Improve Type Safety in public.ts and Remove Remaining `any` Usage

[Harxhit]

Summary

Improve type safety in public.ts by removing remaining usages of any and replacing them with proper Fastify, TypeScript, and application-specific types.

Contexts

The public routes currently contain several usages of any that bypass TypeScript's type checking and reduce maintainability.

Examples include:

(cl: any)

(request.query as any).format

(request.query as any).size

Some of these usages are related to query parameter handling, response mapping, and route typing. Existing Fastify and application-specific types should be reused where available instead of introducing duplicate definitions.

Removing these usages will improve maintainability, reduce unsafe casts, and make future refactoring easier.

Tasks

• Identify all remaining any usages in public.ts
• Replace (request.query as any) with properly typed query parameters
• Replace callback parameter typings such as (cl: any) with appropriate types
• Reuse existing Fastify and application-specific types where available
• Improve route and response typing where applicable
• Verify TypeScript passes without introducing new type errors
• Update tests if required

Acceptance Criteria

• No any usages remain in public.ts
• Query parameters are properly typed
• Response mapping uses appropriate TypeScript types
• Existing shared types are reused where applicable
• TypeScript checks pass successfully
• Existing public route functionality continues to work
• Tests pass successfully

Area

backend

Difficulty

Good First Issue

[github-actions]

Hi @Harxhit,

Thanks for opening this issue.

Please reply with one of the following areas so the issue can be routed to the appropriate team member:

- /backend
- /web
- /mobile
- /devops

Once an area is selected, the corresponding label will be added automatically.

[Harxhit]

/backend

[github-actions]

The issue has been classified as backend.

@Harxhit, please review and triage this issue when available.

The backend label has been applied and the issue has been routed accordingly.

[Satvik-art-creator]

@Harxhit I would like to work on this..

[hariom888]

Looked through routes/public.ts — only 3 any usages, all isolated and straightforward

1. Line 93: card.cardLinks.map((cl: any) => ({...})) — card comes from publicService.getCardById(), which has an inferred return type from Prisma's include. The any here is purely because getCardById's return type isn't exported/named, so the .map callback param falls back to any.
2. Lines 190 & 195: (request.query as any).format / (request.query as any).size — the route's generic is already correctly declared as FastifyRequest<{ Params: { username: string }; Querystring: { format?: string; size?: string } }>, so request.query is already properly typed as { format?: string; size?: string }. These two as any casts are redundant and can simply be deleted — request.query.format and request.query.size already typecheck.

Proposed fix approach:

• For line 93: export a proper return type from publicService.ts for getCardById (e.g. define a CardWithLinks type matching the Prisma include shape, similar to how cardService.ts defines RawCard/CardResponse), then type the cardLinks array element explicitly — (cl: CardLinkWithPlatform) => ({...}) — instead of any. This avoids duplicating Prisma's generated types by reusing the Prisma.CardGetPayload<{include: ...}> pattern already used elsewhere in the codebase (e.g. cardService.ts's RawCard).
• For lines 190/195: drop the as any casts entirely — request.query.format and request.query.size are already typed via the route generic.

Affected files: apps/backend/src/routes/public.ts, apps/backend/src/services/publicService.ts (adding the named return type for getCardById).

Test considerations: Pure typing change, no runtime behavior difference expected. tsc --noEmit should pass with zero new errors. Existing __tests__/public.test.ts should pass unchanged — confirm both the /card/:cardId response shape and the QR /qr/:username?format=&size= query handling still behave identically (size bounds validation, format default to 'png').

I'd like to take this one under GSSoC'26.

[Harxhit]

@Satvik-art-creator I have assigned this issue to you.