Flask template
In the previous example, the main function of the view function is to generate a response to the request, which is the simplest request. In fact, the view function has two functions:
- Processing business logic
- Return response content
In large-scale applications, putting business logic and performance content together will increase code complexity and maintenance costs.
- A template is actually a file containing response text, where a placeholder (variable) is used to represent the dynamic part, telling the template engine that its specific value needs to be obtained from the data used
- Replace variables with real values and return the final string. This process is called'rendering'
- Flask uses Jinja2, a template engine to render templates
Benefits of using templates
- View functions are only responsible for business logic and data processing (business logic aspects)
- The template takes the data results of the view function for display (trying to display aspects)
- Clear code structure and low coupling
Basic use of templates
Create a templates folder under the project to store all template files, and create a template file html file hello.html in the directory
Sample code:
from flask import Flask, render_template
app = Flask(__name__)
@app.route('/')
def index():
my_int = 18
my_str = 'curry'
my_list = [1, 5, 4, 3, 2]
my_dict = {
'name': 'durant',
'age': 28
}
# render_template方法:渲染模板
# 参数1: 模板名称 参数n: 传到模板里的数据
return render_template('hello.html',
my_int=my_int,
my_str=my_str,
my_list=my_list,
my_dict=my_dict)
if __name__ == '__main__':
app.run(debug=True)Create a new folder templates under the folder where py is located, and then create a new hello.html in templates
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<h2>我是模板</h2>
{
{ my_int }}
<br>
{
{ my_str }}
<br>
{
{ my_list }}
<br>
{
{ my_dict }}
<hr>
<h2>模板的list数据获取</h2>
<hr>
{
{ my_list[0] }}
<br>
{
{ my_list.1 }}
<hr>
<h2>字典数据获取</h2>
<hr>
{
{ my_dict['name'] }}
<br>
{
{ my_dict.age }}
<hr>
<h2>算术运算</h2>
<br>
{
{ my_list.0 + 10 }}
<br>
{
{ my_list[0] + my_list.1 }}
</body>
</html>Visit htpp://127.0.0.1:5000/ to run the test
use
- { {}} to represent the variable name, this { {}} syntax is called variable code block
<h1>{
{post.title}}</h1>
The variable code block in the Jinja2 template can be any Python type or object, as long as it can be converted into a string by Python's str() method. For example, an element in a dictionary or list can be displayed in the following way
{
{your_dict['key']}}
{
{your_list[0]}}
- The control code block defined by {%%} can realize some language-level functions, such as loop statements
{% if user %}
{
{ user }}
{% else %}
hello!
<ul>
{% for index in indexs %}
<li> {
{ index }} </li>
{% endfor %}
</ul>
Comment
- Use {##} to comment, the content of the comment will not be rendered in html
{#{
{ name }}#}