Question

我有一个Scrapy项目，我正在尝试将输出项目保存为Django模型定义中的对象（我没有使用DjangoItem）。

我正在按照指定的here导入Django设置。

def setup_django_env(path):
    import imp, os
    from django.core.management import setup_environ

    f, filename, desc = imp.find_module('settings', [path])
    project = imp.load_module('settings', f, filename, desc)       

    setup_environ(project)

setup_django_env(PATH_TO_DJANGO_PROJECT)

在我的Scrapy项目中，我有一个管道类，它处理最后的所有项目并将其保存到数据库：

from my_django_project.apps.my_books.models import Book, Category, Image

class DjangoPipeline(object):

    def process_item(self, item, spider):
        category = Category.objects.get(name='Horror')
        book = Book(name='something', category=category)
        book.save()
        image = Image(name='something', book=book)
        image.save()
        return item

然而，发生了一些奇怪的事情，对于第一个项目我得到了一个错误（见下文）。对于其他项目，一切都很好。假设我有7个要保存的项目，所以我在第一个中得到一个错误而另外6个被保存。

Traceback (most recent call last):
  File "/users/ale/virtualenvs/books/lib/python2.6/site-packages/scrapy/middleware.py", line 54, in _process_chain
    return process_chain(self.methods[methodname], obj, *args)
  File "/users/ale/virtualenvs/books/lib/python2.6/site-packages/scrapy/utils/defer.py", line 65, in process_chain
    d.callback(input)
  File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/twisted/internet/defer.py", line 243, in callback
    self._startRunCallbacks(result)
  File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/twisted/internet/defer.py", line 312, in _startRunCallbacks
    self._runCallbacks()
--- <exception caught here> ---
  File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/twisted/internet/defer.py", line 328, in _runCallbacks
    self.result = callback(self.result, *args, **kw)
  File "/users/ale/djcode/books/lib/scraper/scraper/djangopipeline.py", line 34, in process_item
    selected_category = Category.objects.get(name='Horror')
  File "/users/ale/virtualenvs/books/lib/python2.6/site-packages/django/db/models/manager.py", line 132, in get
    return self.get_query_set().get(*args, **kwargs)
  File "/users/ale/virtualenvs/books/lib/python2.6/site-packages/django/db/models/query.py", line 333, in get
    clone = self.filter(*args, **kwargs)
  File "/users/ale/virtualenvs/books/lib/python2.6/site-packages/django/db/models/query.py", line 550, in filter
    return self._filter_or_exclude(False, *args, **kwargs)
  File "/users/ale/virtualenvs/books/lib/python2.6/site-packages/django/db/models/query.py", line 568, in _filter_or_exclude
    clone.query.add_q(Q(*args, **kwargs))
  File "/users/ale/virtualenvs/books/lib/python2.6/site-packages/django/db/models/sql/query.py", line 1131, in add_q
    can_reuse=used_aliases)
  File "/users/ale/virtualenvs/books/lib/python2.6/site-packages/django/db/models/sql/query.py", line 1026, in add_filter
    negate=negate, process_extras=process_extras)
  File "/users/ale/virtualenvs/books/lib/python2.6/site-packages/django/db/models/sql/query.py", line 1182, in setup_joins
    field, model, direct, m2m = opts.get_field_by_name(name)
  File "/users/ale/virtualenvs/books/lib/python2.6/site-packages/django/db/models/options.py", line 291, in get_field_by_name
    cache = self.init_name_map()
  File "/users/ale/virtualenvs/books/lib/python2.6/site-packages/django/db/models/options.py", line 321, in init_name_map
    for f, model in self.get_all_related_m2m_objects_with_model():
  File "/users/ale/virtualenvs/books/lib/python2.6/site-packages/django/db/models/options.py", line 396, in get_all_related_m2m_objects_with_model
    cache = self._fill_related_many_to_many_cache()
  File "/users/ale/virtualenvs/books/lib/python2.6/site-packages/django/db/models/options.py", line 410, in _fill_related_many_to_many_cache
    for klass in get_models():
  File "/users/ale/virtualenvs/books/lib/python2.6/site-packages/django/db/models/loading.py", line 167, in get_models
    self._populate()
  File "/users/ale/virtualenvs/books/lib/python2.6/site-packages/django/db/models/loading.py", line 61, in _populate
    self.load_app(app_name, True)
  File "/users/ale/virtualenvs/books/lib/python2.6/site-packages/django/db/models/loading.py", line 76, in load_app
    app_module = import_module(app_name)
  File "/users/ale/virtualenvs/books/lib/python2.6/site-packages/django/utils/importlib.py", line 35, in import_module
    __import__(name)
exceptions.ImportError: No module named my_books

如果我这样做，所有7项都会保存：

from my_django_project.apps.my_app.models import Book, Category, Image

class DjangoPipeline(object):

    def process_item(self, item, spider):
        try:
            category = Category.objects.get(name='something')
        except:
            category = Category.objects.get(name='something')
        book = Book(name='something', category=category)
        try:
            book.save()
        except:
            book.save()
        image = Image(name='something', book=book)
        try:
            image.save()
        except:
            image.save()
        return item

我不知道我做错了什么。有人可以帮帮我吗？

谢谢！

Answer 1

我有同样的问题，我找到了解决方案。至少，它对我有用。

在我的情况下，问题出在Django项目的setting.py文件中 - 我没有将我的应用程序的FQN (fully qualified name)添加到INSTALLED_APPS元组中，但它是短名称。

谈到您的示例，可能是您添加到INSTALLED_APPS my_books元素，而不是my_django_project.apps.my_books。

Answer 2

我记得错过了__init__.py文件会导致一些奇怪的问题。你在所有模块上都有它吗？

从Scrapy项目中保存Django模型

2 个答案: