UCAN RPC validators
npm install @le-space/ucanto-validator@le-space/ucanto-validator provides validation mechanisms for UCAN-based capabilities, ensuring that invocations comply with defined rules and security policies.
@le-space/ucanto-core: Uses validation mechanisms to enforce capability constraints.@le-space/ucanto-server: Ensures only valid UCANs are processed by services.@le-space/ucanto-interface: Defines standard validation-related types.@le-space/ucanto-principal: Verifies cryptographic signatures for UCAN validation.For an overview and detailed usage information, refer to the main ucanto README.
sh
npm install @le-space/ucanto-validator
`Example Usage
ts
import { access, DID, capability, fail, Link, Schema } from '@le-space/ucanto-validator'
import { Verifier, ed25519 } from '@le-space/ucanto-principal'// Sample identities
const alice = await ed25519.generate()
const bob = await ed25519.generate()
// Define a known capability
const storeAdd = capability({
can: 'store/add',
with: DID,
nb: Schema.struct({
link: Link,
size: Schema.integer().optional(),
}),
derives: (claim, proof) => {
if (claim.with !== proof.with) {
return fail('with field does not match')
}
return { ok: {} }
}
})
// Alice delegates the capability to Bob
const proof = await storeAdd.delegate({
issuer: alice,
audience: bob,
capabilities: [
{
with: alice.did(),
can: 'store/add',
nb: {
link: Link.parse('bafkqaaa')
}
}
]
})
// Bob tries to invoke the capability
const invocation = storeAdd.invoke({
issuer: bob,
audience: alice,
with: alice.did(),
nb: {
link: Link.parse('bafkqaaa')
},
proofs: [proof]
})
// Validate the invocation
const result = await access(await invocation.delegate(), {
authority: alice,
capability: storeAdd,
principal: Verifier,
validateAuthorization: () => ({ ok: {} }),
})
// Check result: ensure the capability is known and valid
if (result.error) {
console.error('Capability validation failed:', result.error)
} else {
console.log('Capability is known and valid!')
}
`