From b09033cb73e3d99bb8b299675a539b4f10e41cb1 Mon Sep 17 00:00:00 2001
From: "Peter W. J. Staar" <91719829+PeterStaar-IBM@users.noreply.github.com>
Date: Tue, 12 Aug 2025 11:02:38 +0200
Subject: [PATCH] feat: add convert_string to document-converter (#2069)

* feat: add convert_string to document-converter

Signed-off-by: Peter Staar <taa@zurich.ibm.com>

* fix unsupported operand type(s) for |: type and NoneType

Signed-off-by: Peter Staar <taa@zurich.ibm.com>

* added tests for convert_string

Signed-off-by: Peter Staar <taa@zurich.ibm.com>

---------

Signed-off-by: Peter Staar <taa@zurich.ibm.com>
---
 docling/document_converter.py  | 30 +++++++++++++++++++
 tests/test_backend_markdown.py | 53 +++++++++++++++++++++++++++++++++-
 2 files changed, 82 insertions(+), 1 deletion(-)

diff --git a/docling/document_converter.py b/docling/document_converter.py
index 5ad19c6d..591c75c1 100644
--- a/docling/document_converter.py
+++ b/docling/document_converter.py
@@ -5,7 +5,9 @@ import threading
 import time
 from collections.abc import Iterable, Iterator
 from concurrent.futures import ThreadPoolExecutor
+from datetime import datetime
 from functools import partial
+from io import BytesIO
 from pathlib import Path
 from typing import Dict, List, Optional, Tuple, Type, Union
 
@@ -275,6 +277,34 @@ class DocumentConverter:
                 "Conversion failed because the provided file has no recognizable format or it wasn't in the list of allowed formats."
             )
 
+    @validate_call(config=ConfigDict(strict=True))
+    def convert_string(
+        self,
+        content: str,
+        format: InputFormat,
+        name: Optional[str],
+    ) -> ConversionResult:
+        name = name or datetime.now().strftime("%Y-%m-%d_%H-%M-%S")
+
+        if format == InputFormat.MD:
+            if not name.endswith(".md"):
+                name += ".md"
+
+            buff = BytesIO(content.encode("utf-8"))
+            doc_stream = DocumentStream(name=name, stream=buff)
+
+            return self.convert(doc_stream)
+        elif format == InputFormat.HTML:
+            if not name.endswith(".html"):
+                name += ".html"
+
+            buff = BytesIO(content.encode("utf-8"))
+            doc_stream = DocumentStream(name=name, stream=buff)
+
+            return self.convert(doc_stream)
+        else:
+            raise ValueError(f"format {format} is not supported in `convert_string`")
+
     def _convert(
         self, conv_input: _DocumentConversionInput, raises_on_error: bool
     ) -> Iterator[ConversionResult]:
diff --git a/tests/test_backend_markdown.py b/tests/test_backend_markdown.py
index 8a0d7b4f..12db89a9 100644
--- a/tests/test_backend_markdown.py
+++ b/tests/test_backend_markdown.py
@@ -2,10 +2,19 @@ from pathlib import Path
 
 from docling.backend.md_backend import MarkdownDocumentBackend
 from docling.datamodel.base_models import InputFormat
-from docling.datamodel.document import DoclingDocument, InputDocument
+from docling.datamodel.document import (
+    ConversionResult,
+    DoclingDocument,
+    InputDocument,
+    SectionHeaderItem,
+)
+from docling.document_converter import DocumentConverter
 from tests.verify_utils import CONFID_PREC, COORD_PREC
 
 from .test_data_gen_flag import GEN_TEST_DATA
+from .verify_utils import verify_document, verify_export
+
+GENERATE = GEN_TEST_DATA
 
 
 def test_convert_valid():
@@ -54,3 +63,45 @@ def test_convert_valid():
             if in_path.stem in yaml_filter:
                 exp_doc = DoclingDocument.load_from_yaml(yaml_gt_path)
                 assert act_doc == exp_doc, f"export to yaml failed on {in_path}"
+
+
+def get_md_paths():
+    # Define the directory you want to search
+    directory = Path("./tests/groundtruth/docling_v2")
+
+    # List all MD files in the directory and its subdirectories
+    md_files = sorted(directory.rglob("*.md"))
+    return md_files
+
+
+def get_converter():
+    converter = DocumentConverter(allowed_formats=[InputFormat.MD])
+
+    return converter
+
+
+def test_e2e_md_conversions():
+    md_paths = get_md_paths()
+    converter = get_converter()
+
+    for md_path in md_paths:
+        # print(f"converting {md_path}")
+
+        with open(md_path) as fr:
+            true_md = fr.read()
+
+        conv_result: ConversionResult = converter.convert(md_path)
+
+        doc: DoclingDocument = conv_result.document
+
+        pred_md: str = doc.export_to_markdown()
+        assert true_md == pred_md
+
+        conv_result_: ConversionResult = converter.convert_string(
+            true_md, format=InputFormat.MD
+        )
+
+        doc_: DoclingDocument = conv_result_.document
+
+        pred_md_: str = doc_.export_to_markdown()
+        assert true_md == pred_md_