Django 提高值错误： 在 POST 上以 10 为基数的 int（） 的文字无效

Question

Django总是在向服务器发送的每个POST请求上抛出＜code＞ValueError＜/code＞。从浏览表单和SE来看，这似乎是我的Django模型的一个问题。但是，我不确定为什么模型会抛出这个错误，或者为什么Django会调用它们，因为这是在POST事件中抛出的。

有问题的视图：

def channel(request, channel):
    user_form = weblog_userForm(request.POST or None)
    if request.method == 'POST' and user_form.is_valid():
        nickname = user_form.cleaned_data['nickname']
        message = user_form.cleaned_data['message']
        password = user_form.cleaned_data['password']
        postDetails = {}

        ... process request and eventually ...

        return HttpResponse(json.dumps(postDetails), content_type="application/json")

我的应用程序模型：

class Line(models.Model):
    message = models.TextField(blank=True, default="")
    nick = models.CharField(max_length=50)
    hostname = models.CharField(max_length=300)
    channel = models.CharField(max_length=200)
    timestamp = models.DateTimeField(auto_now_add=True)
    LINE_TYPES = (
        ('PMSG', 'PRIVMSG'),
        ('SMSG', 'SOCKETMSG'),
        ('WMSG', 'WEBMSG'),
        ('NTCE', 'NOTICE'),
        ('ACTN', 'ACTION'),
        ('JOIN', 'JOIN'),
        ('PART', 'PART'),
        ('QUIT', 'QUIT'),
        ('NICK', 'NICK'),
        ('TPIC', 'TOPIC'),
    )
    msgType = models.CharField(max_length=4, choices=LINE_TYPES, default='PRIVMSG')

    def __str__(self):
        return self.message

class banned_ips(models.Model):
    bannedIp = models.GenericIPAddressField()

追溯:

Traceback (most recent call last):
File "/usr/local/lib/python3.5/dist-packages/django/core/handlers/exception.py", line 35, in inner
    response = get_response(request)
File "/usr/local/lib/python3.5/dist-packages/django/core/handlers/base.py", line 128, in _get_response
    response = self.process_exception_by_middleware(e, request)
File "/usr/local/lib/python3.5/dist-packages/django/core/handlers/base.py", line 126, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/home/django/weblogs/log/views.py", line 96, in channel
    json_data = serializers.serialize("json", list(reversed(Line.objects.filter(id__gt=latest_line_id, channel=channel).order_by('-id')[:100])))
File "/usr/local/lib/python3.5/dist-packages/django/db/models/manager.py", line 82, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
File "/usr/local/lib/python3.5/dist-packages/django/db/models/query.py", line 836, in filter
    return self._filter_or_exclude(False, *args, **kwargs)
File "/usr/local/lib/python3.5/dist-packages/django/db/models/query.py", line 854, in _filter_or_exclude
    clone.query.add_q(Q(*args, **kwargs))
File "/usr/local/lib/python3.5/dist-packages/django/db/models/sql/query.py", line 1252, in add_q
    clause, _ = self._add_q(q_object, self.used_aliases)
File "/usr/local/lib/python3.5/dist-packages/django/db/models/sql/query.py", line 1276, in _add_q
    split_subq=split_subq,
File "/usr/local/lib/python3.5/dist-packages/django/db/models/sql/query.py", line 1214, in build_filter
    condition = self.build_lookup(lookups, col, value)
File "/usr/local/lib/python3.5/dist-packages/django/db/models/sql/query.py", line 1084, in build_lookup
    lookup = lookup_class(lhs, rhs)
File "/usr/local/lib/python3.5/dist-packages/django/db/models/lookups.py", line 18, in __init__
    self.rhs = self.get_prep_lookup()
File "/usr/local/lib/python3.5/dist-packages/django/db/models/lookups.py", line 68, in get_prep_lookup
    return self.lhs.output_field.get_prep_value(self.rhs)
File "/usr/local/lib/python3.5/dist-packages/django/db/models/fields/__init__.py", line 947, in get_prep_value
    return int(value)
ValueError: invalid literal for int() with base 10: ''

任何帮助或想法都将不胜感激，这真的让我摸不着头脑。

Answer 1

吉列尔莫·查莫罗和口袋国王都在这里为我找到了陷阱。在我的 views.py 截图中发布的（看似不相关的）逻辑块中，是以下代码：

if (request.is_ajax()):
    latest_line_id = request.GET.get('latest_id', '')
    if latest_line_id == '-1': # Return all lines
        json_data = serializers.serialize("json", list(reversed(Line.objects.filter(channel=channel).order_by('-id')[:100])))
    else:
        json_data = serializers.serialize("json", list(reversed(Line.objects.filter(id__gt=latest_line_id, channel=channel).order_by('-id')[:100])))
    return HttpResponse(json_data, content_type="application/json")

尽管在逻辑上从未被调用，但这两个响应程序都是正确的，因为＜code＞ValueError＜/code＞失败源于Django，尽管如此，它们仍然试图计算＜code〕json_data＜/code＞。

如果latest_line_id为空（就像在POST请求中一样），它将被设置为"，这将在尝试基于此ID的数据库查询时触发Django的ValueError。这可以通过尝试在Django shell中自己查询过滤器来证明（通过使用$python shell）manage.py：

(注意:如果使用django shell，不要忘记从

>>> list(Line.objects.filter(channel="test").filter(id__lte='').order_by('id'))
Traceback (most recent call last):
...
ValueError: invalid literal for int() with base 10: ''

吸取了教训，编辑视图时要非常勤奋，记得仔细检查所有逻辑块，阅读回溯时要小心（一双额外的眼睛可以帮助；））。希望我的疏忽可以节省别人失去的时间。