Warning: After v0.2.19, the develop branch will do a structure refactor and big optimization.

scale.rb

Ruby SCALE Codec Library

SCALE is a lightweight, efficient, binary serialization and deserialization codec used by substrate. Most of the input and output data of the substrate API are encoded in SCALE data format.

This is a SCALE codec library implemented in ruby language for general use. It contains the implementation of low-level data formats, various substrate types, metadata support.

This work is the prerequisite of our subsequent series of projects. We hope to familiarize and quickly access Polkadot and Substrate through ruby. We plan to develop the back end of our applications in ruby language, and then interact with nodes or synchronize data through this library.

Please refer to the official doc for more details about SCALE low-level data format.

Because the feature of ruby 2.6 is used, the ruby version is required to be >= 2.6. it will be compatible with older ruby versions when released.

Installation

Add this line to your application's Gemfile:

gem 'scale.rb', '0.2.19'

And then execute:

$ bundle

Or install it yourself as:

$ gem install scale

Usage

1. decode

require "scale"

Scale::TypeRegistry.instance.load # default
# Scale::TypeRegistry.instance.load spec_name: "pangolin"
# Scale::TypeRegistry.instance.load spec_name: "kusama"

# print hex changes if you set debug to true, default is false
Scale::Types.debug = true

# decode a compact integer
scale_bytes = Scale::Bytes.new("0x1501") # create scale_bytes object from scale encoded hex string
o = Scale::Types::Compact.decode(scale_bytes) # use scale type to decode scale_bytes object
p o.value # 69

#
type = Scale::Types::get("Vec<U8>")
o = type.decode(Scale::Bytes.new("0x080001"))
assert_eq o.value, [Scale::Types::U8.new(0), Scale::Types::U8.new(1)]

2. encode

require "scale"

Scale::TypeRegistry.instance.load

o = Scale::Types::Compact.new(69)
p o.encode # "1501"

type = Scale::Types::get("Vec<U8>")
o = type.new([Scale::Types::U8.new(0), Scale::Types::U8.new(1)])
p o.encode # "080001"

3. client

require "scale"
client = SubstrateClient.new "wss://rpc.darwinia.network"

v = Scale::Types.get("EthereumTransactionIndex")
  .new(
    [
      Scale::Types::H256.new("0x803054c2beacabc36e15c3147bb87d8320a02e9b601be28820a622dedd1c7717"),
      Scale::Types::U64.new(266)
    ]
  )

storage = client.get_storage("EthereumBacking", "VerifiedProof", [v])
puts storage.to_human

# get the raw data
key = client.generate_storage_key("EthereumBacking", "VerifiedProof", [v])[0]
storage_raw = client.state_getStorageAt(key)
puts storage_raw

Please go to spec dir for more examples.

Command line tools

After install scale.rb gem, there is a command named scale available. You can use it directly in your terminal.

> scale
Commands:
  scale decode TYPE_NAME HEX SPEC_NAME SPEC_VERSION  # decode HEX string using TYPE_NAME
  scale help [COMMAND]                               # Describe available commands or one specific command
  scale specs                                        # list all chain specs
  scale type TYPE_NAME SPEC_NAME SPEC_VERSION        # show type's ruby class
  scale types SPEC_NAME SPEC_VERSION                 # list all types implemented for chain

examples in exec/scale

Running tests

1. Download or clone the code to local, and enter the code root directory
2. If rust is installed on your system (for instance, curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh), call make to build the FFI library
3. Run all tests

rspec

To run single test file:

rspec spec/types_spec.rb
rspec spec/extrinsic_spec.rb
rspec spec/metadata_spec.rb
rspec spec/types_ffi_spec.rb

Docker

1. update to latest image

   docker pull itering/scale:latest

2. Run image:

   docker run -it itering/scale:latest

   This will enter the container with a linux shell opened.

   /usr/src/app # 

3. Type rspec to run all tests

   /usr/src/app # rspec
   ...................
   
   Finished in 0.00883 seconds (files took 0.09656 seconds to load)
   19 examples, 0 failures

4. Or, type ./bin/console to enter the ruby interactive environment and run any decode or encode code

   /usr/src/app # ./bin/console
   [1] pry(main)> scale_bytes = Scale::Bytes.new("0x1501")
   => #<Scale::Bytes:0x000055daa883ba70 @bytes=[21, 1], @data="0x1501", @offset=0>
   [2] pry(main)> o = Scale::Types::Compact.decode(scale_bytes)
   => #<Scale::Types::Compact:0x000055daa89b0db0 @value=69>
   [3] pry(main)> p o.value
   69
   => 69
   [4] pry(main)>

5. Or, run command line tool:

   /usr/src/app # scale types kusama
   HeadData => Scale::Types::HeadData
   Conviction => Scale::Types::Conviction
   EraRewards => Scale::Types::EraRewards
   ...
   
   Count: 303

Development

After checking out the repo, run bin/setup to install dependencies. 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.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/itering/scale.rb.

License

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