Rename get_history to limited_history

- make it async and run in a thread

contrib/query.py

@@ -73,8 +73,8 @@ async def query(args):
         if not hashX:
             continue
         n = None
-        for n, (tx_hash, height) in enumerate(db.get_history(hashX, limit),
-                                              start=1):
+        history = await db.limited_history(hashX, limit=limit)
+        for n, (tx_hash, height) in enumerate(history, start=1):
             print(f'History #{n:,d}: height {height:,d} '
                   f'tx_hash {hash_to_hex_str(tx_hash)}')
         if n is None:

electrumx/server/chain_state.py

@@ -8,8 +8,6 @@
 
 import asyncio
 
-from aiorpcx import run_in_thread
-
 from electrumx.lib.hash import hash_to_hex_str
 
 
@@ -28,6 +26,7 @@ class ChainState(object):
         self.tx_branch_and_root = self._bp.merkle.branch_and_root
         self.read_headers = self._bp.read_headers
         self.all_utxos = self._bp.all_utxos
+        self.limited_history = self._bp.limited_history
 
     async def broadcast_transaction(self, raw_tx):
         return await self._daemon.sendrawtransaction([raw_tx])
@@ -46,18 +45,6 @@ class ChainState(object):
             'db_height': self.db_height(),
         }
 
-    async def get_history(self, hashX):
-        '''Get history asynchronously to reduce latency.'''
-        def job():
-            # History DoS limit.  Each element of history is about 99
-            # bytes when encoded as JSON.  This limits resource usage
-            # on bloated history requests, and uses a smaller divisor
-            # so large requests are logged before refusing them.
-            limit = self._env.max_send // 97
-            return list(self._bp.get_history(hashX, limit=limit))
-
-        return await run_in_thread(job)
-
     def header_branch_and_root(self, length, height):
         return self._bp.header_mc.branch_and_root(length, height)
 
@@ -102,8 +89,8 @@ class ChainState(object):
             if not hashX:
                 continue
             n = None
-            for n, (tx_hash, height) in enumerate(
-                    db.get_history(hashX, limit), start=1):
+            history = await db.limited_history(hashX, limit=limit)
+            for n, (tx_hash, height) in enumerate(history):
                 lines.append(f'History #{n:,d}: height {height:,d} '
                              f'tx_hash {hash_to_hex_str(tx_hash)}')
             if n is None:

electrumx/server/db.py

@@ -227,15 +227,19 @@ class DB(object):
 
         return [self.coin.header_hash(header) for header in headers]
 
-    def get_history(self, hashX, limit=1000):
-        '''Generator that returns an unpruned, sorted list of (tx_hash,
-        height) tuples of confirmed transactions that touched the address,
-        earliest in the blockchain first.  Includes both spending and
-        receiving transactions.  By default yields at most 1000 entries.
-        Set limit to None to get them all.
+    async def limited_history(self, hashX, *, limit=1000):
+        '''Return an unpruned, sorted list of (tx_hash, height) tuples of
+        confirmed transactions that touched the address, earliest in
+        the blockchain first.  Includes both spending and receiving
+        transactions.  By default returns at most 1000 entries.  Set
+        limit to None to get them all.
         '''
-        for tx_num in self.history.get_txnums(hashX, limit):
-            yield self.fs_tx_hash(tx_num)
+        def read_history():
+            tx_nums = list(self.history.get_txnums(hashX, limit))
+            fs_tx_hash = self.fs_tx_hash
+            return [fs_tx_hash(tx_num) for tx_num in tx_nums]
+
+        return await run_in_thread(read_history)
 
     # -- Undo information
 

electrumx/server/session.py

@@ -444,11 +444,17 @@ class SessionManager(object):
         '''The number of connections that we've sent something to.'''
         return len(self.sessions)
 
-    async def get_history(self, hashX):
+    async def limited_history(self, hashX):
         '''A caching layer.'''
         hc = self._history_cache
         if hashX not in hc:
-            hc[hashX] = await self.chain_state.get_history(hashX)
+            # History DoS limit.  Each element of history is about 99
+            # bytes when encoded as JSON.  This limits resource usage
+            # on bloated history requests, and uses a smaller divisor
+            # so large requests are logged before refusing them.
+            limit = self.env.max_send // 97
+            hc[hashX] = await self.chain_state.limited_history(hashX,
+                                                               limit=limit)
         return hc[hashX]
 
     async def _notify_sessions(self, height, touched):
@@ -773,7 +779,7 @@ class ElectrumX(SessionBase):
         '''
         # Note history is ordered and mempool unordered in electrum-server
         # For mempool, height is -1 if unconfirmed txins, otherwise 0
-        history = await self.session_mgr.get_history(hashX)
+        history = await self.session_mgr.limited_history(hashX)
         mempool = await self.mempool.transaction_summaries(hashX)
 
         status = ''.join('{}:{:d}:'.format(hash_to_hex_str(tx_hash), height)
@@ -873,7 +879,7 @@ class ElectrumX(SessionBase):
 
     async def confirmed_and_unconfirmed_history(self, hashX):
         # Note history is ordered but unconfirmed is unordered in e-s
-        history = await self.session_mgr.get_history(hashX)
+        history = await self.session_mgr.limited_history(hashX)
         conf = [{'tx_hash': hash_to_hex_str(tx_hash), 'height': height}
                 for tx_hash, height in history]
         return conf + await self.unconfirmed_history(hashX)