useHostChainInfo

useHostChainInfo resolves protocol-defined chain roles ("Relay" | "AssetHub" | "People" | "Bulletin") to the genesis hashes the host serves them under, plus the ecosystem the host is configured for ("polkadot", "paseo", …) as data.network. It is the wire method behind the hostChain field in your chain config: instead of baking a genesis hash into the bundle and shipping a new build after every testnet reset, the app asks the host which chain plays which role.

Roles the host does not serve are absent from data.chains. data is null standalone, on hosts that predate discovery, and when the host serves none of the requested roles, so keep a fallback (the descriptor's own genesis) for those cases. The answer is stable for the life of the connection and cached per set of roles; a host that changes network expects products to reconnect.

Usage

import { useFeatureSupported, useHostChainInfo } from "@use-truapi/react";
import { paseo_asset_hub } from "@parity/product-sdk-descriptors/paseo-asset-hub";

function ChainStatus() {
  const { data: discovery } = useHostChainInfo(["AssetHub", "People"]);
  const assetHub = discovery?.chains.AssetHub ?? (paseo_asset_hub.genesis as `0x${string}`);
  const { data: supported } = useFeatureSupported({ tag: "Chain", value: assetHub });

  return (
    <p>
      {discovery ? `${discovery.network} network` : "network unknown"} · asset hub{" "}
      {supported ? "supported" : "unsupported"}
    </p>
  );
}

<script setup lang="ts">
import { useHostChainInfo } from "@use-truapi/vue";

const { data: discovery } = useHostChainInfo(["AssetHub", "People"]);
</script>

<template>
  <p v-if="discovery">
    {{ discovery.network }}: asset hub {{ discovery.chains.AssetHub }}, people
    {{ discovery.chains.People }}
  </p>
  <p v-else>No chain discovery (standalone or legacy host).</p>
</template>

Config integration

Most apps never call this hook directly. Name the role in the chain config and the runtime resolves the genesis before it asks the host for a provider:

defineConfig({
  chains: {
    assetHub: {
      descriptor: paseo_asset_hub,
      hostChain: "AssetHub",                                // discovered inside a host
      genesisHash: paseo_asset_hub.genesis as `0x${string}`, // fallback for legacy hosts
      wsUrls: ["wss://…"],                                   // standalone
    },
  },
});

See also

• useChainSpec reads name and token properties once the genesis is known.
• useFeatureSupported probes a single genesis hash.

API reference

React

function useHostChainInfo(identifiers, options?): UseQueryResult<HostChainDiscovery | null, Error>;

RFC-0026 chain discovery: the host's network name plus the genesis hash of each requested role ("Relay" | "AssetHub" | "People" | "Bulletin") it serves. null standalone, on legacy hosts, or when none of the roles is served.

Parameters

Returns

UseQueryResult<HostChainDiscovery | null, Error>

Vue

function useHostChainInfo(identifiers, options?): QueryResult<HostChainDiscovery | null>;

RFC-0026 chain discovery: the host's network name plus the genesis hash of each requested role ("Relay" | "AssetHub" | "People" | "Bulletin") it serves. null standalone, on legacy hosts, or when none of the roles is served.

Parameters

Returns

QueryResult<HostChainDiscovery | null>