239 lines
8.5 KiB
Python
239 lines
8.5 KiB
Python
# Copyright (c) 2009-2011 testtools developers. See LICENSE for details.
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"""Content - a MIME-like Content object."""
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__all__ = [
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'attach_file',
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'Content',
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'content_from_file',
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'content_from_stream',
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'text_content',
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'TracebackContent',
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]
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import codecs
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import os
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from testtools import try_import
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from testtools.compat import _b
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from testtools.content_type import ContentType, UTF8_TEXT
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from testtools.testresult import TestResult
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functools = try_import('functools')
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_join_b = _b("").join
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DEFAULT_CHUNK_SIZE = 4096
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def _iter_chunks(stream, chunk_size):
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"""Read 'stream' in chunks of 'chunk_size'.
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:param stream: A file-like object to read from.
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:param chunk_size: The size of each read from 'stream'.
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"""
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chunk = stream.read(chunk_size)
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while chunk:
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yield chunk
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chunk = stream.read(chunk_size)
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class Content(object):
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"""A MIME-like Content object.
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Content objects can be serialised to bytes using the iter_bytes method.
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If the Content-Type is recognised by other code, they are welcome to
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look for richer contents that mere byte serialisation - for example in
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memory object graphs etc. However, such code MUST be prepared to receive
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a generic Content object that has been reconstructed from a byte stream.
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:ivar content_type: The content type of this Content.
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"""
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def __init__(self, content_type, get_bytes):
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"""Create a ContentType."""
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if None in (content_type, get_bytes):
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raise ValueError("None not permitted in %r, %r" % (
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content_type, get_bytes))
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self.content_type = content_type
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self._get_bytes = get_bytes
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def __eq__(self, other):
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return (self.content_type == other.content_type and
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_join_b(self.iter_bytes()) == _join_b(other.iter_bytes()))
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def iter_bytes(self):
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"""Iterate over bytestrings of the serialised content."""
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return self._get_bytes()
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def iter_text(self):
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"""Iterate over the text of the serialised content.
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This is only valid for text MIME types, and will use ISO-8859-1 if
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no charset parameter is present in the MIME type. (This is somewhat
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arbitrary, but consistent with RFC2617 3.7.1).
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:raises ValueError: If the content type is not text/\*.
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"""
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if self.content_type.type != "text":
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raise ValueError("Not a text type %r" % self.content_type)
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return self._iter_text()
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def _iter_text(self):
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"""Worker for iter_text - does the decoding."""
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encoding = self.content_type.parameters.get('charset', 'ISO-8859-1')
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try:
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# 2.5+
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decoder = codecs.getincrementaldecoder(encoding)()
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for bytes in self.iter_bytes():
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yield decoder.decode(bytes)
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final = decoder.decode(_b(''), True)
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if final:
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yield final
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except AttributeError:
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# < 2.5
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bytes = ''.join(self.iter_bytes())
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yield bytes.decode(encoding)
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def __repr__(self):
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return "<Content type=%r, value=%r>" % (
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self.content_type, _join_b(self.iter_bytes()))
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class TracebackContent(Content):
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"""Content object for tracebacks.
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This adapts an exc_info tuple to the Content interface.
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text/x-traceback;language=python is used for the mime type, in order to
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provide room for other languages to format their tracebacks differently.
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"""
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def __init__(self, err, test):
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"""Create a TracebackContent for err."""
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if err is None:
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raise ValueError("err may not be None")
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content_type = ContentType('text', 'x-traceback',
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{"language": "python", "charset": "utf8"})
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self._result = TestResult()
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value = self._result._exc_info_to_unicode(err, test)
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super(TracebackContent, self).__init__(
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content_type, lambda: [value.encode("utf8")])
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def text_content(text):
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"""Create a `Content` object from some text.
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This is useful for adding details which are short strings.
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"""
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return Content(UTF8_TEXT, lambda: [text.encode('utf8')])
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def maybe_wrap(wrapper, func):
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"""Merge metadata for func into wrapper if functools is present."""
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if functools is not None:
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wrapper = functools.update_wrapper(wrapper, func)
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return wrapper
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def content_from_file(path, content_type=None, chunk_size=DEFAULT_CHUNK_SIZE,
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buffer_now=False):
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"""Create a `Content` object from a file on disk.
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Note that unless 'read_now' is explicitly passed in as True, the file
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will only be read from when ``iter_bytes`` is called.
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:param path: The path to the file to be used as content.
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:param content_type: The type of content. If not specified, defaults
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to UTF8-encoded text/plain.
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:param chunk_size: The size of chunks to read from the file.
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Defaults to `DEFAULT_CHUNK_SIZE`.
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:param buffer_now: If True, read the file from disk now and keep it in
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memory. Otherwise, only read when the content is serialized.
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"""
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if content_type is None:
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content_type = UTF8_TEXT
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def reader():
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# This should be try:finally:, but python2.4 makes that hard. When
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# We drop older python support we can make this use a context manager
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# for maximum simplicity.
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stream = open(path, 'rb')
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for chunk in _iter_chunks(stream, chunk_size):
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yield chunk
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stream.close()
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return content_from_reader(reader, content_type, buffer_now)
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def content_from_stream(stream, content_type=None,
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chunk_size=DEFAULT_CHUNK_SIZE, buffer_now=False):
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"""Create a `Content` object from a file-like stream.
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Note that the stream will only be read from when ``iter_bytes`` is
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called.
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:param stream: A file-like object to read the content from. The stream
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is not closed by this function or the content object it returns.
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:param content_type: The type of content. If not specified, defaults
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to UTF8-encoded text/plain.
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:param chunk_size: The size of chunks to read from the file.
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Defaults to `DEFAULT_CHUNK_SIZE`.
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:param buffer_now: If True, reads from the stream right now. Otherwise,
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only reads when the content is serialized. Defaults to False.
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"""
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if content_type is None:
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content_type = UTF8_TEXT
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reader = lambda: _iter_chunks(stream, chunk_size)
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return content_from_reader(reader, content_type, buffer_now)
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def content_from_reader(reader, content_type, buffer_now):
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"""Create a Content object that will obtain the content from reader.
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:param reader: A callback to read the content. Should return an iterable of
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bytestrings.
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:param content_type: The content type to create.
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:param buffer_now: If True the reader is evaluated immediately and
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buffered.
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"""
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if content_type is None:
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content_type = UTF8_TEXT
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if buffer_now:
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contents = list(reader())
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reader = lambda: contents
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return Content(content_type, reader)
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def attach_file(detailed, path, name=None, content_type=None,
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chunk_size=DEFAULT_CHUNK_SIZE, buffer_now=True):
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"""Attach a file to this test as a detail.
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This is a convenience method wrapping around `addDetail`.
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Note that unless 'read_now' is explicitly passed in as True, the file
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*must* exist when the test result is called with the results of this
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test, after the test has been torn down.
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:param detailed: An object with details
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:param path: The path to the file to attach.
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:param name: The name to give to the detail for the attached file.
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:param content_type: The content type of the file. If not provided,
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defaults to UTF8-encoded text/plain.
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:param chunk_size: The size of chunks to read from the file. Defaults
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to something sensible.
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:param buffer_now: If False the file content is read when the content
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object is evaluated rather than when attach_file is called.
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Note that this may be after any cleanups that obj_with_details has, so
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if the file is a temporary file disabling buffer_now may cause the file
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to be read after it is deleted. To handle those cases, using
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attach_file as a cleanup is recommended because it guarantees a
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sequence for when the attach_file call is made::
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detailed.addCleanup(attach_file, 'foo.txt', detailed)
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"""
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if name is None:
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name = os.path.basename(path)
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content_object = content_from_file(
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path, content_type, chunk_size, buffer_now)
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detailed.addDetail(name, content_object)
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