fix: prevent handle leak and add configurable statement_timeout for D…

[slowbackspace]

…B Sync

[Copilot]

Pull request overview

This PR addresses a streaming resource leak when clients disconnect mid-response and introduces a configurable PostgreSQL statement_timeout for DB Sync queries via config/env var.

Changes:

• Destroy JSON streaming readable when the client connection closes to prevent stream handle leaks.
• Add dbSync.statementTimeout / BLOCKFROST_CONFIG_DBSYNC_STATEMENT_TIMEOUT and wire it to Postgres statement_timeout.
• Bump version to 6.3.1 and document the release in the changelog.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
src/utils/string-utils.ts	Adds client-disconnect cleanup for toJSONStream to prevent handle leaks.
src/config.ts	Loads optional DB Sync statement timeout from env/config.
src/app.ts	Passes statement timeout into @fastify/postgres connection options.
package.json	Version bump to 6.3.1.
CHANGELOG.md	Documents 6.3.1 changes (timeout + leak fix).

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[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

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[Copilot]

cleanup can be invoked more than once because it is registered separately with once('close') and once('error'). If both events fire (e.g., write error followed by close), this can double-destroy/unpipe streams and lead to noisy errors. Consider making cleanup idempotent with a cleaned flag (or wrap it in a one-time guard) before calling unpipe()/destroy().

[Copilot]

toJSONStream attaches listeners only for close/error on the provided Writable. Many Writable implementations (including custom ones) may never emit close on normal completion, which can leave the cleanup listener (and captured dataStream/transformStream) referenced longer than necessary. Consider also cleaning up on finish (and/or removing the listeners when the piping completes) so cleanup reliably runs and listeners don’t linger.

Suggested change

	const cleanup = () => {
	dataStream.unpipe(transformStream);
	dataStream.destroy();
	if (typeof (transformStream as stream.Transform).destroy === 'function') {
	(transformStream as stream.Transform).destroy();
	}
	};
	serverResponse.once('close', cleanup);
	serverResponse.once('error', cleanup);
	function cleanup() {
	// Remove listeners so the closure and streams can be garbage-collected.
	serverResponse.removeListener('close', onClose);
	serverResponse.removeListener('error', onError);
	serverResponse.removeListener('finish', onFinish);
	dataStream.unpipe(transformStream);
	dataStream.destroy();
	if (typeof (transformStream as stream.Transform).destroy === 'function') {
	(transformStream as stream.Transform).destroy();
	}
	}
	function onClose() {
	cleanup();
	}
	function onError() {
	cleanup();
	}
	function onFinish() {
	cleanup();
	}
	serverResponse.once('close', onClose);
	serverResponse.once('error', onError);
	serverResponse.once('finish', onFinish);