DeCeuvalAirQualityOracle.sol

// SPDX-License-Identifier: MIT



pragma solidity ^0.8.7;

import "@chainlink/contracts/src/v0.8/ChainlinkClient.sol";

contract APIConsumer is ChainlinkClient {
    using Chainlink for Chainlink.Request;
  
    uint256 public airquality;
    
    address private oracle;
    bytes32 private jobId;
    uint256 private fee;

    event recordedAirQuality(
        uint, //timestamp
        uint256  //airquality
    );
    
    /**
     * Network: Kovan
     * Oracle: 0xc57B33452b4F7BB189bB5AfaE9cc4aBa1f7a4FD8 (Chainlink Devrel   
     * Node)
     * Job ID: d5270d1c311941d0b08bead21fea7747
     * Fee: 0.1 LINK
     * Oracle 0xc57B33452b4F7BB189bB5AfaE9cc4aBa1f7a4FD8
     * HTttpGetJsonParseMultiplyEthInt256 83ba9ddc927946198fbd0bf1bd8a8c25
     **/

// Kovan Link oracle address 0xa36085F69e2889c224210F603D836748e7dC0088



    constructor() {
        setPublicChainlinkToken();
        oracle = 0xc57B33452b4F7BB189bB5AfaE9cc4aBa1f7a4FD8;
        jobId = "d5270d1c311941d0b08bead21fea7747";
        fee = 0.1 * 10 ** 18; // (Varies by network and job)
    }
    
    /**
     * Create a Chainlink request to retrieve API response, find the target
     * data, then multiply by 1000000000000000000 (to remove decimal places from data).
     */
    function requestAirQualityData() public returns (bytes32 requestId) 
    {
        Chainlink.Request memory request = buildChainlinkRequest(jobId, address(this), this.fulfill.selector);
        
        // Set the URL to perform the GET request on
        request.add("get", "https://data.waag.org/api/holu/holukit/calibrated/recent");
        request.add("path", "$[?(@.id=='115')].pm25_mean"); //this PATH will find the data for De Ceuval
        
        // Multiply the result by 1000 to remove decimals
        int timesAmount = 1000;
        request.addInt("times", timesAmount);
        
        // Sends the request
        return sendChainlinkRequestTo(oracle, request, fee);
    }
    
    /**
     * Receive the response in the form of uint256
     */ 
    function fulfill(bytes32 _requestId, uint256 _airquality) public recordChainlinkFulfillment(_requestId)
    {
        airquality = _airquality;
        // now we emit an event to ensure this is recorded to the blockchain
        emit recordedAirQuality(
            block.timestamp, // timestamp
            airquality //the value
        );
    }

    function getDeCeuvelAirQuality() external view returns (uint256)
    {
        // This function allows other smart contracts to get the current air quality at DeCeuvel
        return airquality;
    } 

    // function withdrawLink() external {} - Implement a withdraw function to avoid locking your LINK in the contract
}