README.md

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<p align="center">

> <img src="./.images/ink-squid.svg" alt="squink, the ink! mascot" style="vertical-align: middle" align="left" height="60" />`cargo-contract` is a CLI tool which helps you develop smart contracts in Parity's <a href="https://github.com/paritytech/ink">ink!</a>.<br/>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.
</p>

<br/>

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

<br/>
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More relevant links:
* Talk to us on [Element][b2] or on [Discord][c2] in the [`ink_smart-contracts`](https://discord.com/channels/722223075629727774/765280480609828864) channel
* [`ink!`](https://github.com/paritytech/ink) ‒ The main ink! repository with smart contract examples
* [Canvas UI](https://paritytech.github.io/canvas-ui/#/upload) ‒ Frontend for contract deployment and interaction
* [Substrate Contracts Node](https://github.com/paritytech/substrate-contracts-node) ‒ Simple Substrate blockchain which includes smart contract functionality


## Installation

* Step 1: `rustup component add rust-src`.

* Step 2: Install `binaryen` in a version >= 99:

  * [Debian/Ubuntu](https://tracker.debian.org/pkg/binaryen): `apt-get install binaryen`
  * [Homebrew](https://formulae.brew.sh/formula/binaryen): `brew install binaryen`
  * [Arch Linux](https://archlinux.org/packages/community/x86_64/binaryen/): `pacman -S binaryen`
  * Windows: [binary releases are available](https://github.com/WebAssembly/binaryen/releases)

  There's only an old version in your distributions package manager? Just use a 
  [binary release](https://github.com/WebAssembly/binaryen/releases).

* Step 3: `cargo install --force cargo-contract`.

You can always update the `cargo-contract` binary to the latest version by running the Step 3.

### Installation using Docker Image

If you prefer to use Docker instead we have a Docker image
[available on the Docker Hub](https://hub.docker.com/r/paritytech/contracts-ci-linux):

```bash
# Pull the latest stable image.
docker pull paritytech/contracts-ci-linux:production

# Create a new contract in your current directory.
docker run --rm -it -v $(pwd):/sources paritytech/contracts-ci-linux:production \
  cargo +nightly 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:production \
  cargo +nightly contract build --manifest-path=/sources/my_contract/Cargo.toml
```

If you want to reproduce other steps of CI process you can use the following
[guide](https://github.com/paritytech/scripts#reproduce-ci-locally).

## 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`](https://github.com/paritytech/ink/blob/master/examples/flipper/lib.rs) 
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 +nightly 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 build` must be run using the `nightly` toolchain. If you have
[`rustup`](https://github.com/rust-lang/rustup) installed, the simplest way to
do so is `cargo +nightly contract build`.

To avoid having to always add `+nightly` you can also set `nightly` as the default
toolchain of a directory by executing `rustup override set nightly` in it.

##### `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 test`

Runs test suites defined for a smart contract off-chain.

##### `cargo contract upload`

Upload a contract to a `pallet-contracts` enabled chain. See [extrinsics](docs/extrinsics.md).

##### `cargo contract instantiate`

Create an instance of a contract on chain. See [extrinsics](docs/extrinsics.md).

##### `cargo contract call`

Invoke a message on an existing contract on chain. See [extrinsics](docs/extrinsics.md).

## License

The entire code within this repository is licensed under the [GPLv3](LICENSE).

Please [contact us](https://www.parity.io/contact/) if you have questions about
the licensing of our products.