protobuf

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Installation

Add this to your application's shard.yml:

dependencies:
  protobuf:
    github: jeromegn/protobuf.cr

Install protobuf

macOS: brew install protobuf

Ubuntu sudo apt-get install -y protobuf

Generating Crystal protobuf messages

Protobuf provides the protoc executable to encode, decode and generate language-specific protobuf messages via plugins.

shards don't yet support shipping binaries, so you'll have to clone and generate yours by yourself.

1. Generate the plugin binary

git clone https://github.com/jeromegn/protobuf.cr
crystal build protobuf.cr/bin/protoc-gen-crystal.cr -o /usr/local/bin/protoc-gen-crystal # or anywhere in your PATH

2. Generate .pb.cr files

protoc -I <.protos_basepath> --crystal_out <path_to_folder_for_protobufs> <path_to_{.proto,*.protos}>

Generator options

The generator is configurable via environment variables:

• PROTOBUF_NS - If your want to namespace everything under a module (default: ""). Please write with a CamelCase format (ie: "MesosMessage" would produce module MesosMessage)
• STRIP_FROM_PACKAGE - Protobuf has package namespaces and sometimes messages reference other namespaces (ie: mesos.v1.scheduler.Call), but you want those to be namespaced in a Crystal-like fashion (ie: Scheduler::Call), then you can specify a string to strip from the packages for each file (ie: STRIP_FROM_PACKAGE=mesos.v1) and the rest will be CamelCased

Known Limitations

• Does not support ASCII strings...

Development

To generate encoded protobufs, you can create a .proto and a "raw" data protobuf file and use protoc to encode the data.

For example:

cat spec/fixtures/test.data | protoc -I spec/fixtures --encode=Test spec/fixtures/test.proto > spec/fixtures/test.data.encoded

Contributing

1. Fork it ( https://github.com/jeromegn/protobuf.cr/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Contributors

• jeromegn Jerome Gravel-Niquet - creator, maintainer