substrate-api-client 0.6.0

substrate-api-client
Documentation 
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# substrate-api-client


<p align="center">
<img src=./web3_foundation_grants_badge_black.svg width = 400>
</p>

substrate-api-client a library written in Rust for connecting to the substrate's RPC interface via WebSockets allowing to

* Compose extrinsics, send them and subscribe to updates (synchronously).
* supports composing extrinsics for `no_std` builds
* Watch events and execute code upon events.
* Parse and print the node metadata.

## Prerequisites


In order to build the substrate-api-client and the examples, Rust and the wasm target are needed. For Linux:

    curl https://sh.rustup.rs -sSf | sh

    rustup default nightly
    rustup target add wasm32-unknown-unknown --toolchain nightly

For more information, please refer to the [substrate](https://github.com/paritytech/substrate) repository.

## Substrate node


To execute the examples, a running substrate node is needed. A slightly extended node-template can be found at https://github.com/scs/substrate-api-client-test-node

To build the test node, execute the following steps:

    git clone https://github.com/scs/substrate-api-client-test-node
    cd substrate-api-client-test-node/
    cargo build --release

Run the node:

    ./target/release/node-template --dev

## Tutorial


There is a detailed tutorial in the [tutorials](/tutorials) folder.

## Examples


To run an example, clone the `substrate-api-client` repository and run the desired example directly with the cargo command:

```bash
    git clone https://github.com/scs/substrate-api-client.git
    cd substrate-api-client
    cargo run --example example_get_storage
```

Set the output verbosity by prepending `RUST_LOG=info` or `RUST_LOG=debug`.

The following examples can be found in the [examples](/src/examples) folder:

* [example_compose_extrinsic_offline](/src/examples/example_compose_extrinsic_offline.rs): Compose an extrinsic without interacting with the node.
* [example_contract](/src/examples/example_contract.rs): Handle ink! contracts (put, create, and call). **DEPRECATED!**
* [example_custom_storage_struct](/src/examples/example_custom_storage_struct.rs): Fetch and decode custom structs from the runtime. **DEPRECATED!**
* [example_event_callback](/src/examples/example_event_callback.rs): Subscribe and react on events.
* [example_generic_extrinsic](/src/examples/example_generic_extrinsic.rs): Compose an extrinsic for any call in any module by supplying the module and call name as strings.
* [example_get_storage](/src/examples/example_get_storage.rs): Read storage values.
* [example_print_metadata](/src/examples/example_print_metadata.rs): Print the metadata of the node in a readable way.
* [example_transfer](/src/examples/example_transfer.rs): Transfer tokens by using a wrapper of compose_extrinsic

## Alternatives


Parity offers a Rust client with similar functionality: https://github.com/paritytech/substrate-subxt

## Acknowledgements


The development of substrate-api-client is financed by [web3 foundation](https://web3.foundation/)'s grant programme.

We also thank the teams at

* [Parity Technologies](https://www.parity.io/) for building [substrate](https://github.com/paritytech/substrate) and supporting us during development.