Json String Comparator

This is a demo Spring Boot application in order to compare 2 JSON Strings.

Requirements

1. Provide 2 http endpoints that accepts JSON base64 encoded binary data on both endpoints.

   <host>/v1/diff/<ID>left and <host>/v1/diff/<ID>right

2. The provided data needs to be diff-ed and the results shall be available on a third endpoint.

   <host>/v1/diff/<ID>

3. The results shall provide the following info in JSON format

   • If equal return that
   • If not of equal size just return that
   • If of same size provide insight in where the diffs are, actual diffs are not needed. So mainly offsets + length in the data

Must haves

• Solution written in Java
• Internal logic shall be under unit test
• Functionality shall be under integration test
• Documentation in code
• Clear and to the point readme on usage

Solution

Within this requirement, a new Spring Boot application created from scratch.

The main purpose of this demo application is to retrieve JSON strings from "/left" and "/right" endpoints, insert these data into local database and return JSON result by comparing them.

JSON Format

Client requests should be in JSON format. If not, then "415 Unsupported Media Type" exception will be thrown.

JSON format - Sample JSON Request:

{
  "content": "Sample JSON content to compare"
}

Application will return JSON responses for each request and generate different JSON content for each request of Success and Failure requests.

JSON format - Success Insertion Request:

{
  "error": false,
  "message": "Inserted successfully."
}

JSON format - Sample Failure Request:

{
  "error": true,
  "message": "Invalid JSON found! Error: Unrecognized token 'content': was expecting (JSON String, ..."
}

JSON format - Sample Success Request:

{
  "error": false,
  "message": "Objects are equal"
}

JSON format - Sample Success Request with Differences:

{
  "error": false,
  "message": "Execution successful.",
  "Differences": [
    {
      "offset": 22,
      "left char": 5,
      "right char": 6
    }
  ]
}

Usage

An executable war file created and placed under project source folder /target directory. In order to execute module and start web server, run below command in terminal.

$ java -jar JsonStringComparator.war

While application is running, typing CTRL + C in terminal will halt the server and stop execution of application.

Service will run and can be available in below url: http://localhost:8080/v1/diff/1

In first run of application, default JSON response will be as:

{
  "error": false,
  "message": "Both objects are NULL"
}

Testing

As a testing tool Postman is highly recommended to be used for making HTTP requests.

Internal logic is under unit test which is available in classes of FakeJsonObjectDaoImplTest, JsonComparatorTest and JsonResponseCreatorTest.

Functionality is under integration test which is available in classes of RestControllerTest and JsonObjectServiceTest.

Testing insertion

Steps;

• Go to /target directory
• Run application via command line: $ java -jar JsonStringComparator.war

• Start Postman and create http request with below characteristics

  Request type	URL
  POST	http://localhost:8080/v1/diff/1/left

  BODY	Media Type
  {“content": "Sample JSON content to compare”}	JSON

• Send request and check if execution is successful for insertion.

{ "error": false, "message": "Inserted successfully." }

Testing invalid JSON

If invalid JSON data is passed, then application will return a message as shown below.

Testing comparison (Success)

Steps;

• Go to /target directory
• Run application via command line: $ java -jar JsonStringComparator.war
• Start Postman and create POST http request for both /left and /right endpoints.

Left endpoint	Request body
http://localhost:8080/v1/diff/1/left	{"content": "Sample JSON content to compare 152”}

Right endpoint	Request body
http://localhost:8080/v1/diff/1/right	{"content": "Sample JSON content to compare 987”}

• And lastly send GET http comparison request as shown below with URL of http://localhost:8080/v1/diff/1/

Technologies

• IntelliJ IDEA 2020.2.3 (Community Edition)
• Runtime version: 11.0.8+10-b944.34 amd64
• VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o.
• Windows 10 10.0
• GC: ParNew, ConcurrentMarkSweep
• Memory: 1963M
• Cores: 8
• Non-Bundled Plugins: in.1ton.idea.spring.assistant.plugin
• JUnit 5
• Apache Maven 3.3.9
• Postman v7.34.0
• Java Development Kit (JDK) 13.0.2

Documentation in code

For the documentation in code (Java docs) please double click on index.html under /target/docs/javadoc/ directory.

Happy coding! 👍 🥇

License

JsonStringComparator, Copyright (C) 2020