1 序列化数据
Flask-RESTful 提供了marshal工具，用来帮助我们将数据序列化为特定格式的字典数据，以便作为视图的返回值。
from flask_restful import Resource, fields, marshal_with
resource_fields = {
'name': fields.String,
'address': fields.String,
'user_id': fields.Integer
}
class Todo(Resource):
@marshal_with(resource_fields, envelope='resource')
def get(self, **kwargs):
return db_get_todo()
也可以不使用装饰器的方式
class Todo(Resource):
def get(self, **kwargs):
data = db_get_todo()
return marshal(data, resource_fields)
示例代码1：
from flask import Flask
from flask_restful import fields, Resource, marshal, marshal_with, Api
app = Flask(__name__)
api = Api(app)
# 用来模拟要返回的数据对象的类
class User(object):
def __init__(self, user_id, name, age):
self.user_id = user_id
self.name = name
self.age = age
resoure_fields = {
'user_id': fields.Integer,
'name': fields.String
}
class Demo1Resource(Resource):
@marshal_with(resoure_fields, envelope='data1')
def get(self):
user = User(1, 'itcast', 12)
return user
class Demo2Resource(Resource):
def get(self):
user = User(1, 'itcast', 12)
return marshal(user, resoure_fields, envelope='data2')
# api.add_resource(Demo1Resource, '/demo1')
api.add_resource(Demo2Resource, '/demo2')
app.run()
运行效果：
测试代码2：
示例代码3：
from flask import Flask
from flask_restful import reqparse, Api, Resource, fields, marshal_with
app = Flask(__name__)
api = Api(app)
# 1. 关于参数解析的部分
# 一组虚拟的数据
TODOS = {
'todo1': {'task': 1},
'todo2': {'task': 2},
'todo3': {'task': 3},
}
# 定义允许的参数为task，类型为int，以及错误时的提示
parser = reqparse.RequestParser()
parser.add_argument('task', type=int, help='Please set a int task content!')
# 真正处理请求的地方
class TodoList(Resource):
def get(self):
return TODOS, 200, {'Etag': 'some-opaque-string'}
def post(self):
args = parser.parse_args()
print(max(TODOS.keys()), type(max(TODOS.keys())))
todo_id = int(max(TODOS.keys()).lstrip('todo')) + 1
todo_id = 'todo%i' % todo_id
TODOS[todo_id] = {'task': args['task']}
return TODOS[todo_id], 201
# 实际定义路由的地方
api.add_resource(TodoList, '/todos', '/all_tasks')
# 2. 关于响应域的部分
# ORM的数据模型
class TodoDao(object):
def __init__(self, todo_id, task):
self.todo_id = todo_id
self.task = task
# 这个域不会被返回
self.status = 'active'
# marshal-蒙板,
resource_fields = {
'task': fields.String,
'url': fields.Url('todo_ep')
}
# 真正处理请求的地方
class Todo(Resource):
# 蒙板 把多余的参数蒙住,只返回resource_fields中声明的键值对
@marshal_with(resource_fields)
def get(self, todo_id):
return TodoDao(todo_id=todo_id, task='Remember the milk'), 200
# 实际定义路由的地方
api.add_resource(Todo, '/todos/', endpoint='todo_ep') # 类Todo中只写了get方法
if __name__ == '__main__':
app.run(debug=True)
运行结果：
get功能：
post功能：
想要接口返回的JSON数据具有如下统一的格式
{"message": "描述信息", "data": {要返回的具体数据}}
在接口处理正常的情况下， message返回ok即可，但是若想每个接口正确返回时省略message字段
class DemoResource(Resource):
def get(self):
return {'user_id':1, 'name': 'itcast'}
对于诸如此类的接口，能否在某处统一格式化成上述需求格式？
{"message": "OK", "data": {'user_id':1, 'name': 'itcast'}}
Flask-RESTful的Api对象提供了一个representation的装饰器，允许定制返回数据的呈现格式
api = Api(app)
@api.representation('application/json')
def handle_json(data, code, headers):
# TODO 此处添加自定义处理
return resp
Flask-RESTful原始对于json的格式处理方式如下：
代码出处：flask_restful.representations.json
from flask import make_response, current_app
from flask_restful.utils import PY3
from json import dumps
def output_json(data, code, headers=None):
"""Makes a Flask response with a JSON encoded body"""
settings = current_app.config.get('RESTFUL_JSON', {})
# If we're in debug mode, and the indent is not set, we set it to a
# reasonable value here. Note that this won't override any existing value
# that was set. We also set the "sort_keys" value.
if current_app.debug:
settings.setdefault('indent', 4)
settings.setdefault('sort_keys', not PY3)
# always end the json dumps with a new line
# see https://github.com/mitsuhiko/flask/pull/1262
dumped = dumps(data, **settings) + "\n"
resp = make_response(dumped, code)
resp.headers.extend(headers or {})
return resp
为满足需求，做如下改动即可
@api.representation('application/json')
def output_json(data, code, headers=None):
"""Makes a Flask response with a JSON encoded body"""
# 此处为自己添加***************
if 'message' not in data:
data = {
'message': 'OK',
'data': data
}
# **************************
settings = current_app.config.get('RESTFUL_JSON', {})
# If we're in debug mode, and the indent is not set, we set it to a
# reasonable value here. Note that this won't override any existing value
# that was set. We also set the "sort_keys" value.
if current_app.debug:
settings.setdefault('indent', 4)
settings.setdefault('sort_keys', not PY3)
# always end the json dumps with a new line
# see https://github.com/mitsuhiko/flask/pull/1262
dumped = dumps(data, **settings) + "\n"
resp = make_response(dumped, code)
resp.headers.extend(headers or {})
return resp
