tx_api: support blockbook, allow url-less operation

Bitcoin Testnet backends were removed.
This broke our tests that work purely on local data but nevertheless
need to know backend URLs. Because the design is less than ideal.

Here, we do a little cleanup:
* blockbook URLs are respected
* Dogecoin is now supported by our blockbook backend so we don't need
  a special tx-api implementation
* it's possible to instantiate a TxApi that is backed by the cache,
  without a known URL
* relevant tests now make use of this feature

trezorlib/coins.py

@@ -17,7 +17,7 @@
 import os.path
 import json
 
-from .tx_api import TxApiInsight, TxApiBlockCypher
+from .tx_api import TxApiInsight
 
 COINS_JSON = os.path.join(os.path.dirname(__file__), 'coins.json')
 
@@ -35,11 +35,11 @@ def _load_coins_json():
 
 
 def _insight_for_coin(coin):
-    if not coin['bitcore']:
+    url = next(iter(coin['blockbook'] + coin['bitcore']), None)
+    if not url:
         return None
     zcash = coin['coin_name'].lower().startswith('zcash')
     network = 'insight_{}'.format(coin['coin_name'].lower().replace(' ', '_'))
-    url = coin['bitcore'][0] + '/api/'
     return TxApiInsight(network=network, url=url, zcash=zcash)
 
 
@@ -54,7 +54,4 @@ except Exception as e:
 slip44 = {name: coin['slip44'] for name, coin in by_name.items()}
 tx_api = {name: _insight_for_coin(coin)
           for name, coin in by_name.items()
-          if coin["bitcore"]}
-
-# fixup for Dogecoin
-tx_api['Dogecoin'] = TxApiBlockCypher(network='blockcypher_dogecoin', url='https://api.blockcypher.com/v1/doge/main/')
+          if coin["blockbook"] or coin["bitcore"]}

trezorlib/tests/device_tests/test_msg_signtx.py

@@ -20,12 +20,12 @@ import pytest
 from .common import TrezorTest
 from .conftest import TREZOR_VERSION
 
-from trezorlib import coins
 from trezorlib import messages as proto
 from trezorlib.client import CallException
 from trezorlib.tools import parse_path
+from trezorlib.tx_api import TxApiInsight
 
-TxApiTestnet = coins.tx_api['Testnet']
+TxApiTestnet = TxApiInsight("insight_testnet")
 
 
 TXHASH_157041 = unhexlify('1570416eb4302cf52979afd5e6909e37d8fdd874301f7cc87e547e509cb1caa6')

trezorlib/tests/device_tests/test_msg_signtx_segwit.py

@@ -21,12 +21,12 @@ from ..support.ckd_public import deserialize
 from .conftest import TREZOR_VERSION
 from .common import TrezorTest
 
-from trezorlib import coins
 from trezorlib import messages as proto
 from trezorlib.client import CallException
 from trezorlib.tools import parse_path
+from trezorlib.tx_api import TxApiInsight
 
-TxApiTestnet = coins.tx_api["Testnet"]
+TxApiTestnet = TxApiInsight("insight_testnet")
 
 
 class TestMsgSigntxSegwit(TrezorTest):

trezorlib/tests/device_tests/test_msg_signtx_segwit_native.py

@@ -18,11 +18,11 @@ from binascii import hexlify, unhexlify
 
 from .common import TrezorTest
 from ..support.ckd_public import deserialize
-from trezorlib import coins
 from trezorlib import messages as proto
 from trezorlib.tools import parse_path
+from trezorlib.tx_api import TxApiInsight
 
-TxApiTestnet = coins.tx_api['Testnet']
+TxApiTestnet = TxApiInsight("insight_testnet")
 
 
 class TestMsgSigntxSegwitNative(TrezorTest):

trezorlib/tests/device_tests/test_multisig_change.py

@@ -19,15 +19,17 @@ from binascii import hexlify, unhexlify
 from .common import TrezorTest
 from ..support import ckd_public as bip32
 from trezorlib import messages as proto
-from trezorlib.coins import tx_api
 from trezorlib.tools import parse_path
+from trezorlib.tx_api import TxApiInsight
+
+TxApiTestnet = TxApiInsight("insight_testnet")
 
 
 class TestMultisigChange(TrezorTest):
 
     def setup_method(self, method):
         super(TestMultisigChange, self).setup_method(method)
-        self.client.set_tx_api(tx_api['Testnet'])
+        self.client.set_tx_api(TxApiTestnet)
 
     node_ext1 = bip32.deserialize('tpubDADHV9u9Y6gkggintTdMjJE3be58zKNLhpxBQyuEM6Pwx3sN9JVLmMCMN4DNVwL9AKec27z5TaWcWuHzMXiGAtcra5DjwWbvppGX4gaEGVN')
     # m/1 => 02c0d0c5fee952620757c6128dbf327c996cd72ed3358d15d6518a1186099bc15e

trezorlib/tests/unit_tests/test_tx_api.py

@@ -20,7 +20,7 @@ from trezorlib import coins
 from trezorlib import tx_api
 
 TxApiBitcoin = coins.tx_api['Bitcoin']
-TxApiTestnet = coins.tx_api['Testnet']
+TxApiTestnet = tx_api.TxApiInsight("insight_testnet")
 
 tests_dir = os.path.dirname(os.path.abspath(__file__))
 

trezorlib/tx_api.py

@@ -25,10 +25,9 @@ cache_dir = None
 
 class TxApi(object):
 
-    def __init__(self, network, url):
+    def __init__(self, network, url=None):
         self.network = network
         self.url = url
-        self.pushtx_url = url
 
     def get_url(self, resource, resourceid):
         url = '%s%s/%s' % (self.url, resource, resourceid)
@@ -44,6 +43,9 @@ class TxApi(object):
             except:
                 pass
 
+        if not self.url:
+            raise RuntimeError("No URL specified and tx not in cache")
+
         try:
             url = self.get_url(resource, resourceid)
             r = requests.get(url, headers={'User-agent': 'Mozilla/5.0'})
@@ -63,9 +65,10 @@ class TxApi(object):
 
 class TxApiInsight(TxApi):
 
-    def __init__(self, network, url, zcash=None):
-        super(TxApiInsight, self).__init__(network, url)
+    def __init__(self, network, url=None, zcash=None):
+        super().__init__(network, url)
         self.zcash = zcash
+        if url:
             self.pushtx_url = url.replace('/api/', '/tx/send')
 
     def get_tx(self, txhash):
@@ -112,38 +115,3 @@ class TxApiInsight(TxApi):
                     t.extra_data = raw[-extra_data_len:]
 
         return t
-
-
-class TxApiBlockCypher(TxApi):
-
-    def __init__(self, network, url, zcash=None):
-        super(TxApiBlockCypher, self).__init__(network, url)
-        self.pushtx_url = url.replace('//api.', '//live.').replace('/v1/', '/').replace('/main/', '/pushtx/')
-
-    def get_tx(self, txhash):
-
-        data = self.fetch_json('txs', txhash)
-
-        t = proto.TransactionType()
-        t.version = data['ver']
-        t.lock_time = data.get('lock_time', 0)
-
-        for vin in data['inputs']:
-            i = t._add_inputs()
-            if 'prev_hash' not in vin:
-                i.prev_hash = b"\0" * 32
-                i.prev_index = 0xffffffff  # signed int -1
-                i.script_sig = binascii.unhexlify(vin['script'])
-                i.sequence = vin['sequence']
-            else:
-                i.prev_hash = binascii.unhexlify(vin['prev_hash'])
-                i.prev_index = vin['output_index']
-                i.script_sig = binascii.unhexlify(vin['script'])
-                i.sequence = vin['sequence']
-
-        for vout in data['outputs']:
-            o = t._add_bin_outputs()
-            o.amount = int(str(vout['value']), 10)
-            o.script_pubkey = binascii.unhexlify(vout['script'])
-
-        return t