GML-2086 add Excel and CSV extraction support with UI warning

[prinskumar-tigergraph]

Added the UI message in case of CSV/XLSX.
XLSX text extraction logic added in the text-extractor file.

[tg-pr-agent]

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⚡ Recommended focus areas for review Dropped formats TextExtractor.supported_extensions no longer includes .png and .gif, while other helper logic still treats image formats as supported. This mismatch can cause uploads that were previously accepted to be skipped or rejected in one path but still appear supported in another. self.supported_extensions = { '.txt': 'text/plain', '.md': 'text/markdown', '.pdf': 'application/pdf', '.docx': 'application/vnd.openxmlformats-officedocument.wordprocessingml.document', '.doc': 'application/msword', '.html': 'text/html', '.htm': 'text/html', '.json': 'application/json', '.csv': 'text/csv', '.xlsx': 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet', '.xls': 'application/vnd.ms-excel', '.xml': 'application/xml', '.jpeg': 'image/jpeg', '.jpg': 'image/jpeg', '.jsonl': 'application/x-jsonlines' Excel memory The Excel extraction path loads every sheet into pandas dataframes and converts them to markdown in memory. Large or multi-sheet spreadsheets may cause high memory usage, long processing times, or oversized extracted documents, so limits and behavior for large files should be validated. elif extension in ['.xlsx', '.xls']: import pandas as pd engine = 'openpyxl' if extension == '.xlsx' else 'xlrd' try: xl = pd.ExcelFile(file_path, engine=engine) except Exception: xl = pd.ExcelFile(file_path) sheet_texts = [] for sheet_name in xl.sheet_names: df = xl.parse(sheet_name) if df.empty: continue df = df.fillna('') sheet_md = df.to_markdown(index=False) sheet_texts.append(f"## Sheet: {sheet_name}\n\n{sheet_md}") return "\n\n".join(sheet_texts) if sheet_texts else "[Excel file is empty or contains no data]" CSV encoding CSV files are still read strictly as UTF-8 text. Real-world spreadsheets exported as CSV often use other encodings, so this path may fail for valid uploads even though spreadsheet support was expanded. elif extension in ['.html', '.htm', '.csv']: with open(file_path, 'r', encoding='utf-8') as f: return f.read().strip()