feat(server): Support setting CSV delimiter read option

arbalister/arrow.py

@@ -115,7 +115,20 @@ def get_table_writer(format: ff.FileFormat) -> WriteCallable:
         case ff.FileFormat.Csv:
             import pyarrow.csv
 
-            out = pyarrow.csv.write_csv
+            def write_csv(
+                data: pa.Table,
+                output_file: str | pathlib.Path,
+                memory_pool: pa.MemoryPool | None = None,
+                **kwargs: dict[str, Any],
+            ) -> None:
+                pyarrow.csv.write_csv(
+                    data=data,
+                    output_file=str(output_file),
+                    memory_pool=memory_pool,
+                    write_options=pyarrow.csv.WriteOptions(**kwargs),
+                )
+
+            out = write_csv
         case ff.FileFormat.Parquet:
             import pyarrow.parquet
 

arbalister/routes.py

@@ -22,12 +22,19 @@ class SqliteReadParams:
     table_name: str | None = None
 
 
+@dataclasses.dataclass(frozen=True, slots=True)
+class CSVReadParams:
+    """Query parameter for the CSV reader."""
+
+    delimiter: str | None = ","
+
+
 @dataclasses.dataclass(frozen=True, slots=True)
 class NoReadParams:
     """Query parameter for readers with no parameters."""
 
 
-FileReadParams = SqliteReadParams | NoReadParams
+FileReadParams = SqliteReadParams | CSVReadParams | NoReadParams
 
 
 class BaseRouteHandler(jupyter_server.base.handlers.APIHandler):
@@ -63,6 +70,8 @@ def get_file_read_params(self, file_format: ff.FileFormat) -> FileReadParams:
         match file_format:
             case ff.FileFormat.Sqlite:
                 return self.get_query_params_as(SqliteReadParams)
+            case ff.FileFormat.Csv:
+                return self.get_query_params_as(CSVReadParams)
         return NoReadParams()
 
 

arbalister/tests/test_routes.py

@@ -17,6 +17,7 @@
     params=[
         (ff.FileFormat.Avro, arb.routes.NoReadParams()),
         (ff.FileFormat.Csv, arb.routes.NoReadParams()),
+        (ff.FileFormat.Csv, arb.routes.CSVReadParams(delimiter=";")),
         (ff.FileFormat.Ipc, arb.routes.NoReadParams()),
         (ff.FileFormat.Orc, arb.routes.NoReadParams()),
         (ff.FileFormat.Parquet, arb.routes.NoReadParams()),
@@ -101,6 +102,8 @@ def table_file(
     table_path = jp_root_dir / f"test.{str(file_format).lower()}"
 
     match file_format:
+        case ff.FileFormat.Csv:
+            write_table(dummy_table_1, table_path, delimiter=getattr(file_params, "delimiter", ","))
         case ff.FileFormat.Sqlite:
             write_table(dummy_table_1, table_path, table_name="dummy_table_1", mode="create_append")
             write_table(dummy_table_2, table_path, table_name="dummy_table_2", mode="create_append")
@@ -159,6 +162,7 @@ async def test_ipc_route_limit(
     table_file: pathlib.Path,
     ipc_params: arb.routes.IpcParams,
     file_params: arb.routes.SqliteReadParams,
+    file_format: ff.FileFormat,
 ) -> None:
     """Test fetching a file returns the limited rows and columns in IPC."""
     response = await jp_fetch(
@@ -200,6 +204,7 @@ async def test_stats_route(
     full_table: pa.Table,
     table_file: pathlib.Path,
     file_params: arb.routes.SqliteReadParams,
+    file_format: ff.FileFormat,
 ) -> None:
     """Test fetching a file returns the correct metadata in Json."""
     response = await jp_fetch(
@@ -212,5 +217,6 @@ async def test_stats_route(
     assert response.headers["Content-Type"] == "application/json; charset=UTF-8"
 
     payload = json.loads(response.body)
+
     assert payload["num_cols"] == len(full_table.schema)
     assert payload["num_rows"] == full_table.num_rows