Call Workflow
This diagram shows the call execution flow: starting with note_preimage, passing through validation
(signature, nonce, mortality, fee payment), then pre-dispatch checks, followed by dispatch which emits events: Noted and modifies storage: PreimageFor, StatusFor, and finally post-dispatch where ExtrinsicSuccess is emitted and fees are settled.
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Used by: validatorsdevelopers
The Big Picture
Stores call data for governance.
Use Cases
- Prepare governance proposals
From Chain Metadata
Register a preimage on-chain. If the preimage was previously requested, no fees or deposits are taken for providing the preimage. Otherwise, a deposit is taken proportional to the size of the preimage.
Input Parameters
| # | Name | Type | Description |
|---|---|---|---|
| 0 | bytes | Vec<u8> Vec | bytes (Vec<u8>) |
Permissions
Origin
Unknown
Required Role
Permission data inferred from metadata. May be incomplete.
Requirements
- Sufficient balance
- Hash is unique
Effects
Events Emitted
Storage Modified
Postconditions
- Preimage stored
- Deposit held
Side Effects
- Emits Noted
Code Examples
import { ApiPromise, WsProvider } from "@polkadot/api";
import { stringCamelCase } from "@polkadot/util";
const provider = new WsProvider("wss://entrypoint-finney.opentensor.ai:443");
const api = await ApiPromise.create({ provider });
// Build note_preimage call
const bytes = 0;
const call = api.tx[stringCamelCase("Preimage")][stringCamelCase("note_preimage")](
bytes
);Runtime Info
- Pallet Index
- 14
- Call Index
- 0
- First Version
- v133
- Current Version
- v393