Using contracts

A contract is distributed as a package, named contract consignment.

Consignment is a term in RGB denoting a package of client-side-validated data passed between peers. Consignments may be of two different types: contract consignments, which distribute public contract information from a contract issuer to users, and transfer consignments, which are used for doing state transfers between contract users. In this chapter we will address the first type of consignments, leaving the second for a next chapter.

RGB stores all data required for its operations in a storage called stash. Since RGB is not a blockchain-based smart contracts, the stash is not replicated to other peer machines and usually keeps the data which nobody else than you know or have access to (at least to some of those data). Thus, losing stash means loosing your assets and contract state, and it has to be backed up with the same effort as a seed phrase or wallet descriptor for a complex wallet setup.

To import a contract into your stash one first needs to get a contract consignment from a contract issuer. A contract consignment is either a binary file – or an ASCII/Base64-armoded text (and example can be found it the "issuing contract" section).

$ rgb import contract.rgb

To list contracts which are part of the stash you need to run rgb commands with no arguments provided (or rgb info as an alternative to this)

$ rgb

Which should output something like

Schemata:
---------
marina-karl-basic-4h3xkAmiRdQs2HwQmnFVqoj5DG3NhGkJRpNZXjNrJT2N: RGB20

Interfaces:
---------
RGB20 complex-field-union-DbwzvSu4BZU81jEpE9FVZ3xjcyuTKWWy2gmdnaxtACrS

Contracts:
---------
rgb:BasilYellowGrand0BgHH3yYaCUvaw5Tc8KfrVB1aWN4vBvCXCuMfK98N3o6Z

Here you see your imported contract id, plus a schema, used by this contract which implements RGB20 interface. Now, you can read the state of the contract through this interface:

$ rgb state BasilYellowGrand0BgHH3yYaCUvaw5Tc8KfrVB1aWN4vBvCXCuMfK98N3o6Z RGB20

Global state:
Nominal:=(ticker=("TEST"), name=("Test asset"), details=~, precision=8)

Owned state:
  (amount=100000000000000, owner=913d9a55efd7748ee89b577328a8f22189432c04275a106c4915cd1dac543562:0, witness=~)

Here you see that the contract has both global state, representing the information about RGB20 token, and an owned state – certain amount of that token assigned to a UTXO.