Authenticate JIRA REST API using OAuth with Node.JS

There is an example for Node.JS with OAuth in the Atlassian repo that Brian also mentioned. I think it is for the 2-legged authentication.

It needs a pre-negotiated consumer key already set up by you. Here is an example how to obtain a token you can save in your config file: https://developer.atlassian.com/jiradev/api-reference/jira-rest-apis/jira-rest-api-tutorials/jira-rest-api-example-oauth-authentication

Here's a blog describing node.js and jira authentication using Oauth

It is in an express framework. I paste some part of the code below.

var base_url = "YOUR_JIRA_BASE_URL"; //example https://test.atlassian.net

app.get('/jira', function(req, res) {

var oa = new OAuth(base_url + "/plugins/servlet/oauth/request-token", //request token
    base_url + "/plugins/servlet/oauth/access-token", //access token
    "mykey", //consumer key 
    "YOUR_PEM_FILE_CONTENT", //consumer secret, eg. fs.readFileSync('jira.pem', 'utf8')
    '1.0', //OAuth version
    "http://localhost:1337/jira/callback", //callback url
    "RSA-SHA1");
oa.getOAuthRequestToken(function(error, oauthToken, oauthTokenSecret) {
    if (error) {
        console.log(error.data);
        response.send('Error getting OAuth access token');
    } else {
        req.session.oa = oa;
        req.session.oauth_token = oauthToken;
        req.session.oauth_token_secret = oauthTokenSecret;
        return res.redirect(base_url + "/plugins/servlet/oauth/authorize?oauth_token=" + oauthToken);
    }
});
});

If anyone is confused about any part of the code, you can add comment to this answer.