general purpose constraints builder

tests/unit/test_database.py

@@ -0,0 +1,23 @@
+from unittest import TestCase
+from torba.basedatabase import constraints_to_sql
+
+
+class TestConstraintBuilder(TestCase):
+
+    def test_any(self):
+        constraints = {
+            'ages__any': {
+                'age__gt': 18,
+                'age__lt': 38
+            }
+        }
+        self.assertEqual(
+            constraints_to_sql(constraints, prepend_sql=''),
+            '(age > :ages__any_age__gt OR age < :ages__any_age__lt)'
+        )
+        self.assertEqual(
+            constraints, {
+                'ages__any_age__gt': 18,
+                'ages__any_age__lt': 38
+            }
+        )

torba/basedatabase.py

@@ -11,6 +11,34 @@ from torba.hash import TXRefImmutable
 log = logging.getLogger(__name__)
 
 
+def constraints_to_sql(constraints, joiner=' AND ', prepend_sql=' AND ', prepend_key=''):
+    if not constraints:
+        return ''
+    extras = []
+    for key in list(constraints):
+        col, op = key, '='
+        if key.endswith('__not'):
+            col, op = key[:-len('__not')], '!='
+        elif key.endswith('__lt'):
+            col, op = key[:-len('__lt')], '<'
+        elif key.endswith('__lte'):
+            col, op = key[:-len('__lte')], '<='
+        elif key.endswith('__gt'):
+            col, op = key[:-len('__gt')], '>'
+        elif key.endswith('__like'):
+            col, op = key[:-len('__like')], 'LIKE'
+        elif key.endswith('__any'):
+            subconstraints = constraints.pop(key)
+            extras.append('({})'.format(
+                constraints_to_sql(subconstraints, ' OR ', '', key+'_')
+            ))
+            for subkey, val in subconstraints.items():
+                constraints['{}_{}'.format(key, subkey)] = val
+            continue
+        extras.append('{} {} :{}'.format(col, op, prepend_key+key))
+    return prepend_sql + joiner.join(extras) if extras else ''
+
+
 class SQLiteMixin:
 
     CREATE_TABLES_QUERY: Sequence[str] = ()
@@ -224,21 +252,8 @@ class BaseDatabase(SQLiteMixin):
             defer.returnValue((None, None, False))
 
     def get_balance_for_account(self, account, include_reserved=False, **constraints):
-        extra_sql = ""
-        if constraints:
-            extras = []
-            for key in constraints:
-                col, op = key, '='
-                if key.endswith('__not'):
-                    col, op = key[:-len('__not')], '!='
-                elif key.endswith('__lte'):
-                    col, op = key[:-len('__lte')], '<='
-                elif key.endswith('__gt'):
-                    col, op = key[:-len('__gt')], '>'
-                extras.append('{} {} :{}'.format(col, op, key))
-            extra_sql = ' AND ' + ' AND '.join(extras)
         if not include_reserved:
-            extra_sql += ' AND is_reserved=0'
+            constraints['is_reserved'] = 0
         values = {'account': account.public_key.address}
         values.update(constraints)
         return self.query_one_value(
@@ -250,24 +265,18 @@ class BaseDatabase(SQLiteMixin):
             WHERE
               pubkey_address.account=:account AND
               txoid NOT IN (SELECT txoid FROM txi)
-            """+extra_sql, values, 0
+            """+constraints_to_sql(constraints), values, 0
         )
 
     @defer.inlineCallbacks
     def get_utxos_for_account(self, account, **constraints):
-        extra_sql = ""
+        constraints['account'] = account.public_key.address
-        if constraints:
-            extra_sql = ' AND ' + ' AND '.join(
-                '{} = :{}'.format(c, c) for c in constraints
-            )
-        values = {'account': account.public_key.address}
-        values.update(constraints)
         utxos = yield self.run_query(
             """
             SELECT amount, script, txid, txo.position
             FROM txo JOIN pubkey_address ON pubkey_address.address=txo.address
             WHERE account=:account AND txo.is_reserved=0 AND txoid NOT IN (SELECT txoid FROM txi)
-            """+extra_sql, values
+            """+constraints_to_sql(constraints), constraints
         )
         output_class = account.ledger.transaction_class.output_class
         defer.returnValue([