python Django 学习笔记（六）—— 写一个简单blog做增删改练手

简单效果图

1,创建一个项目myblog 可参考这里

myblog/
　　manage.py
　　myblog/
　　　　　　__init__.py
　　　　　　settings.py
　　　　　　urls.py
　　　　　　wsgi.py

2,创建blogs app 可参考这里

myblog/myblog/blogs/
    __init__.py
    models.py
    tests.py
    views.py

• 编写models.py

#vim: set fileencoding=utf-8:

from django.db import models

# Create your models here.

class Blog(models.Model):
    title     = models.CharField(u'标题', max_length=50)
    author     = models.CharField(u'作者', max_length=10)
    content　　 = models.CharField(u'正文', max_length=2000)
    post_date 　= models.DateTimeField(u'发布时间',auto_now_add=True)

    class Meta:
        ordering = ['-post_date']

• 模型安装（修改settings.py）

import os.path #加载模版需要导入库

#数据库连接
DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql', # Add 'postgresql_psycopg2', 'mysql', 'sqlite3' or 'oracle'.
        'NAME': 'myblog',                      # Or path to database file if using sqlite3.
        # The following settings are not used with sqlite3:
        'USER': 'root',
        'PASSWORD': 'root',
        'HOST': '127.0.0.1',                      # Empty for localhost through domain sockets or '127.0.0.1' for localhost through TCP.
        'PORT': '',                      # Set to empty string for default.
    }
}

#模型安装
INSTALLED_APPS = (
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.sites',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    # Uncomment the next line to enable the admin:
    'django.contrib.admin',
    'myblog.blogs',
    # Uncomment the next line to enable admin documentation:
    # 'django.contrib.admindocs',
)

#加载模版
TEMPLATE_DIRS = (
    # Put strings here, like "/home/html/django_templates" or "C:/www/django/templates".
    # Always use forward slashes, even on Windows.
    # Don't forget to use absolute paths, not relative paths.
     os.path.join(os.path.dirname(__file__), 'templates').replace('\\','/'),
)

MIDDLEWARE_CLASSES = (
'django.middleware.common.CommonMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',  #csrf防御，post提交跨站请求伪造
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
# Uncomment the next line for simple clickjacking protection:
# 'django.middleware.clickjacking.XFrameOptionsMiddleware',
)

#settings.py基本修改就这些了

• 采用 python manage.py validate 检查模型的语法和逻辑是否正确。

  没有错误则执行 python manage.py syncdb创建数据表。

3,编写forms.py

myblog/myblog/forms.py

#vim: set fileencoding=utf-8:

from django import forms

class BlogForm(forms.Form):
    title =  forms.CharField(label='标题')
    author = forms.CharField(label='作者')
    content = forms.CharField(label='正文',widget=forms.Textarea)

4，编写views.py

myblog/myblog/views.py

#vim: set fileencoding=utf-8:

from django.http import HttpResponseRedirect
from django.shortcuts import render_to_response
from myblog.blogs.models import Blog
from myblog import forms
from django.template import RequestContext

def blog_list(request):
    blog_list = Blog.objects.all()
    return render_to_response('blog_list.html',{'blog_list':blog_list})

def blog_form(request):
    if request.method == 'POST':
        form = forms.BlogForm(request.POST)
        if form.is_valid():
            data = form.cleaned_data
            if 'id' not in data:
                blog = Blog(title=data['title'],author=data['author'],content=data['content'])
                blog.save()
            else:
                blog = Blog.object.get(id=data.id)
                blog.title = data['title']
                blog.author = data['author']
                blog.content = data['content']
                blog.save()
            return HttpResponseRedirect('/blog/list')
    else:
        form = forms.BlogForm()
        return render_to_response('blog_form.html',{'form':form},context_instance=RequestContext(request))

def blog_del(request):
    errors = []
    if 'id' in request.GET:
        bid_ = request.GET['id']
        Blog.objects.filter(id=bid_).delete()
        return HttpResponseRedirect('/blog/list')
    else:
        errors.append("参数异常请刷新后重试")
        return render_to_response('blog_list.html', {'errors': errors})

def blog_view(request):
    errors = []
    if 'id' in request.GET:
        bid_ = request.GET['id']
        blog = Blog.objects.get(id=bid_)
        return render_to_response('blog_view.html',{'blog':blog})
    else:
        errors.append("参数异常请刷新后重试")
        return render_to_response("blog_list.hmtl",{'errors':errors})

def blog_edit(request):
    errors = []
    if 'id' in request.GET:
        bid_ = request.GET['id']
        blog = Blog.objects.get(id=bid_)
        form = forms.BlogForm(
                initial = {'id':blog.id,'title':blog.title,'author':blog.author,'content':blog.content}
        )
        return render_to_response('blog_form.html',{'form':form},context_instance=RequestContext(request))
    else:
        errors.append("参数异常请刷新后重试")
        return render_to_response("blog_list.html",{'errors':errors})

5,创建模版文件

myblog/myblog/templates/
　　　　　　　　　　　　　　blog_form.html
　　　　　　　　　　　　　　blog_list.html
　　　　　　　　　　　　　　blog_view.html
　　　　　　　　　　　　

#blog_form.html
<html>
    <meta http-equiv="Content-type" content="text/html; charset=utf-8">
    <title>博客编辑</title>
    <head></head>
    <body>
       {% if errors %}
        <ul>
            {% for error in errors %}
            <li style="color: red;">{{error}}</li>
            {% endfor %}
        </ul>
        {% endif %}
    <a href="/blog/list">返回主页>></a><p/>
    <form action="/blog/form" method="post">
       {% csrf_token %}
       <table>
            {{ form.as_table }}
        </table>
        <input type="submit" value="保存">
    </form>       

    </body>
</html>

#blog_list.html
<html>
    <meta http-equiv="Content-type" content="text/html; charset=utf-8">
    <title>主页-博客列表</title>
    <head></head>
    <body>
       {% if errors %}
        <ul>
            {% for error in errors %}
            <li style="color: red;">{{error}}</li>
            {% endfor %}
        </ul>
        {% endif %}
    <a href="/blog/form">去写博客>></a><p/>
       <table cellpadding="0" cellpadding="0" width="100%" border="1" >
        <tr height="20">
            <td>编号</td>
            <td>标题</td>
            <td>作者</td>
            <td>发布时间</td>
            <td>操作</td>
        </tr>
        {% for blog in blog_list %}
        <tr>
            <td>{{forloop.counter}}</td>
            <td><a href="/blog/view?id={{blog.id}}">{{blog.title}}</a></td>
            <td>{{blog.author}}</td>
            <td>{{blog.post_date | date:"Y-m-d H:i:s"}}</td>
            <td><a href="/blog/edit?id={{blog.id}}">修改</a>&nbsp;<a href="/blog/delete?id={{blog.id}}">删除</a></td>
        </tr>
        {% empty %}
        <tr><td colspan="4">还没有添加博客内容</td></tr>
        {% endfor %}

    </table>
    </body>
</html>

#blog_view.html
<html>
    <meta http-equiv="Content-type" content="text/html; charset=utf-8">
    <title>{{blog.title}}</title>
    <head></head>
    <body>
       {% if errors %}
        <ul>
            {% for error in errors %}
            <li style="color: red;">{{error}}</li>
            {% endfor %}
        </ul>
        {% endif %}
    <a href="/blog/list">返回主页>></a><p/>

    <h2>{{blog.title}}</h2>
    <p>作者：{{blog.author}}&nbsp;&nbsp;{{blog.post_date | date:'Y-m-d H:i:s'}}<p>
    <p>{{blog.content}}</p>
    </body>
</html>

6，修改urls.py

from django.conf.urls import patterns, include, url
from myblog import views

# Uncomment the next two lines to enable the admin:
# from django.contrib import admin
# admin.autodiscover()

urlpatterns = patterns('',
    # Examples:
    # url(r'^$', 'myblog.views.home', name='home'),
    # url(r'^myblog/', include('myblog.foo.urls')),

    # Uncomment the admin/doc line below to enable admin documentation:
    # url(r'^admin/doc/', include('django.contrib.admindocs.urls')),

    # Uncomment the next line to enable the admin:
    # url(r'^admin/', include(admin.site.urls)),
    url(r'^blog/list$', views.blog_list),
    url(r'^blog/form$', views.blog_form),
    url(r'^blog/delete$', views.blog_del),
    url(r'^blog/view$', views.blog_view),
    url(r'^blog/edit$', views.blog_edit),
)

7，启动开发服务器 http://127.0.0.1:8000/blog/list

8，遇到的问题

1,CSRF verification failed. Request aborted.

Forbidden (403)
CSRF verification failed. Request aborted.
Help
Reason given for failure:
    CSRF token missing or incorrect.

In general, this can occur when there is a genuine Cross Site Request Forgery, or when Django's CSRF mechanism has not been used correctly. For POST forms, you need to ensure:
Your browser is accepting cookies.
The view function uses RequestContext for the template, instead of Context.
In the template, there is a {% csrf_token %} template tag inside each POST form that targets an internal URL.
If you are not using CsrfViewMiddleware, then you must use csrf_protect on any views that use the csrf_token template tag, as well as those that accept the POST data.
You're seeing the help section of this page because you have DEBUG = True in your Django settings file. Change that to False, and only the initial error message will be displayed.
You can customize this page using the CSRF_FAILURE_VIEW setting.

解决方法：

• 在视图函数里用RequestContext类代替Context。RequestContext是Context的子类，具体可自行google。
• 在模版表单中插入 {% csrf_token%}

　　　(本例子采用以上方法，可查看views.py 中blog_form（）函数，和blog_form.html模版页面)

　

　　另外也可以注释掉settings.py

　　#'django.middleware.csrf.CsrfViewMiddleware', #csrf防御，post提交跨站请求伪造

2，还有个问题，就是在修改的时候怎么把对应id传入模版blog_form.html页面。暂未解决..