phydy / cross-contract-example

A simple example demonstrating cross-contract calls in CosmWasm smart contracts

Cross-contract calls

This tutorial demonstrates cross-contract calls with CosmWasm v1.

Overview

An end user calls the reservation contract to register for an upcoming dinner. The user will have to pay a little to get on the list, unless they've been given a scholarship and added to a special list. The special list is its own contract, and the list of registrants also lives in another contract.

This is a trivial example to demonstrate cross-contract calls.

Contracts

There are three contracts here:

1. Reservation — this contract doesn't do much besides perform cross-contract calls to dinner contracts. It also stores how many times this contract has successfully registered people for dinner. 🍽️
2. Scholarship list — using the whitelist contract from cw-plus, we keep a list of addresses that can register for dinner without paying. The compiled contract lives in the directory whitelist-binary.
3. Dinners — the dinner contract keeps track of dinner attendees. For demonstration purposes, each instance keeps track of only one dinner. For production, you may not want to implement it this way.

Scenarios

Assuming there haven't been mistakes in deploying and initializing the three contracts, here are the success and failure scenarios.

Success

A normal person calls the reservation contract attaching funds to pay for their attendance.

A person whose address exists on the scholarship contract calls the reservation contract, without attaching funds.

Failure

A normal person calls the reservation contract but doesn't attach enough funds.

A person calls the reservation contract, but provides an invalid dinner contract address.

A registered person attempts to register again.

The dinner registration window has closed and a person tries to register.

Starting csli

/Users/mike/Documents/csli/bin/cosmjs-cli.mjs --init cosmjs-cli-helpers/cosmwasm-init.ts --code cosmjs-cli-helpers/cosmwasm-code.ts