Extra string in transfer

Question

I want to send transactions/assets and store a 32 byte string along with the transfer in the blockchain - but it doesn't appear to be possible in the current assets API.

Answer 1

* Call preparelockunspent to create a single transaction output containing the assets you want to send.

* Use createrawtransaction to create a raw transaction, which spends that output and sends its contents to the other address (see MultiChain docs for how createrawtransaction is extended to support assets).

* Append the metadata to the raw transaction returned by createrawtransaction before calling signrawtransaction and sendrawtransaction. See the OP_RETURN_create_txn function in our PHP and Python libraries linked below - just skip the first line that calls createrawtransaction and instead set raw_txn/$raw_txn to the hexadecimal already generated by your call to createrawtransaction.

https://github.com/coinspark/php-OP_RETURN

https://github.com/coinspark/python-OP_RETURN

Comments

As of alpha 7 there is a much easier way to add metadata to a transaction, via the appendrawmetadata API - see the 'Transaction metadata' section of the Getting Started guide for a full example: http://www.multichain.com/getting-started/

Answer 2

You may be interested that alpha 12 adds new sendwithmetadata and sendwithmetadatafrom APIs that make all this a lot easier.