[英]How to apply the same decorator chain to multiple functions
@extend_schema(
methods=['GET'],
responses={(200, STYLES_MIME_TYPE): OpenApiTypes.BINARY})
@extend_schema(
methods=['PUT'],
request={STYLES_MIME_TYPE: OpenApiTypes.BINARY},
responses={(204, 'application/json'): OpenApiResponse(
response={'type': 'array', 'items': {'type': 'integer', 'format': 'int32'}},
examples=[OpenApiExample(
'Returned style IDs example',
status_codes=['204'],
value=[101, 102, 103])])})
@api_view(['GET', 'PUT'])
@permission_classes([IsAuthenticated|ReadOnly])
@renderer_classes([StylesRenderer, StylesJSONRenderer])
@parser_classes([StylesParser])
def styles(request: Request, pid: int) -> Response:
"""
Get or save styles for a project.
GET - protobuf binary response
POST - returnd IDs for saved styles
"""
try:
project = Project.objects.get(pk=pid)
return _handle_styles(request, project)
except Project.DoesNotExist:
raise Http404()
@extend_schema(
methods=['GET'],
responses={(200, STYLES_MIME_TYPE): OpenApiTypes.BINARY})
@extend_schema(
methods=['PUT'],
request={STYLES_MIME_TYPE: OpenApiTypes.BINARY},
responses={(204, 'application/json'): OpenApiResponse(
response={'type': 'array', 'items': {'type': 'integer', 'format': 'int32'}},
examples=[OpenApiExample(
'Returned style IDs example',
status_codes=['204'],
value=[101, 102, 103])])})
@api_view(['GET', 'PUT'])
@permission_classes([IsAuthenticated|ReadOnly])
@renderer_classes([StylesRenderer, StylesJSONRenderer])
@parser_classes([StylesParser])
def styles_xref(request: Request, xref: uuid.UUID) -> Response:
"""
Get or save styles for a project.
GET - protobuf binary response
POST - returnd IDs for saved styles
"""
try:
project = Project.objects.get(xref=xref)
return _handle_styles(request, project)
except Project.DoesNotExist:
raise Http404()
這是 Django,顯然我想對這 2 個視圖使用相同的裝飾器。 唯一的區別是一個通過 int ID 查找 object,另一個通過 UUID 外部引用字段查找。 我怎樣才能保持干燥?
您可以定義一個新的裝飾器,它返回一個帶有您想要的鏈的預裝飾 function 。 例如,我們可以先定義三個自定義裝飾器:
import functools
# A decorator factory which returns a new decorator.
def decorator_factory(message):
def decorator(function):
# Wraps the decorated function.
@functools.wraps(function)
def wrapper(*args, **kwargs):
# Example behavior:
# - Prints a message before calling the decorated function.
print(message)
# Calls the decorated function.
return function(*args, **kwargs)
return wrapper
return decorator
# Defines three new decorators.
decorator_1 = decorator_factory("Ham")
decorator_2 = decorator_factory("Spam")
decorator_3 = decorator_factory("Eggs")
目前調用這些裝飾器的方式類似於以下內容,它很快就會對多個函數重復:
@decorator_1
@decorator_2
@decorator_3
def f():
pass # Do something.
@decorator_1
@decorator_2
@decorator_3
def g():
pass # Do something.
@decorator_1
@decorator_2
@decorator_3
def h():
pass # Do something.
但是,您可以在裝飾器的主體內裝飾包裝器 function:
def decorator_chain(function):
@functools.wraps(function)
@decorator_1
@decorator_2
@decorator_3
def wrapper(*args, **kwargs):
return function(*args, **kwargs)
return wrapper
這將 function 的定義簡化為:
@decorator_chain
def f():
pass # Do something.
@decorator_chain
def g():
pass # Do something.
@decorator_chain
def h():
pass # Do something.
在您提供的示例中,這可能類似於以下內容:
import functools
def decorator_chain(function):
@functools.wraps(function)
@extend_schema(
methods = ['GET'],
responses = {(200, STYLES_MIME_TYPE): OpenApiTypes.BINARY}
)
@extend_schema(
methods = ['PUT'],
request = {STYLES_MIME_TYPE: OpenApiTypes.BINARY},
responses = {
(204, 'application/json'): OpenApiResponse(
response = {'type': 'array', 'items': {'type': 'integer', 'format': 'int32'}},
examples = [
OpenApiExample(
'Returned style IDs example',
status_codes = ['204'],
value = [101, 102, 103]
)
]
)
}
)
@api_view(['GET', 'PUT'])
@permission_classes([IsAuthenticated | ReadOnly])
@renderer_classes([StylesRenderer, StylesJSONRenderer])
@parser_classes([StylesParser])
def wrapper(*args, **kwargs):
return function(*args, **kwargs)
return wrapper
@decorator_chain
def styles(request: Request, pid: int) -> Response:
"""
Get or save styles for a project.
GET - protobuf binary response
POST - returnd IDs for saved styles
"""
try:
project = Project.objects.get(pk=pid)
return _handle_styles(request, project)
except Project.DoesNotExist:
raise Http404()
@decorator_chain
def styles_xref(request: Request, xref: uuid.UUID) -> Response:
"""
Get or save styles for a project.
GET - protobuf binary response
POST - returnd IDs for saved styles
"""
try:
project = Project.objects.get(xref=xref)
return _handle_styles(request, project)
except Project.DoesNotExist:
raise Http404()
使用裝飾器工廠甚至可以讓您快速創建給定裝飾器鏈的不同變體。
來自GeeksForGeeks的修改示例
裝飾器本質上是普通函數。 因此,您可以使用部分方法向他們提供一組 arguments 而無需實際調用該方法。
from functools import partial
def decorator(like):
print("Inside decorator")
def inner(func):
print(like)
func()
return inner
premade_decorator = partial(decorator, like = "geeksforgeeks")
@premade_decorator()
def my_func():
print("Inside actual function")
現在我們知道如何將參數預先應用到裝飾器,我們可以嘗試鏈接它們:
def chain_decorator(dec_list):
def inner(func):
for dec in dec_list:
func = partial(dec(), func)
return func
return inner
@chain_decorator([premade_decorator1, premade_decorator2])
def my_func():
print("Inside actual function")
return 1
print(my_func())
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