aegis-rag-engine / pdf_processor.py
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Initial commit of Aegis RAG Engine
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import os
import re
from typing import List, Dict, Any
from pypdf import PdfReader
def extract_text_from_pdf(pdf_path: str) -> List[Dict[str, Any]]:
"""
Extracts text from a PDF file page by page.
"""
if not os.path.exists(pdf_path):
raise FileNotFoundError(f"PDF file not found at: {pdf_path}")
pages_data = []
try:
reader = PdfReader(pdf_path)
num_pages = len(reader.pages)
if num_pages == 0:
raise ValueError(f"The PDF file '{pdf_path}' has 0 pages or could not be read.")
for i in range(num_pages):
page = reader.pages[i]
text = page.extract_text()
if text:
cleaned_text = re.sub(r'\s+', ' ', text).strip()
if cleaned_text:
pages_data.append({
"page_num": i + 1,
"text": cleaned_text
})
except Exception as e:
if isinstance(e, ValueError) or isinstance(e, FileNotFoundError):
raise e
raise Exception(f"Failed to read PDF file '{pdf_path}': {str(e)}")
if not pages_data:
raise ValueError(f"No readable text could be extracted from PDF file '{pdf_path}'.")
return pages_data
def extract_text_from_docx(docx_path: str) -> List[Dict[str, Any]]:
"""
Extracts text from a Word DOCX file paragraph by paragraph.
"""
if not os.path.exists(docx_path):
raise FileNotFoundError(f"DOCX file not found at: {docx_path}")
try:
import docx
except ImportError:
raise ImportError("The 'python-docx' library is required to parse DOCX files. "
"Please install it using 'pip install python-docx'.")
try:
doc = docx.Document(docx_path)
paragraphs_text = []
for para in doc.paragraphs:
clean_p = para.text.strip()
if clean_p:
paragraphs_text.append(clean_p)
# Merge paragraphs with double newlines
full_text = "\n\n".join(paragraphs_text)
if not full_text.strip():
raise ValueError(f"The DOCX file '{docx_path}' has no readable text content.")
return [{
# DOCX does not have native easy page-numbering without layout parsing,
# so we treat it as page_num = 1
"page_num": 1,
"text": full_text
}]
except Exception as e:
if isinstance(e, ValueError) or isinstance(e, FileNotFoundError) or isinstance(e, ImportError):
raise e
raise Exception(f"Failed to read DOCX file '{docx_path}': {str(e)}")
def extract_text_from_txt(txt_path: str) -> List[Dict[str, Any]]:
"""
Extracts text from a plain TXT file.
"""
if not os.path.exists(txt_path):
raise FileNotFoundError(f"TXT file not found at: {txt_path}")
try:
with open(txt_path, 'r', encoding='utf-8', errors='ignore') as f:
text = f.read()
cleaned_text = text.strip()
if not cleaned_text:
raise ValueError(f"The TXT file '{txt_path}' is empty.")
return [{
"page_num": 1,
"text": cleaned_text
}]
except Exception as e:
if isinstance(e, ValueError) or isinstance(e, FileNotFoundError):
raise e
raise Exception(f"Failed to read TXT file '{txt_path}': {str(e)}")
def extract_text_from_file(file_path: str) -> List[Dict[str, Any]]:
"""
Dispatcher to extract text from a file based on its file extension.
"""
ext = os.path.splitext(file_path)[1].lower()
if ext == '.pdf':
return extract_text_from_pdf(file_path)
elif ext == '.docx':
return extract_text_from_docx(file_path)
elif ext in ('.txt', '.md', '.py', '.json', '.env', '.csv'):
return extract_text_from_txt(file_path)
else:
raise ValueError(f"Unsupported file type '{ext}'. Supported types: .pdf, .docx, .txt (and code files like .md, .py)")
def chunk_text(pages_data: List[Dict[str, Any]], chunk_size: int, chunk_overlap: int, source_name: str) -> List[Dict[str, Any]]:
"""
Splits page/document texts into chunks using a character-based sliding window with overlap.
Args:
pages_data: List of dictionaries with 'page_num' and 'text'.
chunk_size: Target size of each chunk in characters.
chunk_overlap: Overlap between consecutive chunks in characters.
source_name: Base name of the source file.
Returns:
List of chunks with source metadata.
"""
if chunk_size <= 0:
raise ValueError("chunk_size must be a positive integer.")
if chunk_overlap < 0:
raise ValueError("chunk_overlap must be non-negative.")
if chunk_overlap >= chunk_size:
raise ValueError("chunk_overlap must be strictly less than chunk_size.")
chunks = []
global_chunk_idx = 1
for page in pages_data:
text = page["text"]
page_num = page["page_num"]
if len(text) <= chunk_size:
chunks.append({
"text": text,
"page_num": page_num,
"chunk_index": global_chunk_idx,
"source_name": source_name
})
global_chunk_idx += 1
continue
start = 0
while start < len(text):
end = start + chunk_size
if end >= len(text):
chunk_text_slice = text[start:]
chunks.append({
"text": chunk_text_slice.strip(),
"page_num": page_num,
"chunk_index": global_chunk_idx,
"source_name": source_name
})
global_chunk_idx += 1
break
search_limit = min(chunk_overlap, 50)
split_at = end
for offset in range(search_limit):
if text[end - offset].isspace():
split_at = end - offset
break
chunk_text_slice = text[start:split_at].strip()
if chunk_text_slice:
chunks.append({
"text": chunk_text_slice,
"page_num": page_num,
"chunk_index": global_chunk_idx,
"source_name": source_name
})
global_chunk_idx += 1
next_start = split_at - chunk_overlap
if next_start <= start:
start = split_at
else:
start = next_start
return chunks