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当我将项目的 django 版本更新到 1.5.x 时，这个问题开始出现。

我的问题是，当使用 mysql 作为后端并且我上传一个文件并尝试将该文件的块保存到另一个模型上时，我得到一个 UnicodeDecodeError。

在 django 1.4.x 中没有抛出错误，并且相关模型被保留。

要重新创建的示例项目： https ://github.com/imtapps/fileuploaderror

模型.py

from django.db import models

class LongBlob(models.Field):
    def db_type(self, connection):
        return "longblob"   

class Document(models.Model):
    document = LongBlob()

class Book(models.Model):
    description = models.CharField(max_length=30)
    document = models.ForeignKey(Document, null=True)

表格.py

from django import forms
from spikeapp.models import Document, Book

class BookForm(forms.ModelForm):
    upload_file = forms.FileField()

    def save(self, *args, **kwargs):
        self.cleaned_data['upload_file'].open()
        data = ''.join([chunk for chunk in self.cleaned_data['upload_file'].chunks()])
        self.cleaned_data['upload_file'].close()
        Document.objects.create(document=data)

    class Meta:
        model = Book
        fields = ('description',)

视图.py

from django.views.generic.edit import FormView
from spikeapp.forms import BookForm

class FileView(FormView):
    template_name = 'file.html'
    form_class = BookForm
    success_url = "/"

    def form_valid(self, form):
        form.save()
        return super(FileView, self).form_valid(form)

这是一个例外：

Traceback:
File "/home/appsdev/.virtualenvs/blobspike/local/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
  115.                         response = callback(request, *callback_args, **callback_kwargs)
File "/home/appsdev/.virtualenvs/blobspike/local/lib/python2.7/site-packages/django/views/generic/base.py" in view
  68.             return self.dispatch(request, *args, **kwargs)
File "/home/appsdev/.virtualenvs/blobspike/local/lib/python2.7/site-packages/django/views/generic/base.py" in dispatch
  86.         return handler(request, *args, **kwargs)
File "/home/appsdev/.virtualenvs/blobspike/local/lib/python2.7/site-packages/django/views/generic/edit.py" in post
  165.             return self.form_valid(form)
File "/home/appsdev/Projects/blobspike/spikeapp/views.py" in form_valid
  11.         form.save()
File "/home/appsdev/Projects/blobspike/spikeapp/forms.py" in save
  12.         Document.objects.create(document=data)
File "/home/appsdev/.virtualenvs/blobspike/local/lib/python2.7/site-packages/django/db/models/manager.py" in create
  149.         return self.get_query_set().create(**kwargs)
File "/home/appsdev/.virtualenvs/blobspike/local/lib/python2.7/site-packages/django/db/models/query.py" in create
  416.         obj.save(force_insert=True, using=self.db)
File "/home/appsdev/.virtualenvs/blobspike/local/lib/python2.7/site-packages/django/db/models/base.py" in save
  546.                        force_update=force_update, update_fields=update_fields)
File "/home/appsdev/.virtualenvs/blobspike/local/lib/python2.7/site-packages/django/db/models/base.py" in save_base
  650.                 result = manager._insert([self], fields=fields, return_id=update_pk, using=using, raw=raw)
File "/home/appsdev/.virtualenvs/blobspike/local/lib/python2.7/site-packages/django/db/models/manager.py" in _insert
  215.         return insert_query(self.model, objs, fields, **kwargs)
File "/home/appsdev/.virtualenvs/blobspike/local/lib/python2.7/site-packages/django/db/models/query.py" in insert_query
  1675.     return query.get_compiler(using=using).execute_sql(return_id)
File "/home/appsdev/.virtualenvs/blobspike/local/lib/python2.7/site-packages/django/db/models/sql/compiler.py" in execute_sql
  937.             cursor.execute(sql, params)
File "/home/appsdev/.virtualenvs/blobspike/local/lib/python2.7/site-packages/django/db/backends/util.py" in execute
  45.             sql = self.db.ops.last_executed_query(self.cursor, sql, params)
File "/home/appsdev/.virtualenvs/blobspike/local/lib/python2.7/site-packages/django/db/backends/mysql/base.py" in last_executed_query
  243.         return cursor._last_executed.decode('utf-8')
File "/home/appsdev/.virtualenvs/blobspike/lib/python2.7/encodings/utf_8.py" in decode
  16.     return codecs.utf_8_decode(input, errors, True)

Exception Type: UnicodeDecodeError at /
Exception Value: 'utf8' codec can't decode byte 0xb5 in position 67: invalid start byte

要复制的版本：MySQLdb-Python = 1.2.4

姜戈 = 1.5.4

4

1 回答 1

5

您偶然发现了 Django 1.5 中的一个错误：#19954 存储二进制字段会导致异常。

已提交的修复是强制使用“替换”对最后执行的查询进行解码：

return force_text(cursor._last_executed, errors='replace')

你可以编辑你的 Django 源代码，或者应用一个猴子补丁：

from django.utils.encoding import force_text
from django.db.backends.mysql.base import DatabaseOperations

def fixed_last_executed_query(self, cursor, sql, params):
    return force_text(cursor._last_executed, errors='replace')

DatabaseOperations.last_executed_query = fixed_last_executed_query

尽早这样做，settings例如，在模块或包的顶部。

我不认为补丁被反向移植。到目前为止，它只进入了 1.6 的开发线，可能是因为 1.6 添加了一个新的 Binary 字段类型。

于 2013-09-20T18:29:34.260 回答