Add project likes backend endpoints

[raza-khan0108]

Summary

Adds backend support for “likes” on projects. Any authenticated user (JWT via existing Authorization: Bearer ... handling) can like/unlike a project, with a hard guarantee of one like per user per project.

What changed

Database

• Added project_likes table via backend/migrations/006_create_project_likes_table.sql
  • Columns: project_id (UUID), user_address (VARCHAR(42)), created_at (timestamptz)
  • Primary key: (project_id, user_address) to enforce one-like-per-user-per-project
  • Foreign key: project_id -> projects(id) with ON DELETE CASCADE
  • Indexes on project_id and user_address

Domain / Infrastructure

• New repository abstraction: ProjectLikeRepository
• New Postgres implementation: PostgresProjectLikeRepository

API

Routes added:

• POST /projects/:id/likes (protected)
  • Creates a like for the authenticated user
  • Returns 201 Created
  • Returns 409 Conflict if the like already exists
  • Returns 404 Not Found if the project doesn’t exist
• DELETE /projects/:id/likes (protected)
  • Removes the authenticated user’s like
  • Returns 204 No Content
  • Returns 404 Not Found if the like doesn’t exist (or project doesn’t exist)
• GET /projects/:id/likes?limit=&offset= (public)
  • Lists likes for a project (paginated)
  • Returns { project_id, total, likes: [{ user_address, created_at }, ...] }

Behavior / Constraints

• Idempotency:
  • POST is not idempotent: duplicate like attempts return 409
  • DELETE is not idempotent: deleting a non-existent like returns 404
• Project existence is validated for all three endpoints.
• User identity comes from the existing auth middleware (VerifiedWallet), including JWT support already implemented in the codebase.

Files of note

• Migration: backend/migrations/006_create_project_likes_table.sql
• API wiring: backend/src/presentation/api.rs
• Handlers: backend/src/presentation/handlers.rs
• DTOs: backend/src/application/dtos/like_dtos.rs
• Commands/Query:
  • backend/src/application/commands/create_project_like.rs
  • backend/src/application/commands/delete_project_like.rs
  • backend/src/application/queries/get_project_likes.rs
• Repository + Postgres implementation:
  • backend/src/domain/repositories/project_like_repository.rs
  • backend/src/infrastructure/repositories/postgres_project_like_repository.rs

Testing

• Added router-level API tests (no DB required):
  • backend/tests/project_likes_api_tests.rs validates the CRD flow and status codes.
• Updated existing Postgres integration tests to skip cleanly when Postgres is unavailable:
  • backend/tests/integration_github_handle.rs

Run:

• cd backend
• cargo test

Notes / Follow-ups

• If we later want “like count” returned on GET /projects/:id, we can extend get_project/project DTOs to include likes_total (and optionally liked_by_me when authenticated).

[joelamouche]

Hi @raza-khan0108 ,

First of all welcome to the project!

A few things...

• please first apply to issue before working on it: Add likes to the projects - backend #172
• this ticket is blocked by add projects to the frontend #174 being merged
• make sure CI passes before asking for a review

Best,

Antoine