def download_file(url, dest=None, chunk_size=1024, replace="ask",
                  label="Downloading {dest_basename} ({size:.2f}MB)",
                  expected_extension=None):
    """Download a file from a given URL and display progress.

    :param dest: If the destination exists and is a directory, the filename
        will be guessed from the Content-Disposition header. If the destination
        is an existing file, the user will either be prompted to overwrite, or
        the file will be replaced (depending on the value of **replace**). If
        the destination does not exist, it will be used as the filename.
    :param int chunk_size: bytes read in at a time.
    :param replace: If `False`, an existing destination file will not be
        overwritten.
    :param label: a string which is formatted and displayed as the progress bar
        label. Variables provided include *dest_basename*, *dest*, and *size*.
    :param expected_extension: if set, the filename will be sanitized to ensure
        it has the given extension. The extension should not start with a dot
        (`.`).
    """
    dest = Path(dest or url.split("/")[-1])
    response = get(url, stream=True)
    if (dest.exists()
            and dest.is_dir()
            and "Content-Disposition" in response.headers):
        content_disposition = rfc6266.parse_requests_response(response)
        if expected_extension is not None:
            filename = content_disposition.filename_sanitized(
                expected_extension)
        filename = secure_filename(filename)
        dest = dest / filename
    if dest.exists() and not dest.is_dir():
        if (replace is False
                or replace == "ask"
                and not click.confirm("Replace {}?".format(dest))):
            return str(dest)
    size = int(response.headers.get("content-length", 0))
    label = label.format(dest=dest, dest_basename=dest.name,
                         size=size/1024.0/1024)
    with click.open_file(str(dest), "wb") as f:
        content_iter = response.iter_content(chunk_size=chunk_size)
        with click.progressbar(content_iter, length=size/1024,
                               label=label) as bar:
            for chunk in bar:
                if chunk:
                    f.write(chunk)
                    f.flush()
    return str(dest)
def testProvenanceItemMetadata(self):
        """
        Test item provenance endpoint with metadata and basic changes
        """
        item = self.item1
        user = self.user
        admin = self.admin

        # check that the first version of the item exists
        # ensure version 1, created by admin user, with creation event
        self._checkProvenance(None, item, 1, admin, 'creation')

        # update meta to {x:y}
        metadata1 = {'x': 'y'}
        resp = self._getProvenanceAfterMetadata(item, metadata1, admin)
        # ensure version 2, updated by admin user, with update event, and meta
        # in provenance matches
        self._checkProvenance(resp, item, 2, admin, 'update',
                              {'new': {'meta': metadata1}})

        # update meta to {} by regular user, we have to send in the key to
        # remove it but check the saved metadata against {}
        metadata2 = {'x': None}
        resp = self._getProvenanceAfterMetadata(item, metadata2, user)
        # ensure version 3, updated by regular user, with update event, and
        # meta in provenance matches
        self._checkProvenance(resp, item, 3, user, 'update',
                              {'old': {'meta': metadata1},
                               'new': {'meta': {}}})

        # update meta to {x:y} by regular user
        metadata3 = {'x': 'y'}
        resp = self._getProvenanceAfterMetadata(item, metadata3, user)
        # ensure version 4, updated by regular user, with update event, and
        # meta in provenance matches
        self._checkProvenance(resp, item, 4, user, 'update',
                              {'old': {'meta': {}},
                               'new': {'meta': metadata3}})

        # update meta to {x:z} by regular user
        metadata4 = {'x': 'z'}
        resp = self._getProvenanceAfterMetadata(item, metadata4, user)
        # ensure version 5, updated by regular user, with update event, and
        # meta in provenance matches
        self._checkProvenance(resp, item, 5, user, 'update',
                              {'old': {'meta': metadata3},
                               'new': {'meta': metadata4}})

        # update meta to {x:z, q:u} by regular user
        metadata5 = {'x': 'z', 'q': 'u'}
        resp = self._getProvenanceAfterMetadata(item, metadata5, user)
        # ensure version 6, updated by regular user, with update event, and
        # meta in provenance matches
        self._checkProvenance(resp, item, 6, user, 'update',
                              {'old': {'meta': metadata4},
                               'new': {'meta': metadata5}})

        # update meta to {q:a} by regular user
        metadata6 = {'x': None, 'q': 'a'}
        resp = self._getProvenanceAfterMetadata(item, metadata6, user)
        # ensure version 7, updated by regular user, with update event, and
        # meta in provenance matches
        self._checkProvenance(resp, item, 7, user, 'update',
                              {'old': {'meta': metadata5},
                               'new': {'meta': {'q': 'a'}}})

        # Change the item name and description
        params = {'name': 'Renamed object', 'description': 'New description'}
        resp = self.request(path='/item/%s' % item['_id'], method='PUT',
                            user=admin, params=params)
        self.assertStatusOk(resp)
        params['lowerName'] = params['name'].lower()
        self._checkProvenance(None, item, 8, admin, 'update', {'new': params})

        # Copy the item and check that we marked it as copied
        params = {'name': 'Copied object'}
        resp = self.request(path='/item/%s/copy' % item['_id'],
                            method='POST', user=admin, params=params)
        self.assertStatusOk(resp)
        newItem = resp.json
        self._checkProvenance(None, newItem, 9, admin, 'copy',
                              {'originalId': str(item['_id'])})