Step-by-step guide for downloading West Bengal electoral roll PDFs from India's ECI portal (voters.eci.gov.in) and the CEO West Bengal historical portal — including CAPTCHA handling, XHR interception to capture the base64 PDF payload, and Bengali OCR for finding names in scanned rolls.

sir-eci-electoral-roll-download.md

Download India ECI Electoral Roll PDFs (West Bengal)

Portals

Year	URL
2025 (recent rolls)	https://voters.eci.gov.in/download-eroll
2002 (historical WB)	https://ceowestbengal.wb.gov.in/Roll_ps/`<AC_NUMBER>`

---

2025 Roll — voters.eci.gov.in

Form Fields (fill in this order)

1. State → West Bengal (code S25)
2. Year of Revision → e.g. 2025
3. Roll Type → Final Roll 2025
4. District → e.g. DARJEELING
5. Assembly Constituency → e.g. 25 - Matigara-Naxalbari
6. Language → BENGALI

Part Selection

• Use the Search box to filter by part number (e.g. 259)
• Check the checkbox next to the matching part
• ⚠️ The checkbox unchecks itself after every CAPTCHA attempt — always re-check it before clicking Download

CAPTCHA Tips

• Always zoom in on the CAPTCHA image before reading it
• Click the ↻ refresh icon to get a new CAPTCHA if unsure
• A 400 response = wrong CAPTCHA
• A 200 response = accepted ✓

How the Download Actually Works (API Flow)

1. POST → gateway-voters.eci.gov.in/api/v1/printing-publish/generate-published-pdfs
         ← { "payload": ["<fileId>"], "status": "Success" }

2. XHR GET → gateway-vpd.eci.gov.in/api/v1/ext-printing-publish/get-published-file?fileId=<fileId>
            ← { "payload": "<base64 PDF>", "refId": "<filename>.pdf" }

⚠️ The fileId expires very quickly — capture the XHR response immediately after clicking Download. The two gateways are different: gateway-voters for POST, gateway-vpd for GET.

Step 1 — Set Up XHR Interceptor (run BEFORE clicking Download)

window._fullPdfPayload = null;
window._fullPdfFilename = null;

const origOpen = XMLHttpRequest.prototype.open;
const origSend = XMLHttpRequest.prototype.send;

XMLHttpRequest.prototype.open = function(m, url, ...r) {
  this._url2 = url;
  return origOpen.apply(this, [m, url, ...r]);
};

XMLHttpRequest.prototype.send = function(b) {
  if ((this._url2 || '').includes('get-published-file')) {
    this.addEventListener('load', function() {
      const data = JSON.parse(this.responseText);
      if (data.payload && data.payload.length > 100) {
        window._fullPdfPayload = data.payload;
        window._fullPdfFilename = data.refId || 'voter_roll.pdf';
      }
    });
  }
  return origSend.apply(this, [b]);
};

Step 2 — Trigger the Save (run after ~5s)

const bytes = new Uint8Array(atob(window._fullPdfPayload).split('').map(c => c.charCodeAt(0)));
const blob = new Blob([bytes], { type: 'application/pdf' });
const a = document.createElement('a');
a.href = URL.createObjectURL(blob);
a.download = window._fullPdfFilename;
document.body.appendChild(a);
a.click();
document.body.removeChild(a);

---

2002 Roll — ceowestbengal.wb.gov.in

Navigation

1. Go to https://ceowestbengal.wb.gov.in/Roll_ps/<AC_NUMBER> (e.g. /Roll_ps/25 for AC 25)
2. Find the Part row and click the Final Roll link
3. Solve the CAPTCHA in the dialog that appears

Step 1 — Intercept window.open (run BEFORE solving CAPTCHA)

window.open = function(url) {
  window._capturedPdfUrl = url;
  return null;
};

Step 2 — Fetch and Save

fetch(window._capturedPdfUrl, { credentials: 'include' })
  .then(r => r.blob())
  .then(blob => {
    const a = document.createElement('a');
    a.href = URL.createObjectURL(blob);
    a.download = '2002_WB_AC025_Part042.pdf';
    document.body.appendChild(a);
    a.click();
  });

---

Decoding the 2025 PDF Filename

2025-EROLLGEN-S25-25-FinalRoll-Revision1-BEN-259-WI.pdf
                │   │                        │
                │   │                        └─ Part number (259 = North Bengal University Primary School)
                │   └─ Assembly Constituency number (25 = Matigara-Naxalbari)
                └─ State code (S25 = West Bengal)

Segment	Meaning
S25	West Bengal state code
25	Assembly Constituency number
FinalRoll	Roll type
BEN	Bengali language
259	Part number
WI	Women Inclusive / Ward Index suffix

---

Finding Names in Downloaded PDFs (Bengali OCR)

Both PDFs are scanned images — pdfplumber and PyPDF2 won't work. Use EasyOCR with the Bengali model.

import fitz
import easyocr
import numpy as np

reader = easyocr.Reader(['bn'], gpu=False)
doc = fitz.open("voter_roll.pdf")

for i, page in enumerate(doc):
    # Render at 3x zoom for better OCR accuracy
    pix = page.get_pixmap(matrix=fitz.Matrix(3, 3))
    img = np.frombuffer(pix.samples, dtype=np.uint8).reshape(pix.h, pix.w, pix.n)
    results = reader.readtext(img, detail=0)
    for text in results:
        if "নন্দ" in text or "আশীষ" in text or "সৌরদীপ" in text:
            print(f"Page {i+1}: {text}")

⚠️ The 2002 PDF uses a non-Unicode legacy Bengali font — the text layer is garbage. OCR is the only reliable method for both PDFs.

---

AC / Part Number Reference (Darjeeling District)

AC No.	Name	Notes
23	Darjeeling
24	Kurseong
25	Matigara-Naxalbari	North Bengal University area
26	Siliguri	Called "Siliguri" in 2002 rolls
27	Phansidewa

Part 259 of AC 25 = North Bengal University Primary School Part 42 of AC 25 = same area in the 2002 roll