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Platform Details

For the full feature list, see Current Features.

File Types & Upload​

Supported Formats (Platform-Wide)​

The same file types are supported everywhere: backend upload/calculate-cost, frontend customer dashboard, customer Flutter app, and shopkeeper app (including print conversion).

TypeExtensionsNotes
PDF.pdfPassthrough; no conversion
Images.png, .jpg, .jpegConverted to single-page PDF (fit to paper) when printing
Word.doc, .docxConverted to PDF via LibreOffice (shopkeeper Windows)
PowerPoint.ppt, .pptxConverted to PDF via LibreOffice (shopkeeper Windows)
  • Max 20MB per file, 100MB total per upload batch.
  • Other formats are rejected with a clear “Supported: PDF, images (PNG/JPG/JPEG), Word (DOC/DOCX), PowerPoint (PPT/PPTX)” message.

Converter Engine (Shopkeeper Windows)​

The shopkeeper Windows app uses a converter engine to turn non-PDF files into PDF before printing:

  • PDF → passthrough
  • Images → image→PDF (fit to paper, preserve aspect ratio)
  • Word / PPT → LibreOffice headless→PDF (optional; requires LibreOffice portable)

See Windows Printing for setup and details.

Payment System​

Flow​

  1. Customer uploads file → calculates cost
  2. Customer creates payment order → Razorpay order created
  3. Customer pays via Razorpay → webhook updates status
  4. File becomes available for printing
  5. Shopkeeper receives payout (for queue prints)

Commission Calculation​

platformCommission := amount * commissionRate  // e.g., 10%
shopkeeperAmount := amount - platformCommission

File Storage​

Local Storage (Default)​

  • Files stored in backend/uploads/
  • File paths: uploads/{unique_code}_{filename}

S3 Storage (Production)​

  • Set AWS_S3_BUCKET, AWS_REGION, AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY
  • File paths: s3://bucket-name/{unique_code}_{filename}

Switching​

  • Set USE_LOCAL_STORAGE=true to force local
  • Remove USE_LOCAL_STORAGE and set AWS vars for S3

Email Service​

  • Works on free tier hosting (Render, etc.)
  • Set RESEND_API_KEY
  • No SMTP ports needed

SMTP (Alternative)​

  • Set SMTP_HOST, SMTP_PORT, SMTP_USER, SMTP_PASSWORD
  • Requires open SMTP ports (not available on free tier)

Queue System​

Queue Print Flow​

  1. Customer selects shopkeeper
  2. Uploads file → added to shop queue
  3. Shopkeeper sees file in queue with position
  4. Shopkeeper prints → status updates
  5. Customer sees status update

Queue Position​

  • Calculated based on existing queue size
  • Updates when files are processed

Location Services​

Distance Calculation​

  • Uses Euclidean distance (can be enhanced with Haversine)
  • Shopkeepers sorted by distance
  • Requires lat and long for shopkeepers

Windows Printing (Shopkeeper App)​

On Windows, the shopkeeper app prints silently (no dialogs) using SumatraPDF CLI with advanced features:

  1. File → Converter by extension → PDF (passthrough or convert)
  2. Printer availability check → Validates printer before sending
  3. SumatraPDF CLI → printer with options (copies, duplex, color, paper size)
  4. Print verification → Monitors job status via WMI until completion
  5. Backend confirmation → Only confirms after successful verification

Key Features​

  • SumatraPDF (required): used to send PDFs to the printer. Setup via scripts/setup_sumatra.ps1 or build_windows.bat.
  • LibreOffice (optional): used for Word/PPT→PDF conversion. Setup via scripts/setup_libreoffice.ps1 or build_windows.bat. If missing, only PDF and image printing work.
  • Print Queue System: Non-blocking queue allows multiple prints, per-job printer selection, real-time status updates
  • Printer Verification: WMI-based status checking ensures prints complete before confirming
  • Optimized Loading: Cached printer lists, lazy loading, timeout protection for better performance

Build: Run build_windows.bat from shopkeeper_app for a clean build with SumatraPDF (and optional LibreOffice) setup, then flutter run -d windows --release.

Full details, troubleshooting, and manual install steps: Windows Printing.

Admin System​

Creating Admin User​

cd backend
go run cmd/create_admin/main.go

Admin Features​

  • User management — View users, user details, delete accounts
  • Order tracking — View all payment orders
  • Payout management — Single/bulk update status, export payouts
  • Manage payments — Per-shop payout history, mark as paid
  • App download links — Set Windows (shopkeeper), Android (customer), iOS (customer) download URLs and "coming soon" flags; shown on the public Download Apps page (/download-apps). Available in main frontend (/admin/downloads) and admin frontend (/downloads)
  • Dashboard statistics — Platform analytics

Shop Auto-Close (Sweeper)​

The backend runs a background sweeper that auto-closes shop status when both app heartbeat and web activity are stale. Configurable via SHOP_APP_HEARTBEAT_TIMEOUT_MINUTES (default 12) and SHOP_WEB_ACTIVITY_TIMEOUT_MINUTES (default 25). Shopkeeper app sends POST /shop/heartbeat; web dashboard sends X-Platform: web (tracked by ShopkeeperActivity middleware).

GDPR — Delete Data Page​

Public GET /delete-data (and frontend /delete-data) provides a page for the Google Play "Delete data" link requirement: explains how users can delete their data (login and use Delete Account, or contact support).