Best Practices for Using CodeIgniter as Frontend with an Expandable Multi‑Platform Backend

Best Practices for Using CodeIgniter as Frontend with an Expandable Multi‑Platform Backend

Short summary

Build your backend API‑first (stable, versioned REST or GraphQL) and treat CodeIgniter (CI) as one of many clients (server‑rendered web, SPA shell, proxy). Push business logic to the backend and keep CI thin so mobile, desktop, and third‑party clients can reuse the same API.

Principles

• API‑first: backend exposes a clear, well‑documented API that all clients consume.
• Keep frontend thin: CI handles rendering and UX logic; backend owns business rules and validation.
• Single source of truth: backend owns data and core business logic.
• Contract‑driven development: publish OpenAPI/GraphQL schemas and auto‑generate SDKs/tests where possible.
• Modular, layered architecture: separate controllers, services, repositories, DTOs, and models so components are replaceable and testable.

API design & contract

• Choose REST+JSON for simplicity or GraphQL if clients need tailored queries and fewer roundtrips.
• Provide an OpenAPI (Swagger) spec for REST APIs and human + machine readable docs.
• Design endpoints with pagination, filtering, sorting, and sparse fieldsets.
• Standardize error responses (HTTP status + structured JSON error body).
• Use consistent endpoint naming and consider HATEOAS or clear discoverability patterns.
• Define rate limits and return meaningful headers when limiting requests.

Authentication & authorization

• Prefer OAuth2 / OpenID Connect for multi‑platform scenarios:
  • Web server (CI): Authorization Code (server‑side) -> store session cookie (HttpOnly, Secure).
  • SPA: Authorization Code with PKCE or secure cookie + CSRF protection; store access token in memory, refresh via HttpOnly refresh cookie.
  • Mobile/Desktop (native): Authorization Code with PKCE; store refresh tokens in secure OS storage (Keychain / Keystore).
• Token handling:
  • Short‑lived access tokens, rotating refresh tokens, server‑side revocation.
  • Store refresh tokens only in secure storage (server session or device secure store).
• If CI acts as a proxy, keep tokens on server so browser never holds them.
• Implement RBAC/scopes and enforce auth checks in backend services.

CodeIgniter (frontend) best practices

• Use CodeIgniter 4 (CI4).
• Structure:
  • Controllers: thin — map requests to service calls.
  • Services / Libraries: encapsulate API client & business mapping.
  • Models/Entities: for CI‑side caching or view shaping only.
  • Filters: authentication/authorization middleware.
  • Helpers: small view helpers and formatters.
• Centralized API client wrapper:
  • Single place for HTTP client config, timeouts, retries, error mapping and logging.
• Environment configuration: keep backend URLs, keys, and timeouts in .env.
• View layer: layouts, partials, and reusable components.
• Asset pipeline: use a modern bundler (Vite/Webpack) and design tokens or a component library.
• Modular architecture (feature modules / HMVC) for large apps.

Multi‑platform considerations (mobile & desktop)

• Ensure the same API supports all clients with appropriate auth flows.
• Auth:
  • Native apps: Authorization Code + PKCE.
  • Desktop (Electron): treat as native or use PKCE.
• Offline & sync:
  • Provide timestamp or change log endpoints for sync.
  • Define conflict resolution strategy (last‑write‑wins, versioning, or CRDTs if needed).
• Push notifications:
  • Use APNs/FCM plus backend notification service.
• SDKs:
  • Publish small SDKs (JS / Kotlin / Swift) or auto‑generate from OpenAPI to accelerate clients.
• UI consistency:
  • Design tokens & component library guidance for web and native platforms.
• File uploads:
  • Use presigned URLs (S3) for direct uploads to reduce backend bandwidth and improve reliability on mobile.

Performance, caching & scalability

• CDN for static assets; edge caching where possible.
• Server caching: Redis for frequent GETs or session storage.
• Backend optimizations: paginated endpoints, bulk endpoints for batch operations.
• Background jobs & queues (Redis / RabbitMQ) for expensive tasks (email, thumbnails).
• Rate limiting and throttling per client with informative headers.
• Keep web servers stateless; sessions in Redis or DB for horizontal scale.
• Real‑time: use dedicated real‑time services (Pusher, Ably, or a separate WebSocket microservice).

Security & hardening

• HTTPS everywhere.
• Secure cookies: HttpOnly, Secure, appropriate SameSite.
• CSRF protection for browser flows; use CI’s CSRF features for forms and AJAX.
• Input validation & output encoding to prevent XSS and injection attacks.
• Parameterized queries and ORM protections for DB access.
• File upload protection: size limits, scanning, store outside webroot.
• Secrets management: avoid committing secrets; use vault/secret manager.
• Rate limit auth endpoints and monitor for abuse.
• Regular penetration tests and dependency vulnerability scanning.

Observability & ops

• Structured logging (JSON), redact sensitive fields.
• Distributed tracing (OpenTelemetry) for cross‑service visibility.
• Metrics: Prometheus + Grafana for latency, error rates and throughput.
• Error reporting: Sentry or equivalent.
• Health checks, readiness, and liveness endpoints.
• Define SLOs and incident runbooks.

Testing strategy

• Unit tests for CI services and utilities.
• Integration tests against a test backend or mocked API.
• Contract testing (e.g., Pact) to ensure client/backend compatibility.
• End‑to‑end tests for core flows (login, upload, purchase).
• Load testing for endpoints and storage flows.

Deployment & CI/CD

• Dockerize apps with multi‑stage builds.
• Automate CI pipeline (lint, tests, build, security scans) with GitHub Actions / GitLab CI.
• Blue/green or canary deployments for safe rollouts.
• Maintain staging environment that mirrors production.
• Use migration tools and feature flags for DB and schema changes.

Versioning & backward compatibility

• Version APIs (path or header): /v1/, /v2/ or header versioning.
• Publish deprecation policy and compatibility windows.
• Use feature flags to roll out breaking changes gradually.
• Maintain older client compatibility when business needs require it.

Files, uploads & large objects

• Use presigned URLs for direct uploads to object storage (S3).
• Validate uploads server‑side for content and size.
• Support chunked/ resumable uploads for mobile reliability.
• Virus scanning and moderation pipeline where applicable.

Roadmap / checklist (practical steps)

1. Make backend API‑first; create OpenAPI spec.
2. Build centralized CI API client wrapper (auth, retries, errors).
3. Implement authentication flows:
   • Server session for CI web
   • OAuth2 + PKCE for native apps
4. Implement CI Filters for auth and optional route group for proxying API calls.
5. Add caching (Redis), logging, and error monitoring.
6. Create automated tests and contract tests.
7. Publish SDKs or Postman/Swagger examples for mobile/desktop devs.
8. Add CI/CD pipeline and staging environment.
9. Produce developer docs and onboarding for client teams.

Quick recommended tech stack

• Backend: API‑first (Node / Go / PHP / Java) + OpenAPI
• API gateway: Kong / Traefik / Nginx (rate limiting)
• Auth: OAuth2 / OIDC (Auth0 / Keycloak / IdentityServer) or self‑hosted with PKCE support
• Cache / Queue: Redis, RabbitMQ
• Storage: S3‑compatible object store
• Observability: Prometheus, Grafana, ELK, Sentry
• CI/CD: GitHub Actions / GitLab CI
• Containers: Docker + Kubernetes for scale

Final notes

Focus first on a robust, versioned API and solid authentication design—these two choices greatly simplify multi‑platform expansion. Keep CodeIgniter as a client that consumes the API rather than owning business logic.