如何将键值传递给 python 中的装饰器？

Question

我正在尝试验证字典参数。

import logging
import os
# decorator
def file_validator(f):
    def wrapped(*args):
        """
        Once there is passed values,
        file_path = os.path.join(path_info, file_info)
        if os.path.exists(file_path):
            logging.info('{} exists'.format(file_info))
        else:
            logging.info('{} does not exist'.format(file_info))
        """

# original function
@file_validator
def original_function(file_dict):
    # pass only specific element to file_validator decorator for checking
    # for example only "pathA": "/files", "fileA": "bar.csv"

sample_dict = {"pathA": "/files", "fileA": "bar.csv", "fileB": "hello.txt"}
original_function(sample_dict)

有没有办法使用装饰器检查这种方式？
编辑这可能相当于我想要做的。

def file_validator(filepath, filename):
    file_path = os.path.join(filepath + filename)
    if os.path.exists(file_path):
        logging.info('{} exists'.format(filename))
    else:
        logging.info('{} does not exist'.format(filename))

def original_function(file_dict):
    file_validator(file_dict['pathA'], file_dict['fileA'])
    file_validator(file_dict['pathA'], file_dict['fileB'])

sample_dict = {"pathA": "/files", "fileA": "bar.csv", "fileB": "hello.txt"}
original_function(sample_dict)

Answer 1

似乎这样的事情应该可以解决问题：

import os
import logging

def file_validator(func):
    def wrapper(file_dict:dict):
        
        # Turn file_dict to two lists:
        #   paths = ["/files"]
        #   files = ["bar.csv", "hello.txt"]
        paths = [
            path 
            for name, path in file_dict.items() 
            if name.startswith("path")
        ]
        files = [
            file 
            for name, file in file_dict.items() 
            if name.startswith("file")
        ]

        # Loop through all the path & file combinations and check if they exist
        for path in paths:
            for file in files:
               
                full_path = os.path.join(path, file)
                if os.path.exists(full_path):
                    logging.info('{} exists'.format(file))
                else:
                    logging.info('{} does not exist'.format(file))

        # Run the actual function
        return func(file_dict)
    return wrapper

@file_validator
def original_function(file_dict):
    ...

files = {"pathA": "/files", "fileA": "bar.csv", "fileB": "hello.txt"}
original_function(files) 
# Note that fileB is not checked as it's missing "pathB" 
# but from the question it is unclear how this should be handled 

但是有一些代码味道。 如果可能的话，我建议不要以这种方式存储您的路径和文件，因为这不容易操作并且容易出现错误。 更好的是通过使用itertools.combinations创建所有组合将它们存储为完整路径的列表，或者只有两个列表：路径和文件。

Answer 2

logging.info 在此处替换为 print 以进行验证。

import logging
import os

def file_validator(f):
    def wrapper(args):
        for path, file in args.items():
            file_path = os.path.join(path, file)
            if os.path.exists(file_path):
                print('{} exists'.format(file_path))
            else:
                print('{} does not exist'.format(file_path))
        f(args)
    return wrapper


@file_validator
def original_function(file_dict):
    print(file_dict)

sample_dict = {"pathA": "\\files", "fileA": "bar.csv", "fileB": "hello.txt"}
original_function(sample_dict)