@bsv/sdk
Version:
BSV Blockchain Software Development Kit
51 lines • 2.31 kB
JavaScript
import { PushDrop } from '../script/index.js';
import * as Utils from '../primitives/utils.js';
import { kvProtocol } from './types.js';
/**
* KVStore interpreter used by Historian.
*
* Validates the KVStore PushDrop tokens: [protocolID, key, value, controller, signature] (old format)
* or [protocolID, key, value, controller, tags, signature] (new format).
* Filters outputs by the provided key in the interpreter context.
* Produces the plaintext value for matching outputs; returns undefined otherwise.
*
* @param transaction - The transaction to inspect.
* @param outputIndex - The index of the output within transaction.outputs.
* @param ctx - { key: string, protocolID: WalletProtocol } — per-call context specifying which key to match.
*
* @returns string | undefined — the decoded KV value if the output is a valid KVStore token for the
* given key; otherwise undefined.
*/
export const kvStoreInterpreter = async (transaction, outputIndex, ctx) => {
try {
const output = transaction.outputs[outputIndex];
if (output == null || output.lockingScript == null)
return undefined;
if (ctx == null || ctx.key == null)
return undefined;
// Decode the KVStore token
const decoded = PushDrop.decode(output.lockingScript);
// Support backwards compatibility: old format without tags, new format with tags
const expectedFieldCount = Object.keys(kvProtocol).length;
const hasTagsField = decoded.fields.length === expectedFieldCount;
const isOldFormat = decoded.fields.length === expectedFieldCount - 1;
if (!isOldFormat && !hasTagsField)
return undefined;
// Only return values for the given key and protocolID
const key = Utils.toUTF8(decoded.fields[kvProtocol.key]);
const protocolID = Utils.toUTF8(decoded.fields[kvProtocol.protocolID]);
if (key !== ctx.key || protocolID !== JSON.stringify(ctx.protocolID))
return undefined;
try {
return Utils.toUTF8(decoded.fields[kvProtocol.value]);
}
catch {
return undefined;
}
}
catch {
// Skip non-KVStore outputs or malformed tokens
return undefined;
}
};
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