De[code] Sub[strate]

_{^{† This software is experimental, and not intended for production use yet. Use at your own risk.}}

Encompassing decoder for substrate/polkadot/kusama types.

Gets type definitions from polkadot-js via JSON and decodes them into components that outline types and make decoding byte-strings possible, as long as the module/generic type name are known.

Supports Metadata versions from v8, which means all of Kusama (from CC1). Older networks are not supported (E.G Alexander).

• makes decoding generic types from the substrate rpc possible
• requires parsing JSON with type definitions, and implementing traits TypeDetective and Decoder in order to work for arbitrary chains. However, if the JSON follows the same format as PolkadotJS definitions (look at definitions.json and overrides.json) it would be possible to simply deserialize into Polkadot structs and utilize those. The decoding itself is generic enough to allow it.
• types must adhere to the conventions set out by polkadot decoding
  • type definitions for Polkadot (Kusama) are taken from Polkadot.js and deserialized into Rust (extras/polkadot)

Currently Supported Metadata Versions (From Kusama CC1):

• V8
• V9
• V10
• V11
• V12
• V13
• V14

(Tentative) Release & Maintenence

Note: Release description is in no way complete because of current & active development for legacy desub types & scale-info based types. it is purely here as a record for things that should be taken into account in the future

• Depending on changes in legacy desub code, bump version in Cargo.toml for desub/, desub-current/, desub-legacy/, desub-common/, desub-json-resolver/
• note upgrade-blocks present here and modify the hard-coded upgrade blocks as necessary in the desub runtimes.rs file.
• Take note of PR's that have been merged since the last release.
  • look over CHANGELOG. Make sure to include any PR's that were missed in the Unreleased section.
  • Move changes in Unreleased section to a new section corresponding to the version being released, making sure to keep the Unreleased header.
• make a PR with these changes
• once PR is merged, push a tag in the form vX.X.X (E.G v0.1.0)

git tag v0.1.0
git push --tags origin master

• Once tags are pushed, a github workflow will start that will draft a release. You should be able to find the workflow running under Actions in the github repository.
  • NOTE: If something goes wrong it is OK. Delete the tag from the repo, re-create the tag locally and re-push. The workflow will run whenever a tag with the correct form is pushed. If more changes need to be made to the repo that will require another PR.
• Once the workflow finishes, make changes to the resulting draft release if necessary, and hit publish.
• Once published on github, publish each crate that has changed to crates.io. Refer to this for how to publish to crates.io.

lib.rs:

A crate to decode extrinsics, signer payloads and storage keys for substrate nodes using V14+ metadata. See decoder for more information.