Detailed explanation and simple examples of python getopt

This article mainly introduces the relevant information of python getopt detailed explanation and simple examples. Friends who need it can refer to it

python getopt detailed explanation

Function prototype:

getopt.getopt(args, shortopts, longopts=[])

Parameter explanation:

• args: args is the parameter list that needs to be parsed. Generally use sys.argv[1:], which can filter out the first parameter (ps: the first parameter is the name of the script, it should not be parsed as a parameter)

• shortopts: abbreviated parameter list

• longopts: long parameter list

Return value:

• opts: The analyzed (option, value) list pairs.

• #args: List of remaining command line arguments that are not format information.

Source code analysis

In the Android build system that generates OTA, the ParseOptions function in the common.py file is used to parse input parameters. , let’s analyze the use of getopt through the implementation of this function.

The function source code is as follows:

def ParseOptions(argv, docstring, extra_opts="", extra_long_opts=(), extra_option_handler=None):
  try:
    opts, args = getopt.getopt(
      argv, "hvp:s:x" + extra_opts,
      ["help", "verbose", "path=", "signapk_path=", "extra_signapk_args=", "java_path=", "public_key_suffix=", "private_key_suffix=", "device_specific=", "extra="] + list(extra_long_opts))
  except getopt.GetoptError, err:
    Usage(docstring)
    print "**", str(err), "**"
    sys.exit(2)

  path_specified = False

  for o, a in opts:
    if o in ("-h", "--help"):
      Usage(docstring)
      sys.exit()
    elif o in ("-v", "--verbose"):
      OPTIONS.verbose = True
    elif o in ("-p", "--path"):
      OPTIONS.search_path = a
    elif o in ("--signapk_path",):
      OPTIONS.signapk_path = a
    elif o in ("--extra_singapk_args",):
      OPTIONS.extra_signapk_args = shlex.split(a)
    elif o in ("--java_path",):
      OPTIONS.java_path = a
    else:
      if extra_option_handler is None or not extra_option_handler(o, a):
      assert False, "unknown option \"%s\"" % (o,)

  os.environ["PATH"] = (os.path.join(OPTIONS.search_path, "bin") + os.pathsep + os.environ["PATH"])

  return args

Among them, extra_option_handler can be understood as a function pointer, and its function is also to parse the key-value pairs of opts.

extra_option_handler source code is as follows:

 def option_handler(o, a):
  if o in ("-b", "--board_config"):
   pass  # deprecated
  elif o in ("-k", "--package_key"):
   OPTIONS.package_key = a
  elif o in ("-i", "--incremental_from"):
   OPTIONS.incremental_source = a
  elif o in ("-w", "--wipe_user_data"):
   OPTIONS.wipe_user_data = True
  elif o in ("-n", "--no_prereq"):
   OPTIONS.omit_prereq = True
  elif o in ("-e", "--extra_script"):
   OPTIONS.extra_script = a
  elif o in ("-a", "--aslr_mode"):
   if a in ("on", "On", "true", "True", "yes", "Yes"):
    OPTIONS.aslr_mode = True
   else:
    OPTIONS.aslr_mode = False
  elif o in ("--worker_threads"):
   OPTIONS.worker_threads = int(a)
  else:
   return False
  return True

Generally, the parameter argv for generating the OAT full package is as follows:

argv = ['-v', '-p', 'out/host/linux-xxx', '-k', 'build/target/product/security/testkey',
 'out/target/product/xxx/obj/PACKAGING/target_files_intermediates/xxx-target_files.zip', 
'out/target/product/xxx/xxx_20150723.1340-ota.zip']

First, analyze the parameters. The short parameters include:

-v,-p,-k,

After analysis, the generated results are as follows Shown:

opts = [('-v', ''), ('-p', 'out/host/linux-x86'), 
('-k', 'build/target/product/security/testkey')]
args =['out/target/product/xxx/obj/PACKAGING/target_files_intermediates/xxx-target_files.zip',
 'out/target/product/xxx/xxx_20150723.1340-ota.zip']

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