import blockcypher utxo client from pybitcoin

blockstack_client/backend/utxo/blockcypher.py

@@ -0,0 +1,106 @@
+#!/usr/bin/env python2
+# -*- coding: utf-8 -*-
+"""
+    Blockstack-client
+    ~~~~~
+    copyright: (c) 2014-2015 by Halfmoon Labs, Inc.
+    copyright: (c) 2016 by Blockstack.org
+
+    This file is part of Blockstack-client.
+
+    Blockstack-client is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Blockstack-client is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+    You should have received a copy of the GNU General Public License
+    along with Blockstack-client. If not, see <http://www.gnu.org/licenses/>.
+"""
+
+import json
+import requests
+
+BLOCKCYPHER_BASE_URL = 'https://api.blockcypher.com/v1/btc/main'
+
+from .blockchain_client import BlockchainClient
+
+
+class BlockcypherClient(BlockchainClient):
+    def __init__(self, api_key=None, timeout=30):
+        self.type = 'blockcypher.com'
+        if api_key:
+            self.auth = (api_key, '')
+        else:
+            self.auth = None
+
+        self.timeout = timeout
+
+
+def format_unspents(unspents):
+
+    # sandowhich confirmed and unconfiremd unspents
+    all_unspents = unspents.get('txrefs', []) + unspents.get('unconfirmed_txrefs', [])
+
+    return [{
+        "transaction_hash": s["tx_hash"],
+        "output_index": s["tx_output_n"],
+        "value": s["value"],
+        "script_hex": s.get("script"),
+        "confirmations": s["confirmations"],
+        }
+        for s in all_unspents
+    ]
+
+
+def get_unspents(address, blockchain_client=BlockcypherClient()):
+    """ Get the spendable transaction outputs, also known as UTXOs or
+        unspent transaction outputs.
+    """
+    if not isinstance(blockchain_client, BlockcypherClient):
+        raise Exception('A BlockcypherClient object is required')
+
+    url = '%s/addrs/%s?unspentOnly=true&includeScript=true' % (
+          BLOCKCYPHER_BASE_URL, address)
+
+    if blockchain_client.auth:
+        r = requests.get(url + '&token=' + blockchain_client.auth[0], timeout=blockchain_client.timeout)
+    else:
+        r = requests.get(url, timeout=blockchain_client.timeout)
+
+    try:
+        unspents = r.json()
+    except ValueError:
+        raise Exception('Received non-JSON response from blockcypher.com.')
+
+    # sandwich unconfirmed and confirmed unspents
+
+    return format_unspents(unspents)
+
+
+def broadcast_transaction(hex_tx, blockchain_client):
+    """ Dispatch a raw hex transaction to the network.
+    """
+    if not isinstance(blockchain_client, BlockcypherClient):
+        raise Exception('A BlockcypherClient object is required')
+
+    url = '%s/txs/push' % (BLOCKCYPHER_BASE_URL)
+    payload = json.dumps({'tx': hex_tx})
+    r = requests.post(url, data=payload, timeout=blockchain_client.timeout)
+
+    try:
+        data = r.json()
+    except ValueError:
+        raise Exception('Received non-JSON from blockcypher.com.')
+
+    if 'tx' in data:
+        reply = {}
+        reply['tx_hash'] = data['tx']['hash']
+        reply['success'] = True
+        return reply
+    else:
+        err_str = 'Tx hash missing from blockcypher response: ' + str(data)
+        raise Exception(err_str)