Accessing Media Files (Audio, Video, Images…) From DigitalOcean Spaces Using Java

Recently, I need to upgrade my English learning app on Android to use multiple servers. Previously, I used two servers already. However, the way I manage media files caused me a lot of headache. So, I decided to switch to DigitalOcean since they have servers around the world and the pricing is good ($5 for 250GB storage and 1TB monthly transfer, which is good).

The initial problem with DigitalOcean spaces

Coming from old-school servers, I thought I can upload the files to DigitalOcean spaces using FTP and access the files directly as I usually used. However, the first problem is you cannot upload to spaces using FTP and the second problem is in order to make a file accessible to public, you need to set it permission to public. If you have one or two files, that wouldn’t be a problem.

I have more than 18,000 files.

The solutions to uploading multiple files

It turned out that DigitalOcean spaces use Amazon s3 technologies. So, in order to upload to spaces, you need to have FileZilla Pro (paid) or CyberDuck(free). I chose FileZilla Pro because it allows you to resume failed transfers while CyberDuck doesn’t allow that (or I couldn’t find where is that option).

The solution to accessing files

As my app used by thousands of people, the media files need to be accessible to all of the users. Actually, it is very easy to generate a public accessible URL for any files (they are called objects) using the aws-android-sdk. In case you need a working sample code, here it is:

public class DigitalOcean implements MediaServer{

    private static final String KEY = "YOUR_KEY";
    private static final String SECRETS = "YOUR_SECRETS";

    private String endpoint, bucketName;
    private AmazonS3Client s3Client;

    public String getEndpoint() {
        return endpoint;

    public String getType() {
        return "s3";

    public DigitalOcean(String endpoint, String bucketName)
        this.bucketName = bucketName;
        this.endpoint = endpoint;
        AWSCredentials myCredentials = new BasicAWSCredentials(

        s3Client = new AmazonS3Client(myCredentials);


    public String getMediaURL(String objectPath)
        GeneratePresignedUrlRequest request = new GeneratePresignedUrlRequest(bucketName, objectPath);
        URL objectURL = s3Client.generatePresignedUrl(request);

        return objectURL.toString();


As you can see, I created an object to generate URL to any files(objects). For example, here is a sample space url:

The bucket name would be data-sample.

If your file, let call it song.mp3 located at /data-sample/media/song.mp3, the objectPath would be: /media/song.mp3.

If you run the method getMediaURL(), you will get the path to the file that is accessible to your users but you don’t have to mark the file public.


How To Combine Multiple Text Files (.txt) Into One Big File

Recently, I have a specific need to combine multiple files into one big file. The task is very simple. However, if I do it manually (combine over 32,000 small text files into one), it may cost me a day, or even more.

How to combine multiple text files into one

So, I decided to make a tool in Java. Its interface is very simple but you can use it right away without much learning. Here is the app’s interface:

As you can see from the interface, there are three buttons and these are the one you need to pay attention to. To start combining  your small .txt files, click on the button “Select files to combine”. Here, I’m going to select all of my .txt file (over 32,000 files). For those of you who are curious, these are the books from project Gutenberg.

Now, click on Open.

Next, you need to select the destination file. This is the file that contains all the text from the small files.

You can see that the path to the destination file is displayed in the text field at the left of the select button.

Now, simply click on combine now. The program will go ahead and combine your files into one file. In my case, all over 32,000 files are combined into one and the destination file is over 250MB! That’s a lot for a .txt file. In fact, there are more than 7 million line of text inside that file.

If you are a Java developer,  you can check out the repo here on Github here to modify it to your needs. If you are an user, you can download the ready built app here to start combining your .txt files:

Click here to download the executable app.