How to use window function in controller (node.js)?

Question

So this is my users controller to upload a file :

exports.postUploadFile = (req, res, next) => {

    var ethereumURI = req.body.ethereumURI;
    var abi = JSON.parse(req.body.abi);
    var contractAddress = req.body.contractAddress;
    let web3 = new Web3();
    web3.setProvider(new web3.providers.HttpProvider(window.web3.currentProvider));
    . . .
}

as you can see when i set my provider with "window.web3.currentProvider" instead of to make my metamask pop up, i got an error "window is undefined" ?

So how to use "window" for backend in node js / express js? I am using web3.js (0.2.x)

Answer 1

Shortly, you cannot.

window is defined only in a browser environment. In your case, since you're running it through Nodejs, window is undefined as expected.