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Deployment

Contract Deployment and Configuration​

Messager​

  • Connecting two chains requires a Messager, with options available here:
    • Choose the appropriate type based on both chains' support, or reuse an existing Messager if available.
    • The type can be found here
  • After deploying the Messager, configure it for bidirectional communication:
    • Use the setRemoteMessager interface to set up connections, noting that interface parameters may vary depending on the Messager type.
  • Grant XTokenBridge (either XTokenBacking or XTokenIssuing) permission to use the Messager:
    • Use setWhiteList to authorize XTokenBridge, which should be configured after deploying XTokenBridge (details below) and obtaining its address.

XTokenBridge (XTokenBacking & XTokenIssuing)​

  • Repository: XToken Contracts
  • Deploy XTokenBacking on the source chain and XTokenIssuing on the issuing chain using a proxy contract method.
  • Once deployed, connect XTokenBacking and XTokenIssuing using the Messager
    • Authorize the Messager before connecting (see authorization details in the Messager section above).
    • Use setSendService and setReceiveService to link both sides, specifying the opposite chain ID, the counterpart XTokenBridge address, and the local Messager Service address.
  • Register Tokens
    • Use registerOriginalToken on XTokenBacking and updateXToken on XTokenIssuing to register native tokens and their mapped counterparts. If no mapped token exists, create one that follows the standard IXToken interface.
    • Set a daily transaction limit with setDailyLimit.

GuardV3 [optional]​

  • Deploy the GuardV3 contract: GuardV3 Contract
  • Use updateGuard to set the guard address. For any XTokenBridge with a non-zero guard address, transactions must go through Guard, and users will need to perform a claim action upon message delivery.

WTokenConvertor [optional]​

  • If native token support is needed, deploy the WTokenConvertor contract: WTokenConvertor Contract
  • This contract allows conversion between native tokens and WToken, enabling cross-chain WToken transfers via XTokenBridge.

Additional Extensions​

  • GuardV3 and WTokenConvertor are specific scenarios for XToken callback extensions. Developers can implement custom extensions, provided they comply with the IXTokenCallback interface.
  • Extensions can be chained in sequence by specifying receipt and extData.

Indexer​

Subgraph​

  • Currently, only supports msgport message types: Subgraph Repository
  • Deploy two subgraphs: transfer (for message sending events) and messageDispatcher (for message receiving events).
  • When Guard is enabled, specify the guard address.
  • For custom extensions, implement a custom subgraph tailored to the specific extension.

Apollo​