认识 Fields marshal marshal_with

Fields

user_fields = {
    'id': fields.Integer,
    'username': fields.String,
    'email': fields.String,
    'user_priority': fields.Integer,
    'custom_greeting': fields.FormattedString('Hey there {username}!'),
    'date_created': fields.DateTime,
    'date_updated': fields.DateTime,
    'links': fields.Nested({
        'friends': fields.Url('/Users/{id}/Friends', absolute=True),
        'posts': fields.Url('Users/{id}/Posts', absolute=True),
    }),
}

class fields.String(default=None,attribute=None)
将获得的值编列为字符串
class fields.Integer(default=o,**kwargs)
将获得的值编列为Int型
class fields.DateTime(dt_format=’rfc822’, **kwargs)
以UTC的格式返回格式化后的时间字符串
class fields.FormattedString(src_str)
在fields的response中插入其他的值

Ex:

fields = {
    'name': fields.String,
    'greeting': fields.FormattedString("Hello {name}")
}
data = {
    'name': 'Doug',
}
marshal(data, fields)

class fields.Nested(nested, allow_null=False, **kwargs)
在响应中创建子对象
class fields.Url(endpoint=None,absolute=False,scheme=None)
UrI的字符串表示，接受一个字符串作为参数，absolute确定生成的Urls是否包含主机名。

参考：http://www.pythondoc.com/Flask-RESTful/intermediate-usage.html

class fields.List(cls_or_instance, **kwargs)
可用于一个参数对应多个值的情况

详见：http://www.pythondoc.com/Flask-RESTful/fields.html#list-field

# marshal

flask.ext.restful.marshal(data, fields, envelope=None)¶

Takes raw data (in the form of a dict, list, object) and a dict of fields to output and filters the data based on those fields.

Parameters:	data – the actual object(s) from which the fields are taken from fields – a dict of whose keys will make up the final serialized response output envelope – optional key that will be used to envelop the serialized response

>>> from flask.ext.restful import fields, marshal
>>> data = { 'a': 100, 'b': 'foo' }
>>> mfields = { 'a': fields.Raw }

>>> marshal(data, mfields)
OrderedDict([('a', 100)])

>>> marshal(data, mfields, envelope='data')
OrderedDict([('data', OrderedDict([('a', 100)]))])

官方API文档：http://www.pythondoc.com/Flask-RESTful/api.html

将原始数据过滤后序列化输出,输出结果的形式与fields参数有关。
data为原始数据，envelope为封装序列化的结果。
fields.Raw:
如mfields={‘a’:fields.Raw} ，原始数据data中’a’:100,故marshal的结果中fields.Raw为100。

OrderedDict，实现了对字典对象中元素的排序。

这里写图片描述

marshal_with

flask.ext.restful.marshal_with(fields, envelope=None)¶

A decorator that apply marshalling to the return values of your methods.

>>> from flask.ext.restful import fields, marshal_with
>>> mfields = { 'a': fields.Raw }
>>> @marshal_with(mfields)
... def get():
...     return { 'a': 100, 'b': 'foo' }
...
...
>>> get()
OrderedDict([('a', 100)])

>>> @marshal_with(mfields, envelope='data')
... def get():
...     return { 'a': 100, 'b': 'foo' }
...
...
>>> get()
OrderedDict([('data', OrderedDict([('a', 100)]))])

see flask.ext.restful.marshal()

marshal_with的用法则和marsh很类似。

原文:

https://blog.csdn.net/qq_37054356/article/details/77145959

认识 Fields marshal marshal_with

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