Adding RPC Endpoints for viewing available gas and claiming gas

[localhuman]

Like calls to the getbalance method of the RPC server, these methods require the wallet to be unlocked on the server side.

sample python usage:

>>> data = {"jsonrpc": "2.0", "method": "getunclaimedgas", "params": [], "id": 1}
>>> req = requests.post(endpoint, json.dumps(data))
>>> req.content
>>> b'{"jsonrpc":"2.0","id":5,"result":{"unavailable":"0.42032656","available":"0"}}'

>>> data = {"jsonrpc": "2.0", "method": "claimgas", "params": [], "id": 1}
>>> req = requests.post(endpoint, json.dumps(data))
>>> req.json()
>>> {'id': 5,
 'jsonrpc': '2.0',
 'result': {'attributes': [],
            'claims': [{'txid': '3be87ae6baa799ca8fb99c1e943e98654993ebcbe1715ec2a61750a90c89bd5e',
                        'vout': 0}],
            'net_fee': '0',
            'scripts': [{'invocation': '400fdbc6b6993cd9b4325b8533b2e963e56d44c18085d99753d96a47b24c8f67f545c32f0fa86e3eb1e7dc78746da9a34032a55ab2ec0cc32b0c91c99953d67251',
                         'verification': '210286c2277497e82d2d0f5c112aa175545fd68ac04b06ec0d4123d4b5ee6a1c5a6cac'}],
            'size': 203,
            'sys_fee': '0',
            'txid': 'd875a010e541f4283d808fc59ccd7c2bb9c0f14153c01778af351e4bd8d5fcac',
            'type': 'ClaimTransaction',
            'version': 0,
            'vin': [],
            'vout': [{'address': 'AFsRovA3GyLznpAyAYXiv8ZwDswKj1g5A2',
                      'asset': '602c79718b16e442de58778e148d0b1084e3b2dffd5de6b7b16cee7969282de7',
                      'n': 0,
                      'value': '9.0552'}]}}

[erikzhang]

If the claim failed, it will print logs to console, which is unexpected.

[localhuman]

I'm going to close this one, as there is currently no pressing use-case for the functionality.
The Light Wallet app however needs a way to calculate the amount of NEOGas to claim in order to send a ClaimTransaction, and to do that the light wallet needs the system fee by block.

Please see PR neo-project/neo#35 for that functionality.

[bmclain]

@localhuman I (respectfully!) beg to differ. If neo-cli is being used as the primary node by an application, being able to claim gas via RPC is essential. @erikzhang is there no way for us to include this in the next version? I really don't want to have to run a custom version of neo-cli locally just to get the ability to claim gas via RPC.

[bmclain]

@erikzhang I'd like to formally request this be re-opened. The use case is for exchanges who are running open wallets on neo-cli and need to be able to claim gas for all addresses within their wallet.