argparse在Python类中的验证

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英文:

argparse validation in a python class

问题

我尝试使用面向对象的方法来处理我的Python代码，最终将其转换为由PyInstaller创建的.EXE文件。这个想法是从用户输入中传递一系列参数给程序，最终会变成类似于(myprogram.exe -secureFolder C:/Users -thisisacsvfile.csv -countyCode 01069 -utmZone 15)的形式。

我可以初始化一个类定义并传递参数，如下所示：

  1. import argparse
  2. import sys
  4. class myprogram():
  5.     def __init__(self, secureFolder, inputCsvFile, countyCode, utmZone):
  6.         self.secureFolder = secureFolder
  7.         self.inputCsvFile = inputCsvFile
  8.         self.countyCode = countyCode
  9.         self.utmZone = utmZone
  12. if __name__ == '__main__':
  13.     parser = argparse.ArgumentParser()
  14.     parser.add_argument("secureFolder", help="A directory where the files are located", type=str)
  15.     parser.add_argument("inputCsvFile", help="A CSV file containing the results for a particular county (e.g. 36107.csv)", type=str)
  16.     parser.add_argument("countyCode", help="The FIPS county code", type=str)
  17.     parser.add_argument("utmZone", help="The UTM zone code for that specific county (e.g. 18)", type=int)

然而，我需要验证每个用户参数，这是我感到困惑的部分。换句话说，我需要检查secureFolder是否存在，inputCsvFile是否确实是CSV文件并且包含特定列以及其他操作来验证其余的参数。我不确定这些操作应该在哪里执行？在类定义之后还是之前？

在采用面向对象的方法之前，我是这样做的：

  1. # 检查是否传递了所有参数
  2. undefined_arguments = [attr for attr in vars(args) if getattr(args, attr) is None]
  3. if undefined_arguments:
  4.     print("以下参数未定义：", undefined_arguments)
  5. else:
  6.     print("所有参数都已定义。")
  8. # 1a. 检查inputCsvFile
  9. if args.inputCsvFile is None:
  10.     sys.exit("请选择要处理的输入CSV文件 (例如：inputCsvFile.../myfile.csv)")
  11. else:
  12.     if not os.path.isfile(args.inputCsvFile):
  13.         sys.exit(f"文件 {args.inputCsvFile} 似乎不存在...请检查文件是否存在或您是否具有访问权限")
  14.     else:
  15.         grid_file_csv = args.inputCsvFile
  16.         print(f"{args.inputCsvFile} 已找到...")
  18. # 1b. 检查inputCsvFile是否为CSV文件
  19. if not args.inputCsvFile.endswith('.csv'):
  20.     raise ValueError("无效的输入文件。预期是一个CSV文件。")
  21.     sys.exit('未传递正确的CSV文件...')

希望这可以帮助你理解在面向对象编程方法中应该如何验证参数。如果需要进一步的帮助，请随时提问。

英文:

I'm trying an OOP approach to my Python code which eventually will be converted to an .EXE file created with PyInstaller. The idea is to pass a series of arguments from the user input (n to a program that eventually will go something like (myprogram.exe -secureFolder C:/Users -thisisacsvfile.csv -countyCode 01069 -utmZone 15).

I can initialize a class definition and pass the arguments like:

  1. import argparse
  2. import sys
  4. class myprogram():
  5.     def __init__(self, secureFolder, inputCsvFile, countyCode, utmZone):
  6.         self.secureFolder = secureFolder
  7.         self.inputCsvFile = inputCsvFile
  8.         self.countyCode = countyCode
  9.         self.utmZone = utmZone
  10.         
  11.         
  12. if __name__ == '__main__':
  13.     parser = argparse.ArgumentParser()
  14.     parser.add_argument("secureFolder", help = "A directory where the files are located", type=str)
  15.     parser.add_argument("inputCsvFile",  help="A CSV file containing the results for a particular county (e.g. 36107.csv)", type=str)
  16.     parser.add_argument("countyCode", help = "The FIPS county code", type = str)
  17.     parser.add_argument("utmZone", help = "The UTM zone code for that specific county (e.g. 18)", type = int)

However, I need to validate every user argument and that's the part where I'm getting confused. In other words, I need to check if the secureFolder exists, if the inputCsvFile is indeed a CSV and contains some specific columns and other operations for the rest of the arguments. What I don't know exactly, where do I perform these operations? After the class definition?
Before the OOP approach, I was doing something like:

  1. # Check if all the arguments were passed
  2. undefined_arguments = [attr for attr in vars(args) if getattr(args, attr) is None]
  3. if undefined_arguments:
  4.     print("The following arguments were not defined:", undefined_arguments)
  5. else:
  6.     print("All arguments were defined.")
  8. # 1a. Check inputCsvFile
  9. if args.inputCsvFile is None:
  10.     sys.exit("Please select an input CSV file to process (e.g. inputCsvFile.../myfile.csv) ")
  11. else:
  12.     if not os.path.isfile(args.inputCsvFile):
  13.         sys.exit (f"File {args.inputCsvFile} doesn't appear to exists...please check if the file exists or if you have privileges to access it")
  14.     else:
  15.         grid_file_csv = args.inputCsvFile 
  16.         print (f"{args.inputCsvFile} found...")
  18. # 1b. Check if inputCsvFile is a CSV:
  19. if not args.inputCsvFile.endswith('.csv'):
  20.     raise ValueError("Invalid input file. Expected a CSV file.")
  21.     sys.exit('No propper CSV file has been passed...')
  23. # 2. Check if the FIPS code
  24. if args.countyCode is None:
  25.    sys.exit("Please specify a valid county code (e.g. -countyCode3607)")
  26.              
  27. # Check the UTM area code
  28. if args.utmzone is None:
  29.    sys.exit("Please specify a valid UTM zone area (e.g. -utmZone 16): ")
  31. if args.utmZone is not None:
  32.     val = args.utmZone 
  33.     if val < 1 and val > 20:
  34.         raise Exception('UTM zone area should be between 1 and 20')
  35.         sys.exit()

答案1

得分: 1

这主要是一个风格和偏好的问题。在我看来，尽可能在构建任何类之前都应该验证构建该类所需的值 - 尤其是当它依赖于用户输入时。

所以，获取命令行参数，验证它们，然后构建你的类。类似于这样：

  1. import argparse
  2. from sys import stderr
  3. import os
  6. class myprogram():
  7.     def __init__(self, secureFolder, inputCsvFile, countyCode, utmZone):
  8.         self.secureFolder = secureFolder
  9.         self.inputCsvFile = inputCsvFile
  10.         self.countyCode = countyCode
  11.         self.utmZone = utmZone
  13.     def __str__(self):
  14.         return f'{self.secureFolder=}, {self.inputCsvFile=}, {self.countyCode=}, {self.utmZone=}'
  15.     
  16.     @staticmethod
  17.     def validate(ns):
  18.         if not os.path.isdir(ns.secureFolder):
  19.             print(f'{ns.secureFolder} is not a valid folder', file=stderr)
  20.             return None
  21.         try:
  22.             with open(ns.inputCsvFile) as _:
  23.                 ...
  24.         except Exception as e:
  25.             print(f'Unable to open {ns.inputCsvFile} due to {e}', file=stderr)
  26.             return None
  27.         if ns.countyCode is None:
  28.             print(f'{ns.countyCode} is an invalid county code', file=stderr)
  29.             return None
  30.         if (z := ns.utmZone) is None or z < 1 or z > 60:
  31.             print(f'{z} is not a valid utmZone', file=stderr)
  32.             return None
  33.         return myprogram(ns.secureFolder, ns.inputCsvFile, ns.countyCode, ns.utmZone)
  36. if __name__ == '__main__':
  37.     parser = argparse.ArgumentParser()
  38.     cli = [
  39.         ('-secureFolder', 'A directory where the files are located', str),
  40.         ('-inputCsvFile', 'A CSV file containing the results for a particular county (e.g., 36107.csv)', str),
  41.         ('-countyCode', 'The FIPS county code', str),
  42.         ('-utmZone', 'The UTM zone code for that specific county (e.g., 18)', int)
  43.     ]
  44.     for c, h, t in cli:
  45.         parser.add_argument(c, help=h, type=t)
  47.     args = parser.parse_args()
  49.     if (mp := myprogram.validate(args)) is None:
  50.         print('Unable to construct class instance')
  51.     else:
  52.         # 此时我们有一个有效的myprogram类实例（mp）
  53.         print(mp)

希望这对你有所帮助。

英文:

This is largely a question of style and preference. In my view, wherever possible, values needed to construct any class should be validated before the class is constructed - especially when it relies on user input.

So, get the command line arguments, validate them, then construct your class. Something like this:

  1. import argparse
  2. from sys import stderr
  3. import os
  4. class myprogram():
  5. def __init__(self, secureFolder, inputCsvFile, countyCode, utmZone):
  6. self.secureFolder = secureFolder
  7. self.inputCsvFile = inputCsvFile
  8. self.countyCode = countyCode
  9. self.utmZone = utmZone
  10. def __str__(self):
  11. return f&#39;{self.secureFolder=}, {self.inputCsvFile=}, {self.countyCode=}, {self.utmZone=}&#39;
  12. @staticmethod
  13. def validate(ns):
  14. if not os.path.isdir(ns.secureFolder):
  15. print(f&#39;{ns.secureFolder} is not a valid folder&#39;, file=stderr)
  16. return None
  17. try:
  18. with open(ns.inputCsvFile) as _:
  19. ...
  20. except Exception as e:
  21. print(f&#39;Unable to open {ns.inputCsvFile} due to {e}&#39;, file=stderr)
  22. return None
  23. if ns.countyCode is None:
  24. print(f&#39;{ns.countyCode} is an invalid county code&#39;, file=stderr)
  25. return None
  26. if (z := ns.utmZone) is None or z &lt; 1 or z &gt; 60:
  27. print(f&#39;{z} is not a valid utmZone&#39;, file=stderr)
  28. return None
  29. return myprogram(ns.secureFolder, ns.inputCsvFile, ns.countyCode, ns.utmZone)
  30. if __name__ == &#39;__main__&#39;:
  31. parser = argparse.ArgumentParser()
  32. cli = [
  33. (&#39;-secureFolder&#39;, &#39;A directory where the files are located&#39;, str),
  34. (&#39;-inputCsvFile&#39;, &#39;A CSV file containing the results for a particular county (e.g., 36107.csv)&#39;, str),
  35. (&#39;-countyCode&#39;, &#39;The FIPS county code&#39;, str),
  36. (&#39;-utmZone&#39;, &#39;The UTM zone code for that specific county (e.g., 18)&#39;, int)
  37. ]
  38. for c, h, t in cli:
  39. parser.add_argument(c, help=h, type=t)
  40. args = parser.parse_args()
  41. if (mp := myprogram.validate(args)) is None:
  42. print(&#39;Unable to construct class instance&#39;)
  43. else:
  44. # at this point we have a valid myprogram class instance (mp)
  45. print(mp)

答案2

得分: 0

argparse库可以为您执行一些验证操作，例如确保参数是必需的。对于其余部分，您可以编写小而简洁的验证函数：

  1. import argparse
  2. import pathlib
  4. class MyProgram:
  5.     def __init__(self, secureFolder, inputCsvFile, countyCode, utmZone):
  6.         self.secureFolder = secureFolder
  7.         self.inputCsvFile = inputCsvFile
  8.         self.countyCode = countyCode
  9.         self.utmZone = utmZone
  11. def validate_dir(value):
  12.     path = pathlib.Path(value)
  13.     if not path.is_dir():
  14.         raise ValueError()
  15.     return value
  17. def validate_csv(value):
  18.     path = pathlib.Path(value)
  19.     if not path.exists():
  20.         raise ValueError()
  21.     if path.suffix != ".csv":
  22.         raise ValueError()
  23.     return value
  25. def validate_utm_zone(value):
  26.     value = int(value)
  27.     if not (1 <= value <= 20):
  28.         raise ValueError()
  29.     return value
  31. if __name__ == "__main__":
  32.     parser = argparse.ArgumentParser()
  33.     parser.add_argument(
  34.         "-secureFolder",
  35.         help="文件所在的目录",
  36.         type=validate_dir,
  37.         required=True,
  38.     )
  39.     parser.add_argument(
  40.         "-inputCsvFile",
  41.         help="包含特定县的结果的CSV文件",
  42.         type=validate_csv,
  43.         required=True,
  44.     )
  45.     parser.add_argument("-countyCode", help="FIPS县代码", required=True)
  46.     parser.add_argument(
  47.         "-utmZone",
  48.         help="特定县的UTM区域代码（例如，18）",
  49.         type=validate_utm_zone,
  50.         required=True,
  51.     )
  53.     options = parser.parse_args()
  54.     print(options)
  55.     my_program = MyProgram(
  56.         secureFolder=options.secureFolder,
  57.         inputCsvFile=options.inputCsvFile,
  58.         countyCode=options.countyCode,
  59.         utmZone=options.utmZone,
  60.     )

以下是一些示例运行：

  1. # 正常情况
  2. $ python3  main.py -secureFolder ./myfolder -inputCsvFile input.csv -countyCode code-blah -utmZone 15 
  3. Namespace(secureFolder='./myfolder', inputCsvFile='input.csv', countyCode='code-blah', utmZone=15)
  5. # 没有提供任何参数
  6. $ python3  main.py                                                                                   
  8. # 目录/foobar不存在
  9. $ python3  main.py -secureFolder /foobar -inputCsvFile input.csv -countyCode code-blah -utmZone 15
  11. # 无效的utmZone
  12. $ python3  main.py -secureFolder ./myfolder -inputCsvFile input.csv -countyCode code-blah -utmZone foo
  14. # utmZone不在范围内
  15. $ python3  main.py -secureFolder ./myfolder -inputCsvFile input.csv -countyCode code-blah -utmZone 21 
  17. # CSV文件不以.csv结尾
  18. $ python3  main.py -secureFolder ./myfolder -inputCsvFile main.py -countyCode code-blah -utmZone 15
  20. # csv文件不存在
  21. $ python3  main.py -secureFolder ./myfolder -inputCsvFile input.csv -countyCode code-blah -utmZone 15
  23. # 获取帮助
  24. $ python3 main.py -h
英文:

The argparse library can do some validations for you, such as ensuring that the argument is required. For the rest, you can write small, concise validation functions:

  1. import argparse
  2. import pathlib
  5. class MyProgram:
  6.     def __init__(self, secureFolder, inputCsvFile, countyCode, utmZone):
  7.         self.secureFolder = secureFolder
  8.         self.inputCsvFile = inputCsvFile
  9.         self.countyCode = countyCode
  10.         self.utmZone = utmZone
  13. def validate_dir(value):
  14.     path = pathlib.Path(value)
  15.     if not path.is_dir():
  16.         raise ValueError()
  17.     return value
  20. def validate_csv(value):
  21.     path = pathlib.Path(value)
  22.     if not path.exists():
  23.         raise ValueError()
  24.     if path.suffix != &quot;.csv&quot;:
  25.         raise ValueError()
  26.     return value
  29. def validate_utm_zone(value):
  30.     value = int(value)
  31.     if not (1 &lt;= value &lt;= 20):
  32.         raise ValueError()
  33.     return value
  36. if __name__ == &quot;__main__&quot;:
  37.     parser = argparse.ArgumentParser()
  38.     parser.add_argument(
  39.         &quot;-secureFolder&quot;,
  40.         help=&quot;A directory where the files are located&quot;,
  41.         type=validate_dir,
  42.         required=True,
  43.     )
  44.     parser.add_argument(
  45.         &quot;-inputCsvFile&quot;,
  46.         help=&quot;A CSV file containing the results for a particular county&quot;,
  47.         type=validate_csv,
  48.         required=True,
  49.     )
  50.     parser.add_argument(&quot;-countyCode&quot;, help=&quot;The FIPS county code&quot;, required=True)
  51.     parser.add_argument(
  52.         &quot;-utmZone&quot;,
  53.         help=&quot;The UTM zone code for that specific county (e.g. 18)&quot;,
  54.         type=validate_utm_zone,
  55.         required=True,
  56.     )
  58.     options = parser.parse_args()
  59.     print(options)
  60.     my_program = MyProgram(
  61.         secureFolder=options.secureFolder,
  62.         inputCsvFile=options.inputCsvFile,
  63.         countyCode=options.countyCode,
  64.         utmZone=options.utmZone,
  65.     )

Here are some sample runs

  1. # Happy path
  2. $ python3  main.py -secureFolder ./myfolder -inputCsvFile input.csv -countyCode code-blah -utmZone 15 
  3. Namespace(secureFolder=&#39;./myfolder&#39;, inputCsvFile=&#39;input.csv&#39;, countyCode=&#39;code-blah&#39;, utmZone=15)
  5. # None of the arguments supplied
  6. $ python3  main.py                                                                                   
  7. usage: main.py [-h] -secureFolder SECUREFOLDER -inputCsvFile INPUTCSVFILE -countyCode COUNTYCODE -utmZone UTMZONE
  8. main.py: error: the following arguments are required: -secureFolder, -inputCsvFile, -countyCode, -utmZone
  10. # Directory /foobar does not exist
  11. $ python3  main.py -secureFolder /foobar -inputCsvFile input.csv -countyCode code-blah -utmZone 15
  12. usage: main.py [-h] -secureFolder SECUREFOLDER -inputCsvFile INPUTCSVFILE -countyCode COUNTYCODE -utmZone UTMZONE
  13. main.py: error: argument -secureFolder: invalid validate_dir value: &#39;/foobar&#39;
  15. # Invalid utmZone
  16. $ python3  main.py -secureFolder ./myfolder -inputCsvFile input.csv -countyCode code-blah -utmZone foo
  17. usage: main.py [-h] -secureFolder SECUREFOLDER -inputCsvFile INPUTCSVFILE -countyCode COUNTYCODE -utmZone UTMZONE
  18. main.py: error: argument -utmZone: invalid validate_utm_zone value: &#39;foo&#39;
  20. # utmZone not in range
  21. $ python3  main.py -secureFolder ./myfolder -inputCsvFile input.csv -countyCode code-blah -utmZone 21 
  22. usage: main.py [-h] -secureFolder SECUREFOLDER -inputCsvFile INPUTCSVFILE -countyCode COUNTYCODE -utmZone UTMZONE
  23. main.py: error: argument -utmZone: invalid validate_utm_zone value: &#39;21&#39;
  25. # CSV file does not end with .csv
  26. $ python3  main.py -secureFolder ./myfolder -inputCsvFile main.py -countyCode code-blah -utmZone 15
  27. usage: main.py [-h] -secureFolder SECUREFOLDER -inputCsvFile INPUTCSVFILE -countyCode COUNTYCODE -utmZone UTMZONE
  28. main.py: error: argument -inputCsvFile: invalid validate_csv value: &#39;main.py&#39;
  30. # csv does not exist
  31. $ python3  main.py -secureFolder ./myfolder -inputCsvFile input.csv -countyCode code-blah -utmZone 15
  32. usage: main.py [-h] -secureFolder SECUREFOLDER -inputCsvFile INPUTCSVFILE -countyCode COUNTYCODE -utmZone UTMZONE
  33. main.py: error: argument -inputCsvFile: invalid validate_csv value: &#39;input.csv&#39;
  35. # Get help
  36. $ python3 main.py -h                                                                                 
  37. usage: main.py [-h] -secureFolder SECUREFOLDER -inputCsvFile INPUTCSVFILE -countyCode COUNTYCODE -utmZone UTMZONE
  39. options:
  40.   -h, --help            show this help message and exit
  41.   -secureFolder SECUREFOLDER
  42.                         A directory where the files are located
  43.   -inputCsvFile INPUTCSVFILE
  44.                         A CSV file containing the results for a particular county
  45.   -countyCode COUNTYCODE
  46.                         The FIPS county code
  47.   -utmZone UTMZONE      The UTM zone code for that specific county (e.g. 18)

huangapple
  • 本文由 发表于 2023年7月3日 16:46:24
  • 转载请务必保留本文链接：https://go.coder-hub.com/76603188.html
  • argparse
  • class
  • oop
  • pyinstaller
  • python
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