Add method for retrieving block headers from daemon

utils/daemoninfo.py

@@ -0,0 +1,45 @@
+#!/usr/bin/python
+import argparse
+import logging
+import operator
+import re
+
+from monero.backends.jsonrpc import JSONRPCDaemon
+from monero.daemon import Daemon
+
+def url_data(url):
+    gs = re.compile(
+        r'^(?P<host>[^:\s]+)(?::(?P<port>[0-9]+))?$'
+        ).match(url).groupdict()
+    return dict(filter(operator.itemgetter(1), gs.items()))
+
+def get_daemon():
+    argsparser = argparse.ArgumentParser(description="Display daemon info")
+    argsparser.add_argument('daemon_rpc_url', nargs='?', type=url_data, default='127.0.0.1:18081',
+        help="Daemon RPC URL [host[:port]]")
+    argsparser.add_argument('-t', dest='timeout', type=int, default=30, help="Request timeout")
+    argsparser.add_argument('-v', dest='verbosity', action='count', default=0,
+        help="Verbosity (repeat to increase; -v for INFO, -vv for DEBUG")
+    args = argsparser.parse_args()
+    level = logging.WARNING
+    if args.verbosity == 1:
+        level = logging.INFO
+    elif args.verbosity > 1:
+        level = logging.DEBUG
+    logging.basicConfig(level=level, format="%(asctime)-15s %(message)s")
+    return Daemon(JSONRPCDaemon(timeout=args.timeout, **args.daemon_rpc_url))
+
+d = get_daemon()
+info = d.info()
+print("Net: {net:>15s}net\n"
+    "Height:      {height:10d}\n"
+    "Difficulty:  {difficulty:10d}\n"
+    "Alt blocks:  {alt_blocks_count:10d}\n".format(
+        net='test' if info['testnet'] \
+            else 'stage' if info['stagenet'] \
+            else 'main' if info['mainnet'] else 'unknown',
+        **info))
+for hdr in reversed(d.headers(info['height']-7, info['height']-1)):
+    print("{height:10d} {hash} {block_size_kb:6.2f} kB {num_txes:3d} txn(s) "
+        "v{major_version:d}".format(
+            block_size_kb=hdr['block_size']/1024.0, **hdr))