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Flask-MongoEngine
一个用来集成MongoEngine的Flask扩展，更多MongoEngine详细信息请参看MongoEngine文档。
它处理应用的连接管理。你也可以用WTForms作为模型的格式。
安装Flask-MongoEngine
使用pip安装：
pip install flask-mongoengine
配置
基本步骤很简单，仅需获取扩展：
from flask import Flask
from flask.ext.mongoengine import MongoEngine
app = Flask(__name__)
app.config.from_pyfile('the-config.cfg')
db = MongoEngine(app)
或者，若你想在应用初始化之前配置数据库，下方是一个应用工厂的列子：
from flask import Flask
from flask.ext.mongoengine import MongoEngine
db = MongoEngine()
...
app = Flask(__name__)
app.config.from_pyfile('the-config.cfg')
db.init_app(app)
默认情况下，Flask-MongoEngine假设mongod实例运行在本地主机的27017端口上，并且你将连接名为test的数据库。
如果MongoDB运行在别处，你需要在app.config的'MONGODB_SETTINGS'字典中配置主机和端口：
app.config['MONGODB_SETTINGS'] = {
'db': 'project1',
'host': '192.168.1.35',
'port': 12345
}
如果数据库需要身份验证，app.config['MONGODB_SETTINGS']字典需要提供username、password参数：
app.config['MONGODB_SETTINGS'] = {
'db': 'project1',
'username':'webapp',
'password':'pwd123'
}
也支持Uri风格的连接，仅需在app.config['MONGODB_SETTINGS']字典中将host值设为uri。注意，自uri获取的数据库名称优先级高于本地设置：
app.config['MONGODB_SETTINGS'] = {
'db': 'project1',
'host': 'mongodb://localhost/database_name'
}
连接配置也可以通过带有MONGODB_前缀的字典单独设置：
app.config['MONGODB_DB'] = 'project1'
app.config['MONGODB_HOST'] = '192.168.1.35'
app.config['MONGODB_PORT'] = 12345
app.config['MONGODB_USERNAME'] = 'webapp'
app.config['MONGODB_PASSWORD'] = 'pwd123'
定制查询集
flask-mongoengine位MongoEngine的默认查询集附加了下列方法：
- get_or_404:类似于.get(),但若对象不存在，返回404中止。
- first_or_404:类似于.first(),并做404判断。
- paginate:为查询集分页。需要俩个参数，page和per_page。
- paginate_field:用查询集中某个文档的字段分页。参数：field_name, doc_id, page, per_page.
例子：
# 404 if object doesn't exist
def view_todo(todo_id):
todo = Todo.objects.get_or_404(_id=todo_id)
..
# Paginate through todo
def view_todos(page=1):
paginated_todos = Todo.objects.paginate(page=page, per_page=10)
# Paginate through tags of todo
def view_todo_tags(todo_id, page=1):
todo = Todo.objects.get_or_404(_id=todo_id)
paginated_tags = todo.paginate_field('tags', page, per_page=10)
分页对象包含以下属性： iter_pages, next, prev, has_next, has_prev, next_num, prev_num.
在模板中：
{% macro render_pagination(pagination, endpoint) %}
<div class=pagination>
{%- for page in pagination.iter_pages() %}
{% if page %}
{% if page != pagination.page %}
<a href="{{ url_for(endpoint, page=page) }}">{{ page }}</a>
{% else %}
<strong>{{ page }}</strong>
{% endif %}
{% else %}
<span class=ellipsis>…</span>
{% endif %}
{%- endfor %}
</div>
{% endmacro %}
MongoEngine 和 WTForms
你可以这样使用MongoEngine 和 WTForms：
from flask.ext.mongoengine.wtf import model_form
class User(db.Document):
email = db.StringField(required=True)
first_name = db.StringField(max_length=50)
last_name = db.StringField(max_length=50)
class Content(db.EmbeddedDocument):
text = db.StringField()
lang = db.StringField(max_length=3)
class Post(db.Document):
title = db.StringField(max_length=120, required=True, validators=[validators.InputRequired(message=u'Missing title.'),])
author = db.ReferenceField(User)
tags = db.ListField(db.StringField(max_length=30))
content = db.EmbeddedDocumentField(Content)
PostForm = model_form(Post)
def add_post(request):
form = PostForm(request.POST)
if request.method == 'POST' and form.validate():
# do something
redirect('done')
return render_template('add_post.html', form=form)
支持字段
- StringField
- BinaryField
- URLField
- EmailField
- IntField
- FloatField
- DecimalField
- BooleanField
- DateTimeField
- ListField (using wtforms.fields.FieldList )
- SortedListField (duplicate ListField)
- EmbeddedDocumentField (using wtforms.fields.FormField and generating inline Form)
- ReferenceField (using wtforms.fields.SelectFieldBase with options loaded from QuerySet or Document)
- DictField
目前不支持字段类型：
- ObjectIdField
- GeoLocationField
- GenericReferenceField
Session Interface
To use MongoEngine as your session store simple configure the session interface:
from flask.ext.mongoengine import MongoEngine, MongoEngineSessionInterface
app = Flask(__name__)
db = MongoEngine(app)
app.session_interface = MongoEngineSessionInterface(db)
调试工具栏面板
调试工具栏面板.png
如果你使用Flask-DebugToolbar，你可以添加
app.config['DEBUG_TB_PANELS'] = ['flask.ext.mongoengine.panels.MongoDebugPanel']
，然后它将自动跟踪查询：
from flask import Flask
from flask_debugtoolbar import DebugToolbarExtension
app = Flask(__name__)
app.config['DEBUG_TB_PANELS'] = ['flask.ext.mongoengine.panels.MongoDebugPanel']
db = MongoEngine(app)
toolbar = DebugToolbarExtension(app)
升级
ListFieldPagination参数的顺序已经改变的更为符合逻辑：
# Old order
ListFieldPagination(self, queryset, field_name, doc_id, page, per_page, total)
# New order
ListFieldPagination(self, queryset, doc_id, field_name, page, per_page, total)
