Compatibility

In order to make sure that our File implementation is complete and functional, we test it against the original functionalities of the zope.app.file version:

>>> from zope.app.file.file import FileChunk
>>> from zope.app.file.interfaces import IFile
>>> from dolmen.file import NamedFile, INamedFile

Let’s test the constructor:

>>> file = NamedFile()
>>> file.contentType
''
>>> file.data
''

>>> file = NamedFile('Foobar')
>>> file.contentType
''
>>> file.data
'Foobar'

>>> file = NamedFile('Foobar', 'text/plain')
>>> file.contentType
'text/plain'
>>> file.data
'Foobar'

>>> file = NamedFile(data='Foobar', contentType='text/plain')
>>> file.contentType
'text/plain'
>>> file.data
'Foobar'

Let’s test the mutators:

>>> file = NamedFile()
>>> file.contentType = 'text/plain'
>>> file.contentType
'text/plain'

>>> file.data = 'Foobar'
>>> file.data
'Foobar'

>>> file.data = None
Traceback (most recent call last):
...
TypeError: Cannot set None data on a file.

Let’s test large data input:

>>> file = NamedFile()

Insert as string:

>>> file.data = 'Foobar'*60000
>>> file.getSize()
360000
>>> file.data == 'Foobar'*60000
True

Insert data as FileChunk:

>>> fc = FileChunk('Foobar'*4000)
>>> file.data = fc
>>> file.getSize()
24000
>>> file.data == 'Foobar'*4000
True

Insert data from file object:

>>> import cStringIO
>>> sio = cStringIO.StringIO()
>>> sio.write('Foobar'*100000)
>>> sio.seek(0)
>>> file.data = sio
>>> file.getSize()
600000
>>> file.data == 'Foobar'*100000
True

Last, but not least, verify the two interfaces:

>>> from zope.interface.verify import verifyClass
>>> INamedFile.extends(IFile)
True
>>> INamedFile.implementedBy(NamedFile)
True
>>> verifyClass(INamedFile, NamedFile)
True

Naming

When no name is provided, the fallback is a simple empty unicode string:

>>> file = NamedFile('Foobar')
>>> file.contentType
''
>>> file.data
'Foobar'
>>> file.filename
u''

To specifiy a filename, we can give it to the constructor:

>>> file = NamedFile('Foobar', filename='foobar.txt')
>>> file.data
'Foobar'
>>> file.filename
u'foobar.txt'

The filename provided had an extension : ‘txt’. This extension is used by the NamedFile, while instanciated, to try and guess the mimetype of the data:

>>> file.contentType
'text/plain'

The filename can be set later, but this won't trigger the mime
type guess::

>>> file.filename = u"something.zip"
>>> file.filename
u'something.zip'
>>> file.contentType
'text/plain'

Access

In order to access our file, dolmen.file provides a view called file_publish that sets the proper headers and returns the data. Let’s set up a simple environment to test that behavior:

>>> from zope.component import getMultiAdapter
>>> from zope.publisher.browser import TestRequest

>>> root = getRootFolder()
>>> root['myfile'] = NamedFile('Foobar', filename='foobar.txt')
>>> myfile = root['myfile']

The `file_publish` view will adapt a IFile and a request and, when
called, will return the data.

>>> request = TestRequest()
>>> view = getMultiAdapter((myfile, request), name='file_publish')
>>> view
<dolmen.file.access.FilePublisher object at ...>

In the update of the view, the headers are set properly, using the info of the file:

>>> view.update()
>>> for key, value in view.response.getHeaders(): print key, repr(value)
X-Powered-By 'Zope (www.zope.org), Python (www.python.org)'
Content-Length '6'
Content-Type 'text/plain'
Content-Disposition 'attachment; filename="foobar.txt"'
>>> view.render()
'Foobar'

Field, download and security

In a site, the file object is rarely accessed directly. Often, it’s just a part of a more complex object. For that matter, we have three dedicated components: the field, the property and the traverser.

>>> from persistent import Persistent
>>> from dolmen.file import FileProperty, FileField
>>> from zope.interface import Interface, implements

>>> class IContent(Interface):
...     binary = FileField(title=u"Binary data")

>>> class MyContent(Persistent):
...     implements(IContent)
...     binary = FileProperty(IContent['binary'])

>>> root['mammoth'] = MyContent()
>>> manfred = root['mammoth']
>>> manfred.binary = FileChunk('Foobar')
>>> manfred.binary
<dolmen.file.file.NamedFile object at ...>

>>> manfred.binary.data
'Foobar'

>>> import zope.security.management as security
>>> from zope.traversing.interfaces import ITraversable
>>> from zope.security.testing import Principal, Participation

>>> judith = Principal('zope.judith', 'Judith')
>>> jason = Principal('zope.jason', 'Jason')

>>> security.newInteraction(Participation(jason))
>>> traverser = getMultiAdapter(
...              (manfred, request), ITraversable, 'download')
>>> traverser
<dolmen.file.access.DownloadTraverser object at ...>
>>> traverser.traverse('binary')
Traceback (most recent call last):
...
Unauthorized: binary
>>> security.endInteraction()

>>> security.newInteraction(Participation(judith))
>>> traverser.traverse('binary')
<dolmen.file.access.FilePublisher object at ...>

>>> traverser.traverse('zorglub')
Traceback (most recent call last):
...
NotFound: Object: <MyContent object at ...>, name: 'zorglub'

>>> traverser.traverse('__name__')
Traceback (most recent call last):
...
TraversalError: '__name__ is not a valid IFile'

>>> security.endInteraction()

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