tx_api: update to assume "/api" path again, let blockHash request be

cached

trezorlib/tests/txcache/insight_zencash_block-index_110000.json

@@ -0,0 +1 @@
+{"blockHash": "000000003f5d6ba1385c6cd2d4f836dfc5adf7f98834309ad67e26faef462454"}

trezorlib/tx_api.py

@@ -29,21 +29,8 @@ class TxApi(object):
         self.network = network
         self.url = url
 
-    def get_url(self, resource, resourceid):
-        url = '%s%s/%s' % (self.url, resource, resourceid)
-        return url
-
-    def current_height(self):
-        r = requests.get(self.url + '/status?q=getBlockCount')
-        j = r.json(parse_float=str)
-        block_height = j['info']['blocks']
-        return block_height
-
-    def get_block_hash(self, block_number):
-        r = requests.get(self.url + '/block-index/' + str(block_number))
-        j = r.json(parse_float=str)
-        block_hash = binascii.unhexlify(j['blockHash'])
-        return block_hash
+    def get_url(self, *args):
+        return "/".join(map(str, [self.url, "api", *args]))
 
     def fetch_json(self, resource, resourceid):
         global cache_dir
@@ -82,8 +69,17 @@ class TxApiInsight(TxApi):
         self.zcash = zcash
         self.bip115 = bip115
         if url:
-            prefix, suffix = url.rsplit('/', maxsplit=1)
-            self.pushtx_url = prefix + '/tx/send'
+            self.pushtx_url = self.url + "/tx/send"
+
+    def get_block_hash(self, block_number):
+        j = self.fetch_json("block-index", block_number)
+        return binascii.unhexlify(j["blockHash"])
+
+    def current_height(self):
+        r = requests.get(self.get_url("status?q=getBlockCount"))
+        j = r.json(parse_float=str)
+        block_height = j["info"]["blocks"]
+        return block_height
 
     def get_tx(self, txhash):