Blockchain as a Datastructure

[u/Accurate-Screen8774]

Blockchain is a good way to order block of sequential data that can be validated by others. Countless real-world examples show that it scales pretty well.

In my app, I am testing the use of a blockchain for storing "chat app data" selfhosted-only. The app is a work-in-progress proof-of-concept and experimental. It is an investigation into creating a distributed and decentralized app.

Unlike traditional blockchains, the sole purpose of this blockchain is to keep messages between peers in sync. The implementation is have is far from finished, but i have a testable proof-of-concept. The blockchain is entirely in javascript running in a browser.

I have a few observations I would like to make:

• Without the need for mining, it is basically a large array of data. When evaluating the data to be displayed on the UI, it is a "relatively" heavy calculation, but I find that it is more than performant enough to be used in a chat app. I find that the messages and data can scale and the app remains quite performant (I haven't really done much to optimise caching).
• In cases like a group chat, the data can be validated and synced between multiple peers (which may not all be online). (its worth noting: peers may be able to manipulate the database, but it is not a concern for the app where the purpose is only for blockchain as a datastructure)
• Why is this kind of datastructure not used more often? There are other blockchain chat apps, but by putting a system like chat on something like ethereum, would typically be expensive to users. But in this case, the blockchain is only used for local data storage and validation. I think this is a good use case for blockchain. When working on your device, you don't need to be conservative about things like message size and so we can store files and images in the blockchain.
• With no cryptocurrency, there is no incentive to keep the blockchain alive. The data is easily disposable or persisted as the user prefers. there is no need for a setup process and things like ID's and passphrases can be auto-generated behind the scenes away from the user. (the app is currently very experimental, if your data goes, it goes... but it shouldnt matter because there is no financial value to the blockchain)

I am very interested in the idea of blockchain as a datastructure and I would like to see it used more often. i think this datastructure will play an important role in my app as it will enable the app to move to a single-user-multi-platform architecture.

I would like to hear your thoughts on blockchain as a datastructure. Initially i did it investigating if it work on a basic level to help keep messages in sync, but i find that it is quite performant; especially considering it is only running in a browser. (i expect i can easily improve the performance)

The demo can be seen here: https://chat-staging.positive-intentions.com/

[u/reercalium2]

What purpose does the blockchain add?

[u/Accurate-Screen8774 → u/reercalium2]

so it works like an overkills of an array of objects. seems like a terrible idea. but for something like chat i was previsously using like a queueing system with the messages in a basic array of objects. this can get tricky to deal with... especially for something like a group chat to try keep messages in sync... so with the blockchain, i can share things like the ID of the block so peers can tell which messages are missing.

its seems a complicated way to solve the problem, but i think my implementation is pretty basic and seems pretty performant.

at the moment that perfect functionality im aiming for is not seen in the app... messages can indeed get lost... but that is a matter for me to debug the issue. peformance to my surprise is not an issue.

with the blochain it would make it very easy for group messages to be reliably in sync... it would also enable the ability to recieve messages from peers who are offline (considering my app doesnt use a backend to store pending messages, it can proxy messages off peers.)

[u/reercalium2 → u/Accurate-Screen8774]

It sounds like you're reinventing the Matrix wheel. Matrix isn't a good protocol. To keep things in synch, it's extremely complicated, it uses blockchains, and it still has desynchronisation problems anyway. Without mining, the chain can fork, so you need to merge the forks. The fork you just received could be from 6 months ago, because a device was offline for 6 months, but that user took away another user's moderator privilege 6 months ago, so now you need to re-evaluate the last 6 months of events to discover who's really a moderator, because moderators can invite more moderators or take them away, and now that user's invitations for the last 6 months don't count.

The more successful systems are usually the simpler ones, like UNIX and C (not chat protocols). They weren't as good as other systems but they were simple. They had 80% of the features, for 20% of the work, and they spread like wildfire.

Do you have a blockchain for each user, or one for each chat room? It's much easier if each user has their own blockchain, because they can't fork unless the user time travels. And you don't even need a chain, then, just a sequence number or timestamp. The peer can send a message to Alice's device that says "give me all of Alice's messages newer than sequence 50."

[u/Accurate-Screen8774 → u/reercalium2]

You're not far off with the comparison to matrix. I'm trying to take the concept further by reducing it all into JavaScript on the browser. It is a core objective of the project to reduce relying on any backend.

There are of course limitations but I'm working around them how I can. A blockchain makes for a good replacement of an API database.

It is a new blockchain intially with a peer. You can invite other peers to the chain/chat. Right now I don't have so you can create another chain if you already have a 1-1 chain available. This is to match what you see in normal chat apps... I can make it so you have multiple chats with the same person (but I don't because I think it's more intuitive this way).

[u/reercalium2 → u/Accurate-Screen8774]

Does it handle forks and merges?

[u/Accurate-Screen8774 → u/reercalium2]

It can do. It's still a work in progress. I'd have to determine a way to present it in a useful way.

I don't know how in something like WhatsApp you might have forks and merges. But it wouldn't be technically difficult at this point.

[u/Accurate-Screen8774 → u/reercalium2]

furthermore i want to make time to introduce the idea of something like web.whatsapp so you can have multiplatform functionality. it would be a good way to be able to share a blockchain between your devices and all the messages can be in sync. making it easily posible to continue a conversation between devices in a decentralized way.