gRPC metadata safe converter.

Converts a gRPC metadata to a Hash which can be safely converted to JSON.

In gRPC, binary metadata is represented by a "-bin" suffix of a key, so gmsc checks the key and converts the value to the Base64 encoded format if necessary.

cf. https://github.com/grpc/grpc/blob/v1.25.0/doc/PROTOCOL-HTTP2.md
cf. https://github.com/grpc/grpc-go/blob/v1.25.0/Documentation/grpc-metadata.md#storing-binary-data-in-metadata

Add this line to your application's Gemfile:

gem 'gmsc'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install gmsc

• without gmsc

[1] pry(main)> metadata = {
[1] pry(main)*   "user-agent"      => "grpc-node/1.19.0 grpc-c/7.0.0 (linux; chttp2; gold)".encode(Encoding::ASCII_8BIT),
[1] pry(main)*   "binary-data-bin" => [0, 1, 2, 234].pack('c*'), # "\x00\x01\x02\xEA" binary data
[1] pry(main)* }
=> {"user-agent"=>"grpc-node/1.19.0 grpc-c/7.0.0 (linux; chttp2; gold)", "binary-data-bin"=>"\x00\x01\x02\xEA"}

[2] pry(main)> metadata.to_json
Encoding::UndefinedConversionError: "\xEA" from ASCII-8BIT to UTF-8
from (pry):5:in `encode'

• with gmsc

[3] pry(main)> GMSC.safe_convert(metadata)
=> {"user-agent"=>"grpc-node/1.19.0 grpc-c/7.0.0 (linux; chttp2; gold)", "binary-data-bin"=>"AAEC6g=="}

[4] pry(main)> GMSC.safe_convert(metadata).to_json
=> "{\"user-agent\":\"grpc-node/1.19.0 grpc-c/7.0.0 (linux; chttp2; gold)\",\"binary-data-bin\":\"AAEC6g==\"}"

After checking out the repo, run bin/setup to install dependencies. Then, run bundle exec spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/wantedly/gmsc. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

The gem is available as open source under the terms of the MIT License.

Everyone interacting in the gmsc project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.