Getblocktemplate doesnt yield coinbasetxn?

milewski commented at 4:11 am on August 16, 2017: none

Hello accordenly with the “help” getblocktemplate shows:

 0Arguments:
 11. template_request         (json object, optional) A json object in the following spec
 2     {
 3       "mode":"template"    (string, optional) This must be set to "template", "proposal" (see BIP 23), or omitted
 4       "capabilities":[     (array, optional) A list of strings
 5           "support"          (string) client side supported feature, 'longpoll', 'coinbasetxn', 'coinbasevalue', 'proposal', 'serverlist', 'workid'
 6           ,...
 7       ],
 8       "rules":[            (array, optional) A list of strings
 9           "support"          (string) client side supported softfork deployment
10           ,...
11       ]
12     }

however passing any of these inputs longpoll, coinbasetxn, coinbasevalue, proposal, serverlist, workid seems to change the result in anyhow…

im trying to get the coinbasetxn but it doesnt seem to yield it doesnt matter what capabilities i fill in… any known bug here?

Bitcoin Core version v0.14.2 (64-bit)

luke-jr commented at 4:13 am on August 16, 2017: member

Bitcoin Core does not support coinbasetxn.

milewski commented at 4:19 am on August 16, 2017: none

So the help that it yields is inaccurate? (maybe outdated?) if so there are any other tools that does it? or i have to generate by hand?

luke-jr commented at 4:22 am on August 16, 2017: member

The help doesn’t say bitcoind does anything in particular with the client capabilities list.

At least Eloipool supports coinbasetxn, but you can also generate one using libblkmaker, the reference GBT client.

milewski commented at 4:25 am on August 16, 2017: none

Look this is the entire output from the bitcoin-core

 0help getblocktemplate
 1
 2getblocktemplate ( TemplateRequest )
 3
 4If the request parameters include a 'mode' key, that is used to explicitly select between the default 'template' request or a 'proposal'.
 5It returns data needed to construct a block to work on.
 6For full specification, see BIPs 22, 23, 9, and 145:
 7    https://github.com/bitcoin/bips/blob/master/bip-0022.mediawiki
 8    https://github.com/bitcoin/bips/blob/master/bip-0023.mediawiki
 9    https://github.com/bitcoin/bips/blob/master/bip-0009.mediawiki#getblocktemplate_changes
10    https://github.com/bitcoin/bips/blob/master/bip-0145.mediawiki
11
12Arguments:
131. template_request         (json object, optional) A json object in the following spec
14     {
15       "mode":"template"    (string, optional) This must be set to "template", "proposal" (see BIP 23), or omitted
16       "capabilities":[     (array, optional) A list of strings
17           "support"          (string) client side supported feature, 'longpoll', 'coinbasetxn', 'coinbasevalue', 'proposal', 'serverlist', 'workid'
18           ,...
19       ],
20       "rules":[            (array, optional) A list of strings
21           "support"          (string) client side supported softfork deployment
22           ,...
23       ]
24     }
25
26
27Result:
28{
29  "version" : n,                    (numeric) The preferred block version
30  "rules" : [ "rulename", ... ],    (array of strings) specific block rules that are to be enforced
31  "vbavailable" : {                 (json object) set of pending, supported versionbit (BIP 9) softfork deployments
32      "rulename" : bitnumber          (numeric) identifies the bit number as indicating acceptance and readiness for the named softfork rule
33      ,...
34  },
35  "vbrequired" : n,                 (numeric) bit mask of versionbits the server requires set in submissions
36  "previousblockhash" : "xxxx",     (string) The hash of current highest block
37  "transactions" : [                (array) contents of non-coinbase transactions that should be included in the next block
38      {
39         "data" : "xxxx",             (string) transaction data encoded in hexadecimal (byte-for-byte)
40         "txid" : "xxxx",             (string) transaction id encoded in little-endian hexadecimal
41         "hash" : "xxxx",             (string) hash encoded in little-endian hexadecimal (including witness data)
42         "depends" : [                (array) array of numbers 
43             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
44             ,...
45         ],
46         "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
47         "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
48         "weight" : n,                (numeric) total transaction weight, as counted for purposes of block limits
49         "required" : true|false      (boolean) if provided and true, this transaction must be in the final block
50      }
51      ,...
52  ],
53  "coinbaseaux" : {                 (json object) data that should be included in the coinbase's scriptSig content
54      "flags" : "xx"                  (string) key name is to be ignored, and value included in scriptSig
55  },
56  "coinbasevalue" : n,              (numeric) maximum allowable input to coinbase transaction, including the generation award and transaction fees (in Satoshis)
57  "coinbasetxn" : { ... },          (json object) information for coinbase transaction
58  "target" : "xxxx",                (string) The hash target
59  "mintime" : xxx,                  (numeric) The minimum timestamp appropriate for next block time in seconds since epoch (Jan 1 1970 GMT)
60  "mutable" : [                     (array of string) list of ways the block template may be changed 
61     "value"                          (string) A way the block template may be changed, e.g. 'time', 'transactions', 'prevblock'
62     ,...
63  ],
64  "noncerange" : "00000000ffffffff",(string) A range of valid nonces
65  "sigoplimit" : n,                 (numeric) limit of sigops in blocks
66  "sizelimit" : n,                  (numeric) limit of block size
67  "weightlimit" : n,                (numeric) limit of block weight
68  "curtime" : ttt,                  (numeric) current timestamp in seconds since epoch (Jan 1 1970 GMT)
69  "bits" : "xxxxxxxx",              (string) compressed target of next block
70  "height" : n                      (numeric) The height of the next block
71}
72
73Examples:
74> bitcoin-cli getblocktemplate 
75> curl --user myusername --data-binary '{"jsonrpc": "1.0", "id":"curltest", "method": "getblocktemplate", "params": [] }' -H 'content-type: text/plain;' http://127.0.0.1:8332/

Close look to

0"coinbasetxn" : { ... },          (json object) information for coinbase transaction

Maybe it’s misleading … i have tried using the bitcoin-cli and that console inside the bitcoin-core also have tried trough json rpc but none seems to work..

laanwj added the label Mining on Aug 17, 2017

annanay25 commented at 7:16 pm on December 18, 2017: none

Bitcoin does not produce the coinbasetxn for you, you will have to build it manually.

As suggested by @luke-jr , you could check the following - bitcoin / libblkmaker. Its official and pretty simple to use.

Or, you could also go through bitcoin’s testing framework and see how coinbase is created. Check this link for starters.

MarcoFalke closed this on Aug 6, 2019

DrahtBot locked this on Dec 16, 2021

Getblocktemplate doesnt yield coinbasetxn? #11061