server.js

'use strict';

const express = require('express');
const path = require('path');
const fileUpload = require('express-fileupload');
const pdf = require('pdf-parse');
const mammoth = require('mammoth');
const fetch = require('node-fetch');
const articleExtractor = require('article-parser').extract;
const contentExtractor = require('node-article-extractor');
const summarizeText = require('./summarizer');

const app = express();

app.use(express.static(path.join(__dirname, 'public')));
app.use(fileUpload());
app.use(express.json());

app.post('/document', extractText, (req, res) => {
    const text = res.locals.text;
    try {
        const summary = summarizeText(text);
        res.status(200).json({
            summary,
        });
    } catch (error) {
        res.status(500).json({
            message: 'Something went wrong',
        });
    }
});

app.post('/article', extractArticle, (req, res) => {
    const data = res.locals.data;
    try {
        const summary = summarizeText(data.text);
        data.text = summary;
        data.type = 'article';
        res.status(200).json(data);
    } catch (error) {
        res.status(500).json({
            message: 'Something went wrong',
        });
    }
});

app.post('/text', (req, res) => {
    try {
        const text = req.body.payload;
        const summary = summarizeText(text);
        res.status(200).json({
            summary,
            type: 'text',
        });
    } catch (error) {
        res.status(500).json({
            message: 'Something went wrong',
        });
    }
});

async function extractText(req, res, next) {
    if (!req.files)
        return res.status(400).json({
            message: 'Please select a document to summarize',
        });

    const document = req.files.document;

    const extractExtension = () => {
        const startIndex = document.name.lastIndexOf('.') + 1;
        const extension = document.name.substring(startIndex);
        return extension;
    };

    try {
        if (document.mimetype === 'text/plain')
            res.locals.text = document.data.toString('UTF-8');
        else if (document.mimetype === 'application/pdf') {
            const data = await pdf(document.data);
            res.locals.text = data.text;
        } else if (['doc', 'docx'].includes(extractExtension())) {
            const data = await mammoth.extractRawText({
                buffer: document.data,
            });
            res.locals.text = data.value;
        } else
            return res.status(400).json({
                message:
                    'Incorrect document type, only PDF, DOC, DOCX and TXT document types are supported',
            });
    } catch (error) {
        return res.status(500).json({
            message: 'Something went wrong',
        });
    }

    next();
}

async function extractArticle(req, res, next) {
    try {
        const URL = req.body.payload;
        const response = await fetch(URL);
        const markup = await response.text();
        const article = await articleExtractor(URL);
        const content = contentExtractor(markup);

        res.locals.data = {
            title: article.title,
            description: article.description,
            author: article.author,
            source: article.source,
            published: article.published,
            text: content.text,
        };

        next();
    } catch (error) {
        res.status(500).json({
            message: 'Something went wrong',
        });
    }
}

app.use((req, res) => {
    res.sendFile(path.join(__dirname, 'public', '404.html'));
});

const PORT = process.env.PORT || 3000;
app.listen(PORT, () => console.log(`Server Listening on Port ${PORT}`));