Action Schema

Actions are constructed using Action Schemas defined by the developers. To define a new action schema, you can use the ActionSchema utility.

schemas.ts

import { ActionSchema } from "@stackr/sdk";

Using the ActionSchema utility, a new action schema can be defined like this:

schemas.ts

export const NewSchema = new ActionSchema("<IDENTIFIER>", {
  <INPUT_FIELD_NAME> : <SOLIDITY_TYPE>
});

Breaking it down we have:

<IDENTIFIER>: A unique identifier for the action schema. This is used to identify the action schema in the MRU.
<INPUT_FIELD_NAME>: The name of the input field in the action.
<SOLIDITY_TYPE>: The solidity type of the input field in the action. This is used to validate the input field and also EIP-712 signing. The supported types are:
- uint256
- address
- bool
- bytes32
- bytes
- string

The solidity types can be accessed using the SolidityType provided with the SDK.

schemas.ts

import { ActionSchema, SolidityType } from "@stackr/sdk";
 
export const NewSchema = new ActionSchema("<IDENTIFIER>", {
  <INPUT_FIELD_NAME> : SolidityType.ADDRESS
BOOL
BYTES
BYTES32
STRING
UINT
});

Same Schema, Multiple transitions

So, for example, if you have a schema to update the count in a counter application, you can use the same schema to increment or decrement the count. It's just the state transition function that decides how to handle the action.

Examples

Simple Counter

For a simple counter application, the action schema can be defined as follows:

counter/src/schemas.ts

import { ActionSchema, SolidityType } from "@stackr/sdk";
 
export const UpdateCount = new ActionSchema("update-count", {
  amount: SolidityType.UINT,
});

This schema just has one field amount which is of type uint256. This can be used to update the count in the counter application.

If you pass the same schema to increment transition function, it will increment the count by the amount passed in the action. Similarly, if you pass the same schema to decrement transition function, it will decrement the count by the amount passed in the action.

CRUD Application

crud/src/schemas.ts

import { ActionSchema, SolidityType } from "@stackr/sdk";
 
export const CreateEntity = new ActionSchema("create-entity", {
  name: SolidityType.STRING,
  age: SolidityType.UINT,
  email: SolidityType.STRING,
});
 
export const UpdateEntity = new ActionSchema("update-entity", {
  id: SolidityType.UINT,
  name: SolidityType.STRING,
  age: SolidityType.UINT,
  email: SolidityType.STRING,
});
 
export const DeleteEntity = new ActionSchema("delete-entity", {
  id: SolidityType.UINT,
});

Token Transfer ERC-20

token/src/schemas.ts

import { ActionSchema, SolidityType } from "@stackr/sdk";
 
export const Transfer = new ActionSchema("transfer", {
  to: SolidityType.ADDRESS,
  amount: SolidityType.UINT,
});
 
export const Approve = new ActionSchema("approve", {
  spender: SolidityType.ADDRESS,
  amount: SolidityType.UINT,
});
 
export const TransferFrom = new ActionSchema("transfer-from", {
  from: SolidityType.ADDRESS,
  to: SolidityType.ADDRESS,
  amount: SolidityType.UINT,
});
 
export const Mint = new ActionSchema("mint", {
  to: SolidityType.ADDRESS,
  amount: SolidityType.UINT,
});
 
export const Burn = new ActionSchema("burn", {
  amount: SolidityType.UINT,
});