Use ethstorage-sdk to upload and download files

Introduction

In this tutorial, we will demonstrate how to upload and download files using the ethstorage-sdk tool.

The ethstorage-sdk provides APIs for file upload, download, and management.

In the following code examples, Super World Computer beta testnet is used by default. You can easily switch to other chains by specify a different RPC endpoint, such as "https://rpc.sepolia.org" for Sepolia.

Step 1: Install ethstorage-sdk

You can install ethstorage-sdk by the following command:

 npm i ethstorage-sdk

Step 2: Manage Files

2.1 Create FlatDirectory

In this section, you will create a FlatDirectory contract for managing files.

const { FlatDirectory } = require("ethstorage-sdk");

const rpc = "https://rpc.beta.testnet.l2.quarkchain.io:8545";
// For Sepolia:
// const rpc = "https://rpc.sepolia.org";
const privateKey = "0x...";

const flatDirectory = await FlatDirectory.create({
    rpc: rpc,
    privateKey: privateKey,
});
const contracAddress = await flatDirectory.deploy();
console.log(`FlatDirectory address: ${contracAddress}.`);
// FlatDirectory address: 0x37df32c7a3c30d352453dadacc838461d8629016

If you already have a FlatDirectory contract, you can set it.

const address = "0x37df32c7a3c30d352453dadacc838461d8629016"; // FlatDirectory address

const flatDirectory = await FlatDirectory.create({
    rpc: rpc,
    privateKey: privateKey,
    address: address,
});

2.2: Upload Files To FlatDirectory

In this section, you will upload some files into the FlatDirectory that you just created.

You can use Buffer to upload files.

const request = {
    key: "test.txt",
    content: Buffer.from("big data"),
    type: 2, // 1 for calldata and 2 for blob
    callback: callback
}
await flatDirectory.upload(request);

You can also upload File objects. This applies to both browser and Node.js environments.

Browser

// <input id='fileToUpload' />
const file = document.getElementById('fileToUpload').files[0];

const request = {
    key: "test.txt",
    content: file,
    type: 2,
    callback: callback
}
await flatDirectory.upload(request);

Node.js

const {NodeFile} = require("ethstorage-sdk/file");
const file = new NodeFile("/usr/download/test.jpg");

const request = {
    key: "test.jpg",
    content: file,
    type: 2,
    callback: callback
}
await flatDirectory.upload(request);

const callback = {
    onProgress: function (progress, count, isChange) {
       ...
    },
    onFail: function (err) {
        ...
    },
    onFinish: function (totalUploadChunks, totalUploadSize, totalStorageCost) {
        ...
    }
};

2.3: Download Files From FlatDirectory

In this section, you will download files from the ethstorage network.

// Note: To download files, you need to specify the `ethStorageRpc`.
// For Sepolia:
// const ethStorageRpc = "http://65.108.236.27:9540";
const ethStorageRpc = "https://rpc.beta.testnet.l2.ethstorage.io:9596";
const flatDirectory = await FlatDirectory.create({
    rpc: rpc,
    ethStorageRpc: ethStorageRpc,
    privateKey: privateKey,
    address: address,
});

const key = "test.txt";
await flatDirectory.download(key, {
    onProgress: function (progress, count, chunk) {
        ...
    },
    onFail: function (error) {
        ...
    },
    onFinish: function () {
        ...
    }
});

Step 3: Manage Blobs

3.1 Create EthStorage

In this section, you can create an EthStorage instance to interact directly with EthStorage for managing blobs.

const { EthStorage } = require("ethstorage-sdk");

// For Sepolia:
// const rpc = "https://rpc.sepolia.org";
const rpc = "https://rpc.beta.testnet.l2.quarkchain.io:8545";

// For Sepolia:
// const ethStorageRpc = "http://65.108.236.27:9540";
const ethStorageRpc = "https://rpc.beta.testnet.l2.ethstorage.io:9596";

const privateKey = "0x...";

const ethStorage = await EthStorage.create({
    rpc: rpc,
    ethStorageRpc: ethStorageRpc,
    privateKey: privateKey,
});

3.2 Write Blob

Write blob data to the EthStorage network.

const key = "test.txt";
const data = Buffer.from("test data");
await ethStorage.write(key, data);

3.3 Read Blob

Read the written data from the EthStorage network.

const key = "test.txt";
const data = await ethStorage.read(key);