Document Classification Showcase Demo Code Sample

1/* side-by-side divs */
2.vertical-container {
3    display: inline-block;
4    vertical-align: top;
5}
6
7/* Button Styles */
8.btn {
9    background-color: #007bff;
10    margin: 0 10px;
11    padding: 5px 10px;
12    border: 1px solid #ccc;
13    border-radius: 4px;
14    cursor: pointer;
15    font-size: 14px;
16    transition: all 0.2s ease;
17    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
18    color: white;
19}
20
21.btn:hover {
22    background-color: #0056b3;
23    transform: translateY(-1px);
24    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
25}
26
27.btn:active {
28    transform: translateY(1px);
29    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.2);
30}
31
32.btn:disabled {
33    background-color: #ccc;
34    cursor: not-allowed;
35    box-shadow: none;
36}
37
38/* Layout Styles */
39.left-panel {
40    width: 40%;
41}
42
43.right-panel {
44    width: 60%; /* right div is wider to accommodate JSON data display */
45}
46
47.result-area {
48    width: 100%;
49    height: 150px;
50    white-space: pre-wrap;
51    font-family: 'Courier New', monospace;
52    font-size: 12px;
53    overflow: auto;
54    background-color: gray;
55    color: white;
56}
57
58/* Responsive Design */
59@media (max-width: 768px) {
60    .btn {
61        width: 100%;
62        margin: 5px 0;
63    }
64}
65

1const { PDFNet } = require('@pdftron/pdfnet-node');
2const path = require('path');
3const fs = require('fs');
4
5// **Important** 
6// You must get a license key from Apryse for the server to run. 
7// A trial key can be obtained from:
8// https://docs.apryse.com/core/guides/get-started/trial-key 
9const licenseKey = 'YOUR_SERVER_LICENSE_KEY';
10const multer = require('multer');
11const { response } = require('express');
12const upload = multer();
13const serverFolder = 'server';
14const sentDocuments = 'sentDocuments';
15const serverHandler = `/${serverFolder}/handler.js`;
16
17// Initialize PDFNet once when the module loads
18let isInitialized = false;
19let initializationError = null;
20
21async function initializeServer() {
22  try {
23    console.log('Initializing PDFNet Data Extraction module...');
24    
25    // Check if DataExtractionModule is available
26    if (!PDFNet.DataExtractionModule) {
27      throw new Error('DataExtractionModule not available');
28    }
29    
30    // Check if document classification is available
31    const isAvailable = await PDFNet.DataExtractionModule.isModuleAvailable(
32      PDFNet.DataExtractionModule.DataExtractionEngine.e_DocClassification);
33    if (!isAvailable) {
34      throw new Error('Document Classification module not available');
35    }
36    
37    isInitialized = true;
38  } catch (error) {
39    console.error('❌ Error initializing Data Extraction module:', error.message);
40    initializationError = error;
41  }
42}
43
44module.exports = async (app) => {
45
46  // Handle POST request sent to '/server/handler.js'
47  // This endpoint receives the currently loaded PDF file in the Apryse webviewer and sends
48  // its classification back to the client as JSON data
49  app.post(serverHandler, upload.any(), async (request, response) => {
50    try {
51      // Check if PDFNet is initialized
52      if (!isInitialized) {
53        return response.status(503).json({ 
54          error: 'Server not properly initialized', 
55          details: initializationError?.message 
56        });
57      }
58
59      if (!fs.existsSync(sentDocuments))
60        fs.mkdirSync(sentDocuments);
61      
62      const sentPdf = path.resolve(__dirname, `./${sentDocuments.split('/').pop()}/${request.query.filename}`);
63      fs.writeFileSync(sentPdf, request.files[0].buffer);
64      
65      response.header('Content-Type', 'application/json');
66      
67      const opts = new PDFNet.DataExtractionModule.DataExtractionOptions(); 
68      opts.setPages('1-2'); // process 2 pages
69      console.log(opts);
70      const json = await PDFNet.DataExtractionModule.extractDataAsString(
71        sentPdf, PDFNet.DataExtractionModule.DataExtractionEngine.e_DocClassification, opts);
72      
73      await fs.promises.unlink(sentPdf); // delete the document after processing
74      response.status(200).send(json);
75    } catch (e) {
76      console.error('Error processing document:', e);
77      response.status(500).json({ 
78        error: `Error extracting JSON text from PDF file ${request.query.filename}`,
79        details: e.message 
80      });
81    }
82  });
83};
84
85// Initialize PDFNet when module loads
86PDFNet.runWithoutCleanup(initializeServer, licenseKey).catch(error => {
87  console.error('❌ Fatal error initializing PDFNet:', error);
88  initializationError = error;
89});

1
2const express = require('express');
3const fs = require('fs');
4const bodyParser = require('body-parser');
5const open = (...args) => import('open').then(({ default: open }) => open(...args));
6const handler = require('./handler.js');
7const port = process.env.PORT || 5050;
8const app = express();
9const sentPdfs = 'sentPdfs';
10
11// CORS middleware to allow cross-origin requests from the playground
12app.use((req, res, next) => {
13  res.header('Access-Control-Allow-Origin', '*');
14  res.header('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE, OPTIONS');
15  res.header('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept, Authorization');
16  
17  // Handle preflight OPTIONS requests
18  if (req.method === 'OPTIONS') {
19    res.sendStatus(200);
20  } else {
21    next();
22  }
23});
24
25app.use(bodyParser.text());
26app.use('/client', express.static('../client')); // For statically serving 'client' folder at '/'
27
28handler(app);
29
30// Run server
31const server = app.listen(port, 'localhost', (err) => {
32  if (err) {
33    console.error(err);
34  } else {
35    console.info(`Server is listening at http://localhost:${port}`);
36    
37  }
38});
39
40// Server shutdown and cleanup
41function shutdown() {
42  console.log('Cleanup started...');
43
44  // Example: Close server
45  server.close(() => {
46    console.log('Server closed.');
47
48    // Removes sent PDFs folder
49    if (fs.existsSync(sentPdfs))
50      fs.rmdirSync(sentPdfs, { recursive: true });
51
52    // If no async cleanup, exit directly
53    process.exit(0);
54  });
55}
56
57// Handle shutdown signals
58process.on('SIGINT', shutdown);   // Ctrl+C
59process.on('SIGTERM', shutdown);  // kill command or Docker stop
60process.on('uncaughtException', (err) => {
61  console.error('Uncaught Exception:', err);
62  shutdown();
63});

1{
2  "name": "document-classification-server",
3  "version": "1.0.0",
4  "description": "Document Classification Demo Server Component",
5  "main": "server.js",
6  "scripts": {
7    "start": "node server.js",
8    "dev": "node server.js"
9  },
10  "dependencies": {
11    "@pdftron/data-extraction": "^11.8.0",
12    "@pdftron/pdfnet-node": "^11.8.0",
13    "body-parser": "^1.20.2",
14    "express": "^4.18.2",
15    "multer": "^1.4.4",
16    "open": "^9.1.0"
17  },
18  "keywords": [
19    "document-classification",
20    "pdf",
21    "server",
22    "pdftron",
23    "webviewer"
24  ],
25  "author": "Apryse",
26  "license": "MIT"
27}
28