对于有效文件,Django FileField(或ImageField)open()方法返回None? [英] Django FileField (or ImageField) open() method returns None for valid file?
本文介绍了对于有效文件,Django FileField(或ImageField)open()方法返回None?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
让我这样说:
model.py:
class Task(models.Model):
...
seq_file = models.FileField(upload_to ='files /',blank = True,null = True)
...
ajax.py(我使用dajaxice但没关系):
...
def startTask(request,name):
task = Task.objects.get(task_name = name )
data = task.seq_file.open()
filename = os.path.join(settings.MEDIA_ROOT,task.seq_file.name)
如果没有os.path.isfile(filename) :
raise异常,file+ filename +找不到。
sequences = parser.parse(data.read())
...
这将返回:
文件/ home / mnowotka / Dokumenty / MgrFuncAdnot / app / django-gui / src / gui / ajax.py,第43行,startTask
sequence = parser.parse(data.read())
AttributeError:'NoneType'对象没有属性'read'
但是:
def startTask(request,name):
task = Task.objects.get(task_name = name)
filename = os.path.join(settings.MEDIA_ROOT,task。 seq_file.name)
如果不是os.path.isfile(filename):
raise异常,file+ filename +not found。
data = open(filename)
sequences = parser.parse(data.read())
...
完美工作!
为什么?
(我使用django 1.3)
解决方案>
因为模型的打开方法.FileField不返回任何东西
你可以使用:
task.seq_file.read()
t需要计算文件的路径以检查文件是否存在。您可以使用task.seq_file.path:
如果不是os.path.isfile(task.seq_file.path):
....
let me put it like this:
model.py:
class Task(models.Model):
...
seq_file = models.FileField(upload_to='files/', blank=True, null=True)
...
ajax.py (I'm using dajaxice but it doesn't matter):
...
def startTask(request, name):
task = Task.objects.get(task_name=name)
data = task.seq_file.open()
filename = os.path.join(settings.MEDIA_ROOT ,task.seq_file.name)
if not os.path.isfile(filename):
raise Exception, "file " + filename + " not found."
sequences = parser.parse(data.read())
...
this returns:
File "/home/mnowotka/Dokumenty/MgrFuncAdnot/app/django-gui/src/gui/ajax.py", line 43, in startTask
sequences = parser.parse(data.read())
AttributeError: 'NoneType' object has no attribute 'read'
but:
...
def startTask(request, name):
task = Task.objects.get(task_name=name)
filename = os.path.join(settings.MEDIA_ROOT ,task.seq_file.name)
if not os.path.isfile(filename):
raise Exception, "file " + filename + " not found."
data = open(filename)
sequences = parser.parse(data.read())
...
works perfectly! Why?
(I'm using django 1.3)
解决方案
because open method of models.FileField doesn't return anything
you can just use:
task.seq_file.read()
and you don't need calculate path of file for checking if file exist. you can use task.seq_file.path:
if not os.path.isfile(task.seq_file.path):
....
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