```ruby
# Copyright 2011-2013 Amazon.com, Inc. or its affiliates. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"). You
# may not use this file except in compliance with the License. A copy of
# the License is located at
#
#     http://aws.amazon.com/apache2.0/
#
# or in the "license" file accompanying this file. This file is
# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
# ANY KIND, either express or implied. See the License for the specific
# language governing permissions and limitations under the License.

require 'multi_xml'

module Aws
  module Plugins
    class ContentLength < Seahorse::Client::Plugin
      handle_request :Handler do |context|
        next if context.http_request.headers['Content-Length']
        length = context.http_request.body.size
        context.http_request.headers['Content-Length'] = length
      end
    end
  end
end
```

Set the content-length plugin to lowest priority.
user
```ruby
# Copyright 2011-2013 Amazon.com, Inc. or its affiliates. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"). You
# may not use this file except in compliance with the License. A copy of
# the License is located at
#
#     http://aws.amazon.com/apache2.0/
#
# or in the "license" file accompanying this file. This file is
# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
# ANY KIND, either express or implied. See the License for the specific
# language governing permissions and limitations under the License.

require 'multi_xml'

module Aws
  module Plugins
    class ContentLength < Seahorse::Client::Plugin
      handle_request(:Handler, step: :sign, priority: 0) do |context|
        next if context.http_request.headers['Content-Length']
        length = context.http_request.body.size
        context.http_request.headers['Content-Length'] = length
      end
    end
  end
end
```
assistant