Monero Stack Exchange is a question and answer site for developers and users of the secure, private and untraceable cryptocurrency Monero. It only takes a minute to sign up.
Sign up to join this community
After mining a correct nonce on the block template (received from rpc method "getblocktemplate") you need to submit the block back to the daemon. However, the rpc method "submitblock" appears to require the entire block blob. The template does not contain the entire block, just the parts necessary for mining. And I don't see any way to derive the full block information from the template to create the block blob.
So how do I mine on the template and then submit the full block back to the daemon?
The getbklocktemplate RPC returns a blockhashing_blob and a blocktemplate_blob.
You can either try to find a nonce (4 bytes) by mining using the blockhashing_blob, or you can try to find two nonces (4 bytes in the block header, reserved_size bytes in the extra field of the mining reward transaction) using the blocktemplate_blob and computing the transaction Merkle tree yourself.
When your nonce(s) pass the difficulty test, you put it/them in the blocktemplate_blob at the right offset(s) and you send the updated blocktemplate_blob to the daemon using the submitblock RPC.
blockhashing_blob contains the transaction tree hash root (because it's a preprocessed block header), but the blocktemplate_blob doesn't (because it is a raw block header). When you submit the blocktemplate_blob updated with your nonce, the daemon processes it, check if it is valid and sends it to the network if it is.