plone.namedfile 1.0b5

File types tand fields for images, files and blob files with filenames

Introduction

This package contains fields and wrapper objects for storing:

• A file with a filename

• An image with a filename

BLOB based types are supported if the z3c.blobfile package is installed. This will also require the ZODB3 package to be at version 3.8.1 or later, and BLOBs to be configured in zope.conf.

One way to make sure that z3c.blobfile is installed is to depend on the [blobs] extra to this package, e.g.:

install_requires = [
    ...
    'plone.namedfile[blobs]',
]

plone.supermodel handlers are registered if plone.supermodel is installed. The [supermodel] extra will ensure this.

See the usage.txt doctest for more details.

Changelog

1.0b5 - 2010-04-19

• Add support for scaled images. See usage.txt for details. [davisagli]

• Fix the field schemata so they can be used as the form schema when adding the field using plone.schemaeditor. [rossp]

1.0b4 - 2009-11-17

• Avoid using the internal _current_filename() helper, which disappeared in ZODB 3.9. [optilude]

• Add field factories for plone.schemaeditor (only installed if plone.schemaeditor is available) [davisagli]

1.0b3 - 2009-10-08

• Add plone.rfc822 field marshaler (only installed if plone.rfc822 is available) [optilude]

1.0b2 - 2009-09-17

• Add plone.supermodel import/export handlers (only installed if plone.supermodel is available). [optilude]

1.0b1 - 2009-05-30

• Make z3c.blobfile (and blobs in general) a soft dependency. You’ll need to separately depend on z3c.blobfile (and probably pin it to versio 0.1.2) to get the NamedBlobFile and NamedBlobImage fields. This means that plone.namedfile can be used with ZODB versions that do not support BLOBs. This policy will probably be revisited for a 2.0 release. [optilude]

1.0a1 - 2009-04-17

• Initial release

Usage

This demonstrates how to use the package. In this instance, we will assume that z3c.blobfile is installed so that BLOB based types are supported.

Test setup

We must first load the package’s ZCML.

>>> configuration = """\
... <configure
...      xmlns="http://namespaces.zope.org/zope"
...      i18n_domain="plone.namedfile.tests">
...
...     <include package="plone.namedfile" />
...
... </configure>
... """

>>> from StringIO import StringIO
>>> from zope.configuration import xmlconfig
>>> xmlconfig.xmlconfig(StringIO(configuration))

Schema fields

The following schema fields can be used to describe file data. We’ll only test the BLOB versions of the fields if z3c.blobfile is installed.

>>> from zope.interface import Interface
>>> from plone.namedfile import field
>>> from plone.namedfile.interfaces import HAVE_BLOBS

>>> class IFileContainer(Interface):
...     simple = field.NamedFile(title=u"Named file")
...     image = field.NamedImage(title=u"Named image file")
...     if HAVE_BLOBS:
...         blob = field.NamedBlobFile(title=u"Named blob file")
...         blobimage = field.NamedBlobImage(title=u"Named blob image file")

These store data with the following types.

>>> from zope.interface import implements
>>> from plone import namedfile

>>> class FileContainer(object):
...     implements(IFileContainer)
...     def __init__(self):
...         self.simple = namedfile.NamedFile()
...         self.image = namedfile.NamedImage()
...         if HAVE_BLOBS:
...             self.blob = namedfile.NamedBlobFile()
...             self.blobimage = namedfile.NamedBlobImage()

File data and content type

Let’s now show how to get and set file data.

The FileContainer class creates empty objects to start with.

>>> container = FileContainer()

>>> container.simple.data
''
>>> container.simple.contentType
''
>>> container.simple.filename is None
True

>>> container.image.data
''
>>> container.image.contentType
''
>>> container.image.filename is None
True

>>> if HAVE_BLOBS:
...     print repr(container.blob.data)
...     print repr(container.blob.contentType)
...     print repr(container.blob.filename is None)
...     print repr(container.blobimage.data)
...     print repr(container.blobimage.contentType)
...     print repr(container.blobimage.filename is None)
... else:
...     print repr('')
...     print repr('')
...     print repr(True)
...     print repr('')
...     print repr('')
...     print repr(True)
''
''
True
''
''
True

Let’s now set some actual data in these files. Notice how the constructor will attempt to guess the filename from the file extension.

>>> container.simple = namedfile.NamedFile('dummy test data', filename="test.txt")
>>> container.simple.data
'dummy test data'
>>> container.simple.contentType
'text/plain'
>>> container.simple.filename
'test.txt'

>>> if HAVE_BLOBS:
...     container.blob = namedfile.NamedBlobFile('dummy test data', filename="test.txt")
...     print repr(container.blob.data)
...     print repr(container.blob.contentType)
...     print repr(container.blob.filename)
... else:
...     print repr('dummy test data')
...     print repr('text/plain')
...     print repr('test.txt')
'dummy test data'
'text/plain'
'test.txt'

Let’s also try to read a GIF, courtesy of the zope.app.file tests:

>>> zptlogo = (
...     'GIF89a\x10\x00\x10\x00\xd5\x00\x00\xff\xff\xff\xff\xff\xfe\xfc\xfd\xfd'
...     '\xfa\xfb\xfc\xf7\xf9\xfa\xf5\xf8\xf9\xf3\xf6\xf8\xf2\xf5\xf7\xf0\xf4\xf6'
...     '\xeb\xf1\xf3\xe5\xed\xef\xde\xe8\xeb\xdc\xe6\xea\xd9\xe4\xe8\xd7\xe2\xe6'
...     '\xd2\xdf\xe3\xd0\xdd\xe3\xcd\xdc\xe1\xcb\xda\xdf\xc9\xd9\xdf\xc8\xd8\xdd'
...     '\xc6\xd7\xdc\xc4\xd6\xdc\xc3\xd4\xda\xc2\xd3\xd9\xc1\xd3\xd9\xc0\xd2\xd9'
...     '\xbd\xd1\xd8\xbd\xd0\xd7\xbc\xcf\xd7\xbb\xcf\xd6\xbb\xce\xd5\xb9\xcd\xd4'
...     '\xb6\xcc\xd4\xb6\xcb\xd3\xb5\xcb\xd2\xb4\xca\xd1\xb2\xc8\xd0\xb1\xc7\xd0'
...     '\xb0\xc7\xcf\xaf\xc6\xce\xae\xc4\xce\xad\xc4\xcd\xab\xc3\xcc\xa9\xc2\xcb'
...     '\xa8\xc1\xca\xa6\xc0\xc9\xa4\xbe\xc8\xa2\xbd\xc7\xa0\xbb\xc5\x9e\xba\xc4'
...     '\x9b\xbf\xcc\x98\xb6\xc1\x8d\xae\xbaFgs\x00\x00\x00\x00\x00\x00\x00\x00'
...     '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
...     '\x00,\x00\x00\x00\x00\x10\x00\x10\x00\x00\x06z@\x80pH,\x12k\xc8$\xd2f\x04'
...     '\xd4\x84\x01\x01\xe1\xf0d\x16\x9f\x80A\x01\x91\xc0ZmL\xb0\xcd\x00V\xd4'
...     '\xc4a\x87z\xed\xb0-\x1a\xb3\xb8\x95\xbdf8\x1e\x11\xca,MoC$\x15\x18{'
...     '\x006}m\x13\x16\x1a\x1f\x83\x85}6\x17\x1b $\x83\x00\x86\x19\x1d!%)\x8c'
...     '\x866#\'+.\x8ca`\x1c`(,/1\x94B5\x19\x1e"&*-024\xacNq\xba\xbb\xb8h\xbeb'
...     '\x00A\x00;'
...     )

>>> container.image = namedfile.NamedImage(zptlogo, filename="zpt.gif")
>>> container.image.data == zptlogo
True
>>> container.image.contentType
'image/gif'
>>> container.image.filename
'zpt.gif'

>>> if HAVE_BLOBS:
...     container.blobimage = namedfile.NamedBlobImage(zptlogo, filename="zpt.gif")
...     print repr(container.blobimage.data == zptlogo)
...     print repr(container.blobimage.contentType)
...     print repr(container.blobimage.filename)
... else:
...     print repr(True)
...     print repr('image/gif')
...     print repr('zpt.gif')
True
'image/gif'
'zpt.gif'

Note that is possible for force the mimetype:

>>> container.image = namedfile.NamedImage(zptlogo, contentType='image/foo', filename="zpt.gif")
>>> container.image.data == zptlogo
True
>>> container.image.contentType
'image/foo'
>>> container.image.filename
'zpt.gif'

>>> if HAVE_BLOBS:
...     container.blobimage = namedfile.NamedBlobImage(zptlogo, contentType='image/foo', filename="zpt.gif")
...     print repr(container.blobimage.data == zptlogo)
...     print repr(container.blobimage.contentType)
...     print repr(container.blobimage.filename)
... else:
...     print repr(True)
...     print repr('image/foo')
...     print repr('zpt.gif')
True
'image/foo'
'zpt.gif'

Download view

This package also comes with a view that can be used to download files. To use it, link to ../context-object/@@download/fieldname, where fieldname is the name of the attribute on the context-object where the named file is stored.

We will test this with a dummy request, faking traversal.

>>> from plone.namedfile.browser import Download
>>> from zope.publisher.browser import TestRequest

>>> request = TestRequest()
>>> download = Download(container, request).publishTraverse(request, 'simple')
>>> download()
'dummy test data'
>>> request.response.getHeader('Content-Length')
'15'
>>> request.response.getHeader('Content-Type')
'text/plain'
>>> request.response.getHeader('Content-Disposition')
'attachment; filename="test.txt"'

>>> if HAVE_BLOBS:
...     request = TestRequest()
...     download = Download(container, request).publishTraverse(request, 'blob')
...     data = download()
...     print repr(isinstance(data, file))
...     print repr(data.read())
...     print repr(request.response.getHeader('Content-Length'))
...     print repr(request.response.getHeader('Content-Type'))
...     print repr(request.response.getHeader('Content-Disposition'))
... else:
...     print repr(True)
...     print repr('dummy test data')
...     print repr('15')
...     print repr('text/plain')
...     print repr('attachment; filename="test.txt"')
True
'dummy test data'
'15'
'text/plain'
'attachment; filename="test.txt"'

>>> request = TestRequest()
>>> download = Download(container, request).publishTraverse(request, 'image')
>>> download() == zptlogo
True

>>> request.response.getHeader('Content-Length')
'341'
>>> request.response.getHeader('Content-Type')
'image/foo'
>>> request.response.getHeader('Content-Disposition')
'attachment; filename="zpt.gif"'

>>> request = TestRequest()
>>> if HAVE_BLOBS:
...     download = Download(container, request).publishTraverse(request, 'blobimage')
...     data = download()
...     print repr(isinstance(data, file))
...     print repr(data.read() == zptlogo)
...     print repr(request.response.getHeader('Content-Length'))
...     print repr(request.response.getHeader('Content-Type'))
...     print repr(request.response.getHeader('Content-Disposition'))
... else:
...     print repr(True)
...     print repr(True)
...     print repr('341')
...     print repr('image/foo')
...     print repr('attachment; filename="zpt.gif"')
True
True
'341'
'image/foo'
'attachment; filename="zpt.gif"'

Image scales

This package can handle the creation, storage, and retrieval of arbitrarily sized scaled versions of images stored in NamedImage or NamedBlobImage fields.

Image scales are accessed via an @@images view that is available for any item providing plone.namedfile.interfaces.IImageScaleTraversable. There are several ways that you may reference scales from page templates.

1. for full control you may do the tag generation explicitly:

   <img tal:define="scales context/@@images;
                    thumbnail python: scales.scale('image', width=64, height=64);"
        tal:condition="thumbnail"
        tal:attributes="src thumbnail/url;
                        width thumbnail/width;
                        height thumbnail/height" />

   This would create an up to 64 by 64 pixel scaled down version of the image stored in the “image” field. It also allows for passing in additional parameters support by plone.scale’s scaleImage function, e.g. direction or quality.

2. for automatic tag generation with extra parameters you would use:

   <img tal:define="scale context/@@images"
        tal:replace="structure python: scale.scale('image',
                     width=1200, height=800, direction='down').tag()" />

3. It is possible to access scales via predefined named scale sizes, rather than hardcoding the dimensions every time you access a scale. The scale sizes are found via calling a utility providing plone.namedfile.interfaces.IAvailableSizes, which should return a dict of scale name => (width, height). A scale called ‘mini’ could then be accessed like this:

   <img tal:define="scale context/@@images"
        tal:replace="structure python: scale.scale('image',
                     scale='mini').tag()" />

   This would use the predefined scale size “mini” to determine the desired image dimensions, but still allow to pass in extra parameters.

4. a convenience short-cut for option 3 can be used:

   <img tal:replace="structure context/@@images/image/mini" />

5. and lastly, the short-cut can also be used to render the unscaled image:

   <img tal:replace="structure context/@@images/image" />