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:

1.     请求收拢到dbgate，可以使dbgate变为无状态的，方便横向扩展
2.     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
3.     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
4.     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
5.     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
6.     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：

1.     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
2.     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
from models import user
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

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。