Dropbox Java API

As well as being useful as general cloud storage, dropbox also has an API that lets you access its contents programmatically. It's a straightforward REST API with a number of language specific libraries to make the going a bit easier. Java is included on the list of SDKs, but at present only Android is included on the list of tutorials. This can be somewhat frustrating because simple examples using Java are lacking.

Fortunately, the process was described by Josh here. So I've taken it and implemented it in Java, and it seems to work. It's a very basic example that authenticates with dropbox then uploads a file called "testing.txt" containing "hello world."

Of course, more functionality is available than this, but this is the hard part (at least I found working this bit out the hard part.) Once you've got your DropboxAPI object, you can work most things from there using the supplied Javadoc.

/**
 * A very basic dropbox example.
 * @author mjrb5
 */
public class DropboxTest {

    private static final String APP_KEY = "APP KEY";
    private static final String APP_SECRET = "SECRET KEY";
    private static final AccessType ACCESS_TYPE = AccessType.APP_FOLDER;
    private static DropboxAPI<WebAuthSession> mDBApi;

    public static void main(String[] args) throws Exception {
        AppKeyPair appKeys = new AppKeyPair(APP_KEY, APP_SECRET);
        WebAuthSession session = new WebAuthSession(appKeys, ACCESS_TYPE);
        WebAuthInfo authInfo = session.getAuthInfo();

        RequestTokenPair pair = authInfo.requestTokenPair;
        String url = authInfo.url;

        Desktop.getDesktop().browse(new URL(url).toURI());
        JOptionPane.showMessageDialog(null, "Press ok to continue once you have authenticated.");
        session.retrieveWebAccessToken(pair);

        AccessTokenPair tokens = session.getAccessTokenPair();
        System.out.println("Use this token pair in future so you don't have to re-authenticate each time:");
        System.out.println("Key token: " + tokens.key);
        System.out.println("Secret token: " + tokens.secret);

        mDBApi = new DropboxAPI<WebAuthSession>(session);
        System.out.println();
        System.out.print("Uploading file...");
        String fileContents = "Hello World!";
        ByteArrayInputStream inputStream = new ByteArrayInputStream(fileContents.getBytes());
        Entry newEntry = mDBApi.putFile("/testing.txt", inputStream, fileContents.length(), null, null);
        System.out.println("Done. \nRevision of file: " + newEntry.rev);
        
    }
}

To use the token pair in future, instead of doing:

WebAuthSession session = new WebAuthSession(appKeys, ACCESS_TYPE);

You would do:

WebAuthSession session = new WebAuthSession(appKeys, ACCESS_TYPE, new AccessTokenPair(key, secret));

...where key and secret are the ones printed in the example above. You can then skip the rest of the auth code (up until you create the DropboxAPI object.)