Crate smoldot_light

Smoldot light client library.

This library provides an easy way to create a light client.

This light client is opinionated towards certain aspects: what it downloads, how much memory and CPU it is willing to consume, etc.

Usage

Initialization

In order to use the light client, call Client::new, passing an implementation of the platform::PlatformRef trait. See the documentation of the platform::PlatformRef trait for more information.

The Client contains two generic parameters:

• An implementation of the platform::PlatformRef trait.
• An opaque user data. If you do not use this, you can simply use ().

When the std feature of this library is enabled, the platform::DefaultPlatform struct can be used as an implementation of platform::PlatformRef.

For example:

use smoldot_light::{Client, platform::DefaultPlatform};
let client = Client::new(DefaultPlatform::new(env!("CARGO_PKG_NAME").into(), env!("CARGO_PKG_VERSION").into()));

If the std feature of this library is disabled, then you need to implement the platform::PlatformRef trait manually.

Adding a chain

After the client has been initialized, use Client::add_chain to ask the client to connect to said chain. See the documentation of AddChainConfig for information about what to provide.

Client::add_chain returns a ChainId, which identifies the chain within the Client. A Client can be thought of as a collection of chain connections, each identified by their ChainId, akin to a HashMap<ChainId, ...>.

A chain can be removed at any time using Client::remove_chain. This will cause the client to stop all connections and clean up its internal services. The ChainId is instantly considered as invalid as soon as the method is called.

JSON-RPC requests and responses

Once a chain has been added, one can send JSON-RPC requests using Client::json_rpc_request.

The request parameter of this function must be a JSON-RPC request in its text form. For example: {"id":53,"jsonrpc":"2.0","method":"system_name","params":[]}.

Calling Client::json_rpc_request queues the request in the internals of the client. Later, the client will process it.

Responses can be pulled by calling the AddChainSuccess::json_rpc_responses that is returned after a chain has been added.

Modules

• network_service
  Background network service.
• platform

Macros

• log
  Helper macro for using the crate::platform::PlatformRef::log function.
• log_inner

Structs

• AddChainConfig
  See Client::add_chain.
• AddChainSuccess
  Returns by Client::add_chain on success.
• ChainId
  Chain registered in a Client.
• Client
  Holds a list of chains, connections, and JSON-RPC services.
• JsonRpcResponses
  Stream of JSON-RPC responses or notifications.

Enums

• AddChainConfigJsonRpc
  See AddChainConfig::json_rpc.
• AddChainError
  Error potentially returned by Client::add_chain.
• HandleRpcError
  Error potentially returned when queuing a JSON-RPC request.