Author Archives: Niklas

H2 Database: Missing UNIX_TIMESTAMP

So maybe you are running tests using an H2 database with your MySQL-based application, and you just got the message that the MySQL function UNIX_TIMESTAMP(value) is missing from the H2 database? No worries. With an H2 database, you can build your own UNIX_TIMESTAMP (or any other function you might need). I’m here going to show you one way to do it:

First, we need to create a class on the classpath of the application that connects to the H2 database, this is normally the application you are testing:

package h2;

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class H2UserDefined {

    public static Long UNIX_TIMESTAMP(String d) throws ParseException {
        DateFormat dateFormat 
                          = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
        Date dateresult = dateFormat.parse(d);
        return dateresult.getTime()/1000;
    }
}

Now we need to tell H2 that we have a new function to use. To do this we need some SQL to run against the H2 database:

CREATE ALIAS UNIX_TIMESTAMP FOR "h2.H2UserDefined.UNIX_TIMESTAMP";

Here we tell the H2 database that there is a new alias called UNIX_TIMESTAMP that can be used and that it is located in the package ‘h2’ with the path ‘H2UserDefines’ and a function name UNIX_TIMESTAMP. Quite simple 🙂

Tested on Play Framework 2.3.6, H2 v1.4

Vue testing with Jest: Mock window.location

The bottom line is that you can not mock window.location, BUT you can delete it and create your own to use in test. I will here show one example of how this can be achived:

describe('methodUnderTest', () => {
  // Save current windows.location
  const oldWindowLocation = window.location;
  // Some mocked value
  const mockedUrl = 'https://blog.niklasottosson.com';

  beforeEach(() => {
    // Remove windows.location so that we can create a new
    delete window.location;

    // Create a new mutable window.location
    window.location = Object.defineProperties(
      {},
       {   // copy all properties from the old window.location
        ...Object.getOwnPropertyDescriptors(oldWindowLocation),
        // Start mocking...
        assign: {
           configurable: true,
           value: jest.fn()
        },
        href: {
            configurable: true,
            value: mockedUrl
        }
     );
  });

  afterEach(() => {
    // Restore window.location
    window.location = oldWindowLocation;
  });

  // Start creating your tests...
  it('should...', () => {
    ...
  } 

Tested on OSX 10.15.7, Vue v2.6.12 and Jest v26.0.14

Spring Boot: Map JSON body with root node in @RequestBody

Say you have the following JSON:

{
  "rootNode": {
    "firstValue":"",
    "secondValue":""
  }
}

The class to use for this could look something like this:

public class MyValues {
  private String firstValue;
  private String secondValue;
  ...
}

This class will however not map directly to the JSON above via @RequestBody, and this is because the JSON contains a root node (“rootNode”)

The solution here is to wrap the MyValues class into a “root class” like this:

public class MyValuesWrapper {
  MyValues rootNode;
  ...
}

After this you should be able to parse the request body automatically with @ResponseBody like this:

 @PostMapping(value = "/myValues")
  public int postValues(@RequestBody MyValuesWrapper wrappedRequest) {
  
  // Optional: Unwrap for easier access
  MyValues request = wrappedRequest.getMyValues();
  ...

Hope this helps somebody (or me in the future 🙂 )

Tested on Spring Boot v2.3.8 and Java 11