Python 瓶内干法验证？

我的瓶子应用程序不是很干，下面是一个测试案例：

from uuid import uuid4
from bottle import Bottle, response

foo_app = Bottle()

@foo_app.post('/foo')
def create():
    if not request.json:
        response.status = 400
        return {'error': 'ValidationError', 'error_message': 'Body required'}
    body = request.json
    body.update({'id': uuid4().get_hex())
    # persist to db
    # ORM might set 'id' on the Model layer rather than setting it here
    # ORM will validate, as will db, so wrap this in a try/catch
    response.status = 201
    return body

@foo_app.put('/foo/<id>')
def update(id):
    if not request.json:
        response.status = 400
        return {'error': 'ValidationError', 'error_message': 'Body required'}
    elif 'id' not in request.json:
        response.status = 400
        return {'error': 'ValidationError', 'error_message': '`id` required'}
    db = {} # should be actual db cursor or whatever
    if 'id' not in db:
        response.status = 404
        return {'error': 'Not Found',
                'error_message': 'Foo `id` "{id}" not found'.format(id)}
    body = request.json
    # persist to db, return updated object
    # another try/catch here in case of update error (from ORM and/or db)
    return body

---

这是我的干式验证解决方案，最终由一个装饰师完成：

from itertools import imap, ifilter    
from bottle import Bottle, request, response

app = Bottle()

middleware = lambda functions: lambda caller: lambda *args, **kwargs: next(
    ifilter(None, imap(lambda g: g(*args, **kwargs), functions)),
    caller(*args, **kwargs)
)


def has_body(*args, **kwargs):
    if not request.json:
        response.status = 400
        return {'error': 'ValidationError',
                'error_message': 'Body is required (and must be JSON).'}


def body_req(required):
    def inner(*args, **kwargs):
        intersection = required.intersection(set(request.json.keys()))
        if intersection != required:
            response.status = 400
            return {'error': 'ValidationError',
                   'error_message': 'Key(s): {} are not in JSON payload'.format(
                    ', '.join(imap(lambda key: "'{key}'".format(key=key),
                              required - intersection)))}

    return inner


@app.post('/foo')
@middleware([has_body, body_req({'id', 'f'})])
def get_foo():
    return {'foo': 'bar'}

---

最终找到了瓶子的内置“中间件”，称为“插件”（）：

---

我只是好奇（因为我到处都在使用它们）-你有关于“装饰者…有开销问题”的参考资料吗？我不记得我什么时候听说过这个，但这里有一篇关于它的博客文章：谢谢，感谢你的参考。FWIW，共识是（比我更伟大的Pythonistas）装饰者天生不会增加太多开销，所以我想我建议重新考虑这个方法。好吧，我想我可以添加一个装饰器（它需要一个函数列表）。请参阅我的答案，并根据您认为合适的方式进行评论/投票。谢谢

from itertools import imap, ifilter    
from bottle import Bottle, request, response

app = Bottle()

middleware = lambda functions: lambda caller: lambda *args, **kwargs: next(
    ifilter(None, imap(lambda g: g(*args, **kwargs), functions)),
    caller(*args, **kwargs)
)


def has_body(*args, **kwargs):
    if not request.json:
        response.status = 400
        return {'error': 'ValidationError',
                'error_message': 'Body is required (and must be JSON).'}


def body_req(required):
    def inner(*args, **kwargs):
        intersection = required.intersection(set(request.json.keys()))
        if intersection != required:
            response.status = 400
            return {'error': 'ValidationError',
                   'error_message': 'Key(s): {} are not in JSON payload'.format(
                    ', '.join(imap(lambda key: "'{key}'".format(key=key),
                              required - intersection)))}

    return inner


@app.post('/foo')
@middleware([has_body, body_req({'id', 'f'})])
def get_foo():
    return {'foo': 'bar'}

from bottle import Bottle, request, response

app = Bottle()


def has_body(f):
    def inner(*args, **kwargs):
        if request.json:
            return f(*args, **kwargs)

        response.status = 400
        return {'error': 'ValidationError',
                'error_message': 'Body is required (and must be JSON).'}
    return inner


def body_req(required):
    def body_req_middleware(f):
        def inner(*args, **kwargs):
            intersection = required.intersection(set(request.json.keys()))
            if intersection != required:
                response.status = 400
                return {'error': 'ValidationError',
                        'error_message': 'Key(s): {} are not in JSON payload'
                        ''.format(', '.join('{!r}'.format(k)
                                            for k in required - intersection))}
            return f(*args, **kwargs)
        return inner
    return body_req_middleware


@app.post('/foo', apply=(has_body, body_req({'id', 'f'})))
def get_foo():
    return {'foo': 'bar'}