How to create a Keypair json in solana.py?

Question

I'm attempting to create a keypair json I can save to my directory in solana.py that I can use on a local Solana test validator. Unsure if there's any built-in functions within solana.py to do so, I attempted to do it through converting the keypair instance created to a dict, then converting that dict to a json, and then I was intending to create a file from the json.

I ran into an issue though attempting to convert the dict into a json. Below is the code attempting to do so.

from solana.keypair import Keypair
import json

#Create Keypair
created_keypair = Keypair()

#Convert Keypair object to a dict
keypair_dict = created_keypair.__dict__
assert type(keypair_dict) is dict

#Convert dict to a json
keypair_json = json.dumps(keypair_dict)

The following is the error I'm running into when converting keypair_dict into a json.

TypeError: Object of type Keypair is not JSON serializable

Answer 1

That library misuses a bunch of words. I believe the secret_key field is in fact the full keypair (ed25519 secret/private keys are 32-bytes). You should be able to convert the byte array into a uint array and JSON encode that.

$ python3
Python 3.8.10 (default, Jun 22 2022, 20:18:18)
[GCC 9.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from solana.keypair import Keypair
>>> keypair = Keypair.generate()
>>> keypair.public_key
Bd4gfiEKWKeRairAHRbni6NHWmghQCksVHa7uMa9p2CD
>>> import json
>>> json.dumps([int(i) for i in keypair.secret_key])
'[180, 107, 77, 46, 147, 221, 193, 153, 12, 122, 232, 70, 37, 87, 183, 74, 134, 182, 192, 1, 4, 152, 198, 178, 121, 234, 26, 122, 176, 45, 249, 202, 157, 209, 241, 157, 189, 171, 216, 122, 125, 17, 77, 237, 208, 239, 88, 136, 90, 91, 38, 166, 190, 152, 159, 13, 250, 243, 8, 100, 68, 162, 78, 38]'
>>>

$ cat >test.json <<<'[180, 107, 77, 46, 147, 221, 193, 153, 12, 122, 232, 70, 37, 87, 183, 74, 134, 182, 192, 1, 4, 152, 198, 178, 121, 234, 26, 122, 176, 45, 249, 202, 157, 209, 241, 157, 189, 171, 216, 122, 125, 17, 77, 237, 208, 239, 88, 136, 90, 91, 38, 166, 190, 152, 159, 13, 250, 243, 8, 100, 68, 162, 78, 38]'
$ solana-keygen pubkey test.json
Bd4gfiEKWKeRairAHRbni6NHWmghQCksVHa7uMa9p2CD