Do not assume that bitcoin.conf file specifies rpcuser

and raise an exception if rpcpassword is not specified.

Comment: You can make RPC calls to bitcoind when bitcoin.conf specifies
just rpcpassword and leaves user name empty.  The class bitcoin.rpc.RawProxy
creates keys of the internal dictionary: conf = {}, based on the entries
in the configuration file.  Then  assumes that the rpcuser key exists and
uses it to create service_url.  This results in an error
when bitcoin.conf contains only rcppassword field and the following code
is executed:
>    proxy = bitcoin.rpc.RawProxy()

Author: Marek Miller

bitcoin/rpc.py

@@ -78,7 +78,8 @@ def __init__(self, service_url=None,
 
             # Extract contents of bitcoin.conf to build service_url
             with open(btc_conf_file, 'r') as fd:
-                conf = {}
+                # Bitcoin Core accepts empty rpcuser, not specified in btc_conf_file
+                conf = {'rpcuser': ""}
                 for line in fd.readlines():
                     if '#' in line:
                         line = line[:line.index('#')]
@@ -99,6 +100,9 @@ def __init__(self, service_url=None,
                 else:
                     raise ValueError('Unknown rpcssl value %r' % conf['rpcssl'])
 
+                if 'rpcpassword' not in conf:
+                    raise ValueError('The value of rpcpassword not specified in the configuration file: %s' % btc_conf_file)
+
                 service_url = ('%s://%s:%s@localhost:%d' %
                     ('https' if conf['rpcssl'] else 'http',
                      conf['rpcuser'], conf['rpcpassword'],