From d62ba74e92c673f170c444899e14cae4b065e79a Mon Sep 17 00:00:00 2001
From: Javier Sancho <jsf@jsancho.org>
Date: Tue, 29 May 2018 13:03:09 +0200
Subject: [PATCH] Fix number of rows returned when limit is present or
 pagination is needed

---
 datasette_pytables/__init__.py | 22 ++++++++++++++++------
 tests/test_api.py              | 29 ++++++++++++++++++++++++++---
 2 files changed, 42 insertions(+), 9 deletions(-)

diff --git a/datasette_pytables/__init__.py b/datasette_pytables/__init__.py
index b3d5b9a..86f879c 100644
--- a/datasette_pytables/__init__.py
+++ b/datasette_pytables/__init__.py
@@ -145,18 +145,14 @@ class Connection:
                 query = parsed_sql['where']
 
         # Limit number of rows
+        limit = None
         if 'limit' in parsed_sql:
-            max_rows = int(parsed_sql['limit'])
-            if end - start > max_rows:
-                end = start + max_rows
+            limit = int(parsed_sql['limit'])
 
         # Truncate if needed
         if page_size and max_returned_rows and truncate:
             if max_returned_rows == page_size:
                 max_returned_rows += 1
-            if end - start > max_returned_rows:
-                end = start + max_returned_rows
-                truncated = True
 
         # Execute query
         if query:
@@ -170,7 +166,14 @@ class Connection:
             rows.append(Row({'count(*)': int(table.nrows)}))
         else:
             if type(table) is tables.table.Table:
+                count = 0
                 for table_row in table_rows:
+                    count += 1
+                    if limit and count > limit:
+                        break
+                    if truncate and max_returned_rows and count > max_returned_rows:
+                        truncated = True
+                        break
                     row = Row()
                     for field in fields:
                         field_name = field['value']
@@ -190,7 +193,14 @@ class Connection:
             else:
                 # Any kind of array
                 rowid = start - 1
+                count = 0
                 for table_row in table_rows:
+                    count += 1
+                    if limit and count > limit:
+                        break
+                    if truncate and max_returned_rows and count > max_returned_rows:
+                        truncated = True
+                        break
                     row = Row()
                     rowid += 1
                     for field in fields:
diff --git a/tests/test_api.py b/tests/test_api.py
index 39c4122..97e07dc 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -55,6 +55,30 @@ def test_database_page(app_client):
     }] == data['tables']
 
 def test_custom_sql(app_client):
+    response = app_client.get(
+        '/test_tables.json?' + urlencode({
+            'sql': 'select identity from [/group1/table1]',
+            '_shape': 'objects'
+        }),
+        gather_request=False
+    )
+    data = response.json
+    assert {
+        'sql': 'select identity from [/group1/table1]',
+        'params': {}
+    } == data['query']
+    assert 1000 == len(data['rows'])
+    assert [
+        {'identity': 'This is particle:  0'},
+        {'identity': 'This is particle:  1'},
+        {'identity': 'This is particle:  2'},
+        {'identity': 'This is particle:  3'}
+    ] == data['rows'][:4]
+    assert ['identity'] == data['columns']
+    assert 'test_tables' == data['database']
+    assert data['truncated']
+
+def test_custom_complex_sql(app_client):
     response = app_client.get(
         '/test_tables.json?' + urlencode({
             'sql': 'select identity from [/group1/table1] where speed > 100 and idnumber < 55',
@@ -63,7 +87,6 @@ def test_custom_sql(app_client):
         gather_request=False
     )
     data = response.json
-    print("*************************", data)
     assert {
         'sql': 'select identity from [/group1/table1] where speed > 100 and idnumber < 55',
         'params': {}
@@ -77,7 +100,7 @@ def test_custom_sql(app_client):
     ] == data['rows']
     assert ['identity'] == data['columns']
     assert 'test_tables' == data['database']
-    assert False == data['truncated']
+    assert not data['truncated']
 
 def test_custom_pytables_sql(app_client):
     response = app_client.get(
@@ -100,7 +123,7 @@ def test_custom_pytables_sql(app_client):
     ] == data['rows'][:3]
     assert ['identity'] == data['columns']
     assert 'test_tables' == data['database']
-    assert data['truncated']
+    assert not data['truncated']
 
 def test_invalid_custom_sql(app_client):
     response = app_client.get(
-- 
2.39.2