/**
* Utility for extracting text from various document formats
* Using established libraries for better reliability
*/
// Using require for pdf-parse due to CommonJS module compatibility
const pdfParse = require('pdf-parse');
import * as mammoth from 'mammoth';
/**
* Extracts text from a PDF document using pdf-parse library
* @param data The PDF document as a Buffer
* @returns The extracted text content
*/
export async function extractTextFromPdf(data: ArrayBuffer): Promise<string> {
try {
// Convert ArrayBuffer to Buffer for pdf-parse
const buffer = Buffer.from(data);
// Parse the PDF
const result = await pdfParse(buffer);
// Get the text content
let extractedText = result.text || '';
// Clean up the text
extractedText = extractedText.replace(/\s+/g, ' ').trim();
if (!extractedText || extractedText.length < 50) {
return 'The document appears to be a PDF file, but no readable text content could be extracted. This might be due to the document structure, content format, or encryption. Please download the original document for full content.';
}
return extractedText;
} catch (error) {
console.error(`Error extracting text from PDF: ${(error as Error).message}`);
return 'Failed to extract text from the PDF document. This might be due to the document structure, content format, or encryption. Please download the original document for full content.';
}
}
/**
* Extracts text from a DOCX document using mammoth library
* @param data The DOCX document as an ArrayBuffer
* @returns The extracted text content
*/
export async function extractTextFromDocx(data: ArrayBuffer): Promise<string> {
try {
// Convert ArrayBuffer to Buffer for mammoth
const buffer = Buffer.from(data);
// Extract text from the DOCX
const result = await mammoth.extractRawText({ buffer });
// Get the text content
let extractedText = result.value || '';
// Clean up the text
extractedText = extractedText.replace(/\s+/g, ' ').trim();
if (!extractedText || extractedText.length < 50) {
return 'The document appears to be a Word file, but no readable text content could be extracted. This might be due to the document structure or content format. Please download the original document for full content.';
}
return extractedText;
} catch (error) {
console.error(`Error extracting text from DOCX: ${(error as Error).message}`);
return 'Failed to extract text from the DOCX document. This might be due to the document structure or content format. Please download the original document for full content.';
}
}
/**
* Summarizes the extracted text to a reasonable length
* @param text The full extracted text
* @param maxLength Maximum length of the summary (default: 8000 characters)
* @param offset Starting position for extraction (default: 0)
* @returns Object containing the summarized text and pagination info
*/
export function summarizeText(text: string, maxLength: number = 8000, offset: number = 0): {
text: string;
isTruncated: boolean;
totalLength: number;
currentOffset: number;
nextOffset: number | null;
remainingLength: number;
} {
const totalLength = text.length;
// Validate offset
if (offset >= totalLength) {
return {
text: 'No more content available. You have reached the end of the document.',
isTruncated: false,
totalLength,
currentOffset: offset,
nextOffset: null,
remainingLength: 0
};
}
// Extract the portion of text from offset to offset + maxLength
const endPosition = Math.min(offset + maxLength, totalLength);
const extractedText = text.substring(offset, endPosition);
const isTruncated = endPosition < totalLength;
// Calculate next offset and remaining length
const nextOffset = isTruncated ? endPosition : null;
const remainingLength = totalLength - endPosition;
return {
text: extractedText + (isTruncated ? '... [Text truncated due to length]' : ''),
isTruncated,
totalLength,
currentOffset: offset,
nextOffset,
remainingLength
};
}
