[Backend] Fix SSE subscribe controller: deprecated substr, Zod error.errors, missing users param

[ogazboiz]

Telegram: https://t.me/+DOylgFv1jyJlNzM0

Why this matters

backend/src/controllers/sse.controller.ts has three small correctness/consistency issues:

1. clientId uses Math.random().toString(36).substr(2, 9) — String.prototype.substr is deprecated; use slice/substring.
2. The catch block returns error.errors for ZodErrors, but Zod's error object exposes .issues (.errors is an alias that is being phased out and is empty under newer Zod), so validation 400s may return an empty errors array.
3. subscribeSchema only parses streams and all, but the /v1/events/subscribe OpenAPI docs advertise a users query param — it is silently dropped here.

Acceptance criteria

• Replace substr with slice
• Use error.issues (and/or instanceof z.ZodError) when building the 400 body
• Either support users in subscribeSchema or remove it from the OpenAPI docs in routes/v1/events.routes.ts

Files to touch

• backend/src/controllers/sse.controller.ts
• backend/src/routes/v1/events.routes.ts (if dropping the documented users param)

Out of scope

• SSE broadcast/heartbeat logic.

[Senorespecial]

please assign this project to me i have experience in it and can deliver professionally

[martoniel]

@martoniel has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Good day Big Dev! Pls I would love to work on this issue carefully and make PR within 24hrs

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[wheval]

@wheval has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Hello i would love to work on this.

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[bigvictoh]

@bigvictoh has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

I would love to work on this issue and contribute to the project.

I’ve reviewed the details and feel confident that I can investigate and implement a solid solution for this.

If this issue is currently unassigned and open for external contributors, could you please assign it to me? I will get started on a fix right away and submit a Pull Request as soon as it's ready.

Please let me know if there are any specific guidelines or approaches you'd like me to follow for this particular task.

Thanks,

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