How to implement this in nodejs? - node.js

Question

I am new to nodejs and working on a proof of concept just for fun.
Background:
I have a cloud directory of user information (like username, password and other info). This cloud directory can be used to authenticate a user only via restful API (i.e. no direct connectivity using LDAP or JDBC etc.).
Aim:
To build an LDAP interface for this cloud directory. To start with I am interested only in authentication (LDAP bind).
Intended Flow:
LDAPClient initiates a standard LDAP simple BIND request:
Host: host where my nodejs app will run
Port: 1389 (port that my nodejs app will be bound to)
Username: a user from cloud directory
Password: user's password
This request is received by my NodeJS app (I am using ldapjs module).
// process ldap bind operation
myLdapServer.bind(searchBase, function (bindReq, bindRes, next) {
// bind creds
var userDn = req.dn.toString();
var userPw = req.credentials;
console.log('bind DN: ' + req.dn.toString());
...
...
}
Within the above callback, I must use http.request to fire a restful API (POST) to the cloud directory with the details I received from the BIND request (i.e. username, password).
If restful api response status is 200 (auth success), then I must return success to the LDAPClient, else I must return invalid credentials error.
Success:
bindRes.end();
return next();
Failure:
Console.log("returning error");
return next(new ldap.InvalidCredentialsError());
Questions:
Is this possible using NodeJS? Asking because of the nesting involved as evident above (calling of REST API from within a callback). Also since this is an authentication operation, this is meant to be a blocking operation(?)
Thanks,
Jatin
UPDATE:
Thanks Klvs, my solution is more or less like the one you posted. Please have a look at the snippet below:
// do the POST call from within callback
var postRequest = https.request(postOptions, function(postResponse) {
console.log("statusCode: ", postResponse.statusCode);
if(postResponse.statusCode!=200) {
console.log("cloud authentication failed: "+postResponse.statusCode);
return next(ldapModule.InvalidCredentialsError());
} else {
postResponse.on('data', function(d) {
console.info('POST result:\n');
process.stdout.write(d);
console.info('\n\nPOST completed');
});
res.end();
return next();
}
});
// write json data
postRequest.write(postData);
postRequest.end();
postRequest.on('error', function(e) {
console.error("postRequest error occured: "+e);
});
Successful authentication works fine, however, failed authentication does not send any response back to the LDAPClient at all. My client just times out instead of showing authentication failure error. I do see the "cloud authentication failed: " log message on the Node console, which means the below statement is not doing what I intend it do:
return next(ldapModule.InvalidCredentialsError());
Note that the above statement works when I remove the rest call etc, and just return the error back to the client.
Am I missing something?
Thanks,
Jatin

Answer 1

Of course it's possible in nodejs. If I understand you want to make an authenticating request to a server and have it either fail or succeed.
const request = require('request')
// process ldap bind operation
myLdapServer.bind(searchBase, function (bindReq, bindRes, next) {
// bind creds
var userDn = req.dn.toString();
var userPw = req.credentials;
console.log('bind DN: ' + req.dn.toString());
request.post({username: userDn, password: userPw}, (err, res, body)=>{
if(err) {
console.log("returning error");
next(new ldap.InvalidCredentialsError());
} else {
bindRes.end();
next();
}
})
}
Is that what you're looking for? If so, you just need to get accustom to callbacks.