Stores of data not financial transactions?

Question

Hey all,

I have experience using and developing on multichain with making my own explorer before the official one was live.

My new project wants to implement a blockchain to store messages/data/files, then attribute meta-data to the record for easy searching on a front-end. I assume I can do this by just converting the raw strings to hexadecimal. What about perhaps a .pdf or .docx? Can this be attached/encoded then sent as a transaction to the network?

This chain will have free transactions.

To achieve meta information on transactions, is it possible to attach the data in a JSON object with the actual file/text in a sub-object?

Comments

How can you make free transaction calls?

 I thought all transactions need to have assets associated with a quantity

Thanks

---

Unless you've configured your blockchain otherwise, you can send transactions that move nil value (use 0 for an 'amount' parameter) but just have metadata attached. For example: sendwithmetadata [to-address] 0 0123456789abcdef

Answer 1

If you configure your blockchain parameters appropriately (see the parameters max-std-op-return-size, maximum-block-size and max-std-tx-size) you can add up to 8MB of metadata per transaction. That should be fine a big JSON object containing your document in some sub-object (base64 encoded?) although most efficient would be to post the document as raw binary metadata instead.