"""Utility functions for Google Docs tools."""
import io
import xml.etree.ElementTree as ET
import zipfile
from typing_extensions import List, Optional
from config.enhanced_logging import setup_logger
logger = setup_logger()
def extract_office_xml_text(file_bytes: bytes, mime_type: str) -> Optional[str]:
"""
Very light-weight XML scraper for Word, Excel, PowerPoint files.
Returns plain-text if something readable is found, else None.
No external deps – just std-lib zipfile + ElementTree.
"""
shared_strings: List[str] = []
ns_excel_main = "http://schemas.openxmlformats.org/spreadsheetml/2006/main"
try:
with zipfile.ZipFile(io.BytesIO(file_bytes)) as zf:
targets: List[str] = []
# Map MIME → iterable of XML files to inspect
if (
mime_type
== "application/vnd.openxmlformats-officedocument.wordprocessingml.document"
):
targets = ["word/document.xml"]
elif (
mime_type
== "application/vnd.openxmlformats-officedocument.presentationml.presentation"
):
targets = [n for n in zf.namelist() if n.startswith("ppt/slides/slide")]
elif (
mime_type
== "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
):
targets = [
n
for n in zf.namelist()
if n.startswith("xl/worksheets/sheet") and "drawing" not in n
]
# Attempt to parse sharedStrings.xml for Excel files
try:
shared_strings_xml = zf.read("xl/sharedStrings.xml")
shared_strings_root = ET.fromstring(shared_strings_xml)
for si_element in shared_strings_root.findall(
f"{{{ns_excel_main}}}si"
):
text_parts = []
# Find all <t> elements, simple or within <r> runs, and concatenate their text
for t_element in si_element.findall(f".//{{{ns_excel_main}}}t"):
if t_element.text:
text_parts.append(t_element.text)
shared_strings.append("".join(text_parts))
except KeyError:
logger.info(
"No sharedStrings.xml found in Excel file (this is optional)."
)
except ET.ParseError as e:
logger.error(f"Error parsing sharedStrings.xml: {e}")
except (
Exception
) as e: # Catch any other unexpected error during sharedStrings parsing
logger.error(
f"Unexpected error processing sharedStrings.xml: {e}",
exc_info=True,
)
else:
return None
pieces: List[str] = []
for member in targets:
try:
xml_content = zf.read(member)
xml_root = ET.fromstring(xml_content)
member_texts: List[str] = []
if (
mime_type
== "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
):
for cell_element in xml_root.findall(
f".//{{{ns_excel_main}}}c"
): # Find all <c> elements
value_element = cell_element.find(
f"{{{ns_excel_main}}}v"
) # Find <v> under <c>
# Skip if cell has no value element or value element has no text
if value_element is None or value_element.text is None:
continue
cell_type = cell_element.get("t")
if cell_type == "s": # Shared string
try:
ss_idx = int(value_element.text)
if 0 <= ss_idx < len(shared_strings):
member_texts.append(shared_strings[ss_idx])
else:
logger.warning(
f"Invalid shared string index {ss_idx} in {member}. Max index: {len(shared_strings)-1}"
)
except ValueError:
logger.warning(
f"Non-integer shared string index: '{value_element.text}' in {member}."
)
else: # Direct value (number, boolean, inline string if not 's')
member_texts.append(value_element.text)
else: # Word or PowerPoint
for elem in xml_root.iter():
# For Word: <w:t> where w is "http://schemas.openxmlformats.org/wordprocessingml/2006/main"
# For PowerPoint: <a:t> where a is "http://schemas.openxmlformats.org/drawingml/2006/main"
if (
elem.tag.endswith("}t") and elem.text
): # Check for any namespaced tag ending with 't'
cleaned_text = elem.text.strip()
if (
cleaned_text
): # Add only if there's non-whitespace text
member_texts.append(cleaned_text)
if member_texts:
pieces.append(
" ".join(member_texts)
) # Join texts from one member with spaces
except ET.ParseError as e:
logger.warning(
f"Could not parse XML in member '{member}' for {mime_type} file: {e}"
)
except Exception as e:
logger.error(
f"Error processing member '{member}' for {mime_type}: {e}",
exc_info=True,
)
# continue processing other members
if not pieces: # If no text was extracted at all
return None
# Join content from different members (sheets/slides) with double newlines for separation
text = "\n\n".join(pieces).strip()
return text or None # Ensure None is returned if text is empty after strip
except zipfile.BadZipFile:
logger.warning(f"File is not a valid ZIP archive (mime_type: {mime_type}).")
return None
except (
ET.ParseError
) as e: # Catch parsing errors at the top level if zipfile itself is XML-like
logger.error(f"XML parsing error at a high level for {mime_type}: {e}")
return None
except Exception as e:
logger.error(
f"Failed to extract office XML text for {mime_type}: {e}", exc_info=True
)
return None
