convert_to_pdfa: Normalize PDF/A output types case-insensitively

- Normalize PDF/A `output_type` values case-insensitively during
  payload validation before enforcing the canonical `PdfAType`
  literals.
- Derive the accepted canonical values from `get_args(PdfAType)`
  instead of maintaining a separate hard-coded list.
- Update unit and live PDF/A tests to cover lowercase inputs.

Assisted-by: Codex

Author: datalogics-cgreen

src/pdfrest/models/_internal.py

@@ -3,7 +3,7 @@
 import re
 from collections.abc import Callable, Mapping, Sequence
 from pathlib import PurePath
-from typing import Annotated, Any, Generic, Literal, TypeVar, cast
+from typing import Annotated, Any, Generic, Literal, TypeVar, cast, get_args
 
 from langcodes import tag_is_valid
 from pydantic import (
@@ -49,6 +49,10 @@
 from .public import PdfRestFile, PdfRestFileID
 
 PdfConvertColorProfile = PdfPresetColorProfile | Literal["custom"]
+PDFA_OUTPUT_TYPES: tuple[PdfAType, ...] = cast(tuple[PdfAType, ...], get_args(PdfAType))
+PDFA_OUTPUT_TYPE_MAP: dict[str, PdfAType] = {
+    output_type.casefold(): output_type for output_type in PDFA_OUTPUT_TYPES
+}
 
 
 def _ensure_list(value: Any) -> Any:
@@ -188,6 +192,12 @@ def _bool_to_true_false(value: Any) -> Any:
     return value
 
 
+def _normalize_pdfa_output_type(value: Any) -> Any:
+    if not isinstance(value, str):
+        return value
+    return PDFA_OUTPUT_TYPE_MAP.get(value.casefold(), value)
+
+
 def _serialize_page_ranges(value: list[str | int | tuple[str | int, ...]]) -> str:
     def join_tuple(value: str | int | tuple[str | int, ...]) -> str:
         if isinstance(value, tuple):
@@ -1344,7 +1354,11 @@ class PdfToPdfaPayload(BaseModel):
         ),
         PlainSerializer(_serialize_as_first_file_id),
     ]
-    output_type: Annotated[PdfAType, Field(serialization_alias="output_type")]
+    output_type: Annotated[
+        PdfAType,
+        Field(serialization_alias="output_type"),
+        BeforeValidator(_normalize_pdfa_output_type),
+    ]
     output: Annotated[
         str | None,
         Field(serialization_alias="output", min_length=1, default=None),

src/pdfrest/types/public.py

@@ -323,7 +323,9 @@ class PdfPemCredentials(TypedDict):
 #: [AsyncPdfRestClient.sign_pdf][pdfrest.AsyncPdfRestClient.sign_pdf].
 PdfSignatureCredentials = PdfPfxCredentials | PdfPemCredentials
 
-#: PDF/A conformance targets accepted by ``convert_to_pdfa``.
+#: Canonical PDF/A conformance targets accepted by ``convert_to_pdfa``.
+#: Payload validation accepts case-insensitive string input and normalizes it
+#: to one of these literals before serialization.
 PdfAType = Literal["PDF/A-1b", "PDF/A-2b", "PDF/A-2u", "PDF/A-3b", "PDF/A-3u"]
 #: PDF/X conformance targets accepted by ``convert_to_pdfx``.
 PdfXType = Literal["PDF/X-1a", "PDF/X-3", "PDF/X-4", "PDF/X-6"]

tests/live/test_live_convert_to_pdfa.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from typing import cast, get_args
+from typing import Any, cast, get_args
 
 import pytest
 
@@ -101,6 +101,28 @@ def test_live_convert_to_pdfa_with_rasterize_option(
     assert str(response.input_id) == str(uploaded_pdf_for_pdfa.id)
 
 
+def test_live_convert_to_pdfa_accepts_lowercase_output_type(
+    pdfrest_api_key: str,
+    pdfrest_live_base_url: str,
+    uploaded_pdf_for_pdfa: PdfRestFile,
+) -> None:
+    with PdfRestClient(
+        api_key=pdfrest_api_key,
+        base_url=pdfrest_live_base_url,
+    ) as client:
+        response = client.convert_to_pdfa(
+            uploaded_pdf_for_pdfa,
+            output_type=cast(Any, "pdf/a-2b"),
+            output="pdfa-lowercase",
+        )
+
+    assert response.output_files
+    output_file = response.output_file
+    assert output_file.name.startswith("pdfa-lowercase")
+    assert output_file.type == "application/pdf"
+    assert str(response.input_id) == str(uploaded_pdf_for_pdfa.id)
+
+
 @pytest.mark.asyncio
 async def test_live_async_convert_to_pdfa_with_rasterize_option(
     pdfrest_api_key: str,
@@ -125,12 +147,34 @@ async def test_live_async_convert_to_pdfa_with_rasterize_option(
     assert str(response.input_id) == str(uploaded_pdf_for_pdfa.id)
 
 
+@pytest.mark.asyncio
+async def test_live_async_convert_to_pdfa_accepts_lowercase_output_type(
+    pdfrest_api_key: str,
+    pdfrest_live_base_url: str,
+    uploaded_pdf_for_pdfa: PdfRestFile,
+) -> None:
+    async with AsyncPdfRestClient(
+        api_key=pdfrest_api_key,
+        base_url=pdfrest_live_base_url,
+    ) as client:
+        response = await client.convert_to_pdfa(
+            uploaded_pdf_for_pdfa,
+            output_type=cast(Any, "pdf/a-2b"),
+            output="async-pdfa-lowercase",
+        )
+
+    assert response.output_files
+    output_file = response.output_file
+    assert output_file.name.startswith("async-pdfa-lowercase")
+    assert output_file.type == "application/pdf"
+    assert str(response.input_id) == str(uploaded_pdf_for_pdfa.id)
+
+
 @pytest.mark.parametrize(
     "invalid_output_type",
     [
         pytest.param("PDF/A-0", id="pdfa-0"),
         pytest.param("PDF/A-99", id="pdfa-99"),
-        pytest.param("pdf/a-2b", id="lowercase"),
     ],
 )
 def test_live_convert_to_pdfa_invalid_output_type(
@@ -159,7 +203,6 @@ def test_live_convert_to_pdfa_invalid_output_type(
     [
         pytest.param("PDF/A-0", id="pdfa-0"),
         pytest.param("PDF/A-99", id="pdfa-99"),
-        pytest.param("pdf/a-2b", id="lowercase"),
     ],
 )
 async def test_live_async_convert_to_pdfa_invalid_output_type(