flask结合jinja2使用详解

2023-03-14 12:03:14 flask jinja2 详解

jinja2简介

特征

  • 沙箱中执行
  • 强大的 html 自动转义系统保护系统免受 XSS
  • 模板继承
  • 及时编译最优的 python 代码
  • 可选提前编译模板的时间
  • 易于调试。异常的行数直接指向模板中的对应行。
  • 可配置的语法

Jinja 分隔符

Jinja 在模板字符串中使用各种分隔符。

  • {% %}-陈述
  • {{ }}-要打印到模板输出的表达式
  • {# #}-模板输出中未包含的注释
  • # ##-行语句

模板渲染

app.py

from flask import Flask,render_template,request
app = Flask(__name__)
 
@app.route('/')
def hello_world():
    return render_template('index.html')
 
@app.route('/blog/<int:blog_id>')
def blog(blog_id):
    page = request.args.get('page', default=1, type=int)
    return render_template('blog.html',id=blog_id,page=page)
 
if __name__ == '__main__':
    app.run()

index.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>coleak's page</title>
</head>
<body>
<h1>START</h1>
<h2>coleak2</h2>
<h3>coleak3</h3>
<h4>coleak4</h4>
<h5>coleak5</h5>
<h1>END</h1>
</body>
</html>

blog.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<h1>这里是第{{ id }}位博客主的第{{ page }}页博客</h1>
</body>
</html>

效果测试 

Http://10.133.5.113:8000
http://10.133.5.113:8000/blog/3
http://10.133.5.113:8000/blog/3?page=6

模板访问变量属性

app.py

from flask import Flask,render_template,request
app = Flask(__name__)
 
class user:
    def __init__(self,username,email):
        self.username=username
        self.email=email
 
@app.route('/')
def hello_world():
    User=user('coleak','123@163.com')
    person={
        "username":"coleak",
        "email":"123@666.com"
    }
    return render_template('index.html',user=User,person=person)
 
@app.route('/blog/<int:blog_id>')
def blog(blog_id):
    page = request.args.get('page', default=1, type=int)
    return render_template('blog.html',id=blog_id,page=page)
 
if __name__ == '__main__':
    app.run()

index.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>coleak's page</title>
</head>
<body>
<h1>START</h1>
<div><h1>welcome {{ user.username }}</h1></div>
<div><h1>你的别名是{{ person.username }},邮箱是{{ person["email"] }}</h1></div>
<h2>coleak2</h2>
<h3>coleak3</h3>
<h4>coleak4</h4>
<h5>coleak5</h5>
<h1>END</h1>
</body>
</html>

效果测试

内置过滤器的使用

可以将过滤器应用于数据以对其进行修改。 例如，sum 筛选器可以对数据求和，escape 筛选器对它们进行转义，sort 筛选器对它们进行排序。

app.py

from flask import Flask,render_template,request
app = Flask(__name__)
 
class user:
    def __init__(self,username,email):
        self.username=username
        self.email=email
 
@app.route('/')
def hello_world():
    User=user('coleak','123@163.com')
    person={
        "username":"coleak",
        "email":"123@666.com"
    }
    return render_template('index.html',user=User,person=person)
 
@app.route('/filter')
def filter():
    User1=user('coleak',-123.456)
    return render_template("filter.html",user=User1)
 
if __name__ == '__main__':
    app.run()

filter.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>过滤器</title>
</head>
<body>
<div>{{ user.username }}长度为{{ user.username|length }}</div>
<div>{{ user.email }}绝对值为{{ user.email|abs }}</div>
</body>
</html>

效果测试

自定义过滤器

app.py

from flask import Flask,render_template,request
from datetime import datetime
app = Flask(__name__)
 
def my_filter(value,fORMat="%Y年-%m月-%d日 %H时:%M分"):
    return value.strftime(format)
 
class user:
    def __init__(self,username,email):
        self.username=username
        self.email=email
app.add_template_filter(my_filter,"time_filter")
 
@app.route('/')
def hello_world():
    User=user('coleak','123@163.com')
    person={
        "username":"coleak",
        "email":"123@666.com"
    }
    return render_template('index.html',user=User,person=person)
 
@app.route('/filter')
def filter():
    mytime=datetime.now()
    User1=user('coleak',-123.456)
    return render_template("filter.html",user=User1,mytime=mytime)
 
if __name__ == '__main__':
    app.run()

filter.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>过滤器</title>
</head>
<body>
<div>{{ mytime }}过滤后为{{ mytime|time_filter }}</div>
</body>
</html>

效果测试

控制语句

app.py

from flask import Flask,render_template,request
from datetime import datetime
app = Flask(__name__)
 
class user:
    def __init__(self,username,email):
        self.username=username
        self.email=email
 
@app.route('/')
def hello_world():
    User=user('coleak','123@163.com')
    person={
        "username":"coleak",
        "email":"123@666.com"
    }
    return render_template('index.html',user=User,person=person)
 
@app.route('/control')
def control():
    age=request.args.get('age')
    age=int (age)
    books=[{"name":"boo1",'price':12},{"name":"boo2",'price':18},{"name":"book3",'price':21}]
    return render_template('control.html',age=age,books=books)
 
if __name__ == '__main__':
    app.run()

control.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>控制语句</title>
</head>
<body>
<div>
    {% if age>18 %}
        <h2>可以进入网吧</h2>
    {% elif age==18 %}
        <h2>家长陪同下进入网吧</h2>
    {% else %}
        <h2>不可以进入网吧</h2>
    {% endif %}
</div>
<div>
    {% for book in books %}
        <p>名称：{{ book.name }}</p>
        <p>价格：{{ book.price }}</p>
    {% endfor %}
</div>
</body>
</html>

 效果测试

模板继承

模板继承是一项强大的功能，可减少代码重复并改善代码组织。 我们定义了一个基本模板，其他模板文件也从中继承。 这些模板文件将覆盖基本模板文件的特定块。

app.py

from flask import Flask,render_template,request
from datetime import datetime
app = Flask(__name__)
 
class user:
    def __init__(self,username,email):
        self.username=username
        self.email=email
 
@app.route('/')
def hello_world():
    User=user('coleak','123@163.com')
    person={
        "username":"coleak",
        "email":"123@666.com"
    }
    return render_template('index.html',user=User,person=person)
 
@app.route('/base')
def base():
    return render_template("base.html")
@app.route('/ch1')
def ch1():
    return render_template("ch1.html")
@app.route('/ch2')
def ch2():
    return render_template("ch2.html")
 
 
if __name__ == '__main__':
    app.run()

base.html

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>{% block title %}{% endblock %}</title>
</head>
<body>
{% block body %}
{% endblock %}
</body>
</html>

ch1.html

{% extends "base.html" %}
{% block title %}
    ch1的标题
{% endblock %}
{% block body %}
    <div>ch1的body</div>
{% endblock %}

ch1.html

{% extends "base.html" %}
{% block title %}
    ch2的标题
{% endblock %}
{% block body %}
    <div>ch2的body</div>
{% endblock %}

加载静态文件

结构框架 

add.py

from flask import Flask,render_template,request
from datetime import datetime
app = Flask(__name__)
 
class user:
    def __init__(self,username,email):
        self.username=username
        self.email=email
 
@app.route('/')
def hello_world():
    User=user('coleak','123@163.com')
    person={
        "username":"coleak",
        "email":"123@666.com"
    }
    return render_template('index.html',user=User,person=person)
 
@app.route('/static')
def static_use():
    return render_template("static.html")
 
if __name__ == '__main__':
    app.run()

static.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>static</title>
    <link rel="stylesheet" href="{{ url_for('static',filename=" rel="external nofollow" CSS/style.css") }}">
    <script src="{{ url_for('static',filename="js/myjs.js") }}"></script>
</head>
<body>
<img src="{{ url_for('static',filename="images/flask.jpg") }}"></img>
</body>
</html>

myjs.js

alert('coleak');

style.css

body{
    background-color: pink;
}

flask.jpg

效果测试

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