I would like to use the Wallet RPC API to determine if the wallet I am connecting to is view-only.
I'm thinking about using the query_key command with key_type=mnemonic. Is it safe to assume that if the command fails to return a mnemonic, the wallet is view-only? Or is there a better way?
I'm guessing this is not the best way, because the documentation mentions that older wallets do not have a mnemonic.
I'm thinking about using query_key command with key_type=mnemonic. Is it safe to assume that if the command fails to return a mnemonic, the wallet is view-only?
Yes.
I'm guessing this is not the best way, because the documentation mentions that older wallets do not have a mnemonic.
It's the only way if you need to check though. The likelihood of such an old wallet I would guess is low due to the fact people actually using monero will have been upgrading.
With all this said, I find it difficult to understand the need to check if a wallet is view-only. The moment you try to spend from a view-only wallet you'll get an error and know then.
If you query the spend key using that same RPC, watch only wallets will have it as 0000000000000000000000000000000000000000000000000000000000000000.
Of course, querying secret keys over RPC (or any other sensitive RPC calls) should be done with caution, since in this case, you're sending secret keys over a network connection, but there does not seem to be any other way. You should use stunnel or similar if calling remotely.
