jinja2语法

妖狐艹你老母 2022-09-06 00:26 158阅读 0赞

本文只是官方文档的部分摘录，只记录了常用语法，和python非常类似，方便快速理解使用  
语法

{% ... %} for Statements
    {
       { ... }} for Expressions to print to the template output
    {# ... #} for Comments not included in the template output
    #  ... ## for Line Statements

获得属性

{
       { foo.bar }}
    {
       { foo['bar'] }}

去掉空白字符

{% for item in seq -%}
        {
       { item }}
    {%- endfor %}

escaping，手动逃逸，自动逃逸会有性能问题

{
       { user.username|e }}

输出大括号，裸语句块

{
 {‘{}’}} 
 {% raw %}
 <ul>
 {% for item in seq %}
 <li>{
 { item }}</li>
 {% endfor %}
 </ul>
 {% endraw %}

Line Statements，需要在在environment中配置line\_statement\_prefix

# for item in seq:
 <li>{
 { item }}</li> ## this comment is ignored
 # endfor

Inheritance

<title>{% block title %}{% endblock title %} - My Webpage</title>
 {% extends “base.html” %}
 {% block title %}Index{% endblock title %}

父模板block提供站位符，子模板block提供数据覆盖  
super()可以获得父模板中的数据  
endblock title可省略title

for

{% for row in rows %}
 <li class="{
 { loop.cycle('odd', 'even') }}">{
 { row }}</li>
 {% endfor %}
 loop.index
 loop.index0
 loop.reindex
 loop.reindex0
 loop.first
 loop.last
 loop.length
 loop.cycle
 loop.depth
 loop.depth0
 loop.previtem
 loop.nextitem

else，iteration为空，执行else

<ul>
 {% for user in users %}
 <li>{
 { user.username|e }}</li>
 {% else %}
 <li>no users found</li>
 {% endfor %}
 </ul>

for if

{% for user in users if not user.hidden %}
 <li>{
 { user.username|e }}</li>
 {% endfor %}

递归 for

<ul class="sitemap">
 {%- for item in sitemap recursive %}
 <li><a href="{
 { item.href|e }}">{
 { item.title }}</a>
 {%- if item.children -%}
 <ul class="submenu">{
 { loop(item.children) }}</ul>
 {%- endif %}</li>
 {%- endfor %}
 </ul>

Loop Controls

{% for user in users %}
        {%- if loop.index is even %}{% continue %}{% endif %}
        ...
    {% endfor %}
    {% for user in users %}
        {%- if loop.index >= 10 %}{% break %}{% endif %}
    {%- endfor %}

if Expression，三元表达式

{% extends layout_template if layout_template is defined else 'master.html' %}

模板中的函数macro

{% macro input(name, value='', type='text', size=20) -%}
 <input type="{
 { type }}" name="{
 { name }}" value="{
 {
 value|e }}" size="{
 { size }}">
 {%- endmacro %}
 {
 { input(‘username’) }}
 {
 { input(‘password’, type=‘password’) }}

块和宏参见(http://www.ttlsa.com/python/flask-jinja2-template-engine-block-and-macro/)

import，导入namespace

{% import 'forms.html' as forms %}
    {% from 'forms.html' import input as input_field, textarea %}

Filter，块级别使用Filter

{% filter upper %}
        This text becomes uppercase
    {% endfilter %}

Assignments，赋值

{% set key, value = call_something() %}

Include 直接导入模板

{% include "sidebar.html" ignore missing %}

Builtin Filters  
List of Builtin Tests  
List of Global Functions  
参见(http://jinja.pocoo.org/docs/2.10/templates/\#list-of-builtin-filters)

With Statement 上下文

{% with %}
        {% set foo = 42 %}
        {
       { foo }}           foo is 42 here
    {% endwith %}
    foo is not visible here any longer