python marshmallow使用示例
作者：互联网
"""
棉花糖，序列化工具
核心方法：
序列化：schema.dump(object)、schema.dumps(object)
反序列化：schema.load(dict)
"""
import uuid
from datetime import datetime
from pprint import pprint
from marshmallow import Schema, fields, post_load, ValidationError, validate
"""
序列化和反序列化
"""
print(" v v v")
print("创建自定义对象----------------------------------------v v")
print(" v")
# 创建自定义对象object
class User:
def __init__(self, name, email, created_at):
self.name = name
self.email = email
self.created_at = created_at
print(" v v v")
print("创建Schema的两种方式----------------------------------v v")
print(" v")
# 创建结构描述
# 方式一
class UserSchema(Schema):
name = fields.Str()
email = fields.Email()
created_at = fields.DateTime()
@post_load
def make_user(self, data, **kwargs):
return User(**data)
# 方式二
UserSchema2 = Schema.from_dict({"name": fields.Str(), "email": fields.Email(), "created_at": fields.DateTime()})
print(" v v v")
print("序列化对象示例----------------------------------------v v")
print(" v")
# 序列化对象
user = User("zht", "2862058843@163.com", datetime.now())
userSchema = UserSchema()
result = userSchema.dump(user)
# 美化输出
pprint(result)
print(type(result))
userSchema2 = UserSchema2()
result2 = userSchema2.dump(user)
pprint(result2)
# print(result)
# 转成json字符串
json_result = userSchema2.dumps(user)
pprint(json_result)
print(type(json_result))
print(" v v v")
print("序列化对象示例(过滤输出)-------------------------------v v")
print(" v")
# 过滤输出
userSchema2 = UserSchema2(only=('name', 'email'))
json_result = userSchema2.dump(user)
pprint(json_result)
print(type(json_result))
print(json_result['name'])
print(" v v v")
print("返序列化对象示例--------------------------------------v v")
print(" v")
# 反序列化对象 注意的是 字典里的key，对象构造函数一定要有此key
user_data = {
"created_at": "2014-08-11T05:26:03.869245",
"email": "ken@yahoo.com",
"name": "Ken",
}
userSchema3 = UserSchema()
result = userSchema3.load(user_data)
pprint(result)
print(type(result))
# 反序列化对象集合
user1 = User("zht1", "2862058843@163.com", datetime.now())
user2 = User("zht2", "2862058843@164.com", datetime.now())
user3 = User("zht3", "2862058843@165.com", datetime.now())
users = [user1, user2, user3]
userSchemas = UserSchema(many=True)
result = userSchemas.dump(users)
pprint(result)
"""
验证属性值
"""
print(" v v v")
print("验证属性值示例----------------------------------------v v")
print(" v")
# 验证一个对象
print("验证一个对象")
try:
result = UserSchema().load({"name": "zht", "email": "zht"})
print(result)
except ValidationError as e:
print(e.messages)
print(e.valid_data)
# 验证多个对象
print("验证多个对象")
class BandMemberSchema(Schema):
name = fields.String(required=True)
email = fields.Email()
user_data = [
{"email": "mick@stones.com", "name": "Mick"},
{"email": "invalid", "name": "Invalid"}, # invalid email
{"email": "keith@stones.com", "name": "Keith"},
{"email": "charlie@stones.com"}, # missing "name"
]
try:
BandMemberSchema(many=True).load(user_data)
print(result)
except ValidationError as e:
print(e.messages)
print(e.valid_data)
# 通过传递 validate参数传递验证器对字段进行验证
print("通过传递 validate参数传递验证器对字段进行验证")
class MemberSchema(Schema):
name = fields.Str(validate=validate.Length(min=1)) # 最小字符长度
permission = fields.Str(validate=validate.OneOf(["read", "write", "admin"])) # 必须是其中一个
age = fields.Int(validate=validate.Range(min=18, max=40)) # 年龄必须是18到40
in_data = {"name": "1", "permission": "invalid", "age": 71}
try:
MemberSchema().load(in_data)
except ValidationError as e:
print(e.messages) # 输出针对每个字段的错误信息
print(e.valid_data) # 输出有效的字段 （验证通过的字段）
# 自己实现一个验证器
def validate_quantity(n):
if n < 0:
raise ValidationError("Quantity must be greater than 0.")
if n > 30:
raise ValidationError("Quantity must not be greater than 30.")
class ItemSchema(Schema):
quantity = fields.Integer(validate=validate_quantity)
in_data = {"quantity": -1}
try:
result = ItemSchema().load(in_data)
print(result)
except ValidationError as e:
print(e.messages) # 输出针对每个字段的错误信息
print(e.valid_data) # 输出有效的字段 （验证通过的字段）
# 自定义错误信息
print("自定义字段验证required的错误消息")
class TRequiredSchema(Schema):
name = fields.String(required=True)
age = fields.Integer(required=True, error_messages={"required": "Age is required."})
city = fields.String(
required=True,
error_messages={"required": {"message": "City required", "code": 400}},
)
email = fields.Email()
try:
result = TRequiredSchema().load({"email": "foo@bar.com"})
except ValidationError as err:
pprint(err.messages)
# {'age': ['Age is required.'],
# 'city': {'code': 400, 'message': 'City required'},
# 'name': ['Missing data for required field.']}
print("指定默认值")
# 指定默认
class DefaultSchema(Schema):
id = fields.UUID(missing=uuid.uuid1)
birthdate = fields.DateTime(default=datetime(2017, 9, 29))
name = fields.String(default="火")
print(DefaultSchema().load({}))
# {'id': UUID('337d946c-32cd-11e8-b475-0022192ed31b')}
print(DefaultSchema().dump({}))
# {'birthdate': '2017-09-29T00:00:00+00:00'}
标签：name,marshmallow,示例,python,fields,result,print,data,email 来源： https://www.cnblogs.com/zht-ytr/p/14041778.html