UrlShortener service built with Spring and Kotlin

Prerequisites

1. Java 8
2. Apache Maven

Source codes

Clone the source codes from Github.

git clone https://github.com/hantsy/urlshortener-kotlins

The source codes are written with Kotlin, and also demonstrate testing codes with Spring test facilities(@DataJpaTest, WebMvcTest, Mockito) and RestAssured.

Build

Enter the project folder, build the project by Maven command.

mvn clean package

When it is done, there is a jar file in the target folder.

Run

Run the application.

java -jar target/app-0.0.1-SNAPSHOT.jar 

Test

It is easy to test the application by curl.

Generate a shorten url by sending request the root endpoint with POST method.

curl -v -X POST http://localhost:8080/ -d "{\"url\":\"test.com\"}" -H "Content-Type:application/json" -H "Accept:application/json"
Note: Unnecessary use of -X or --request, POST is already inferred.
*   Trying ::1...
* TCP_NODELAY set
* Connected to localhost (::1) port 8080 (#0)
> POST / HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.55.1
> Content-Type:application/json
> Accept:application/json
> Content-Length: 18
>
* upload completely sent off: 18 out of 18 bytes
< HTTP/1.1 201
< Location: http://localhost:8080/t8ldiTo6nA
< Content-Type: application/json;charset=UTF-8
< Transfer-Encoding: chunked
< Date: Thu, 07 Mar 2019 07:23:40 GMT
<
{"id":"t8ldiTo6nA","originUrl":"test.com"}* Connection #0 to host localhost left intact

NOTE: There is a Location header has been added in the response headers, it is easy to visit the new created resource by this url provided.

Access the single resource by generated id.

curl -v http://localhost:8080/t8ldiTo6nA
*   Trying ::1...
* TCP_NODELAY set
* Connected to localhost (::1) port 8080 (#0)
> GET /t8ldiTo6nA HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.55.1
> Accept: */*
>
< HTTP/1.1 308
< Location: test.com
< Content-Length: 0
< Date: Thu, 07 Mar 2019 07:23:50 GMT
<
* Connection #0 to host localhost left intact

When a generated id is found, then return a 308 status code. If you request this url in browser, it should redirect the location set in the header.

How it works

1. When you send a shorten url generation request to http://localhost:8080/.
2. Internally, the save method of UrlShortenerController will handle this request, including:
   • Generate a ramdon string as id of the short url
   • Save a mapping between the short url and long url into database, Spring Data JPA and H2 is used for data operations
   • Set the Location header(the shorten url link) to the new created resource(RegisteredUrl)
   • Return the saved resource into the response body.
3. Access the short url that extracted from the Location from response headers, the get method of UrlShortenerController will perform the following steps:
   • Extract the id from url, and find the RegisteredUrl by id
   • If it is existed, return 308 status and set Location header to the origin url.
   • If it is not existed, return 404