examples

Example contracts

Example smart contracts illustrating the use of the tools for developing smart contracts in Rust.

Contracts are not meant for production, they are used to illustrate how to use the standard library and the tooling Concordium provides. There is no claim that the logic of the contract is reasonable, or safe.

Do not use these contracts as-is for anything other then experimenting.

The examples

The list of contracts is as follows:

• account-signature-checks A simple contract that demonstrates how account signature checks can be performed in smart contracts.
• two-step-transfer A contract that acts like an account (can send, store and accept CCD), but requires n > 1 ordained accounts to agree to the sending of CCD before it is accepted.
• auction A contract implementing an simple auction.
• piggy-bank The smart contract created as part of the Piggy Bank tutorial.
• memo An extremely minimal contract that can be used to mimic the memo feature. Normally a transfer between accounts cannot add any information other than the amount being transferred. Making transfers to this intermediate contract instead works around this limitation.
• cis2-dynamic-nft An example implementation of the CIS-2 Concordium Token Standard containing dynamic NFTs.
• cis2-multi An example implementation of the CIS-2 Concordium Token Standard and CIS-3 Concordium Sponsored Transaction Standard containing multiple token types.
• cis2-multi-royalties An example implementation of the CIS-2 Concordium Token Standard which allows the token minter to be paid royalties containing multiple token types.
• cis2-nft An example implementation of the CIS-2 Concordium Token Standard containing NFTs.
• cis2-wccd An upgradable example implementation of the CIS-2 Concordium Token Standard containing a single fungible token which is a wrapped CCD.
• counter-notify A contract that works as a counter and can invoke another contract with the current counter value.
• factory An example of implementing a factory pattern with smart contracts.
• fib A contract that calculates and stores the nth Fibonacci number by recursively calling itself.
• icecream A contract for buying ice cream only when it is sunny. A weather service oracle smart contract is used.
• proxy A proxy contract that can be put in front of another contract. It works with V0 as well as V1 smart contracts.
• recorder A contract that records account addresses, and has an entry point to invoke transfers to all those addresses.
• signature-verifier An example of how to use crypto_primitives. The contract verifies an Ed25519 signature.
• cis5-smart-contract-wallet An example of how to implement a CIS5 compatible smart contract wallet.
• nametoken An example of how to register and manage names as tokens in a smart contract.
• voting An example of how to conduct an election using a smart contract.
• transfer-policy-check A contract that showcases how to use policies.
• eSealing A contract implementing an eSealing service.
• credential-registry A contract for storing and managing public data of verifiable credentials.
• sponsoredTransactions A contract implementing the sponsored transaction mechanism (CIS3 standard).
• smartContractUpgrade An example of how to upgrade a smart contract. The state is migrated during the upgrade.

Running the tests

To run the tests for an example contract in the folder EXAMPLE open a terminal an run the following commands:

1. cd EXAMPLE
2. cargo concordium test --out concordium-out/module.wasm.v1

The smart contract upgrade example has specific instructions for running the tests. See the module documentation in ./smart-contract-upgrade/contract-version1/tests/tests.rs.

To learn more about testing contracts, please refer to our integration testing documentation.