Java RESTful Interface

What You Need

• Java 11+
• Gradle 4+
• Spring Boot 2.6.7+

How it Works

This Java application makes use of Spring Boot to create a RESTful interface which is exposed on the port 8080. This interface returns the full directory listing of a given path. Depending on the system it is run on, either Windows, Linux or Docker, the interface will only have access to that system's directories.
An exception for this is when the interface is run using Windows Subsystem for Linux (WSL). Windows directories can then be accessed via the endpoint /api/dirlist?path=/mnt/c/.

Installation

Clone This Repository

git clone https://github.com/tjrich/java-restful-interface.git

cd into the directory of the repository.

Wait for Gradle to initialise all required files. You should see directories such as .gradle and bin once initialisation is complete.

Run the following command

~$ gradle build

Docker Guide

Make sure that Docker is already running on your machine.

Build Docker Image

To build the Docker image, run the following command

docker build -t <tag> .

Example

docker build -t restful-interface .

Run in Docker Container

Once the build process has completed, run the following command

docker run -p 8080:8080 <tag>

Example

docker run -p 8080:8080 restful-interface

Run Natively

Linux

~$ gradle bootRun

Windows

> gradle bootRun

Consuming the REST Service

First make sure that the RESTful interface is running.

Consumer class

Contained in this repo is a class named Consumer.java
Consumer.java class makes use of a GET request supported by the built-in Java class HttpUrlConnection.

package com.trich.restfulinterface;

import java.net.*;
import java.io.*;

public class Consumer {

    public static String getData(String apiEndpoint) throws Exception {
        StringBuilder sb = new StringBuilder();
        String[] filesList; // String list to hold formatted results
        URL query = new URL(apiEndpoint);
        HttpURLConnection conn = (HttpURLConnection) query.openConnection();
        conn.setRequestMethod("GET");

        BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
        for (String line; (line = reader.readLine()) != null;) {
            sb.append(line);
        }
        /* Cleanup directory listing results */

        // Splits results by comma delimiter
        filesList = sb.toString().split(",");

        // Removes square bracket in the beginning of results
        filesList[0] = filesList[0].replace("[", " ");

        // Removes sqaure bracket at the end of results
        filesList[filesList.length - 1] = filesList[filesList.length - 1].replace("]", "");

        // Individually print out file, path, attributes and size
        for (String s : filesList) {
            System.out.println(s);
        }
        return "";

    }

    public static void main(String[] args) throws Exception {
        // Obtain directory listing via a run argument
        System.out.println(getData(args[0]));
    }

}

Run the Consumer

cd into the directory that contains Consumer.java

~$ cd /src/main/java/com/trich/restfulinterface

Once inside the directory of Consumer.java, run the following command

~$ java Consumer.java http://localhost:8080/api/dirlist?path="PATH"

Example - Linux

If the RESTful interface was run on Linux, run the following command

~$ java Consumer.java http://localhost:8080/api/dirlist?path=/

Example - Windows

If the RESTful interface was run on Windows, run the following command

~$ java Consumer.java http://localhost:8080/api/dirlist?path=C://

Output Example - Linux

$ java Consumer.java http://localhost:8080/api/dirlist?path=/
 /boot Attributes: Read: true Write: false Directory: true Last Modified: 03/10/2021 11:15:00 Is Hidden: false Size: 4096 bytes
 /bin Attributes: Read: true Write: false Directory: true Last Modified: 30/04/2022 21:57:18 Is Hidden: false Size: 4096 bytes
 /run Attributes: Read: true Write: false Directory: true Last Modified: 05/05/2022 19:36:54 Is Hidden: false Size: 300 bytes
 /init Attributes: Read: true Write: false Directory: false Last Modified: 26/04/2022 09:34:05 Is Hidden: false Size: 1440152 bytes
 /proc Attributes: Read: true Write: false Directory: true Last Modified: 05/05/2022 17:13:40 Is Hidden: false Size: 0 bytes
 /tmp Attributes: Read: true Write: true Directory: true Last Modified: 05/05/2022 23:53:47 Is Hidden: false Size: 12288 bytes
 /var Attributes: Read: true Write: false Directory: true Last Modified: 11/03/2022 23:17:17 Is Hidden: false Size: 4096 bytes
 /lost+found Attributes: Read: false Write: false Directory: true Last Modified: 10/04/2019 18:35:05 Is Hidden: false Size: 16384 bytes