update: Blog update function (data update) --Delete: Blog deletion function (data deletion)
You can create a set of functions by satisfying CRUD. This function can also be applied when creating other applications.
Create
Blog posting screen creation
--Addition of navigation bar
<div class="collapse navbar-collapse" id="navbarNav">
<ul class="nav navbar-nav navbar-lighy">
{% if not session.logged_in %}
<li class="nav-item">
<a class="nav-link" href="{{ url_for('login') }}">LogIn</a>
</li>
{% else %}
<li class="nav-item">
<a class="nav-link" href="{{url_for('new_add')}}"> New registration </a>
</li>
<li class="nav-item">
<a class="nav-link" href="{{ url_for('logout') }}">Logout</a>
</li>
{% endif %}
</ul>
</div>
--Posting form
{% extends "./layout.html" %}
{% block body %}
<form action="{{ url_for('add_entry') }}" method=post class=add-entry>
<div class=form-group>
<label for = "InputTitle"> Title </label>
<input type="text" class="form-control" id="InputTitle" name=title>
</div>
<div class="form-group">
<label for = "InputText"> Body </label>
<textarea name=text id="InputText" rows="10" class="form-control"></textarea>
</div>
<button type = "submit" class = "btn btn-primary"> Create </button>
</form>
{% endblock %}
~~~
#### Creating a blog posting function
~~~:src/views.py
from src import app, db
from flask import flash
from flask import redirect
from flask import request
from flask import render_template
from flask import url_for
from flask import session
from src.domains.entry import Entry
User = {
'username': 'test',
'password': 'testpass'
}
@app.route('/')
def index():
if not session.get('logged_in'):
return redirect('/login')
return render_template('index.html')
@app.route('/login', methods=['GET', 'POST'])
def login():
if request.method == 'POST':
if request.form['username'] != User['username']:
flash (f'username is different')
elif request.form['password'] != User['password']:
flash (f'password is different')
else:
session['logged_in'] = True
flash ('logged in')
return redirect('/')
return render_template('login.html')
@app.route('/logout', methods=['GET'])
def logout():
session.pop('logged_in', None)
flash ('logged out')
return redirect('/')
@app.route('/new_add', methods=['GET','POST'])
def new_add():
return render_template('/new.html')
@app.route('/add_entry', methods=['POST'])
def add_entry():
if not session.get('logged_in'):
return redirect(url_for('login'))
entry = Entry(
title = request.form['title'],
text = request.form['text'])
db.session.add(entry)
db.session.commit()
flash ('new article created')
return redirect(url_for('index'))
~~~
Read
#### List function
~~~:src/templates/index.html
{% extends "./layout.html" %}
{% block body %}
{% for entry in entries %}
<ul class="card">
<div class="card-body">
<h5 class="card-title">
<a href="{{ url_for('show_entry', id=entry.id) }}">{{ entry.title }}</a>
</h5>
</div>
</ul>
{% else %}
No posts
{% endfor %}
{% endblock %}
~~~
~~~:src/views.py
@app.route('/')
def index():
if not session.get('logged_in'):
return redirect('/login')
entries = Entry.query.order_by(Entry.id.desc()).all()
return render_template('index.html', entries=entries)
~~~
#### Detailed function
~~~:src/views.py
@app.route('/entry/<int:id>', methods=['GET'])
def show_entry(id):
if not session.get('logged_in'):
return redirect(url_for('login'))
entry = Entry.query.get(id)
return render_template('show.html', entry=entry)
~~~
~~~:src/templates/show.html
{% extends "./layout.html" %}
{% block body %}
<h2>{{ entry.title }}</h2>
<br />
{{ entry.text }}
<br /><br />
Post date: {{entry.create_at}}
{% endblock %}
~~~
Update
--Create edit button
~~~:src/templates/show.html
{% extends "./layout.html" %}
{% block body %}
<h2>{{ entry.title }}</h2>
<br />
{{ entry.text }}
<br /><br />
Post date: {{entry.create_at}}
<br /><br />
<div class="btn-group">
<form action="{{ url_for('edit_entry', id=entry.id) }}" method="GET">
<button type="submit" class="btn btn-secondary">Edit</button>
</form>
</div>
{% endblock %}
~~~
--Creating an edit screen
~~~:src/templates/edit.html
{% extends "./layout.html" %}
{% block body %}
<form action="{{ url_for('update_entry', id=entry.id) }}" method="POST" class="add-entry">
<div class="form-group">
<label> Title </label>
<input type="text" class="form-control" name="title" value={{ entry.title}}>
</div>
<div class="form-group">
<label> Body </label>
<textarea class="form-control" name="text" cols="100" rows="3">{{ entry.text | safe }}</textarea>
</div>
<button type="submit" class="btn btn-primary">Update</button>
</form>
{% endblock %}
~~~
--Creating an update function
~~~:src.views.py
@app.route('/entry/<int:id>/edit', methods=['GET'])
def edit_entry(id):
if not session.get('logged_in'):
return redirect(url_for('login'))
entry = Entry.query.get(id)
return render_template('edit.html', entry=entry)
@app.route('/entry/<int:id>/update', methods=['POST'])
def update_entry(id):
if not session.get('logged_in'):
return redirect(url_for('login'))
entry = Entry.query.get(id)
entry.title = request.form['title']
entry.text = request.form['text']
db.session.merge(entry)
db.session.commit()
flash ('article updated')
return redirect(url_for('index'))
~~~
--Detail screen
- Editing screen
Delete
--Create a delete button
~~~:src/templates/show.html
{% extends "./layout.html" %}
{% block body %}
<h2>{{ entry.title }}</h2>
<br />
{{ entry.text }}
<br /><br />
Post date: {{entry.create_at}}
<br /><br />
<div class="btn-group">
<form action="{{ url_for('edit_entry', id=entry.id) }}" method="GET">
<button type="submit" class="btn btn-secondary">Edit</button>
</form>
<form action="{{ url_for('delete_entry', id=entry.id) }}" method="POST">
<button type="submit" class="btn btn-danger" style="margin-left:5px">Delete</button>
</form>
</div>
{% endblock %}
~~~
--Creating a delete function
~~~:src/views.py
@app.route('/entry/<int:id>/delete', methods=['POST'])
def delete_entry(id):
if not session.get('logged_in'):
return redirect(url_for('login'))
entry = Entry.query.get(id)
db.session.delete(entry)
db.session.commit()
flash ('post deleted')
return redirect(url_for('index'))
~~~
--Detail screen
--Screen after deletion
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