Add text as html to orig elements chunks (#3779)

This simplest solution doesn't drop HTML from metadata when merging
Elements from HTML input. We still need to address how to handle nested
elements, and if we want to have `LayoutElements` in the metadata of
Composite Elements, a unit test showing the current behavior.
Note: metadata still contains `orig_elements` which has all the
metadata.

CHANGELOG.md

@@ -7,6 +7,7 @@
 ### Features
 
 ### Fixes
+- **ElementMetadata consolidation** Now `text_as_html` metadata is combined across all elements in CompositeElement when chunking HTML output
 
 ## 0.16.5
 

test_unstructured/chunking/test_html_output.py

@@ -0,0 +1,90 @@
+from functools import partial
+
+import pytest
+
+from unstructured.chunking.basic import chunk_elements
+from unstructured.chunking.title import chunk_by_title
+from unstructured.documents.elements import ElementMetadata, NarrativeText, Text, Title
+
+
+@pytest.fixture(params=[chunk_elements, partial(chunk_by_title, combine_text_under_n_chars=0)])
+def chunking_fn(request):
+    return request.param
+
+
+def test_combining_html_metadata_when_multiple_elements_in_composite_element(chunking_fn):
+    metadata_1 = '<h1 class="Title" id="1">Header </h1>'
+    metadata_2 = '<time class="CalendarDate" id="2">Date: October 30, 2023 </time>'
+    metadata_3 = (
+        '<form class="Form" id="3"> '
+        '<label class="FormField" for="company-name" id="4">Form field name </label>'
+        '<input class="FormFieldValue" id="5" value="Example value" />'
+        "</form>"
+    )
+    combined_metadata = " ".join([metadata_1, metadata_2, metadata_3])
+
+    elements = [
+        Title(text="Header", metadata=ElementMetadata(text_as_html=metadata_1)),
+        Text(text="Date: October 30, 2023", metadata=ElementMetadata(text_as_html=metadata_2)),
+        Text(
+            text="Form field name Example value", metadata=ElementMetadata(text_as_html=metadata_3)
+        ),
+    ]
+    chunks = chunking_fn(elements)
+    assert len(chunks) == 1
+    assert chunks[0].metadata.text_as_html == combined_metadata
+
+
+def test_combining_html_metadata_with_nested_relationship_between_elements(chunking_fn):
+    """
+    Ground truth
+    <Document>
+        <Page>
+            <Section>
+                <p>First</p>
+                <p>Second</p>
+            </Section>
+        </Page>
+    </Document>
+    Elements: Document, Page, Section, Paragraph, Paragraph
+    Chunk 1: Document, Page, Section, Paragraph
+
+    Chunk 2:
+        Paragraph
+    """
+
+    metadata_1 = '<div class="Section" id="1" />'
+    metadata_2 = '<p class="Paragraph" id="2">First </p>'
+    metadata_3 = '<p class="Paragraph" id="3">Second </p>'
+
+    elements = [
+        Text(text="", metadata=ElementMetadata(text_as_html=metadata_1)),
+        NarrativeText(
+            text="First", metadata=ElementMetadata(text_as_html=metadata_2, parent_id="1")
+        ),
+        NarrativeText(
+            text="Second", metadata=ElementMetadata(text_as_html=metadata_3, parent_id="1")
+        ),
+    ]
+    chunks = chunking_fn(elements, max_characters=6)
+    assert len(chunks) == 2
+    assert chunks[0].text == "First"
+    assert chunks[1].text == "Second"
+
+    assert chunks[0].metadata.text_as_html == metadata_1 + " " + metadata_2
+    assert chunks[1].metadata.text_as_html == metadata_3
+
+
+def test_html_metadata_exist_in_both_element_when_text_is_split(chunking_fn):
+    """Mimic behaviour of elements with non-html metadata"""
+    metadata_1 = '<h1 class="Title" id="1">Header </h1>'
+    elements = [
+        Title(text="Header", metadata=ElementMetadata(text_as_html=metadata_1)),
+    ]
+    chunks = chunking_fn(elements, max_characters=3)
+    assert len(chunks) == 2
+
+    assert chunks[0].text == "Hea"
+    assert chunks[1].text == "der"
+    assert chunks[0].metadata.text_as_html == '<h1 class="Title" id="1">Header </h1>'
+    assert chunks[1].metadata.text_as_html == '<h1 class="Title" id="1">Header </h1>'

unstructured/chunking/base.py

@@ -774,6 +774,8 @@ def iter_kwarg_pairs() -> Iterator[tuple[str, Any]]:
                     # -- Python 3.7+ maintains dict insertion order --
                     ordered_unique_keys = {key: None for val_list in values for key in val_list}
                     yield field_name, list(ordered_unique_keys.keys())
+                elif strategy is CS.STRING_CONCATENATE:
+                    yield field_name, " ".join(val.strip() for val in values)
                 elif strategy is CS.DROP:
                     continue
                 else:  # pragma: no cover

unstructured/documents/elements.py

@@ -458,6 +458,9 @@ class ConsolidationStrategy(enum.Enum):
     FIRST = "first"
     """Use the first value encountered, omit if not present in any elements."""
 
+    STRING_CONCATENATE = "string_concatenate"
+    """Combine the values of this field across elements. Only suitable for fields of `str` type."""
+
     LIST_CONCATENATE = "LIST_CONCATENATE"
     """Concatenate the list values across elements. Only suitable for fields of `List` type."""
 
@@ -507,7 +510,7 @@ def field_consolidation_strategies(cls) -> dict[str, ConsolidationStrategy]:
             "sent_to": cls.FIRST,
             "signature": cls.FIRST,
             "subject": cls.FIRST,
-            "text_as_html": cls.FIRST,  # -- only occurs in Table --
+            "text_as_html": cls.STRING_CONCATENATE,
             "table_as_cells": cls.FIRST,  # -- only occurs in Table --
             "url": cls.FIRST,
             "key_value_pairs": cls.DROP,  # -- only occurs in FormKeysValues --