User Story: Find invitation in wallet for offer

[katelynsills]

Story

As a user, I can find an invitation in my wallet to use for an offer, without having to know the details (such as the invitation handle) for that particular invitation. Just knowing the instance and description should be enough to choose an invitation to use.

Status

A user can do this, but they can only try to match the keys and values of invitation details exactly and the search is not very efficient. It might get slow if there are a very large number of invitations in the user's wallet.

Details

As of 2/5/2021, a dapp can specify an invitation to use for a particular proposed offer in the wallet by including the property invitationQuery with the keys and values that they wish to use to match. The included keys and values are matched against exactly, and keys and values that are not included are ignored. This does not allow for general amount patterns, but does allow for this user story to be fulfilled. Additionally, it is not very efficient:

agoric-sdk/packages/dapp-svelte-wallet/api/src/findOrMakeInvitation.js

Lines 49 to 60 in 0f02d52

	const findByKeyValuePairs = async (invitationPurseBalance, kvs) => {
	// TODO: use an AmountMath method instead to improve efficiency
	// For every key and value in `query`, return an amount
	// with any matches for those exact keys and values. Keys not in
	// `query` count as a match
	const matches = invitationDetail =>
	Object.entries(kvs).every(
	([key, value]) => invitationDetail[key] === value,
	);
	const matchingValue = invitationPurseBalance.value.find(matches);

There is also a deploy-script-support helper findInvitationAmount which is used within the offer helper. It has the same efficiency problems as the wallet method:

agoric-sdk/packages/deploy-script-support/src/offer.js

Lines 15 to 30 in 0f02d52

	const findInvitationAmount = async invitationDetailsCriteria => {
	const invitationAmount = await E(zoeInvitationPurse).getCurrentAmount();
	// TODO: use a new AmountMath method instead to improve efficiency
	// For every key and value in invitationDetailsCriteria, return an amount
	// with any matches for those exact keys and values. Keys not in
	// invitationDetails count as a match
	const matches = invitationDetail =>
	Object.entries(invitationDetailsCriteria).every(
	([key, value]) => invitationDetail[key] === value,
	);
	const matchingValue = invitationAmount.value.find(matches);
	const value =
	matchingValue === undefined ? harden([]) : harden([matchingValue]);
	return invitationMath.make(value);

Next Steps

Please see the Amount Patterns Implementation Plan issue