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    在Python的框架中为MySQL实现restful接口的教程

    作者:vimer 时间:2021-07-30 19:00

    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

    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:

    201548172936523.png (600×545)

    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:

    201548173034739.png (600×353)

    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。

    jsjbwy
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