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Helper Functions for Koii Middleman Server

Overview​

The Koii Middleman Server template provides a set of helper functions to streamline the processing of tasks. These functions handle task data retrieval, data storage, and IPFS content fetching.

Helper Functions​

getTaskData​

const { getTaskStateInfo } = require("@_koii/create-task-cli");

Description​

Retrieves task data from K2 network, including submissions and round information.

Parameters​

  • connection: K2 network connection instance
  • taskID: The task identifier
  • round: Current round number being tracked

Returns​

{
    submissionFullList: Object,  // Complete submission data for the round
    submissions: Array,          // List of submission values
    submitters: Array,          // List of submitter addresses
    maxRound: Number,           // Current round number
    roundTime: Number           // Round duration
}

Key Features​

  • Validates task ID existence
  • Fetches latest task state using getTaskStateInfo
  • Processes submissions for the latest round
  • Includes error handling and round validation

storeData​

const { MongoClient } = require("mongodb");

Description​

Stores task data in MongoDB database.

Parameters​

  • taskId: Task identifier
  • round: Round number
  • data: Data to be stored

Configuration​

const client = new MongoClient(process.env.MONGO_URI);
const dbName = process.env.DB_NAME;
const collectionName = process.env.COLLECTION_NAME;

Required environment variables:

  • MONGO_URI: MongoDB connection string
  • DB_NAME: Database name
  • COLLECTION_NAME: Collection name

Workflow​

  1. Connects to MongoDB
  2. Inserts data with task ID and round information
  3. Closes connection after operation

dataFromCid​

const { KoiiStorageClient } = require("@_koii/storage-task-sdk");

Description​

Retrieves data from IPFS using Content Identifiers (CIDs).

Primary Function: fetchCidFromGetFile​

async function fetchCidFromGetFile(cid, fileName) {
    const blob = await storageClient.getFile(cid, fileName);
    const text = await blob.text();
    return JSON.parse(text);
}

Parameters​

  • cid: IPFS Content Identifier
  • fileName: Name of the file to retrieve
  • maxRetries (optional): Maximum retry attempts (default: 2)
  • retryDelay (optional): Delay between retries in ms (default: 3000)

Features​

  • Uses Koii Storage SDK for reliable IPFS access
  • Includes error handling and retry logic
  • Converts IPFS content to JSON format

Backup Method: directFetchCid​

async function directFetchCid(cid, fileName) {
    const response = await axios.get(
        `https://ipfs-gateway.koii.live/ipfs/${cid}/${fileName}`,
        { timeout: 530000 }
    );
    return response.data.map((item) => item.data);
}
note

Direct IPFS gateway fetching is available but not recommended for production use.

Usage Example​

const data = await dataFromCid("bafybei...", "data.json");
if (data) {
    // Process the retrieved data
}