blockchain.block.header

Return the block header at the given height.

Signature

Function: blockchain.block.header(height, cp_height=0)

Version added: 1.3

Version changed: 1.4 cp_height parameter added

Version changed: 1.4.1

height

The height of the block, a non-negative integer.

cp_height

Checkpoint height, a non-negative integer. Ignored if zero, otherwise the following must hold:

height <= cp_height

Result

If cp_height is zero, the raw block header as a hexadecimal string.

Otherwise a dictionary with the following keys. This provides a proof that the given header is present in the blockchain; presumably the client has the merkle root hard-coded as a checkpoint.

branch

The merkle branch of header up to root, deepest pairing first.

header

The raw block header as a hexadecimal string. Starting with version 1.4.1, AuxPoW data (if present in the original header) is truncated.

root

The merkle root of all blockchain headers up to and including cp_height.

Example Result

With height 5 and cp_height 0 on the Bitcoin Cash chain:

"0100000085144a84488ea88d221c8bd6c059da090e88f8a2c99690ee55dbba4e00000000e11c48fecdd9e72510ca84f023370c9a38bf91ac5cae88019bee94d24528526344c36649ffff001d1d03e477"

With cp_height 8:

{
  "branch": [
     "000000004ebadb55ee9096c9a2f8880e09da59c0d68b1c228da88e48844a1485",
     "96cbbc84783888e4cc971ae8acf86dd3c1a419370336bb3c634c97695a8c5ac9",
     "965ac94082cebbcffe458075651e9cc33ce703ab0115c72d9e8b1a9906b2b636",
     "89e5daa6950b895190716dd26054432b564ccdc2868188ba1da76de8e1dc7591"
     ],
  "header": "0100000085144a84488ea88d221c8bd6c059da090e88f8a2c99690ee55dbba4e00000000e11c48fecdd9e72510ca84f023370c9a38bf91ac5cae88019bee94d24528526344c36649ffff001d1d03e477",
  "root": "e347b1c43fd9b5415bf0d92708db8284b78daf4d0e24f9c3405f45feb85e25db"
}