python，django，solr，haystack：編輯solr_build_schema BaseCommand.add_argument（）時出現arg_parse錯誤

Question

請幫助...。我正在Django網站搜索中嘗試使用solr，pysolr和haystack。 我已經編輯了haystack build_solr_schema腳本以使用BaseCommand.add_argument（），刪除了默認的options_list。 以下是我使用的版本； Python 3.5.2 Django 1.11.11 solr-7.3.0 django-haystack 2.4.0 pysolr 3.7.0

# encoding: utf-8

from __future__ import absolute_import, division, print_function, unicode_literals

import sys
from optparse import make_option
from django.core.exceptions import ImproperlyConfigured
from django.core.management.base import BaseCommand
from django.template import Context, loader
from haystack import constants
from haystack.backends.solr_backend import SolrSearchBackend

class Command(BaseCommand):
    help = "Generates a Solr schema that reflects the indexes."

    def add_arguments(self, parser):
        # positional arguments
        parser.add_argument("-f", "--filename", action="store", type="string", dest="filename",
                help='If provided, directs output to a file instead of stdout.',),
       # optional positional arguments
       parser.add_argument("-u", "--using", action="store", type="string", dest="using", default=constants.DEFAULT_ALIAS,
                help='If provided, chooses a connection to work with.')

      """
       base_options = (
       make_option("-f", "--filename", action="store", type="string", dest="filename",
                help='If provided, directs output to a file instead of stdout.'),
       make_option("-u", "--using", action="store", type="string", dest="using", default=constants.DEFAULT_ALIAS,
                help='If provided, chooses a connection to work with.'),
       )
      option_list = BaseCommand.option_list + base_options
      """
     def  handle(self, **options):
         """Generates a Solr schema that reflects the indexes."""
         using = options.get('using')
         schema_xml = self.build_template(using=using)

         if options.get('filename'):
            self.write_file(options.get('filename'), schema_xml)
         else:
             self.print_stdout(schema_xml)

    def build_context(self, using):
        from haystack import connections, connection_router
        backend = connections[using].get_backend()

        if not isinstance(backend, SolrSearchBackend):
            raise ImproperlyConfigured("'%s' isn't configured as a SolrEngine)." % backend.connection_alias)

        content_field_name, fields = backend.build_schema(connections[using].get_unified_index().all_searchfields())
        return Context({
            'content_field_name': content_field_name,
            'fields': fields,
            'default_operator': constants.DEFAULT_OPERATOR,
            'ID': constants.ID,
            'DJANGO_CT': constants.DJANGO_CT,
            'DJANGO_ID': constants.DJANGO_ID,
        })

    def build_template(self, using):
        t = loader.get_template('search_configuration/solr.xml')
        c = self.build_context(using=using)
        return t.render(c)

    def print_stdout(self, schema_xml):
        sys.stderr.write("\n")
        sys.stderr.write("\n")
        sys.stderr.write("\n")
        sys.stderr.write("Save the following output to 'schema.xml' and place it in your Solr configuration directory.\n")
        sys.stderr.write("--------------------------------------------------------------------------------------------\n")
        sys.stderr.write("\n")
        print(schema_xml)

    def write_file(self, filename, schema_xml):
        schema_file = open(filename, 'w')
        schema_file.write(schema_xml)
        schema_file.close()

錯誤給出如下

Traceback (most recent call last):
File "manage.py", line 22, in <module>
execute_from_command_line(sys.argv)
File "/usr/local/lib/python3.5/dist-packages/django/core/management/__init__.py", line 364, in execute_from_command_line
utility.execute()
File "/usr/local/lib/python3.5/dist-packages/django/core/management/__init__.py", line 356, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
File "/usr/local/lib/python3.5/dist-packages/django/core/management/base.py", line 275, in run_from_argv
    parser = self.create_parser(argv[0], argv[1])
File "/usr/local/lib/python3.5/dist-packages/django/core/management/base.py", line 249, in create_parser
    self.add_arguments(parser)
File "/home/tochie/virtual_django/myblog_env/mysite/venv/lib/python3.5/site-packages/haystack/management/commands/build_solr_schema.py", line 22, in add_arguments
    help='If provided, directs output to a file instead of stdout.',),
File "/usr/lib/python3.5/argparse.py", line 1344, in add_argument
    raise ValueError('%r is not callable' % (type_func,))
ValueError: 'string' is not callable

如果有其他方法可以解決此問題，而不必編輯haystack的build_solr_schema或任何其他解決此問題的方法，請提供幫助。

Answer 1

問題出在type參數上。 顧名思義，它必須是python類型str而不是python字符串'string' 。 意思就是你需要的

def add_arguments(self, parser):
    # positional arguments
    parser.add_argument("-f", "--filename", action="store", type=str, dest="filename",
                        help='If provided, directs output to a file instead of stdout.', )
    # optional positional arguments

    parser.add_argument("-u", "--using", action="store", type=str, dest="using",
                        default=constants.DEFAULT_ALIAS, help='If provided, chooses a connection to work with.')

當您確實將type作為字符串而不是類型str傳遞時， argparse假定您正在提供可調用的執行代碼。 參見https://docs.python.org/3/library/argparse.html#type

type =可以接受帶有單個字符串參數並返回轉換后值的任何可調用項：

def perfect_square(string):
    value = int(string)
    sqrt = math.sqrt(value)
    if sqrt != int(sqrt):
        msg = "%r is not a perfect square" % string
        raise argparse.ArgumentTypeError(msg)
    return value

parser = argparse.ArgumentParser(prog='PROG')
parser.add_argument('foo', type=perfect_square)
parser.parse_args(['9'])

parser.parse_args(['7'])