gae meets django
TRANSCRIPT
• Google App Engine介绍
• Django介绍
• 代码示例
Google App Engine介绍
什么是Google App Engine• Google的Web Hosting服务
•将你的Web应用部署到Google的基础设施之上
•使你的应用能够自动Scaling和load balancing
•提供数据存储服务
•集成了Google User认证和Gmail等服务
运行环境和限制• Python 2.5.2
•内置Django 0.96.1，并支持所有支持CGI的框架（以及任何使用CGI适配器的WSGI框架）
•运行在Sandbox中，不能访问文件系统，不能建立socket，不支持cron job，不能创建子进程
•限定时间内必须返回response
•应用必须是纯Python，不支持C的扩展
存储－Datastore•基于Google BigTable，分布式存储服务
•面向对象，非关系型数据库，不支持ORM
•相同Model可以有不同的属性
•支持查询，排序，事务
•不支持join, sum, avg等，不支持存储过程
•每次查询最多返回1000条记录
•全文检索？
App Engine Service
• Google帐号认证
• Gmail（发送email）
• URL Fetch
• Memcached
• Image (PIL)
价格(免费部分)Fixed Quota Per Day Usage Quotas
大约500万PV/月
价格（收费部分）
• $0.10 - $0.12 per CPU core-hour
• $0.15 - $0.18 per GB-month of storage
• $0.11 - $0.13 per GB outgoing bandwidth
• $0.09 - $0.11 per GB incoming bandwidth
申请Google App Engine• http://appengine.google.com/
•通过Gmail帐号
•通过短信认证
•域名: http://yourapp.appspot.com
•可以通过Google Apps绑定自己的域名
用途
•学习Web开发
•尝试各种idea, 减少startup的前期投入成本
•解决scalability问题
• App Gallery http://appgallery.appspot.com/
未来计划•对更多语言的支持
•收费计划
•大数据量的上传和下载
•离线处理
•数据导入/导出
Django简介
Django简介
•一个基于Python的full-stack Web框架
• ORM, URL mapping, admin interface, template, middleware, i18n, cache...
•很快很强大
为什么用Django（而不是webapp）
• Google App Engine Helper for Django
•功能更强大
•可移植性
项目示例－Blog系统
项目名称 － OnlyPython
创建开发环境
• 下载Google App Engine SDK
http://code.google.com/appengine/downloads.html
• 从SVN下载最新的Django源代码
http://code.djangoproject.com/svn/django/trunk/
• 下载Google App Engine Helper for Django
http://code.google.com/p/google-app-engine-django/
项目目录结构--- appengine-django (app engine helper for django 源文件目录)
--- django (django源文件目录)
--- onlypy (项目代码目录)
--- static (静态文件目录，存放js, css, 图片等)
--- app.yaml (app engine配置文件)
--- index.yaml (app engine索引配置文件)
--- main.py (app engine的启动脚本)
--- manage.py (Django的管理脚本)
--- settings.py (项目配置文件)
--- urls.py (URL mapping)
app.yamlapplication: onlypython
version: 1
runtime: python
api_version: 1
handlers:
-‐ url: /static
static_dir: static
-‐ url: /.*
script: main.py
main.pyimport osimport sysimport logging
from appengine_django import InstallAppengineHelperForDjangoInstallAppengineHelperForDjango()
# Google App Engine imports.from google.appengine.ext.webapp import util
# Import the part of Django that we use here.import django.core.handlers.wsgi
def main(): # Create a Django application for WSGI. application = django.core.handlers.wsgi.WSGIHandler()
# Run the WSGI CGI handler with that application. util.run_wsgi_app(application)
if __name__ == '__main__': main()
settings.pyTIME_ZONE = 'UTC'
MIDDLEWARE_CLASSES = (
'django.middleware.common.CommonMiddleware',
'appengine_django.auth.middleware.AuthenticationMiddleware',
)
ROOT_URLCONF = 'urls'
ROOT_PATH = os.path.dirname(__file__)
TEMPLATE_DIRS = (
os.path.join(ROOT_PATH, 'onlypy/templates')
)
INSTALLED_APPS = (
'appengine_django',
'django.contrib.auth',
'onlypy.blog',
)
TODO: 添加Blog
models.pyfrom google.appengine.ext import db
class Category(db.Model): name = db.StringProperty() def __str__(self): return self.name
class Post(db.Model): author = db.UserProperty() title = db.StringProperty(required=True, verbose_name=u'标题') tag = db.StringProperty(verbose_name=u'标签') content = db.TextProperty(required=True, verbose_name=u'内容')
create_time = db.DateTimeProperty(auto_now_add=True) update_time = db.DateTimeProperty(auto_now=True) category = db.ReferenceProperty(Category, required=True, verbose_name=u'类别')
is_published = db.BooleanProperty(verbose_name=u'已发布')
def get_absolute_url(self) : return '/post/%s/'%self.key().id()
forms.pyfrom google.appengine.ext.db import djangoforms as formsfrom models import Post
class PostForm(forms.ModelForm): class Meta: model = Post exclude = ['author']
views.pydef add_post(request):
if request.method == 'GET': form = PostForm() if request.method == 'POST': form = PostForm(request.POST) if form.is_valid(): post = form.save() post.author = users.get_current_user() post.put() return HttpResponseRedirect('/post/add/')
return render_to_response('blog/add_post.html', {'form': form}, context_instance=RequestContext(request))
add_post.html{% extends "base.html" %}
{% block content %}<h1>添加新文章</h1>
<form name="mainForm" method="post" action=""> {{form.as_p}} <input type="submit" value="保存"/>
</form>{% endblock %}
urls.pyfrom django.conf.urls.defaults import *
urlpatterns = patterns('onlypy.blog.views', (r'^post/add/$', 'add_post'),)
Run• cd /yourpath/onlypython/
• python ./manage.py runserver 127.0.0.1:8000
TODO: 显示Blog列表
views.pydef list_post(request):
posts = Post.all().order('-‐create_time') if (not is_admin()): posts = posts.filter("is_published", True) return object_list(request, queryset=posts, allow_empty=True, template_name='blog/list_post.html', extra_context={'is_admin': is_admin()}, paginate_by=20)
index.yamlindexes:
-‐ kind: Post properties: -‐ name: is_published -‐ name: create_time direction: desc
list_post.html{% extends "base.html" %}{% load markup %}{% load paginator %}
{% block content %}{% for post in object_list %} <table border="0" cellspacing="0" cellpadding="0" width="100%"> <tr> <td valign="top"> <h1 style="margin-‐bottom: 2px;"> <a href="/post/{{post.key.id}}"> [{{ post.category.name }}] {{ post.title }}{% if post.is_published %}{%else%}(未发布){%endif%}
</a> </h1> <p style="padding:0px; margin: 0px;" class="small_font"> 类别: <a href="/category/{{ post.category.key.id }}/">
{{ post.category.name }}</a> <span style="padding-‐left: 10px;">{{ post.author.nickname }}写于{{ post.create_time|date:"Y-‐M-‐d H:i" }}</span>
</p> </td> </tr></table><div style="padding-‐left: 30px;"> {{ post.content|markdown }}</div>{% endfor %}{% paginator %}{% endblock %}
urls.pyfrom django.conf.urls.defaults import *
urlpatterns = patterns('onlypy.blog.views', (r'^post/add/$', 'add_post'), (r'^$', 'list_post'),)
项目信息• 项目代码 http://code.google.com/p/onlypy/
• 项目演示 http://www.onlypython.com
Q&A