# Data Consumer Demo

Note the "is ConsumerBase", to extend https://github.com/unification-com/xfund-router/blob/main/contracts/lib/ConsumerBase.sol ConsumerBase.sol interacts with the deployed Router.sol smart contract which will route data requests and fee payment to the selected provider and handle data fulfilment.

The selected provider will listen to the Router for requests, then send the data back to the Router, which will in turn forward the data to your smart contract after verifying the source of the data.

# Functions:

# Events:

# Function constructor(address _router, address _xfund, address _provider, uint256 _fee) public

constructor must pass the address of the Router and xFUND smart contracts to the constructor of your contract! Without it, this contract cannot interact with the system, nor request/receive any data. The constructor calls the parent ConsumerBase constructor to set these.

# Parameters:

  • _router: address of the Router smart contract

  • _xfund: address of the xFUND smart contract

  • _provider: address of the default provider

  • _fee: uint256 default fee

# Function setProvider(address _provider) external

setProvider change default provider. Uses OpenZeppelin's onlyOwner modifier to secure the function.

# Parameters:

  • _provider: address of the default provider

# Function setFee(uint256 _fee) external

setFee change default fee. Uses OpenZeppelin's onlyOwner modifier to secure the function.

# Parameters:

  • _fee: uint256 default fee

# Function getData(bytes32 _data) external -> bytes32

getData the actual function to request data.

NOTE: Calls ConsumerBase.sol's requestData function.

Uses OpenZeppelin's onlyOwner modifier to secure the function. The data format can be found at https://docs.finchains.io/guide/ooo_api.html Endpoints should be Hex encoded using, for example the web3.utils.asciiToHex function.

# Parameters:

  • _data: bytes32 data being requested.

# Function increaseRouterAllowance(uint256 _amount) external

increaseRouterAllowance allows the Router to spend xFUND on behalf of this smart contract.

NOTE: Calls the internal _increaseRouterAllowance function in ConsumerBase.sol.

Required so that xFUND fees can be paid. Uses OpenZeppelin's onlyOwner modifier to secure the function.

# Parameters:

  • _amount: uint256 amount to increase

# Function setRouter(address _router) external

setRouter allows updating the Router contract address

NOTE: Calls the internal setRouter function in ConsumerBase.sol.

Can be used if network upgrades require new Router deployments. Uses OpenZeppelin's onlyOwner modifier to secure the function.

# Parameters:

  • _router: address new Router address

# Function withdrawxFund(address _to, uint256 _value) external

increaseRouterAllowance allows contract owner to withdraw any xFUND held in this contract. Uses OpenZeppelin's onlyOwner modifier to secure the function.

# Parameters:

  • _to: address recipient

  • _value: uint256 amount to withdraw

# Function receiveData(uint256 _price, bytes32 _requestId) internal

recieveData - example end user function to receive data. This will be called by the data provider, via the Router's fulfillRequest, and through the ConsumerBase's rawReceiveData function.

Note: validation of the data and data provider sending the data is handled by the Router smart contract prior to it forwarding the data to your contract, allowing devs to focus on pure functionality. ConsumerBase.sol's rawReceiveData function can only be called by the Router smart contract.

# Parameters:

  • _price: uint256 result being sent

  • _requestId: bytes32 request ID of the request being fulfilled

# Event PriceDiff(bytes32 requestId, uint256 oldPrice, uint256 newPrice, int256 diff)

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Last Updated: 4/21/2021, 1:09:18 PM