gsrpc

Overview ¶

Package gsrpc (Go Substrate RPC Client) provides APIs and types around Polkadot and any Substrate-based chain RPC calls. This client is modelled after polkadot-js/api(https://github.com/polkadot-js/api).

Calling RPC methods ¶

Simply instantiate the gsrpc with a URL of your choice, e. g.

api, err := gsrpc.NewSubstrateAPI("wss://poc3-rpc.polkadot.io")

and run any of the provided RPC methods from the api:

hash, err := api.RPC.Chain.GetBlockHashLatest()

Further examples can be found below.

Types ¶

The package [types](https://godoc.org/github.com/centrifuge/go-substrate-rpc-client/types/) exports a number of useful basic types including functions for encoding and decoding them.

To use your own custom types, you can simply create structs and arrays composing those basic types. Here are some examples using composition of a mix of these basic and builtin Go types:

1. Vectors, lists, series, sets, arrays, slices: https://godoc.org/github.com/centrifuge/go-substrate-rpc-client/types/#example_Vec_simple

2. Structs: https://godoc.org/github.com/centrifuge/go-substrate-rpc-client/types/#example_Struct_simple

There are some caveats though that you should be aware of:

1. The order of the values in your structs is of relevance to the encoding. The scale codec Substrate/Polkadot uses does not encode labels/keys.

2. Some types do not have corresponding types in Go. Working with them requires a custom struct with Encoding/Decoding methods that implement the Encodeable/Decodeable interfaces. Examples for that are enums, tuples and vectors with any types, you can find reference implementations of those here: types/enum_test.go , types/tuple_test.go and types/vec_any_test.go

For more information about the types sub-package, see https://godoc.org/github.com/centrifuge/go-substrate-rpc-client/types

package main

import (
	"fmt"

	gsrpc "github.com/centrifuge/go-substrate-rpc-client"
	"github.com/centrifuge/go-substrate-rpc-client/config"
)

func main() {
	api, err := gsrpc.NewSubstrateAPI(config.NewDefaultConfig().RPCURL)
	if err != nil {
		panic(err)
	}

	hash, err := api.RPC.Chain.GetBlockHashLatest()
	if err != nil {
		panic(err)
	}

	fmt.Println(hash.Hex())
}

Output: