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> `cargo-contract` is a CLI tool which helps you develop smart contracts in Parity's ink!.
ink! is a Rust [eDSL](https://wiki.haskell.org/Embedded_domain_specific_language) which allows you to write smart contracts for blockchains built on the [Substrate](https://github.com/paritytech/substrate) framework.

[Guided Tutorial for Beginners](https://docs.substrate.io/tutorials/v3/ink-workshop/pt1/)  •   [ink! Documentation Portal](https://ink.substrate.io)

More relevant links:

• Find answers to your questions by joining our [Stack Exchange][s2] community
• ink! ‒ The main ink! repository with smart contract examples
• Contracts UI ‒ Frontend for contract deployment and interaction
• Substrate Contracts Node ‒ Simple Substrate blockchain which includes smart contract functionality

Installation

In addition to Rust, installation requires a C++ compiler that supports C++17. Modern releases of gcc and clang, as well as Visual Studio 2019+ should work.

• Step 1: rustup component add rust-src.

• Step 2: cargo install --force --locked cargo-contract.

• Step 3: (Optional) Install dylint for linting.

  • (MacOS) brew install openssl
  • cargo install cargo-dylint dylint-link.

• Step 4: (Optional) Install Docker Engine to be able to produce verifiable builds.

You can always update the cargo-contract binary to the latest version by running the Step 2.

Installation using Docker Image

If you prefer to use Docker instead we have a Docker image available on the Docker Hub:

```bash

Pull the latest stable image.

docker pull paritytech/contracts-ci-linux

Create a new contract in your current directory.

docker run --rm -it -v $(pwd):/sources paritytech/contracts-ci-linux \ cargo contract new --target-dir /sources my_contract

Build the contract. This will create the contract file under

my_contract/target/ink/my_contract.contract.

docker run --rm -it -v $(pwd):/sources paritytech/contracts-ci-linux \ cargo contract build --manifest-path=/sources/my_contract/Cargo.toml ```

Windows: If you use PowerShell, change $(pwd) to ${pwd}.

```bash

Create a new contract in your current directory (in Windows PowerShell).

docker run --rm -it -v ${pwd}:/sources paritytech/contracts-ci-linux \ cargo contract new --target-dir /sources my_contract ```

If you want to reproduce other steps of CI process you can use the following guide.

Verifiable builds

Some block explorers require the Wasm binary to be compiled in the deterministic environment. To achieve it, you should build your contract using Docker image we provide:

bash cargo contract build --verifiable

You can find more detailed documentation how to use the image here

Usage

You can always use cargo contract help to print information on available commands and their usage.

For each command there is also a --help flag with info on additional parameters, e.g. cargo contract new --help.

cargo contract new my_contract

Creates an initial smart contract with some scaffolding code into a new folder my_contract .

The contract contains the source code for the Flipper contract, which is about the simplest "smart" contract you can build ‒ a bool which gets flipped from true to false through the flip() function.

cargo contract build

Compiles the contract into optimized WebAssembly bytecode, generates metadata for it, and bundles both together in a <name>.contract file, which you can use for deploying the contract on-chain.

cargo contract check

Checks that the code builds as WebAssembly. This command does not output any <name>.contract artifact to the target/ directory.

cargo contract upload

Upload a contract to a pallet-contracts enabled chain. See extrinsics.

cargo contract instantiate

Create an instance of a contract on chain. See extrinsics.

cargo contract call

Invoke a message on an existing contract on chain. See extrinsics.

cargo contract decode

Decodes a contracts input or output data.

This can be either an event, an invocation of a contract message, or an invocation of a contract constructor.

The argument has to be given as hex-encoding, starting with 0x.

cargo contract remove

Remove a contract from a pallet-contracts enabled chain. See extrinsics.

cargo contract info

Fetch and display contract information of a contract on chain. See info.

Publishing

In order to publish a new version of cargo-contract:

• Bump all crate versions, we move them in lockstep.
• Make sure your PR is approved by one or more core developers.
• Publish metadata ➜ transcode ➜ build ➜ extrinsics ➜ cargo-contract.
• Merge you PR and push a tag vX.X with your version number.
• Create a GitHub release with the changelog entries.

License

The entire code within this repository is licensed under the GPLv3.

Please contact us if you have questions about the licensing of our products.