@barric/next

barric firewall middleware for Next.js Route Handlers. Scans inbound prompts, sanitizes input before your handler runs, and scans outbound LLM responses.

Install

npm install @barric/core @barric/next

Quick Start

// app/api/chat/route.ts
import { createFirewall } from '@barric/core'
import { withBarric } from '@barric/next'

const firewall = createFirewall({
  rules: ['prompt-injection', 'pii-redaction'],
  injection: { threshold: 0.7, action: 'block' },
})

export const POST = withBarric(firewall)(async (req, sanitizedBody) => {
  const prompt = sanitizedBody.prompt as string
  // prompt is already sanitized — PII redacted, injection checked
  const result = await llm.complete(prompt)
  return Response.json({ reply: result })
})

How It Works

withBarric is a higher-order function that wraps your Route Handler:

1. Reads prompt or message from the request body
2. Runs inbound scanners (injection detection, PII redaction, encoding detection, rate limiting, input limits)
3. Your handler receives sanitizedBody with the sanitized string
4. Outbound scanners run on the response (system prompt leak detection, output limits, PII re-injection)
5. If any scanner triggers block, returns a 403 JSON response — your handler is never called

Automatic Context

The middleware extracts context from request headers:

| Header | Maps to | |--------|---------| | x-forwarded-for / x-real-ip | context.ip (used for rate limiting) | | x-session-id | context.sessionId |

Shared Firewall Instance

Define the firewall once and reuse across routes:

// lib/firewall.ts
import { createFirewall } from '@barric/core'

export const firewall = createFirewall({
  rules: ['prompt-injection', 'pii-redaction', 'rate-limit'],
  injection: { threshold: 0.7, action: 'block' },
  pii: { mode: 'redact', types: ['email', 'phone'] },
  rateLimit: { maxRequests: 20, windowMs: 60_000 },
})

// app/api/chat/route.ts
import { withBarric } from '@barric/next'
import { firewall } from '@/lib/firewall'

export const POST = withBarric(firewall)(async (req, sanitizedBody) => {
  // ...
})

Blocked Requests

When blocked, the middleware returns:

HTTP 403
{ "error": "Request blocked by barric firewall" }

License

MIT