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;


    @Override
    public String getEndpoint() {
        return endpoint;
    }

    @Override
    public String getType() {
        return "s3";
    }

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

        s3Client = new AmazonS3Client(myCredentials);

        s3Client.setEndpoint(this.endpoint);
    }

    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.

https://data-sample.ams3.digitaloceanspaces.com/media/song.mp3?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Date=20180925T060309Z&X-Amz-SignedHeaders=host&X-Amz-Expires=899&X-Amz-Credential=BP5K25LRRQWYV2CMHZLL%2F20180925%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Signature=6a21133ced60047cfba60053afcdf712997c474585ade2f0050bc853b0a4db89

 

How To Filter Non Alphanumerics Characters From Your String And Its Application In Excel

If you are like me, I have to deal with text a lot in my work. As a programmer, I need to find and match string. Recently, a friend of mine, who is an accountant gave me a list of books’ titles. Most of them are fine. However, there are some contains strange characters and she wanted to remove such titles.

As you can see in the picture, there titles with @ and Chinese characters. Using filters doesn’t work because there are more than 1000 rows. That was when I said to myself: “I need a tool”.

So, I made one for this specific purpose: “to help my friend remove all the strange characters in her Excel workbook”.

Here is how the tool look like:

As you can see, you can put the original text in the source string box, adjust a few options above and click on filter. The result will be shown in the Result string box:

As you can see that all the rows that contain strange characters are removed.

However, what if you have some special characters that is allowed to appear in the title? No worries! You can put that into the Allowed characters box and separated them by spaces.

For example, It is OK for me to have the character @ in the title, I would put @ into the Allowed characters box. In addition, that title Blog@books.de contains the character dot (.) so you need to put that into the list of allowed characters too.

Let’s see what we’ll have:

As you can see now, the title with . and @ is accepted.

There are also two checkboxes that allowed you to filter the text further. You can decide to allow numbers or spaces in the title by checking these checkboxes.

I put the full source code for the tool here:

https://github.com/datmt/Remove-Lines-Contain-NonAlphaNumeric-Characters

If you are not a programmer, you can download the application here to start using it:

Download the .jar file

If you have any suggestions, please let me know. Thank you very much!