关于django

为什么选用django

python代表最优的设计模式，最简单的句法。而django是公认的流行框架。

安装

python安装

python命令和python3命令检查版本。

使用虚拟环境：

pip install virtualenv && pip install virtualenv --upgrade&& mkdir proj && cd proj && virtualenv . && source bin/activate

pip freeze && pip install django==1.10 && pip uninstall django  -y && pip install django && pip install django --upgrade

创建项目

django-admin.py startproject trydjango && cd trydjango && python manage.py makemigrations && python manage.py migrate && python manage.py runserver 8888

项目准备

python manage.py createsuperuser --user username --noinput or --email xxxxxx something like this.

经典blog

pyhton manage.py startapp posts

+ INSTALLED_APPS添加name
+ models.py添加class Post(models.Model): CharField(max_length=200), TextField(), DatetimeField(auto_now=True, auto_now_add=False)<em>update, true is for add</em>, __unicode__ is for python2, __str__ for python3
+ python manage.py makemigrations && python manage.py migrate
+ admin.py添加admin.site.register(Post)

修改admin

admin.py添加

class PostModelAdmin(admin.ModdelAdmin):
    list_display = ["title","updated","timestamp"]
    list_display_links = [updated]
    list_filter = ["updated","timestamp"]
    search_fields = ["title", "content"]
    list_editable = ["title"]
    class Meta:
        model = Post

view

regular expressions FunctionBasedViews vs ClassBasedViews

def posts_home(request):
    return HttpResponse(`"<h1>hello</h1>"`)

urlpatterns = [
    url(r'^posts/$', posts.views.posts_home),# include("posts.urls")
]

template

BASE_DIR: where manage.py inside,
TEMPLATE: DIRS setting the directory,
render(request, "index.html", {}),
error to see how it load templates

if request.user.is_authenticated():
```
  context = {}
```
else:
```
  context = {}
```

Queryset

首先用python shell python manage.py shell

from posts.models import Post
Post.objects.all()
Post.objects.filter(title="adb")
Post.objects.filter(title__icontains="abc")
Post.object.create(title="abc",content='abc')
queryset=Post.objects.all()
for obj in queryset
    print obj.title
    print obj.id
    print obj.id
context = {"object_list":queryset}
{{object_list}}
{% for obj in obj_list %}
{{ obj.title }}
{% endfor %}

getItem

ref

instance = get_object_or_404(Post, id=1)
url(r'^detail/(?P<id>\d+)/$', post_detail),
def post_detail(request, id=None)

P参数，<id>或者<pk>为关键字参数，request后面的参数名可以是其他 urls 后面的name = "detail", 在htmlpage <a href='{% url "detail" id=obj.id %}'></a>避免url硬编码。把url编码写入model

def get_abs_url(self):
return "/posts/%s/" %(self.id)
or return django.core.urlresolvers.reverse("detail", kwargs={"id": self.id})

在htmlpage <a href='{% obj.get_abs_url %}'></a>

Model Form && create view

#############forms.py part    #############

from django import forms from .models import Post

class PostForm(forms.ModelForm): class Meta: model= Post fields = ["title",]

from .forms import PostForm

#############view part###############
def post_create(request):
    form = PostForm(request.POST or None)
    if form.is_valid():
        instance = form.save(commit=False)
    print form.cleaned_data.get("content")
        instance.save()
    return HttpResponseRedirect(instance.get_abs_url())
    #form = PostForm
    context = {"form": form,}
    #print request.method +' ' + request.POST.get("content")
    #Post.objects.create()
    return render(request, "post_detail.html", context)
#############html part    #############


    <form method='POST'>{% csrf_token %}
    {{ form.as_p }}
    <input type='submit' value='create' />
    </form>

update single record

message

    def post_update(request, id=None):
        instance = get_object_or_404(Post, id=id)
        form = PostForm(request.Post or None, instance = instance)
        if form.is_valid():
        instance = form.save(commit=False)
        instance.save()
            message.success(request, "succeed")
        return HttpResponseRedirect(instance.get_abs_url())
        else:
            message.error(request, "failed")
      #####################the same with detail page###############

#### delete record

    def post_delete(request, id=None):
    instance = get_object_or_404(Post, id=id)
    instance.delete()
    message.success(request, "succeed")
    return jdango.shortcuts.redirect("posts:list")

template example

    <title>{% block head_title%} abc {% endblock head_title %}
    {% extends "base.html" %}
    {% block head_title %} {{instance.title}} | {{block.super}} {{% endblock head_title %}}
    {% block content%}
    {% block.super %}
    {% endblock %}

数据库安装

参考除了数据库后台，还要安装相应的python客户端/绑定/驱动/DB API driver. mysqlclient，替代过时的MySQLdb。Django提供ORM到驱动的适配器 MySQL Connector/Python， oracle提供的纯python驱动，自己包含ORM到驱动的适配器。参考

生产环境安装apache 和 mod_wsgi

生产环境下有两种工作模式：嵌入式和后台daemon式，前者把python引入到apache内部，所有的代码都在内存，效率较高。后者mod_wsgi生出独立的daemon进程来处理请求。可以独立于apache启动。参考

1 2 3

安装django

首先安装pip， pip -V显示版本。 pip install -U pip更新, 出现permisson denied, 加上参数， pip install --user -U pip安装到用户本地目录而不是系统目录安装virtualenv

sudo pip install virtualenv && virtualenv ENV`
virtualenv --python=/usr/bin/python3 ENV3 && cd ENV3 && pip install django`

 `pip install django~=1.10.0`

ENV是用来存放虚拟环境的目录。lib,include目录包含库文件，包。所有安装的package在ENV/lib/pythonX.X/site-packages/
bin可执行脚本
pip,setuptools, python工具
激活脚本source bin/activate更改系统环境变量$PATH,让使用虚拟环境的可执行文件。如果你直接在bin目录下执行或者指定目录执行，不用执行activate。deactivate使设置失效。
去掉虚拟环境，确保deactivate之后，删掉ENV目录就行。
不用virtualenv的解析器。在mod_python或者mod_wsgi环境下，

cd ENV && source bin/activate && pip install Django && python3 -m django --version

 >>> import django
 >>> print(django.get_version())

建立项目

ref1

django-admin startproject mysite

manage.py: 与这个django项目交互的命令行工具。
The inner mysite/ 项目的python包
mysite/init.py: 空文件，告诉Python这个目录是个Python包。
mysite/settings.py: dango项目的设置。
mysite/urls.py: django的url设置。驱动的站点url。
mysite/wsgi.py: WSGI web服务器的入口。

启动项目python manage.py runserver

advancing

1， google marked min.js cdn

安装modwsgi

modwsgi是一个apache的模块，支持python wsgi规范。

1参考中说明了两种方式，在docker环境下推荐后一种。

2怎样使用wsgi

pip3 install mod_wsgi-httpd && pip3 install mod_wsgi && pip3 install django

容器运行django

参考

pip3 install mod_wsgi-httpd && pip3 install mod_wsgi && pip3 install django

python manage.py runmodwsgi --reload-on-changes --user mod_wsgi

要运行以上指令，先运行

修改setting.py,增加STATIC_ROOT
python manage.py collectstatic
修改settings.py,增加INSTALLED_APPS mod_wsgi.server

python manage.py xxx 4 source code for the youtube video 4 webpage-django 5 youtube 6 https 7 youtube chinese yt

django