通过 Flask Restful Api 对model进行CRUD （create,read,update,delete）
开始
源代码 here
$ git clone https://github.com/rahmanfadhil/flask-rest-api.git
创建venv，安装依赖
$ python -m venv env
$ source env/bin/activate
(env) $ pip install -r requirements.txt
依赖
- Flask SQLAlchemy: A Flask extension that adds support for SQLAlchemy, 关联数据库
- Flask RESTful: 创建restful接口
- Flask Marshmallow: 序列化对象方法Marshmallow
step1
$ python3 -m venv env
$ source env/bin/activate
$ pip install Flask \
Flask-SQLAlchemy \
Flask-RESTful \
flask-marshmallow
创建主函数 main.py
from flask import Flask
app = Flask(__name__)
if __name__ == '__main__':
app.run(debug=True)
测试一下
(env) $ python main.py
Open http://localhost:5000, and you will see a 404 page.
数据库
这里选用sqlite，记得生产用postsql或mysql
from flask import Flask
from flask_sqlalchemy import SQLAlchemy # new
app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///test.db' # new
db = SQLAlchemy(app) # new
if __name__ == '__main__':
app.run(debug=True)
Database model
class Post(db.Model):
id = db.Column(db.Integer, primary_key=True)
title = db.Column(db.String(50))
content = db.Column(db.String(255))
def __repr__(self): # str(post) 时会调用，即print时显示的string
return '' % self.title
在restful api中返回的数据是json格式，所以需要把model转换为json，这就需要
flask_marshmallow ，先定义schema，再通过schema转化为json
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from flask_marshmallow import Marshmallow # new
app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///test.db'
db = SQLAlchemy(app)
ma = Marshmallow(app) # new
# ...
if __name__ == '__main__':
app.run(debug=True)
定义了两个schema实例
class PostSchema(ma.Schema):
class Meta:
fields = ("id", "title", "content")
post_schema = PostSchema()
posts_schema = PostSchema(many=True)
初始化数据库，当然也可以使用flask migrate，这里使用最简单的方式。
(env) $ python
>>> from main import db
>>> db.create_all()
>>> exit()
RESTful 路由
Get Posts api
class PostListResource(Resource):
def get(self):
posts = Post.query.all()
return posts_schema.dump(posts) # schema 作用就是将posts转为dict
api.add_resource(PostListResource, '/posts') # 绑定了路由
测试
$ curl http://localhost:5000/posts
[]
Create Api
# ...
from flask import Flask, request # change
# ...
class PostListResource(Resource):
def get(self):
posts = Post.query.all()
return posts_schema.dump(posts)
# create api
def post(self):
new_post = Post(
title=request.json['title'],
content=request.json['content']
)
db.session.add(new_post)
db.session.commit()
return post_schema.dump(new_post)
# ...
测试
$ curl http://localhost:5000/posts \
-X POST \
-H "Content-Type: application/json" \
-d '{"title":"Post 1", "content":"Lorem ipsum"}'
{
"content": "Lorem ipsum",
"id": 1,
"title": "Post 1"
}
根据id获取post，get_or_404: 在获取不到时，返回404
class PostResource(Resource):
def get(self, post_id):
post = Post.query.get_or_404(post_id)
return post_schema.dump(post)
api.add_resource(PostResource, '/posts/')
测试1
$ curl http://localhost:5000/posts/1
{
"title": "Post 1",
"content": "Lorem ipsum",
"id": 1
}
测试2
$ curl http://localhost:5000/posts/12 -I
HTTP/1.0 404 NOT FOUND
...
新增 update和delete
class PostResource(Resource):
# ...
def patch(self, post_id):
post = Post.query.get_or_404(post_id)
if 'title' in request.json:
post.title = request.json['title']
if 'content' in request.json:
post.content = request.json['content']
db.session.commit()
return post_schema.dump(post)
def delete(self, post_id):
post = Post.query.get_or_404(post_id)
post.delete()
db.session.commit()
return '', 204
测试 Update :
$ curl http://localhost:5000/posts/1 \
-X PATCH \
-H "Content-Type: application/json" \
-d '{"title":"Updated Post", "content":"Updated post content"}'
{
"content": "Updated post content",
"id": 1,
"title": "Updated Post"
}
** 测试 Delete :**
$ curl http://localhost:5000/posts/1 -X DELETE -I
HTTP/1.0 204 NO CONTENT
...