getblocktemplate ( "template_request" )
If the request parameters include a 'mode' key, that is used to explicitly select between the default 'template' request or a 'proposal'.
It returns data needed to construct a block to work on.
For full specification, see BIPs 22, 23, 9, and 145:
https://github.com/bitcoin/bips/blob/master/bip-0022.mediawiki
https://github.com/bitcoin/bips/blob/master/bip-0023.mediawiki
https://github.com/bitcoin/bips/blob/master/bip-0009.mediawiki#getblocktemplate_changes
https://github.com/bitcoin/bips/blob/master/bip-0145.mediawiki
Arguments:
1. template_request (json object, optional, default={}) Format of the template
{
"mode": "str", (string, optional) This must be set to "template", "proposal" (see BIP 23), or omitted
"capabilities": [ (json array, optional) A list of strings
"str", (string) client side supported feature, 'longpoll', 'coinbasevalue', 'proposal', 'serverlist', 'workid'
...
],
"rules": [ (json array, required) A list of strings
"segwit", (string, required) (literal) indicates client side segwit support
"str", (string) other client side supported softfork deployment
...
],
}
Result:
{ (json object)
"version" : n, (numeric) The preferred block version
"rules" : [ (json array) specific block rules that are to be enforced
"str", (string) name of a rule the client must understand to some extent; see BIP 9 for format
...
],
"vbavailable" : { (json object) set of pending, supported versionbit (BIP 9) softfork deployments
"rulename" : n, (numeric) identifies the bit number as indicating acceptance and readiness for the named softfork rule
...
},
"vbrequired" : n, (numeric) bit mask of versionbits the server requires set in submissions
"previousblockhash" : "str", (string) The hash of current highest block
"transactions" : [ (json array) contents of non-coinbase transactions that should be included in the next block
{ (json object)
"data" : "hex", (string) transaction data encoded in hexadecimal (byte-for-byte)
"txid" : "hex", (string) transaction id encoded in little-endian hexadecimal
"hash" : "hex", (string) hash encoded in little-endian hexadecimal (including witness data)
"depends" : [ (json array) array of numbers
n, (numeric) transactions before this one (by 1-based index in 'transactions' list) that must be present in the final block if this one is
...
],
"fee" : n, (numeric) difference in value between transaction inputs and outputs (in satoshis); for coinbase transactions, this is a negative Number of the total collected block fees (ie, not including the block subsidy); if key is not present, fee is unknown and clients MUST NOT assume there isn't one
"sigops" : n, (numeric) total SigOps cost, as counted for purposes of block limits; if key is not present, sigop cost is unknown and clients MUST NOT assume it is zero
"weight" : n (numeric) total transaction weight, as counted for purposes of block limits
},
...
],
"coinbaseaux" : { (json object) data that should be included in the coinbase's scriptSig content
"key" : "hex", (string) values must be in the coinbase (keys may be ignored)
...
},
"coinbasevalue" : n, (numeric) maximum allowable input to coinbase transaction, including the generation award and transaction fees (in satoshis)
"longpollid" : "str", (string) an id to include with a request to longpoll on an update to this template
"target" : "str", (string) The hash target
"mintime" : xxx, (numeric) The minimum timestamp appropriate for the next block time, expressed in UNIX epoch time
"mutable" : [ (json array) list of ways the block template may be changed
"str", (string) A way the block template may be changed, e.g. 'time', 'transactions', 'prevblock'
...
],
"noncerange" : "hex", (string) A range of valid nonces
"sigoplimit" : n, (numeric) limit of sigops in blocks
"sizelimit" : n, (numeric) limit of block size
"weightlimit" : n, (numeric) limit of block weight
"curtime" : xxx, (numeric) current timestamp in UNIX epoch time
"bits" : "str", (string) compressed target of next block
"height" : n, (numeric) The height of the next block
"default_witness_commitment" : "str" (string, optional) a valid witness commitment for the unmodified block template
}
Examples:
> bitcoin-cli getblocktemplate '{"rules": ["segwit"]}'
> curl --user myusername --data-binary '{"jsonrpc": "1.0", "id": "curltest", "method": "getblocktemplate", "params": [{"rules": ["segwit"]}]}' -H 'content-type: text/plain;' http://127.0.0.1:8332/
