在Python的框架中为MySQL实现restful接口的教程
最近在做游戏服务分层的时候，一直想把mysql的访问独立成一个单独的服务DBGate，原因如下:
- 请求收拢到DBGate，可以使DBGate变为无状态的，方便横向扩展
- 当请求量或者存储量变大时，mysql需要做分库分表，DBGate可以内部直接处理，外界无感知
- 通过restful限制对数据请求的形式，仅支持简单的get/post/patch/put 进行增删改查，并不支持复杂查询。这个也是和游戏业务的特性有关，如果网站等需要复杂查询的业务，对此并不适合
- DBGate使用多进程模式，方便控制与mysql之间的链接数，进行mysql访问量阀值保护
- 方便在DBGate上进行访问量统计，慢查询统计、权限控制等等一系列逻辑
- 目前是使用python，以后要使用其他语言进行mysql操作时，只要进行标准的http请求即可，不会出现不兼容的情况
当然坏处也是有的：
- 首当其冲就是单次请求的响应时间变长，毕竟中间加了一层服务，并且还是http格式
- 部署上比原来复杂了一些，很多对mysql直接操作的思维需要进行转变，一开始可能会有些不适
不过总的来说，还是利大于弊，所以最终还是决定搭建DBGate
当然，我们不可能去手工挨个写每个库表对应的restful服务，值得庆幸的是django和flask都提供了对应的解决方案，我们一个个介绍.
Flask
参考链接: flask-restless
flask-restless使用方法比较简单，我直接贴一下代码即可:
# -*- coding: utf-8 -*-
import datetime
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from flask_restless import APIManager
app = Flask(__name__)
db = SQLAlchemy(app)
restless = APIManager(app, flask_sqlalchemy_db=db)
class User(db.Model):
"""
user
"""
id = db.Column(db.Integer, primary_key=True)
username = db.Column(db.String(255), unique=True, nullable=False)
password = db.Column(db.String(255), nullable=False)
create_time = db.Column(db.DateTime, nullable=False, default=datetime.datetime.utcnow)
login_time = db.Column(db.DateTime)
restless.create_api(User, methods=['GET', 'POST', 'DELETE', 'PATCH', 'PUT'], results_per_page=100)
db.create_all()
if __name__ == '__main__':
app.run(port=25000)
# -*- coding: utf-8 -*-
import datetime
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from flask_restless import APIManager
app = Flask(__name__)
db = SQLAlchemy(app)
restless = APIManager(app, flask_sqlalchemy_db=db)
class User(db.Model):
"""
user
"""
id = db.Column(db.Integer, primary_key=True)
username = db.Column(db.String(255), unique=True, nullable=False)
password = db.Column(db.String(255), nullable=False)
create_time = db.Column(db.DateTime, nullable=False, default=datetime.datetime.utcnow)
login_time = db.Column(db.DateTime)
restless.create_api(User, methods=['GET', 'POST', 'DELETE', 'PATCH', 'PUT'], results_per_page=100)
db.create_all()
if __name__ == '__main__':
app.run(port=25000)
其对应的restful操作如下:
获取用户列表: GET /user
添加用户: POST /user
获取单个用户: GET /user/1
覆盖单个用户: PUT /user/1
修改单个用户: PATCH /user/1
获取用户列表: GET /user
添加用户: POST /user
获取单个用户: GET /user/1
覆盖单个用户: PUT /user/1
修改单个用户: PATCH /user/1
注意:
- 在http请求中，记得加入header: Content-Type: application/json
- flask-restless中，PUT和PATCH一样，都是传入什么字段，只修改什么字段，不会完全覆盖
Django
参考链接: Django REST framework
Django用起来要更复杂一些，也因为django版自带了一个可视化的操作页面，如下:
1. 在settings中添加:
REST_FRAMEWORK = {
# Use hyperlinked styles by default.
# Only used if the `serializer_class` attribute is not set on a view.
'DEFAULT_MODEL_SERIALIZER_CLASS':
'rest_framework.serializers.HyperlinkedModelSerializer',
# Use Django's standard `django.contrib.auth` permissions,
# or allow read-only access for unauthenticated users.
'DEFAULT_PERMISSION_CLASSES': [
#'rest_framework.permissions.DjangoModelPermissionsOrAnonReadOnly',
'rest_framework.permissions.IsAdminUser',
]
}
REST_FRAMEWORK = {
# Use hyperlinked styles by default.
# Only used if the `serializer_class` attribute is not set on a view.
'DEFAULT_MODEL_SERIALIZER_CLASS':
'rest_framework.serializers.HyperlinkedModelSerializer',
# Use Django's standard `django.contrib.auth` permissions,
# or allow read-only access for unauthenticated users.
'DEFAULT_PERMISSION_CLASSES': [
#'rest_framework.permissions.DjangoModelPermissionsOrAnonReadOnly',
'rest_framework.permissions.IsAdminUser',
]
}
2. 通过startapp建立一个app: demo
3. 修改demo的models:
class User(models.Model): # key是保留字 password = models.IntegerField() nick = models.CharField(max_length=255) create_time = models.DateTimeField(default=datetime.datetime.now) class User(models.Model): # key是保留字 password = models.IntegerField() nick = models.CharField(max_length=255) create_time = models.DateTimeField(default=datetime.datetime.now)
4. 在demo下新建serializers.py
from rest_framework import serializers
class UserSerializer(serializers.ModelSerializer): class Meta: model = User from rest_framework import serializers from models import User class UserSerializer(serializers.ModelSerializer): class Meta: model = User
from models import User
5. 在demo下修改views.py
from django.shortcuts import render from rest_framework import viewsets from serializers import UserSerializer from models import User class UserViewSet(viewsets.ModelViewSet): queryset = User.objects.all() serializer_class = UserSerializer from django.shortcuts import render from rest_framework import viewsets from serializers import UserSerializer from models import User class UserViewSet(viewsets.ModelViewSet): queryset = User.objects.all() serializer_class = UserSerializer
6. 在demo下新建urls.py
import os.path
from django.conf.urls import patterns, include, url
from django.conf.urls.static import static
from django.conf import settings
import views
from rest_framework import routers
appname = os.path.basename(os.path.dirname(os.path.abspath(__file__)))
router = routers.DefaultRouter()
router.register('users', views.UserViewSet, appname)
urlpatterns = patterns('',
url(r'^', include(router.urls)),
)
import os.path
from django.conf.urls import patterns, include, url
from django.conf.urls.static import static
from django.conf import settings
import views
from rest_framework import routers
appname = os.path.basename(os.path.dirname(os.path.abspath(__file__)))
router = routers.DefaultRouter()
router.register('users', views.UserViewSet, appname)
urlpatterns = patterns('',
url(r'^', include(router.urls)),
)
7. 在mysite.urls下include demo.urls和rest_framework.urls
urlpatterns = patterns('',
url(r'^demo/', include('demo.urls')),
url(r'^admin/', include(admin.site.urls)),
url(r'^api-auth/', include('rest_framework.urls', namespace='rest_framework'))
)
urlpatterns = patterns('',
url(r'^demo/', include('demo.urls')),
url(r'^admin/', include(admin.site.urls)),
url(r'^api-auth/', include('rest_framework.urls', namespace='rest_framework'))
)
8. 执行初始化数据操作:
python manage.py syncdb python manage.py syncdb
之后访问: http://127.0.0.1:8000/demo 即可看到如下界面了:
对应的测试代码如下:
import json
import requests
from urlparse import urljoin
BASE_URL = 'http://127.0.0.1:16500/'
AUTH = ('admin', 'admin')
def test_get_user_list():
rsp = requests.get(urljoin(BASE_URL, '/demo/users/'), auth=AUTH, headers={
'Accept': 'application/json'
})
assert rsp.ok
def test_post_user_list():
json_data = dict(
password=0,
nick='oo',
create_time='2014-03-3T03:3:3'
)
rsp = requests.post(urljoin(BASE_URL, '/demo/users/'), auth=AUTH, headers={
'Accept': 'application/json',
'Content-Type': 'application/json',
}, data=json.dumps(json_data))
assert rsp.ok
def test_get_user():
rsp = requests.get(urljoin(BASE_URL, '/demo/users/1'), auth=AUTH, headers={
'Accept': 'application/json',
'Content-Type': 'application/json',
})
assert rsp.ok
def test_put_user():
json_data = dict(
password=100,
nick='xx',
create_time='2014-03-3T03:3:3'
)
# 注意最后的 /
rsp = requests.put(urljoin(BASE_URL, '/demo/users/1/'), auth=AUTH, headers={
'Accept': 'application/json',
'Content-Type': 'application/json',
}, data=json.dumps(json_data),
)
assert rsp.ok, rsp.status_code
Django REST framework 是严格区分PUT和PATCH的，这一点和flask-restless 不一样，需要注意。
OK，就这样。
