Result pagination

buscribe-api/buscribeapi/buscribeapi.py

@@ -81,9 +81,12 @@ def get_json():
     # I think websearch_to_tsquery() sanitizes its own input.
     query = request.args.get('query', default=None)
 
+    limit = request.args.get('limit', default=None, type=int)
+    offset = request.args.get('offset', default=None, type=int)
+
     db_conn = app.db_manager.get_conn()
 
-    results = fetch_lines(db_conn, start_time, end_time, query)
+    results = fetch_lines(db_conn, start_time, end_time, query, limit, offset)
 
     return jsonify([{"start_time": row.start_time.isoformat(),
                      "start_bus_time": round_bus_time(row.start_time - app.bustime_start),
@@ -92,20 +95,28 @@ def get_json():
                      "text": row.transcription_line} for row in results])
 
 
-def fetch_lines(db_conn, start_time, end_time, query=None):
+def fetch_lines(db_conn, start_time, end_time, ts_query=None, limit=None, offset=None):
-    if query is None:
+    query = "SELECT * FROM buscribe_transcriptions WHERE start_time > %(start_time)s AND end_time < %(end_time)s "
-        return database.query(db_conn, "SELECT * FROM buscribe_transcriptions WHERE "
+
-                                       "start_time > %s AND "
+    if ts_query is not None:
-                                       "end_time < %s;",
+        query += "AND to_tsvector(transcription_line) @@ websearch_to_tsquery(%(text_query)s) " \
-                              start_time if start_time is not None else '-infinity',
+                 "ORDER BY ts_rank_cd(to_tsvector(transcription_line), websearch_to_tsquery(%(text_query)s)) DESC, " \
-                              end_time if end_time is not None else 'infinity')
+                 "start_time"
-    else:
+
-        return database.query(db_conn, "SELECT * FROM buscribe_transcriptions WHERE "
+    if limit is not None:
-                                       "start_time > %(start_time)s AND "
+        query += "LIMIT %(limit)s"
-                                       "end_time < %(end_time)s AND "
+
-                                       "to_tsvector(transcription_line) @@ websearch_to_tsquery(%(text_query)s) "
+    if offset is not None:
-                                       "ORDER BY ts_rank_cd(to_tsvector(transcription_line), websearch_to_tsquery(%(text_query)s)) DESC, "
+        query += "OFFSET %(limit)s"
-                                       "start_time;",
+
-                              start_time=start_time if start_time is not None else '-infinity',
+    query += ";"
-                              end_time=end_time if end_time is not None else 'infinity',
+
-                              text_query=query)
+    print(query)
+
+    return database.query(db_conn, query,
+                          start_time=start_time if start_time is not None else '-infinity',
+                          end_time=end_time if end_time is not None else 'infinity',
+                          text_query=ts_query,
+                          limit=limit,
+                          offset=offset
+                          )