Python 如何创建具有参数的装饰器来解析请求?
我有以下方法:Python 如何创建具有参数的装饰器来解析请求?,python,decorator,Python,Decorator,我有以下方法: @try_except_decorator @json_response_decorator async def find_videos_in_polygon(request): points = request.query['points'] end_date = request.query['end_date'] start_date = request.query['start_date'] ding_kind = request.query
@try_except_decorator
@json_response_decorator
async def find_videos_in_polygon(request):
points = request.query['points']
end_date = request.query['end_date']
start_date = request.query['start_date']
ding_kind = request.query.get('ding_kind', 'all')
search_service = request.app['search_service']
data = await search_service.search_in_polygon(points, start_date,
end_date,
ding_kind=ding_kind,
doorbot_kind=doorbot_kind)
return {'videos': data}
如何创建一个将解析请求的装饰器?我想要这样的东西:
@try_except_decorator
@json_response_decorator
@parse_request('points', 'end_date', 'start_date', ('ding_kind', 'all'))
async def find_videos_in_polygon(request):
search_service = request.app['search_service']
data = await search_service.search_in_polygon(???)
return {'videos': data}
另外,我不想更改
在多边形中查找视频(请求)
的签名。通常,您可以使用这种模式:
from functools import wraps
def your_decorator(arg1, arg2, arg3, kwarg1=None):
def wrapper(f):
@wraps(f)
def wrapped(*args, **kwargs):
# Do things with arg1, arg2, arg3 and kwarg1
# if the inner function `f` needs to access these arguments, you need to pass it in somehow.
return f(*args, **kwargs)
return wrapped
return wrapper
每次调用函数作用域时,似乎都希望将一些变量注入函数作用域。一种方法是临时将数据插入函数的全局作用域(
find\u videos\u in\u polygon.\uuuuu globals\uuu
),然后将其清除
def inject_variables(func, _new_values=None):
for k, v in _new_values.items():
func.__globals__[k] = v
def cleanup_variables(func, _default=None, _new_values=None, _old_values=None):
"""
Reset function's global scope with data in `_old_value`.
If a particular key's value is sentinel then it means the
key didn't exist and we can remove it.
"""
for k, v in _old_values.items():
old_value = _old_values[k]
if old_value is _default:
del func.__globals__[k]
else:
func.__globals__[k] = old_value
def parse_request(*names):
def decorator(func):
async def wrapper(*args, **kwargs):
request = args[0]
new_values = {}
current_global_values = {}
sentinel = object()
for var in names:
name = var
if isinstance(var, tuple):
name, value = var
new_values[name] = request.query.get(name, value)
else:
try:
new_values[name] = request.query[name]
except KeyError:
raise UnboundLocalError("local variable '{name}' referenced before assignment".format(
name=name
))
current_global_values[name] = func.__globals__.get(name, sentinel)
inject_variables(func, _new_values=new_values)
val = await func(*args, **kwargs)
cleanup_variables(func, _default=sentinel, _new_values=new_values, _old_values=current_global_values)
return val
return wrapper
return decorator
测试代码:
from asyncio import get_event_loop
missing = 10000
@parse_request('foo', 'bar', 'spam', 'eggs', ('missing', '10'))
async def func(request):
print(foo, bar, spam, eggs, missing)
class Request:
pass
loop = get_event_loop()
Request.query = {'foo': 1, 'bar': 2, 'spam': 3, 'eggs': 4}
loop.run_until_complete(func(Request))
print(missing)
Request.query = {'foo': 1, 'bar': 2, 'spam': 3, 'eggs': 4, 'missing': 15}
loop.run_until_complete(func(Request))
print(missing)
# Missing required key 'eggs', should raise an error
Request.query = {'foo': 1, 'bar': 2, 'spam': 3}
loop.run_until_complete(func(Request))
print(missing)
1 2 3 4 10
10000
1 2 3 4 15
10000
...
UnboundLocalError: local variable 'eggs' referenced before assignment
>>> Request.query = {'foo': 1, 'bar': 2, 'spam': 3, 'eggs': 4}
>>> loop.run_until_complete(func(Request))
{'foo': 1, 'bar': 2, 'spam': 3, 'eggs': 4, 'missing': '10'}
>>> Request.query = {'foo': 1, 'bar': 2, 'spam': 3, 'eggs': 4, 'missing': 15}
>>> loop.run_until_complete(func(Request))
{'foo': 1, 'bar': 2, 'spam': 3, 'eggs': 4, 'missing': 15}
>>> Request.query = {'foo': 1, 'bar': 2, 'spam': 3}
>>> loop.run_until_complete(func(Request))
---------------------------------------------------------------------------
KeyError: 'eggs'
输出:
from asyncio import get_event_loop
missing = 10000
@parse_request('foo', 'bar', 'spam', 'eggs', ('missing', '10'))
async def func(request):
print(foo, bar, spam, eggs, missing)
class Request:
pass
loop = get_event_loop()
Request.query = {'foo': 1, 'bar': 2, 'spam': 3, 'eggs': 4}
loop.run_until_complete(func(Request))
print(missing)
Request.query = {'foo': 1, 'bar': 2, 'spam': 3, 'eggs': 4, 'missing': 15}
loop.run_until_complete(func(Request))
print(missing)
# Missing required key 'eggs', should raise an error
Request.query = {'foo': 1, 'bar': 2, 'spam': 3}
loop.run_until_complete(func(Request))
print(missing)
1 2 3 4 10
10000
1 2 3 4 15
10000
...
UnboundLocalError: local variable 'eggs' referenced before assignment
>>> Request.query = {'foo': 1, 'bar': 2, 'spam': 3, 'eggs': 4}
>>> loop.run_until_complete(func(Request))
{'foo': 1, 'bar': 2, 'spam': 3, 'eggs': 4, 'missing': '10'}
>>> Request.query = {'foo': 1, 'bar': 2, 'spam': 3, 'eggs': 4, 'missing': 15}
>>> loop.run_until_complete(func(Request))
{'foo': 1, 'bar': 2, 'spam': 3, 'eggs': 4, 'missing': 15}
>>> Request.query = {'foo': 1, 'bar': 2, 'spam': 3}
>>> loop.run_until_complete(func(Request))
---------------------------------------------------------------------------
KeyError: 'eggs'
当然,这样做会降低代码的可读性和调试难度。因此,最好是明确的,做一些更容易理解和测试的事情。我建议添加一个helper函数,该函数可以解析并返回dict,其中包含
search\u in\u polygon
所需的所有关键字参数
def parse_request(request, *names):
data = {}
for var in names:
name = var
if isinstance(var, tuple):
name, value = var
data[name] = request.query.get(name, value)
else:
data[name] = request.query[name]
return data
async def func(request):
request_data = parse_request(request, 'foo', 'bar', 'spam', 'eggs', ('missing', '10'))
print(request_data)
# data = await search_in_polygon(**request_data)
演示:
from asyncio import get_event_loop
missing = 10000
@parse_request('foo', 'bar', 'spam', 'eggs', ('missing', '10'))
async def func(request):
print(foo, bar, spam, eggs, missing)
class Request:
pass
loop = get_event_loop()
Request.query = {'foo': 1, 'bar': 2, 'spam': 3, 'eggs': 4}
loop.run_until_complete(func(Request))
print(missing)
Request.query = {'foo': 1, 'bar': 2, 'spam': 3, 'eggs': 4, 'missing': 15}
loop.run_until_complete(func(Request))
print(missing)
# Missing required key 'eggs', should raise an error
Request.query = {'foo': 1, 'bar': 2, 'spam': 3}
loop.run_until_complete(func(Request))
print(missing)
1 2 3 4 10
10000
1 2 3 4 15
10000
...
UnboundLocalError: local variable 'eggs' referenced before assignment
>>> Request.query = {'foo': 1, 'bar': 2, 'spam': 3, 'eggs': 4}
>>> loop.run_until_complete(func(Request))
{'foo': 1, 'bar': 2, 'spam': 3, 'eggs': 4, 'missing': '10'}
>>> Request.query = {'foo': 1, 'bar': 2, 'spam': 3, 'eggs': 4, 'missing': 15}
>>> loop.run_until_complete(func(Request))
{'foo': 1, 'bar': 2, 'spam': 3, 'eggs': 4, 'missing': 15}
>>> Request.query = {'foo': 1, 'bar': 2, 'spam': 3}
>>> loop.run_until_complete(func(Request))
---------------------------------------------------------------------------
KeyError: 'eggs'
可能是重复的,那么你的问题到底是什么?你现在有什么关于
parse\u request
的代码?我不知道如何实现@parse\u request()
decorator并在search\u服务中使用解析后的参数。像我以前做的那样在\u polygon(…)
中搜索。