Viacoin Core 0.16 RPC changes

As mentioned in the Viacoin Core 0.16 article, several RPC changes and other command line options have been changed:

New rescanblockchain RPC

A new RPC rescanblockchain has been added to manually invoke a blockchain rescan. The RPC supports start and end-height arguments for the rescan, and can be used in a multiwallet environment to rescan the blockchain at runtime.

New savemempool RPC

A new savemempool RPC has been added which allows the current mempool to be saved to disk at any time to avoid it being lost due to crashes / power loss.

Safe mode disabled by default

Safe mode is now disabled by default and must be manually enabled (with -disablesafemode=0) if you wish to use it. Safe mode is a feature that disables a subset of RPC calls - mostly related to the wallet and sending - automatically in case certain problem conditions with the network are detected. However, developers have come to regard these checks as not reliable enough to act on automatically. Even with safe mode disabled, they will still cause warnings in the warnings field of the getneworkinfo RPC and launch the -alertnotify command.

Renamed script for creating JSON-RPC credentials

The share/rpcuser/rpcuser.py script was renamed to share/rpcauth/rpcauth.py. This script can be used to create rpcauth credentials for a JSON-RPC user.

Validateaddress improvements

The validateaddress RPC output has been extended with a few new fields, and support for segwit addresses (both P2SH and Bech32). Specifically: * A new field iswitness is True for P2WPKH and P2WSH addresses (“bc1…” addresses), but not for P2SH-wrapped segwit addresses (see below). * The existing field isscript will now also report True for P2WSH addresses. * A new field embedded is present for all script addresses where the script is known and matches something that can be interpreted as a known address. This is particularly true for P2SH-P2WPKH and P2SH-P2WSH addresses. The value for embedded includes much of the information validateaddress would report if invoked directly on the embedded address. * For multisig scripts a new pubkeys field was added that reports the full public keys involved in the script (if known). This is a replacement for the existing addressesfield (which reports the same information but encoded as P2PKH addresses), represented in a more useful and less confusing way. The addresses field remains present for non-segwit addresses for backward compatibility. * For all single-key addresses with known key (even when wrapped in P2SH or P2WSH), the pubkeyfield will be present. In particular, this means that invoking validateaddress on the output of getnewaddress will always report the pubkey, even when the address type is P2SH-P2WPKH.

Low-level changes

• The deprecated RPC getinfo was removed. It is recommended that the more specific RPCs are used:
• getblockchaininfo
• getnetworkinfo
• getwalletinfo
• getmininginfo
• The wallet RPC getreceivedbyaddress will return an error if called with an address not in the wallet.
• The wallet RPC addwitnessaddress was deprecated and will be removed in version 0.17, set the address_type argument of getnewaddress, or option -addresstype=[bech32|p2sh-segwit] instead.
• dumpwallet now includes hex-encoded scripts from the wallet in the dumpfile, and importwallet now imports these scripts, but corresponding addresses may not be added correctly or a manual rescan may be required to find relevant transactions.
• The RPC getblockchaininfo now includes an errors field.
• A new blockhash parameter has been added to the getrawtransaction RPC which allows for a raw transaction to be fetched from a specific block if known, even without -txindex enabled.
• The decoderawtransaction and fundrawtransaction RPCs now have optional iswitness parameters to override the heuristic witness checks if necessary.
• The walletpassphrase timeout is now clamped to 2^30 seconds.
• Using addresses with the createmultisig RPC is now deprecated, and will be removed in a later version. Public keys should be used instead.
• Blockchain rescans now no longer lock the wallet for the entire rescan process, so other RPCs can now be used at the same time (although results of balances / transactions may be incorrect or incomplete until the rescan is complete).
• The logging RPC has now been made public rather than hidden.
• An initialblockdownload boolean has been added to the getblockchaininfo RPC to indicate whether the node is currently in IBD or not.
• minrelaytxfee is now included in the output of getmempoolinfo

Other changed command-line options

• -debuglogfile=<file> can be used to specify an alternative debug logging file.
• viacoin-cli now has an -stdinrpcpass option to allow the RPC password to be read from standard input.
• The -usehd option has been removed.
• viacoin-cli now supports a new -getinfo flag which returns an output like that of the now-removed getinfo RPC.