[Ethereum] What are providers in the Ethereum

web3-providers

The below given code is from the a tutorial given here at one of the tutorials on Truffle

// Set the provider for our contract
App.contracts.Adoption.setProvider(App.web3Provider);

I see we set up a Web3 provider for the contract.

What basically are providers? What do they do?

web3 is a client to connect to the blockchain. But

1- you need to tell web3 which blockchain you are connecting to.

2- After you are connected to the specified blockchain, you need to send messages or data to the web3

those 2 tasks are done by a provider.

You are asking about very niche and complex problem, so one cannot expect ready made tutorials to be available.

I would suggest

Reverse engineering web3.js
Reverse engineering MetaMask
Reverse engineering Trust wallet
Reverse engineering web3.py (might be the most readable source code of all these)

In fact with web3-react:

const provider = new providers.Web3Provider(library.provider);

is equal to:

const context = useWeb3React();
const { library } = context;

Then you can do everything that provider do using library