The aim of LightDHT is to provide a simple, flexible implementation of the Bittorrent mainline DHT for use in research applications. If you want to trade files, you have come to the wrong place. LightDHT does not implement the actual file transfer parts of the bittorrent protocol. It only takes part in the DHT.
Philosophy:
- Ease of use over performance
- Adaptability over scalability
In order to keep LightDHT easy to use, you have the option to perform DHT RPC calls synchronously. This means that when you call a DHT method, your program will block until you have an answer to your request. That answer will be the return value of the function. This has the advantage that it keeps the logical program flow intact, and makes it more comfortable to use. You can also schedule a callback function, that will be called when the response arrives. This requires more complex code, but enables you to do multiple things at once. Your specific application will dictate whether you should be using synchronous or asynchronous communication.
In order to maintain O(log N) scaling across the network, BEP0005 (the standard governing the DHT) mandates that implementations use a bucket-based approach to the routing table. This enables the node to fulfill all requests in constant time and (more or less) constant memory. In LightDHT, we throw that recommendation to the wind.
Since the main focus of LightDHT is reseach, we are going to keep around all the data we can. This means that we keep around every single node we know about. You can choose between using a simple flat routing table, where all the node information is stored in a single dictionary, or a slightly more complex multi-level prefix-based routing table, where nodes are grouped together based on their node IDs.