flask_restful中的输出域(Resource、fields、marshal、marshal_with)

示例代码：

import json
from datetime import datetime
from flask_restful import Resource, fields, marshal_with, marshal

# 基本例子
resource_fields = {
    'name': fields.String,
    'address': fields.String,
    'date_updated': fields.DateTime(dt_format='rfc822'),
}


class UserInfo(object):
    def __init__(self, name, address, date_updated=datetime.now()):
        self.name = name
        self.address = address
        self.date_updated = date_updated


print(UserInfo('dgw', 'beijing'))
print(UserInfo('dgw', 'beijing').name, UserInfo('dgw', 'beijing').address)
print(json.dumps(marshal(UserInfo('dgw', 'beijing'), resource_fields)))


class Todo(Resource):
    @marshal_with(resource_fields, envelope='resource')
    def get(self, **kwargs):
        return UserInfo('dgw', 'beijing')


# 输出域别名
resource_fields2 = {
    'open_name': fields.String(attribute='name'),
    'address': fields.String,
    'date_updated': fields.DateTime(dt_format='rfc822'),
}
print(json.dumps(marshal(UserInfo('dgw', 'beijing'), resource_fields2)))


# # 输出域默认值
class UserInfo2(object):

    def __init__(self, address):
        self.address = address


resource_fields3 = {
    'open_name': fields.String(default='add_dgw'),
    'address': fields.String,
    'date_updated': fields.DateTime(dt_format='rfc822', default=str(datetime.now())),
}

print(json.dumps(marshal(UserInfo2(address='beijing'), resource_fields3)))


# # 自定义输出域
class UserInfo2(object):
    def __init__(self, address, flag, date_updated=datetime.now()):
        self.address = address
        self.date_updated = date_updated
        self.flags = flag


class UrgentItem(fields.Raw):
    def format(self, value):
        return "Urgent" if value & 0x01 else "Normal"


resource_fields4 = {
    'open_name': fields.String(default='add_DGW'),
    'address': fields.String,
    'date_updated': fields.DateTime(dt_format='rfc822'),
    'priority': UrgentItem(attribute='flags'),
}
print(json.dumps(marshal(UserInfo2(address='beijing', flag=0), resource_fields4)))
print(json.dumps(marshal(UserInfo2(address='beijing', flag=1), resource_fields4)))

# # 复杂结构
resource_fields = {'name': fields.String}
resource_fields['address'] = {}
resource_fields['address']['line 1'] = fields.String(attribute='addr1')
resource_fields['address']['line 2'] = fields.String(attribute='addr2')
resource_fields['address']['city'] = fields.String
resource_fields['address']['state'] = fields.String
resource_fields['address']['zip'] = fields.String
data = {'name': 'bob', 'addr1': 'shanghai', 'addr2': '', 'city': 'New York', 'state': 'NY', 'zip': '10468'}
print(json.dumps(marshal(data, resource_fields)))

# 嵌套域
address_fields = {}
address_fields['line 1'] = fields.String(attribute='addr1')
address_fields['line 2'] = fields.String(attribute='addr2')
address_fields['city'] = fields.String(attribute='city')
address_fields['state'] = fields.String(attribute='state')
address_fields['zip'] = fields.String(attribute='zip')

resource_fields = {}
resource_fields['name'] = fields.String
resource_fields['billing_address'] = fields.Nested(address_fields)
resource_fields['shipping_address'] = fields.Nested(address_fields)
address1 = {'addr1': 'qingdao', 'city': 'New York', 'state': 'NY', 'zip': '10468'}
address2 = {'addr1': 'nanjing', 'city': 'New York', 'state': 'NY', 'zip': '10468'}

address3 = {'line 1': 'wuhan', 'line 2': 'tianmen', 'city': 'New York', 'state': 'NY', 'zip': '10468'}
address4 = {'addr1': 'wuhan', 'addr2': 'tianmen', 'city2': 'New York', 'state': 'NY2', 'zip': '11002'}

data1 = {'name': 'bob', 'billing_address': address1, 'shipping_address': address2}
data2 = {'name': 'bob', 'billing_address': address3, 'shipping_address': address4}

print(json.dumps(marshal(data1, resource_fields)))
print(json.dumps(marshal(data2, resource_fields)))

运行结果：