Question

我正在使用Django来执行一个非常简单的功能。随着时间的推移，应用程序的大小会增加，但是现在，我想要做的就是运行我所有Facebook消息的html文档，并为每个用户保存一个模型，并为该用户附加每条消息。但是，在尝试创建我创建的模型的实例时，FacebookUser，我得到了错误＆＃34; NoneType＆＃34;对象不可调用。我阅读了其他SO文章，并浏览了互联网以寻找其他问题，并发现错误通常源于尝试对类本身做某事，而不是类的实例化。但是我正在创建这个类的实例，但仍然会收到此错误。

models.py

from django.db import models

class FacebookUser(models.Model):
    full_name = models.CharField(max_length=255, null=True, blank=True)

    def __str__(self):
        return self.full_name

class Message(models.Model):
    user = models.ForeignKey(FacebookUser)
    content = models.TextField(max_length=10000, null=True, blank=True)
    date_sent = models.DateTimeField(null=True, blank=True)

    def __str__(self):
        return '#{} {}'.format(self.id, self.user.full_name)

views.py

from django.http import HttpResponse
from facebook_user.models import FacebookUser, Message
from bs4 import BeautifulSoup

def crawl_messages(request):
    data = open('messages.html', 'r').read()
    soup = BeautifulSoup(data)

    all_messages = soup.findAll("div", {"class": "message"})
    msg_dictionaries = [{
                            'user': el.findAll('span')[0],
                            'time': el.findAll('span')[1],
                            'content': el.nextSibling.nextSibling
                        } for el in all_messages]

    for msg in msg_dictionaries:
        try:
            fbuser = FacebookUser.objects.get(full_name=msg['user'])
            print('Try One')
            print(fbuser)
        except FacebookUser.DoesNotExist:
            fbuser = FacebookUser.objects.create(full_name=msg['user'])
            print('Try Two')
            print(fbuser)
        except Exception as e:
            print('Try Three')
            print(e)
            fbuser = None

        if fbuser:
            new_msg = Message()

            new_msg.content = msg['content']
            new_msg.user = fbuser
            new_msg.save()

    return HttpResponse('Worked ! Check the Admin')

堆栈跟踪

Traceback (most recent call last):
  File "/Users/timothybaney/Library/Python/3.5/lib/python/site-packages/django/core/handlers/base.py", line 149, in get_response
    response = self.process_exception_by_middleware(e, request)
  File "/Users/timothybaney/Library/Python/3.5/lib/python/site-packages/django/core/handlers/base.py", line 147, in get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/Users/timothybaney/Data Science/facebook_sentiment_analysis/facebook_user/views.py", line 19, in crawl_messages
    fbuser = FacebookUser.objects.create(full_name=msg['user'])
  File "/Users/timothybaney/Library/Python/3.5/lib/python/site-packages/django/db/models/manager.py", line 122, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/Users/timothybaney/Library/Python/3.5/lib/python/site-packages/django/db/models/query.py", line 401, in create
    obj.save(force_insert=True, using=self.db)
  File "/Users/timothybaney/Library/Python/3.5/lib/python/site-packages/django/db/models/base.py", line 708, in save
    force_update=force_update, update_fields=update_fields)
  File "/Users/timothybaney/Library/Python/3.5/lib/python/site-packages/django/db/models/base.py", line 736, in save_base
    updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)
  File "/Users/timothybaney/Library/Python/3.5/lib/python/site-packages/django/db/models/base.py", line 820, in _save_table
    result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
  File "/Users/timothybaney/Library/Python/3.5/lib/python/site-packages/django/db/models/base.py", line 859, in _do_insert
    using=using, raw=raw)
  File "/Users/timothybaney/Library/Python/3.5/lib/python/site-packages/django/db/models/manager.py", line 122, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/Users/timothybaney/Library/Python/3.5/lib/python/site-packages/django/db/models/query.py", line 1039, in _insert
    return query.get_compiler(using=using).execute_sql(return_id)
  File "/Users/timothybaney/Library/Python/3.5/lib/python/site-packages/django/db/models/sql/compiler.py", line 1059, in execute_sql
    for sql, params in self.as_sql():
  File "/Users/timothybaney/Library/Python/3.5/lib/python/site-packages/django/db/models/sql/compiler.py", line 1019, in as_sql
    for obj in self.query.objs
  File "/Users/timothybaney/Library/Python/3.5/lib/python/site-packages/django/db/models/sql/compiler.py", line 1019, in <listcomp>
    for obj in self.query.objs
  File "/Users/timothybaney/Library/Python/3.5/lib/python/site-packages/django/db/models/sql/compiler.py", line 1018, in <listcomp>
    [self.prepare_value(field, self.pre_save_val(field, obj)) for field in fields]
  File "/Users/timothybaney/Library/Python/3.5/lib/python/site-packages/django/db/models/sql/compiler.py", line 946, in prepare_value
    value = value.resolve_expression(self.query, allow_joins=False, for_save=True)
TypeError: 'NoneType' object is not callable

Answer 1

这很可能意味着msg['user']不是字符串，而是在调用该属性时设置任何属性的对象。因此它会收到导致上述错误的resolve_expression属性。

要修复，请尝试将msg['user']转换为create语句中的字符串： fbuser = FacebookUser.objects.create(str(msg['user'])

这只是一个猜测，没有完整的资源来运行它，无法确定。

尝试保存Model的实例时，NoneType对象不可调用

1 个答案: