00. Templates
In the Django framework, templates can help developers to quickly generate presented to the tool user page.
Template processing:
a. Load
b. Rendering
Template has two major components
a.HTML static code
b. snippet dynamically inserted (digging, filled pit)
01. Syntax
a. dot syntax template: grades grade
Properties or methods: grade.gname
Index: grades.0.gname
b. template tags: {% tag%} Syntax
Role: b1 incoming load external variables.
b2. Create a text in the output
b3. logic or control loop
cif statement
Expression {%}%
Statement
%} {% Elif
Statement
{% else %}
Statement
{% endif% }
d.for statement
Variable in the list {% for%}
Statement
{% empty %}
Statement
{% endfor %}
e. Comment
Single-line comments
Multi-line comments
. f filter {{var | filter}}
Role: modified before variable display
add {{p.page | add:5}}
No subtraction filters, but where you can add a negative wig
{{p.page | add: -5}}
lower
{{p.pname|lower}}
join: pass parameters
{{students|join '='}}
{{var|defualt value}}
dateVal: Specifies the date string format conversion, the processing time
{{dateVal | data:'y-m-d'}}
g.html Escape: The received data is treated as an ordinary character string as to render the HTML code of a problem
html:{{code|safe}}
{%}% Off autoescape
code
%}% {Endautoesape
{%}% Is autoescape
code
%}% {Endautoesape
05. View Summary
Structure tags
*block
Piece
We used to plan the layout (digging)
For the first time, representatives of planning
The second time, on behalf of filling the previous plan
The third time, on behalf of filling the previous plan, the default action style cover
* If you do not cover, may be added {{block.super}}
* Achieved an incremental operation
super: representatives inherit the parent class or superclass
*extends
inherit
You can get all the structural character templates clock
*block+entends
Dismembered
*include
*contain
* As part of the page may be embedded into other pages
* Include + block (by the poly-zero)
* You can also mix the three labels, try not to use include
* If we inherit from a character template, directly from their own templates page rewrite the formula does not take effect, and can only be filled in the existing pit.
urls
* Routers
- to match the writing order list
- from top to bottom match, there is no optimal matching of concepts
* Write routing rules
- We usually directly added directly at the end of a backslash
- Parameters
Path parameter (position parameter - to match the writing order)
Keyword arguments (in accordance with the parameter name matching, and is unrelated to the order)
The number of parameters must be consistent with the number of parameters view function (other than the default request)
* Parameters using the router () were acquired
- a view function corresponds to a parenthesis in
06. view
Python is a view of the nature of the function
In response to the view into two categories:
Returns the data format JSON
The situation returned to the page: redirect to another page / wrong view (40x, 50x)
View response process: Browser Input -> django Ip port and remove access to information,
The remaining path -> route matches the URL -> response View -> back to the browser
07.URL reverse lookup
url reverse lookup
In the root urls:
path('view/',include('view.learn', namespace='view'))
在子urls中
path('hello/', views.hello, name=‘sayhello’)
使用反向解析优点：如果在视图，模板中使用硬编码连接，在url配置发生改变时，需要变更代码非常多，这样导致我们的代码结构不是很容易维护，使用反向解析可以提高我们代码的扩展性和课维护性。
解决问题： https://docs.djangoproject.com/en/3.0/topics/http/urls/
Reversing namespaced URLs
反向解析：
*根据路由中注册的namespace和在子路由中注册name,这两个参数来动态获取我们的路径
*在模板中使用{% url`namesspace'}
错误页面定制
*在错误中重写对应错误状态码的页面
*关闭Debug
*实现原则(就近原则)
07.HttpRequest
-------------------------------------------
双R
*Request
内置属性(method/path/GET/POST/META)
*Response
备注：
静态资源:
*动静分离
*创建静态文件夹
*在setting中注册STATICFILES_DIRS=[]
*在模板中使用
——先加载静态资源(%load static %)
——使用{% static xxx %} xxx相对路径
*坑点
——仅在debug模式可以使用
——以后需要自己单独处理
备注：pycharm手动修改py文件才会重载，修改html不会重载