feat: add selectable fields to measurement query

Author: NejcKle

rest_api/main.py

@@ -157,6 +157,7 @@ def get_measurements(
     offset=None,
     start_time=None,
     end_time=None,
+    fields=[],
     conn=Depends(partial(get_db_connection, connection_pool)),
     user: UserInfo = Depends(get_current_user),
 ):
@@ -165,13 +166,17 @@ def get_measurements(
         limit = int(limit)
     if offset is not None:
         offset = int(offset)
+    if fields is not None:
+        fields = [f.strip() for f in fields.split(",")]
 
     measurements = fetch_measurements_for_sensor(
-        conn, sensor_name, start_time, end_time
+        conn, sensor_name, start_time, end_time, fields
     )
 
     if len(measurements) == 0:
-        return ORJSONResponse(content={"error": "Sensor not found"}, status_code=404)
+        return ORJSONResponse(
+            content={"error": "Sensor not found or data not available"}, status_code=404
+        )
     # Calculate pagination details
     total_measurements = len(measurements)
 

rest_api/src/handlers.py

@@ -75,7 +75,7 @@ def fetch_table_names_from_app_id(conn, app_id: int) -> list | None:
 
 
 def fetch_measurements_for_sensor(
-    conn, sensor_name: str, start_time: str | None, end_time: str | None
+    conn, sensor_name: str, start_time: str | None, end_time: str | None, fields: list
 ) -> list:
     """Fetch all measurements for a given sensor_name from all relevant tables."""
     with conn.cursor() as cur:
@@ -120,22 +120,57 @@ def fetch_measurements_for_sensor(
 
         # Step 3: Query each table for its measurement_ids
         for table_name, ids in table_to_ids.items():
-            query = sql.SQL("SELECT * FROM {} WHERE id = ANY(%s)").format(
-                sql.Identifier(table_name)
-            )
-            cur.execute(query, (ids,))
-            columns = [desc[0] for desc in cur.description]
-            for row in cur.fetchall():
-                data = {col: val for col, val in zip(columns[3:], row[3:])}
-                filtered_data = {k: v for k, v in data.items() if v is not None}
-                measurements.append(
-                    Measurement(
-                        # sensor_id=row[1],
-                        table_name=table_name,
-                        timestamp=str(row[2]),
-                        data=filtered_data,
-                    )
+            if fields:
+                select_fields = sql.SQL(", ").join(
+                    [
+                        sql.Identifier(f)
+                        for f in ["id", "sensor_id", "timestamp"] + fields
+                    ]
                 )
+            else:
+                select_fields = sql.SQL("*")
+            query = sql.SQL("SELECT {} FROM {} WHERE id = ANY(%s)").format(
+                select_fields, sql.Identifier(table_name)
+            )
+            print(f"Executing query on table {table_name} for IDs: {ids}")
+            print(f"Query: {query.as_string(conn)}")
+
+            try:
+                cur.execute(query, (ids,))
+                if fields:
+                    columns = ["id", "sensor_id", "timestamp"] + fields
+                else:
+                    columns = [desc[0] for desc in cur.description]
+                for row in cur.fetchall():
+                    data = {col: val for col, val in zip(columns[3:], row[3:])}
+                    filtered_data = {k: v for k, v in data.items() if v is not None}
+
+                    if filtered_data:
+                        measurements.append(
+                            Measurement(
+                                table_name=table_name,
+                                timestamp=str(row[2]),
+                                data=filtered_data,
+                            )
+                        )
+            except Exception as e:
+                print(f"Error executing query on table {table_name}: {e}")
+            # query = sql.SQL("SELECT * FROM {} WHERE id = ANY(%s)").format(
+            #     sql.Identifier(table_name)
+            # )
+            # cur.execute(query, (ids,))
+            # columns = [desc[0] for desc in cur.description]
+            # for row in cur.fetchall():
+            #     data = {col: val for col, val in zip(columns[3:], row[3:])}
+            #     filtered_data = {k: v for k, v in data.items() if v is not None}
+            #     measurements.append(
+            #         Measurement(
+            #             # sensor_id=row[1],
+            #             table_name=table_name,
+            #             timestamp=str(row[2]),
+            #             data=filtered_data,
+            #         )
+            #     )
 
         # Now sort all measurements by timestamp descending
         measurements.sort(key=lambda x: x.timestamp, reverse=True)