PdfDing

PdfDing is a lightweight, self‑hosted PDF management platform that combines viewing, editing, and organizational features into a single web service. From a developer standpoint, it is built as a Python/Django application with an emphasis on fast startup times and minimal external dependencies. The core logic resides in the pdfding Django project, which exposes a REST‑like API under /api/ for CRUD operations on PDFs, tags, annotations, and user accounts. The UI is a single‑page application rendered by Django templates and enhanced with Alpine.js, ensuring that most of the front‑end state is managed client‑side while still benefiting from Django’s robust authentication and CSRF protection.

• Backend: Python 3.10+, Django 4.x, Django‑Rest‑Framework for API endpoints. The application relies on the built‑in SQLite or PostgreSQL backends; however, all data models are database‑agnostic thanks to Django’s ORM.
• Storage: PDF files and user uploads are stored in a dedicated media directory (/home/nonroot/pdfding/media), while the SQLite or PostgreSQL database holds metadata, tags, and annotations.
• Containerization: The official Docker image (mrmn/pdfding) is a slim Python runtime with all dependencies baked in. It exposes port 8000 and accepts volume mounts for persistent storage, making it trivial to run in any container orchestrator.
• Deployment: In addition to Docker, a Helm chart is available for Kubernetes deployments, providing configurable resource limits and persistent volume claims out of the box. The chart also supports SSO via OIDC, which can be wired to any OpenID provider.

• PDF Rendering: Uses PDF.js (bundled with the static assets) for client‑side rendering, enabling fast navigation and annotation without server roundtrips.
• Annotation API: Exposes endpoints to create, read, update, and delete annotations (comments, highlights, drawings). Annotations are stored as JSON blobs linked to a PDF and can be exported in bulk.
• Tagging & Search: Multi‑level tags are stored as a many‑to‑many relation, and full‑text search is powered by PostgreSQL’s tsvector or SQLite’s FTS5, depending on the backend.
• Progress Tracking: The server calculates reading progress based on page positions stored in the user session, and exposes this via a lightweight endpoint consumed by the UI.
• Export & Sharing: PDFs can be shared via signed URLs or QR codes; the API supports optional access control headers, making it straightforward to integrate with external services.

• Self‑Hosting: No native OS dependencies beyond Python and a database; the Docker image is ready for production with minimal configuration.
• Scalability: While designed for small to medium workloads, the stateless nature of the API allows horizontal scaling behind a load balancer. PDF.js rendering is entirely client‑side, so server CPU usage remains low even under concurrent users.
• Persistence: Docker volumes or Kubernetes PVCs are required for both the media directory and the database. The Helm chart automatically creates these claims when storageClass is set.

• Webhooks: The project includes a pluggable webhook system that can notify external services on events such as PDF upload, annotation creation, or user login.
• Plugin Architecture: Developers can extend PdfDing by creating Django apps that hook into signals (post_save, pre_delete) and register new API endpoints.
• Customization: The UI theme is fully configurable via CSS variables; developers can override templates to inject custom components or integrate with other front‑end frameworks.

• Configuration: Environment variables (HOST_NAME, SECRET_KEY, OIDC settings) control most runtime behavior, making it straightforward to adapt the service for different environments.
• Documentation: The README provides a concise guide, while the source code is well‑structured and commented. API routes are auto‑documented by Django‑Rest‑Framework’s browsable interface, and the Helm chart includes a values.yaml with detailed explanations.
• Community: The project is actively maintained on GitHub, with a responsive issue tracker and continuous integration via GitHub Actions. The Docker Hub image receives regular updates, ensuring that security patches are propagated quickly.

• Enterprise Knowledge Base: A small company can host PdfDing to centralize policy documents, meeting minutes, and design PDFs, leveraging the tagging system for quick retrieval.
• Academic Research: Researchers can annotate papers, export highlights, and share annotated PDFs with collaborators via secure links.
• Compliance Audits: The audit trail of annotations and sharing events can be integrated with logging systems, satisfying regulatory requirements.
• Embedded Documentation: Developers can embed PdfDing in internal portals, using its API to pull PDFs into custom dashboards or workflow tools.

• Performance: Client‑side rendering with PDF.js keeps server load minimal, and the lightweight Django stack boots in seconds.
• Flexibility: The API-first design means PdfDing can be consumed by any language or framework, from a React SPA to a Go microservice.
• Licensing: Open‑source under the MIT license, allowing unrestricted use in commercial or proprietary projects.