Part 4: Implement Gateway Client

TODO

• Client side typescript library

• Write functions

Recall how we map adapter program to the base program eariler, now we'll need to generate all accounts the instruction needed and wrap it through gateway. That's take a closer look at builder.ts, you might notice almost all functions in GatewayBuilder class returned GatewayBuilder type, which means user can chain all kinds of DeFi actions together, will see more about how to compose them together in the test script later.

export class GatewayBuilder {
  async swap(swapParams: SwapParams): Promise<GatewayBuilder> {
    ...
  }
  async addLiquidity(addLiquidityParams: AddLiquidityParams): Promise<GatewayBuilder> {
    ...
  }
  async removeLiquidity(removeLiquidityParams: RemoveLiquidityParams): Promise<GatewayBuilder> {
    ...
  }
  async stake(stakeParams: StakeParams): Promise<GatewayBuilder> {
    ...
  }
  async unstake(unstakeParams: UnstakeParams): Promise<GatewayBuilder> {
    ...
  }
  async harvest(harvestParams: HarvestParams): Promise<GatewayBuilder> {
    ...
  }
}

And now let's start to implement write functions in gateway. Find corresponding functions you have to code in types.ts, for Genopests IProtocolFarm is the only one interface they needed. The type of interfaces should be instantiated depends on what kind of actions the base program supports.

export class ProtocolGenopets implements IProtocolFarm {
  constructor(
    private _connection: anchor.web3.Connection,
    private _gatewayProgram: anchor.Program<Gateway>,
    private _gatewayStateKey: anchor.web3.PublicKey,
    private _gatewayParams: GatewayParams
  ) {}

  async stake(
    params: StakeParams,
    farmInfo: IFarmInfo,
    userKey: anchor.web3.PublicKey
  ): Promise<{ txs: anchor.web3.Transaction[]; input: Buffer }> {
    ...
    return { txs: [txStake], input: payload };
  }

  async unstake(
    params: UnstakeParams,
    farmInfo: IFarmInfo,
    userKey: anchor.web3.PublicKey
  ): Promise<{ txs: anchor.web3.Transaction[]; input: Buffer }> {
    ...
    return { txs: [txUnstake], input: payload };
  }

  async harvest(
    params: HarvestParams,
    farmInfo: IFarmInfo,
    userKey: anchor.web3.PublicKey
  ): Promise<{ txs: anchor.web3.Transaction[]; input: Buffer }> {
    ...
    return { txs: [txHarvest], input: payload };
  }
}

After all functions implemented, by adding switch case for all actions you just implemented in builder.ts, and it's good to support new protocol in gateway now!

case SupportedProtocols.Genopets:
  this._metadata.farm = await genopets.infos.getFarm(
    this._provider.connection,
    stakeParams.farmId
  );
  protocol = new ProtocolGenopets(
    this._provider.connection,
    this._program,
    await this.getGatewayStateKey(),
    this.params
  );

  break;