feat: Use csv.DictReader to parse header fields

dataclass_io/_lib/assertions.py

@@ -4,6 +4,7 @@
 from os import access
 from os import stat
 from pathlib import Path
+from typing import Any
 
 from dataclass_io._lib.dataclass_extensions import DataclassInstance
 from dataclass_io._lib.dataclass_extensions import fieldnames
@@ -98,20 +99,20 @@ def assert_file_is_appendable(
 def assert_file_header_matches_dataclass(
     file: Path | ReadableFileHandle,
     dataclass_type: type[DataclassInstance],
-    delimiter: str,
     comment_prefix: str,
+    **kwargs: Any,
 ) -> None:
     """
     Check that the specified file has a header and its fields match those of the provided dataclass.
     """
     header: FileHeader | None
     if isinstance(file, Path):
         with file.open("r") as fin:
-            header = get_header(fin, delimiter=delimiter, comment_prefix=comment_prefix)
+            header = get_header(reader=fin, comment_prefix=comment_prefix, **kwargs)
     else:
         pos = file.tell()
         try:
-            header = get_header(file, delimiter=delimiter, comment_prefix=comment_prefix)
+            header = get_header(reader=file, comment_prefix=comment_prefix, **kwargs)
         finally:
             file.seek(pos)
 

dataclass_io/_lib/file.py

@@ -1,3 +1,4 @@
+from csv import DictReader
 from dataclasses import dataclass
 from enum import Enum
 from enum import unique
@@ -66,8 +67,8 @@ class FileHeader:
 
 def get_header(
     reader: ReadableFileHandle,
-    delimiter: str,
     comment_prefix: str,
+    **kwargs: Any,
 ) -> Optional[FileHeader]:
     """
     Read the header from an open file.
@@ -85,6 +86,7 @@ def get_header(
     Args:
         reader: An open, readable file handle.
         comment_char: The character which indicates the start of a comment line.
+        **kwargs: Additional keyword arguments to pass to `csv.DictReader`.
 
     Returns:
         A `FileHeader` containing the field names and any preceding lines.
@@ -103,6 +105,9 @@ def get_header(
     else:
         return None
 
-    fieldnames = line.strip().split(delimiter)
+    # msto#19 Read header fields
+    # Use csv.DictReader because RFC4180 is tricky to implement correctly
+    header_reader = DictReader([line], **kwargs)
+    fieldnames = list(header_reader.fieldnames)
 
     return FileHeader(preface=preface, fieldnames=fieldnames)

dataclass_io/reader.py

@@ -25,16 +25,17 @@ def __init__(
         self,
         fin: ReadableFileHandle,
         dataclass_type: type[DataclassInstance],
-        delimiter: str = "\t",
         comment_prefix: str = "#",
-        **kwds: Any,
+        delimiter: str = "\t",
+        **kwargs: Any,
     ) -> None:
         """
         Args:
             fin: Open file handle for reading.
             dataclass_type: Dataclass type.
             delimiter: The input file delimiter.
             comment_prefix: The prefix for any comment/preface rows preceding the header row.
+            quoting: Quoting style (enum value from Python csv package).
             dataclass_type: Dataclass type.
 
         Raises:
@@ -46,17 +47,22 @@ def __init__(
             dataclass_type=dataclass_type,
             delimiter=delimiter,
             comment_prefix=comment_prefix,
+            **kwargs,
         )
 
         self._dataclass_type = dataclass_type
         self._fin = fin
         self._header = get_header(
-            reader=self._fin, delimiter=delimiter, comment_prefix=comment_prefix
+            reader=self._fin,
+            delimiter=delimiter,
+            comment_prefix=comment_prefix,
+            **kwargs,
         )
         self._reader = DictReader(
             f=self._fin,
             fieldnames=fieldnames(dataclass_type),
             delimiter=delimiter,
+            **kwargs,
         )
 
     def __iter__(self) -> "DataclassReader":

dataclass_io/writer.py

@@ -31,7 +31,7 @@ def __init__(
         include_fields: list[str] | None = None,
         exclude_fields: list[str] | None = None,
         write_header: bool = True,
-        **kwds: Any,
+        **kwargs: Any,
     ) -> None:
         """
         Args:
@@ -65,6 +65,7 @@ def __init__(
             f=self._fout,
             fieldnames=self._fieldnames,
             delimiter=delimiter,
+            **kwargs,
         )
 
         # TODO: permit writing comment/preface rows before header
@@ -124,9 +125,9 @@ def open(
         dataclass_type: type[DataclassInstance],
         mode: str = "write",
         overwrite: bool = True,
-        delimiter: str = "\t",
         comment_prefix: str = "#",
-        **kwds: Any,
+        delimiter: str = "\t",
+        **kwargs: Any,
     ) -> Iterator["DataclassWriter"]:
         """
         Open a new `DataclassWriter` from a file path.
@@ -142,11 +143,11 @@ def open(
                 `exclude_fields`.
             overwrite: If `True`, and `mode="write"`, the file specified at `path` will be
                 overwritten if it exists.
-            delimiter: The output file delimiter.
             comment_prefix: The prefix for any comment/preface rows preceding the header row.
                 (This argument is ignored when `mode="write"`. It is used when `mode="append"` to
                 validate that the existing file's header matches the specified dataclass.)
-            **kwds: Additional keyword arguments to be passed to the `DataclassWriter` constructor.
+            delimiter: The output file delimiter.
+            **kwds: Additional keyword arguments to be passed to `csv.DictWriter`.
 
         Yields:
             A `DataclassWriter` instance.
@@ -178,6 +179,7 @@ def open(
                 dataclass_type=dataclass_type,
                 delimiter=delimiter,
                 comment_prefix=comment_prefix,
+                **kwargs,
             )
 
         fout = filepath.open(write_mode.abbreviation)
@@ -186,7 +188,7 @@ def open(
                 fout=fout,
                 dataclass_type=dataclass_type,
                 write_header=(write_mode is WriteMode.WRITE),  # Skip header when appending
-                **kwds,
+                **kwargs,
             )
         finally:
             fout.close()

tests/conftest.py

@@ -0,0 +1,10 @@
+from pathlib import Path
+
+import pytest
+
+
+@pytest.fixture(scope="session")
+def datadir() -> Path:
+    """Path to the test data directory."""
+
+    return Path(__file__).parent / "data"

tests/data/reader_should_parse_quotes.tsv

@@ -0,0 +1,3 @@
+"id"	"title"
+"fake"	"A fake object"
+"also_fake"	"Another fake object"

tests/test_reader.py

@@ -35,3 +35,23 @@ class FakeDataclass:
         assert isinstance(rows[0], FakeDataclass)
         assert rows[0].foo == "abc"
         assert rows[0].bar == 1
+
+
+def test_reader_should_parse_quotes(datadir: Path) -> None:
+    """
+    Test that having quotes around column names in header row doesn't break anything
+    https://github.com/msto/dataclass_io/issues/19
+    """
+    fpath = datadir / "reader_should_parse_quotes.tsv"
+
+    @dataclass
+    class FakeDataclass:
+        id: str
+        title: str
+
+    # Parse CSV using DataclassReader
+    with DataclassReader.open(fpath, FakeDataclass) as reader:
+        records = [record for record in reader]
+
+        assert records[0] == FakeDataclass(id="fake", title="A fake object")
+        assert records[1] == FakeDataclass(id="also_fake", title="Another fake object")