README.md

Overview

This project contains Jackson extension component for reading and writing Bencode encoded data, either as "raw" data (sequence of String arrays), or via data binding to/from Java Objects (POJOs).

The primary objective of this project is to take advantage of Jackson's easy to use and fast object mapper, and make serializing and de-serializing Bencoded content pussible using either full data-binding or streaming (tree model is not supported yet).

Project is licensed under Apache License 2.0.

Usage

As it is a data type extension to Jackson, it could be used like the usual JSON data format.

Given the following Bencoded data - identical counterpart of JSON example, used as a data binding example in Jackson in 5 minutes tutorial (please note that actual binary data replaced with asterisks, as Bencode format has raw binary representation):

d6:gender4:MALE4:named5:first3:Joe4:last7:Sixpacke9:userImage5:*****8:verified5:falsee

It could be turned into a Java POJO with the following code:

ObjectMapper mapper = new BEncodeMapper();
User u = mapper.readValue(new File("user.bencode"), User.class)

Or similarly a Java POJO could be turned into a Bencoded stream:

mapper.writeValue(new File("user.bencode"), u);

Where the user class used above is a simple POJO:

public class User {
    public enum Gender { MALE, FEMALE }

    public static class Name {
        private String first, last;

        public String getFirst() { return first; }
        public String getLast() { return last; }

        public void setFirst(String s) { first = s; }
        public void setLast(String s) { last = s; }
    }

    private Gender gender;
    private Name name;
    private boolean isVerified;
    private byte[] userImage;

    public Name getName() { return name; }
    public boolean isVerified() { return isVerified; }
    public Gender getGender() { return gender; }
    public byte[] getUserImage() { return userImage; }

    public void setName(Name n) { name = n; }
    public void setVerified(boolean b) { isVerified = b; }
    public void setGender(Gender g) { gender = g; }
    public void setUserImage(byte[] b) { userImage = b; }
}

Of course the POJOs could be decorated with the usual Jackson annotations like @JsonProperty. There is a more complex class within tests, com.fasterxml.jackson.dataformat.bencode.types.Torrent, which represents a complete BitTorent file.

Status

Initial release with decent unit test coverage. Ready to use, but might develop some unexpected surprises.

Next steps:

• Add benchmarks, optimize to reach a level where this is as fast as JSON - theoretically it should be, cause Bencode is simpler than JSON.
• Add proper encoding support; currently UTF-8 is hardwired as default.
• Add some useful features.