Extracting URL components in Java

URL, Uniform Resource Locator is composed of
1) protocol
2) domain
3) path
4) query string
4) reference/ anchor

example:

[https]://[www.introverse.com]/[abc/def]?[id=1&id=2]#[index1]

scala> import java.net.URL
scala> val url = new URL("https://www.introverse.com/abc/def?id=1&id=2#index1")
url: java.net.URL = https://www.introverse.com/abc/def?id=1&id=2#index1

scala> url.getProtocol
res1: String = https

scala> url.getHost
res2: String = www.introverse.com

scala> url.getPath
res3: String = /abc/def

scala> url.getQuery
res4: String = id=1&id=2

scala> url.getRef
res5: String = index1

oracle create Entity Relation Diagram(ERD) from existing SQL DDL

I have a existing DDL for my application but I wanted to see the ERD for that. Oracle SQL developer provides Data modeler feature to generate ERD from existing DDL as shown in following screenshot
(import as Data Dictionary)

nodejs - call REST api with url encoded parameters

I have a REST API that expects url encoded request params as POST request body. So, API schema looks like

POST /login HTTP/1.1
Host: intro-api.com
Accept: */*
Content-Type: application/x-www-form-urlencoded
Content-Length: xxx

And, If you use curl request would look like,

curl -v --request POST -H "Content-Type: application/x-www-form-urlencoded" intro-api.com/login -d 'username=admin' -d 'password=admin'

Also, since content-type is urlencoded type, request params are in query string format. So -d "username=admin&password=admin" is valid as well.

Now,

I have a frontend(html/js) served by nodejs server which would have to validate user login by calling above REST api. This is what I'm talking in this article.

So, first of all I tried standard nodejs http library as a http client. But could not make it work for url encoded params. I was getting 408 error, which means it never sent the params?

function getUserSession(username, password) {

  const postData = qs.stringify({
    'username': username,
    'password': password
  });

  var options = {
    protocol: 'https:',
    host: 'intro.com',
    port: 443,
    path: '/login',
    method: 'POST',
    headers: {
      'Content-Type'  : 'application/x-www-form-urlencoded',
      'Content-Length': Buffer.byteLength(postData)
    }
  };

  https.request(options, function(resp){
    var response = '';
    resp.on('data', function(chunk){
      response += chunk;
      console.log(response)
    });
  }).on("error", function(e){
    console.log("Got error: " + e.message);
  });

}

So I ended up using request library. which needs to added to package.json (can also be done with npm install request, for more see official documentation).

Next, I will create auth.js with with a function that expects username and password and call the REST api, and respond the cookie value.

var request = require('request');

function getUserSessionId(username, password) {
  console.log("making login request")

  request.post({
    url: 'https://intro.com/login',
    form: {
      username: username,
      password: password
    }
  }).on("response", function(httpResponse) {
        var session = httpResponse.headers['set-cookie']
        console.log("session: " + session)
        return session
  });

}

var token = getUserSessionId('admin', 'admin')

Now, lets run it on terminal using node runtime (without having run it on http)

node auth.js

That is it to call "a REST api with url encoded params" using nodejs.