handlers.py 文件源码

def set_operation_specific_signer(context, signing_name, **kwargs):
    """ Choose the operation-specific signer.

    Individual operations may have a different auth type than the service as a
    whole. This will most often manifest as operations that should not be
    authenticated at all, but can include other auth modes such as sigv4
    without body signing.
    """
    auth_type = context.get('auth_type')

    # Auth type will be None if the operation doesn't have a configured auth
    # type.
    if not auth_type:
        return

    # Auth type will be the string value 'none' if the operation should not
    # be signed at all.
    if auth_type == 'none':
        return botocore.UNSIGNED

    if auth_type.startswith('v4'):
        signature_version = 'v4'
        if signing_name == 's3':
            signature_version = 's3v4'

        # If the operation needs an unsigned body, we set additional context
        # allowing the signer to be aware of this.
        if auth_type == 'v4-unsigned-body':
            context['payload_signing_enabled'] = False

        return signature_version