Added HTML backend implementation, few improvements for other backends

Signed-off-by: Maxim Lysak <mly@zurich.ibm.com>

docling/backend/html_backend.py

@@ -1,26 +1,49 @@
+import logging
 from io import BytesIO
 from pathlib import Path
 from typing import Set, Union
 
+from bs4 import BeautifulSoup
 from docling_core.types.experimental import (
+    BasePictureData,
+    BaseTableData,
     DescriptionItem,
     DocItemLabel,
     DoclingDocument,
+    DocumentOrigin,
+    ImageRef,
+    PictureItem,
+    SectionHeaderItem,
+    TableCell,
+    TableItem,
 )
+from docling_core.types.experimental.labels import DocItemLabel, GroupLabel
 
 from docling.backend.abstract_backend import DeclarativeDocumentBackend
 from docling.datamodel.base_models import InputFormat
 
+_log = logging.getLogger(__name__)
+
 
 class HTMLDocumentBackend(DeclarativeDocumentBackend):
     def __init__(self, path_or_stream: Union[BytesIO, Path], document_hash: str):
         super().__init__(path_or_stream, document_hash)
+        self.soup = None
+        # HTML file:
+        self.path_or_stream = path_or_stream
+        # Initialise the parents for the hierarchy
+        self.max_levels = 10
+        self.level = 0
+        self.parents = {}
+        for i in range(0, self.max_levels):
+            self.parents[i] = None
+        self.labels = {}
 
     def is_valid(self) -> bool:
         return True
 
     def is_paginated(cls) -> bool:
-        False
+        return False
 
     def unload(self):
         if isinstance(self.path_or_stream, BytesIO):
@@ -33,8 +56,338 @@ class HTMLDocumentBackend(DeclarativeDocumentBackend):
         return {InputFormat.HTML}
 
     def convert(self) -> DoclingDocument:
-
         # access self.path_or_stream to load stuff
         doc = DoclingDocument(description=DescriptionItem(), name="dummy")
-        doc.add_text(text="I am a HTML document.", label=DocItemLabel.TEXT)
+
+        try:
+            with open(self.path_or_stream, "r", encoding="utf-8") as f:
+                html_content = f.read()
+                self.soup = BeautifulSoup(html_content, "html.parser")
+        except Exception as e:
+            _log.error("could not parse html: {}".format(e))
+            return doc
+
+        # Replace <br> tags with newline characters
+        for br in self.soup.body.find_all("br"):
+            br.replace_with("\n")
+        doc = self.walk(self.soup.body, doc)
+
         return doc
+
+    def walk(self, element, doc):
+        try:
+            # Iterate over elements in the body of the document
+            for idx, element in enumerate(element.children):
+                try:
+                    self.analyse_element(element, idx, doc)
+                except Exception as exc_child:
+                    _log.error(" -> error treating child: ", exc_child)
+                    _log.error(" => element: ", element, "\n")
+                    pass
+
+        except Exception as exc:
+            pass
+
+        return doc
+
+    def analyse_element(self, element, idx, doc):
+        """
+        if element.name!=None:
+            print("\t"*self.level, idx, "\t", f"{element.name} ({self.level})")
+        """
+
+        if element.name in self.labels:
+            self.labels[element.name] += 1
+        else:
+            self.labels[element.name] = 1
+
+        if element.name in ["h1", "h2", "h3", "h4", "h5", "h6"]:
+            self.handle_header(element, idx, doc)
+        elif element.name in ["p"]:
+            self.handle_paragraph(element, idx, doc)
+        elif element.name in ["ul", "ol"]:
+            self.handle_list(element, idx, doc)
+        elif element.name in ["li"]:
+            self.handle_listitem(element, idx, doc)
+        elif element.name == "table":
+            self.handle_table(element, idx, doc)
+        elif element.name == "figure":
+            self.handle_figure(element, idx, doc)
+        elif element.name == "img":
+            self.handle_image(element, idx, doc)
+        else:
+            self.walk(element, doc)
+
+    def get_direct_text(self, item):
+        """Get the direct text of the <li> element (ignoring nested lists)."""
+        text = item.find(string=True, recursive=False)
+
+        if isinstance(text, str):
+            return text.strip()
+
+        return ""
+
+    # Function to recursively extract text from all child nodes
+    def extract_text_recursively(self, item):
+        result = []
+
+        if isinstance(item, str):
+            return [item]
+
+        result.append(self.get_direct_text(item))
+
+        try:
+            # Iterate over the children (and their text and tails)
+            for child in item:
+                try:
+                    # Recursively get the child's text content
+                    result.extend(self.extract_text_recursively(child))
+                except:
+                    pass
+        except:
+            _log.warn("item has no children")
+            pass
+
+        return " ".join(result)
+
+    def handle_header(self, element, idx, doc):
+        """Handles header tags (h1, h2, etc.)."""
+        hlevel = int(element.name.replace("h", ""))
+        slevel = hlevel - 1
+
+        label = DocItemLabel.SECTION_HEADER
+        text = element.text.strip()
+
+        if hlevel == 1:
+            for key, val in self.parents.items():
+                self.parents[key] = None
+
+            self.level = 1
+            self.parents[self.level] = doc.add_text(
+                parent=self.parents[0], label=DocItemLabel.TITLE, text=text
+            )
+
+        elif hlevel == self.level:
+            self.parents[hlevel] = doc.add_text(
+                parent=self.parents[hlevel - 1], label=label, text=text
+            )
+
+        elif hlevel > self.level:
+
+            # add invisible group
+            for i in range(self.level + 1, hlevel):
+                self.parents[i] = doc.add_group(
+                    name=f"header-{i}",
+                    label=GroupLabel.SECTION,
+                    parent=self.parents[i - 1],
+                )
+
+            self.parents[hlevel] = doc.add_text(
+                parent=self.parents[hlevel - 1], label=label, text=text
+            )
+            self.level = hlevel
+
+        elif hlevel < self.level:
+
+            # remove the tail
+            for key, val in self.parents.items():
+                if key > hlevel:
+                    self.parents[key] = None
+
+            self.parents[hlevel] = doc.add_text(
+                parent=self.parents[hlevel - 1], label=label, text=text
+            )
+            self.level = hlevel
+
+    def handle_paragraph(self, element, idx, doc):
+        """Handles paragraph tags (p)."""
+        if element.text is None:
+            return
+        text = element.text.strip()
+        label = DocItemLabel.PARAGRAPH
+        if len(text) == 0:
+            return
+        doc.add_text(parent=self.parents[self.level], label=label, text=text)
+
+    def handle_list(self, element, idx, doc):
+        """Handles list tags (ul, ol) and their list items."""
+
+        # create a list group
+        self.parents[self.level + 1] = doc.add_group(
+            parent=self.parents[self.level], name="list", label=GroupLabel.LIST
+        )
+        self.level += 1
+
+        self.walk(element, doc)
+
+        self.parents[self.level + 1] = None
+        self.level -= 1
+
+    def handle_listitem(self, element, idx, doc):
+        """Handles listitem tags (li)."""
+        nested_lists = element.find(["ul", "ol"])
+        if nested_lists:
+            name = element.name
+            text = self.get_direct_text(element)
+
+            # create a list-item
+            self.parents[self.level + 1] = doc.add_text(
+                label=DocItemLabel.LIST_ITEM, text=text, parent=self.parents[self.level]
+            )
+            self.level += 1
+
+            self.walk(element, doc)
+
+            self.parents[self.level + 1] = None
+            self.level -= 1
+
+        elif isinstance(element.text, str):
+            text = element.text.strip()
+
+            doc.add_text(
+                label=DocItemLabel.LIST_ITEM, text=text, parent=self.parents[self.level]
+            )
+        else:
+            _log.warn("list-item has no text: ", element)
+
+    def handle_table(self, element, idx, doc):
+        """Handles table tags."""
+
+        nested_tables = element.find("table")
+        if nested_tables is not None:
+            _log.warn("detected nested tables: skipping for now")
+            return
+
+        # Count the number of rows (number of <tr> elements)
+        num_rows = len(element.find_all("tr"))
+
+        # Find the number of columns (taking into account colspan)
+        num_cols = 0
+        for row in element.find_all("tr"):
+            col_count = 0
+            for cell in row.find_all(["td", "th"]):
+                colspan = int(cell.get("colspan", 1))
+                col_count += colspan
+            num_cols = max(num_cols, col_count)
+
+        grid = [[None for _ in range(num_cols)] for _ in range(num_rows)]
+
+        data = BaseTableData(num_rows=num_rows, num_cols=num_cols, table_cells=[])
+
+        # Iterate over the rows in the table
+        for row_idx, row in enumerate(element.find_all("tr")):
+
+            # For each row, find all the column cells (both <td> and <th>)
+            cells = row.find_all(["td", "th"])
+
+            # Check if each cell in the row is a header -> means it is a column header
+            col_header = True
+            for j, html_cell in enumerate(cells):
+                if html_cell.name == "td":
+                    col_header = False
+
+            col_idx = 0
+            # Extract and print the text content of each cell
+            for _, html_cell in enumerate(cells):
+
+                text = html_cell.text
+                try:
+                    text = self.extract_table_cell_text(html_cell)
+                except Exception as exc:
+                    _log.warn("exception: ", exc)
+                    exit(-1)
+
+                # label = html_cell.name
+
+                col_span = int(html_cell.get("colspan", 1))
+                row_span = int(html_cell.get("rowspan", 1))
+
+                while grid[row_idx][col_idx] is not None:
+                    col_idx += 1
+                for r in range(row_span):
+                    for c in range(col_span):
+                        grid[row_idx + r][col_idx + c] = text
+
+                cell = TableCell(
+                    text=text,
+                    row_span=row_span,
+                    col_span=col_span,
+                    start_row_offset_idx=row_idx,
+                    end_row_offset_idx=row_idx + row_span,
+                    start_col_offset_idx=col_idx,
+                    end_col_offset_idx=col_idx + col_span,
+                    col_header=col_header,
+                    row_header=((not col_header) and html_cell.name == "th"),
+                )
+                data.table_cells.append(cell)
+
+        doc.add_table(data=data, parent=self.parents[self.level])
+
+    def get_list_text(list_element, level=0):
+        """Recursively extract text from <ul> or <ol> with proper indentation."""
+        result = []
+        bullet_char = "*"  # Default bullet character for unordered lists
+
+        if list_element.name == "ol":  # For ordered lists, use numbers
+            for i, li in enumerate(list_element.find_all("li", recursive=False), 1):
+                # Add numbering for ordered lists
+                result.append(f"{'    ' * level}{i}. {li.get_text(strip=True)}")
+                # Handle nested lists
+                nested_list = li.find(["ul", "ol"])
+                if nested_list:
+                    result.extend(get_list_text(nested_list, level + 1))
+        elif list_element.name == "ul":  # For unordered lists, use bullet points
+            for li in list_element.find_all("li", recursive=False):
+                # Add bullet points for unordered lists
+                result.append(
+                    f"{'    ' * level}{bullet_char} {li.get_text(strip=True)}"
+                )
+                # Handle nested lists
+                nested_list = li.find(["ul", "ol"])
+                if nested_list:
+                    result.extend(get_list_text(nested_list, level + 1))
+
+        return result
+
+    def extract_table_cell_text(self, cell):
+        """Extract text from a table cell, including lists with indents."""
+        contains_lists = cell.find(["ul", "ol"])
+        if contains_lists is None:
+            return cell.text
+        else:
+            _log.warn(
+                "should extract the content correctly for table-cells with lists ..."
+            )
+            return cell.text
+
+    def handle_figure(self, element, idx, doc):
+        """Handles image tags (img)."""
+
+        # Extract the image URI from the <img> tag
+        # image_uri = root.xpath('//figure//img/@src')[0]
+
+        contains_captions = element.find(["figcaption"])
+        if contains_captions is None:
+            doc.add_picture(
+                data=BasePictureData(), parent=self.parents[self.level], caption=None
+            )
+
+        else:
+            texts = []
+            for item in contains_captions:
+                texts.append(item.text)
+
+            fig_caption = doc.add_text(
+                label=DocItemLabel.CAPTION, text=("".join(texts)).strip()
+            )
+            doc.add_picture(
+                data=BasePictureData(),
+                parent=self.parents[self.level],
+                caption=fig_caption,
+            )
+
+    def handle_image(self, element, idx, doc):
+        """Handles image tags (img)."""
+        doc.add_picture(
+            data=BasePictureData(), parent=self.parents[self.level], caption=None
+        )

docling/backend/mspowerpoint_backend.py

@@ -43,7 +43,7 @@ class MsPowerpointDocumentBackend(DeclarativeDocumentBackend):
         return True
 
     def is_paginated(cls) -> bool:
-        False
+        return False  # True? if so, how to handle pages...
 
     def unload(self):
         if isinstance(self.path_or_stream, BytesIO):

docling/backend/msword_backend.py

@@ -55,7 +55,7 @@ class MsWordDocumentBackend(DeclarativeDocumentBackend):
         return True
 
     def is_paginated(cls) -> bool:
-        False
+        return False
 
     def unload(self):
         if isinstance(self.path_or_stream, BytesIO):
@@ -63,6 +63,24 @@ class MsWordDocumentBackend(DeclarativeDocumentBackend):
 
         self.path_or_stream = None
 
+    @classmethod
+    def supported_formats(cls) -> Set[InputFormat]:
+        return {InputFormat.DOCX}
+
+    def convert(self) -> DoclingDocument:
+        # Parses the DOCX into a structured document model.
+        doc = DoclingDocument(description=DescriptionItem(), name="dummy")
+        docx_obj = None
+        try:
+            docx_obj = docx.Document(self.path_or_stream)
+        except Exception:
+            _log.error("could not parse docx")
+            return doc
+
+        # self.initialise()
+        doc = self.walk_linear(docx_obj.element.body, docx_obj, doc)
+        return doc
+
     def update_history(self, name, level, numid, ilevel):
         self.history["names"].append(name)
         self.history["levels"].append(level)
@@ -89,24 +107,6 @@ class MsWordDocumentBackend(DeclarativeDocumentBackend):
                 return k
         return 0
 
-    @classmethod
-    def supported_formats(cls) -> Set[InputFormat]:
-        return {InputFormat.DOCX}
-
-    def convert(self) -> DoclingDocument:
-        # Parses the DOCX into a structured document model.
-        doc = DoclingDocument(description=DescriptionItem(), name="dummy")
-        docx_obj = None
-        try:
-            docx_obj = docx.Document(self.path_or_stream)
-        except Exception:
-            _log.error("could not parse docx")
-            return doc
-
-        # self.initialise()
-        doc = self.walk_linear(docx_obj.element.body, docx_obj, doc)
-        return doc
-
     def walk_linear(self, body, docx_obj, doc) -> DoclingDocument:
         for element in body:
             tag_name = etree.QName(element).localname