Topic: [python] Bitcoin-friendly JSON-RPC library (Read 4654 times)
Yep, I meant along the lines of: increment class counter, store it as private ID.
Using the ID count is clever. Would it maybe be a good idea to either make that a class variable? For when people instantiate multiple Proxies across threads or something.
ID is unique per connection, and multiple threads / instances should use their own id counter. It is used to match query and response.
The class on the wiki already supports automatic introspection and uses python's Decimal class:
[...]
How does this improve on that? I saw that you're using httplib instead of urllib. Any reasons for that?
[...]
How does this improve on that? I saw that you're using httplib instead of urllib. Any reasons for that?
There is a list in the source code and top post that answers these questions...
The class on the wiki already supports automatic introspection and uses python's Decimal class:
https://en.bitcoin.it/wiki/API_reference_%28JSON-RPC%29#Python
How does this improve on that? I saw that you're using httplib instead of urllib. Any reasons for that?
Also you may wish to read,
http://www.python.org/dev/peps/pep-0008/
Python libraries generally follow that style as to provide a consistent API. It doesn't always happen but everybody tries to use that same standard
Using the ID count is clever. Would it maybe be a good idea to either make that a class variable? For when people instantiate multiple Proxies across threads or something.
https://en.bitcoin.it/wiki/API_reference_%28JSON-RPC%29#Python
Code:
import urllib
import decimal
import json
class JSONRPCException(Exception):
def __init__(self, rpcError):
Exception.__init__(self)
self.error = rpcError
class ServiceProxy(object):
def __init__(self, serviceURL, serviceName=None):
self.__serviceURL = serviceURL
self.__serviceName = serviceName
def __getattr__(self, name):
if self.__serviceName != None:
name = "%s.%s" % (self.__serviceName, name)
return ServiceProxy(self.__serviceURL, name)
def __call__(self, *args):
postdata = json.dumps({"method": self.__serviceName, 'params': args, 'id':'jsonrpc'})
respdata = urllib.urlopen(self.__serviceURL, postdata).read()
resp = json.loads(respdata, parse_float=decimal.Decimal)
if resp['error'] != None:
raise JSONRPCException(resp['error'])
else:
return resp['result']
How does this improve on that? I saw that you're using httplib instead of urllib. Any reasons for that?
Also you may wish to read,
http://www.python.org/dev/peps/pep-0008/
Python libraries generally follow that style as to provide a consistent API. It doesn't always happen but everybody tries to use that same standard
Using the ID count is clever. Would it maybe be a good idea to either make that a class variable? For when people instantiate multiple Proxies across threads or something.
The HTTP/1.1 improvements aside... the use of Decimal is in fact a regression. Here's why:
It will encourage people to treat bitcoin values as BTC internally, rather than atomic units. Besides being simply wrong, this also creates a problem because according to the current JSON-RPC rules, one end is allowed to send the value "0.999999999" and the other end should process it as 100000000 units (eg, 1 BTC).
Whether the library returns float or Decimal, the application still needs to process all amounts with round(1e8 * amount). Float is more efficient, and clearly discourages bad behaviour, so is a better fit in this particular case.
It will encourage people to treat bitcoin values as BTC internally, rather than atomic units. Besides being simply wrong, this also creates a problem because according to the current JSON-RPC rules, one end is allowed to send the value "0.999999999" and the other end should process it as 100000000 units (eg, 1 BTC).
Whether the library returns float or Decimal, the application still needs to process all amounts with round(1e8 * amount). Float is more efficient, and clearly discourages bad behaviour, so is a better fit in this particular case.
When hacking JSON-RPC calls together for bitcoin, in python, a common solution appears to be using python-jsonrpc. This choice is less than optimal, for [at least] two reasons: (1) no way to use Decimal with JSON values, as is required in monetary software, and (2) does not support HTTP/1.1 persistent connections.
So, I have created the python AuthServiceProxy class specifically for bitcoin users, based on the usage model of python-jsonrpc:
http://yyz.us/bitcoin/authproxy.py
This creates a python object whose methods are the JSON-RPC method calls. Example:
This should be all that is needed for python programmers to use bitcoin's unique flavor of JSON-RPC over http or https.
In the latter 'getinfo' case, you can see that Decimal values are properly returned, rather than floats, as recently discussed in this thread:
So, I have created the python AuthServiceProxy class specifically for bitcoin users, based on the usage model of python-jsonrpc:
http://yyz.us/bitcoin/authproxy.py
This creates a python object whose methods are the JSON-RPC method calls. Example:
Code:
import authproxy
import pprint
BITCOINRPC = 'http://myusername:[email protected]:8332/'
pp = pprint.PrettyPrinter(indent=4)
bitcoin = authproxy.AuthServiceProxy(BITCOINRPC)
data = bitcoin.getwork() # call bitcoin 'getwork' RPC
pp.pprint(data)
data = bitcoin.getinfo() # call bitcoin 'getinfo' RPC
pp.pprint(data)
This should be all that is needed for python programmers to use bitcoin's unique flavor of JSON-RPC over http or https.
In the latter 'getinfo' case, you can see that Decimal values are properly returned, rather than floats, as recently discussed in this thread:
Code:
{ 'balance': Decimal('1.10000000'),
'blocks': 116260,
'connections': 48,
'difficulty': Decimal('68978.89245792'),
'errors': '',
'generate': False,
'genproclimit': 1,
'hashespersec': 0,
'keypoololdest': 1296778330,
'paytxfee': Decimal('0.01000000'),
'proxy': '',
'testnet': False,
'version': 32100}
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