rust_imgapi/prompt.md

Copilot Prompt for Rust Image Manipulation API

You are working on a Rust API project built with:

• Axum 0.8.8
• SeaORM 1.1.20 with PostgreSQL
• Tokio full runtime
• tower-http trace

The project already has an account system. Do not redesign it unless asked.

Main Goal

Build an image manipulation API that:

• supports avif, png, jpg, jpeg, webp
• accepts width, height, format, quality, and crop
• supports crop modes like cover and other common crop strategies
• uses time-limited access tokens for protected image operations
• uses Redis for token validation and temporary access control

Important Constraints

• Use idiomatic Rust
• Follow Axum conventions
• Keep business logic in services
• Keep DB and Redis logic in repositories
• Use SeaORM for database access
• Validate all inputs
• Return structured JSON errors
• Do not panic in handlers
• Do not expose internal file paths or secrets

Implementation Guidance

When generating or modifying code:

1. Split code by module:

   • controller/handler
   • service
   • repository
   • dto
   • model
   • processor

2. For image processing:

   • decode input image
   • validate requested dimensions and format
   • apply crop/resize strategy
   • convert to requested output format
   • encode with requested quality
   • return the transformed image

3. For token access:

   • read token from request
   • verify token in Redis
   • reject expired/invalid tokens
   • proceed only if valid

4. For API design:

   • keep routes clean and versioned if needed
   • use consistent request/response shapes
   • add tracing/logging where useful

Default Behaviors

• default format: webp
• default crop: cover
• default quality: 80
• if only width or only height is provided, preserve aspect ratio when possible

Output Expectations

When asked to generate code:

• provide complete Rust code snippets
• include file names
• keep code ready to integrate
• minimize unnecessary abstractions
• match the existing codebase style

If there is ambiguity

Prefer:

• safe validation over permissive behavior
• explicit errors over silent fallback
• modular design over monolithic handlers
• Redis-backed token checks over in-memory shortcuts