This article will be based on the knowledge points and blueprints of the previous chapter , Explain one with flask The simple login and registration business implemented by the framework .

The blueprint

When the business volume is increasing , In different businesses, it is easy to have more than add、insert、update、delete Such a word named route , This makes the routing name difficult to control . So in Flask The concept of blueprint is introduced into the framework , Every business belongs to a blueprint , Under every blueprint, there can be add、insert The route named like this , However, there cannot be the same route name under the same blueprint . The emergence of the blueprint concept greatly simplifies the entire application , Split application components , Make the application components as low as possible , It has the following features ：

• Decompose an application into a collection of blueprints , There can be many routes under a blueprint , Different blueprints can have the same route （ It can be distinguished by blueprints ）
• Use different ones in an application URL The rule registers a blueprint multiple times
• Provide template filters through blueprints 、 Static files 、 Templates and other features
• Initialize a Flask When expanding , In these cases, register a blueprint

Blueprint implementation steps ：

1、 Declare creating a blueprint in the view

#  Declare a route prefix as user, The name is user_bp The blueprint of   The first parameter is zero ：url_prefix
user_bp = Blueprint('user',__name__)

2、 stay app Registration blueprint

#  stay Flask Core objects of app Middle statement template、static Storage address , That is, the path of the blueprint folder 
app = Flask(' Folder path of different blueprints ',__name__,template_folder='../templates',static_folder='../static')
#  Register associated blueprints 
app.register_blueprint(user_bp)
#  Print out app Under the url
print(app.url_map)
#  View the contents of the resource folder 
print(user.root_path)

Example

We all know web The three components of the project framework ：MVC, namely model（ Model ）、view（ View ） as well as controller（ controller ）. stay flask Of app Under the folder , Extract each different business code , Such as user business , Commodity business, etc , Under each business , Pulled out again model Store the data model ,controller Control business logic and jump view . And with the app The folder at the same level stores each jump view View interface .

The overall framework of the project （ here view.py For the control layer ）：

First , We create a settings.py Store configuration information

#  The configuration file 

ENV = 'development'
DEBUG = True

stay app Under bag __init__.py Create a create_app Method , The main function of this method is to extract app.py The creation of flask Examples and some code associated between modules . Instantiation Flask You can specify templates and static The storage path of the folder , Blueprints increase with the increase of view control , Here is the blueprint associated with a user

from flask import Flask

import settings
from app.user.view import user_bp


def create_app():
    # app It's a core object , Create... Here 
    app = Flask(__name__,template_folder='../templates',static_folder='../static')
    #  Load the configuration 
    app.config.from_object(settings)
    #  Blueprint Association 
    app.register_blueprint(user_bp)
    print(app.url_map)

    return app

To write app.py file , This file is a startup file , It is the key to start the whole program

from app import create_app

app = create_app()

if __name__ == '__main__':
    app.run()

Create a model.py, To write User class ,

class User:
    def __init__(self,username,password,phone=None):
        self.username = username
        self.password = password
        self.phone = phone

    def __str__(self):
        return self.username
        

To write view.py, There is a registered one named user The blueprint of , And registration 、 Sign in 、 sign out 、 modify 、 Delete 、 Presentation method

from flask import Flask, Blueprint, request, render_template
from werkzeug.utils import redirect

from app.user.model import User

user_bp = Blueprint('user',__name__)

users = []

@user_bp.route('/')
def user_center():
    return render_template('user/show.html',users=users)

@user_bp.route('/register',methods=['GET','POST'])
def register():
    if request.method == 'POST':
        #  get data 
        username = request.form.get('username')
        password = request.form.get('password')
        repassword = request.form.get('repassword')
        phone = request.form.get('phone')
        if password == repassword:
            #  The only user 
            for user in users:
                if user.username == username:
                    return render_template('user/register.html',msg=' User name already exists ！')
            #  establish user object 
            user = User(username,password,phone)
            #  Add to user list 
            users.append(user)
            return redirect('/')
    return render_template('user/register.html')

@user_bp.route('/login',methods=['GET','POST'])
def login():
    return ' The user login '

@user_bp.route('/logout',methods=['GET','POST'])
def logout():
    return ' User exits '

@user_bp.route('/del')
def del_user():
    #  Get the delivered username
    username = request.args.get('username')
    #  according to username Find... In the list user object 
    for user in users:
        if user.username == username:
            #  Delete user
            users.remove(user)
            return redirect('/')
        else:
            return ' Delete failed ！'

@user_bp.route('/update',methods=['GET','POST'],endpoint='update')
def update_user():
    if request.method == 'POST':
        username = request.form.get('username')
        password = request.form.get('password')
        phone = request.form.get('phone')
        for user in users:
            if user.username == username:
                return render_template('show.html',user=user)
    else:
        username = request.args.get('username')
        for user in users:
            if user.username == username:
                return render_template('user/register.html',user=user)
    return

Jump to the parent view base.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>{% block title %}  User center  {% endblock %}</title>
    <style> </style>
    {% block mycss %}
    {% endblock %}
</head>
<body>
<div id="header">
  <ul>
    <li><a href=""> home page </a></li>
    <li><a href=""> seckill </a></li>
    <li><a href=""> The supermarket </a></li>
    <li><a href=""> The book </a></li>
    <li><a href=""> members </a></li>
  </ul>
</div>
<div id="middle">
  {% block middle %}

  {% endblock %}

</div>
<div id="footer"></div>

{% block myjs %}
{% endblock %}
</body>
</html>

Jump to view register.html

{% extends 'base.html' %}
{% block title %}
     User registration 
{% endblock %}

{% block middle %}
    <p style="color: red">{
   { msg }}</p>
    <form action="{
     {url_for('user.register')}}" method="post">
        <p><input type="text" name="username" placeholder=" user name "></p>
        <p><input type="password" name="password" placeholder=" password "></p>
        <p><input type="password" name="repassword" placeholder=" Confirm the password "></p>
        <p><input type="number" name="phone" placeholder=" Phone number "></p>
        <p><input type="submit" value=" User registration "></p>
    </form>
{% endblock %}

Jump to view login.html Untreated

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

</body>
</html>

Jump to view show.html

{% extends 'base.html' %}
{% block middle %}
    <h1> User information </h1>
        <span> The current number of users is ：{
   { users | length }}  people </span>
        <table border="1" cellspacing="0" width="60%">
            {% for user in users %}
                <tr>
                    <td>{
   { loop.index }}</td>
                    <td>{
   { user.username }}</td>
                    <td>{
   { user.password }}</td>
                    <td>{
   { user.phone }}</td>
                    <td><a href="javascript:;" onclick="update('{
        { user.username }}')"> modify </a><a href="javascript:;" onclick="del('{
        { user.username }}')"> Delete </a> </td>
                </tr>
            {% endfor %}
        </table>
{% endblock %}

{% block myjs  %}
    <script> //  Delete user  function del(username){
       // console.log(username) location.href = '/del?username'+username' } //  Modify user information  function update(username){
       alert(username) console.log(username) location.href = '/update?username'+username' } </script>
{% endblock %}

Jump to view update.html

{% extends 'base.html' %}
{% block title %}
   User information modification 
{% endblock %}

{% block middle %}
  <h1> User information update </h1>
  <form action="{
     { url_for('user.update') }}" method="post">
    <p><input type="hidden" name="realname" value="{
     { user.username }}"></p>
    <p><input type="text" name="username" placeholder=" user name " value="{
     { user.username }}"></p>
    <p><input type="text" name="password" placeholder=" password " value="{
     { user.password }}" disabled></p>
    <p><input type="text" name="pone" placeholder=" Phone number " value="{
     { user.phone }}"></p>
    <p><input type="submit" value=""></p>
  </form>
{% endblock %}

{% block  %}
{% endblock %}

result ：