handlers.py 文件源码

def add_glacier_checksums(params, **kwargs):
    """Add glacier checksums to the http request.

    This will add two headers to the http request:

        * x-amz-content-sha256
        * x-amz-sha256-tree-hash

    These values will only be added if they are not present
    in the HTTP request.

    """
    request_dict = params
    headers = request_dict['headers']
    body = request_dict['body']
    if isinstance(body, six.binary_type):
        # If the user provided a bytes type instead of a file
        # like object, we're temporarily create a BytesIO object
        # so we can use the util functions to calculate the
        # checksums which assume file like objects.  Note that
        # we're not actually changing the body in the request_dict.
        body = six.BytesIO(body)
    starting_position = body.tell()
    if 'x-amz-content-sha256' not in headers:
        headers['x-amz-content-sha256'] = utils.calculate_sha256(
            body, as_hex=True)
    body.seek(starting_position)
    if 'x-amz-sha256-tree-hash' not in headers:
        headers['x-amz-sha256-tree-hash'] = utils.calculate_tree_hash(body)
    body.seek(starting_position)