share-link

What this skill does

# Share Link

Token-based public sharing system that lets authenticated users generate shareable URLs for private content. Tokens are URL-safe, 12 characters, and support optional expiry and view-count limits. Revocation sets a `revokedAt` timestamp so history is preserved.

## Prerequisites

- Next.js app with App Router (no `src/` directory)
- `@/lib/auth` exporting `auth` (better-auth)
- `@/db` exporting `db` (Drizzle + Postgres)
- `db/schema/index.ts` exporting all schema tables
- `NEXT_PUBLIC_APP_URL` set in environment

## Installation

No new packages required. Uses Node.js built-in `crypto`.

## What Gets Created

```
app/
└── api/
    └── share/
        ├── route.ts            POST create link, GET list my links
        └── [token]/
            └── route.ts        GET public access, DELETE revoke
db/
└── schema/
    └── shared-links.ts
lib/
└── share-link/
    └── index.ts
```

## Setup Steps

### Step 1: Create `db/schema/shared-links.ts`

```typescript
import { integer, jsonb, pgTable, text, timestamp, uuid } from "drizzle-orm/pg-core"

export const sharedLinks = pgTable("shared_links", {
  id: uuid("id").primaryKey().defaultRandom(),
  userId: text("user_id").notNull(),
  token: text("token").notNull().unique(),
  resourceType: text("resource_type").notNull(),
  resourceId: text("resource_id").notNull(),
  resourceData: jsonb("resource_data").notNull(),
  label: text("label"),
  expiresAt: timestamp("expires_at"),
  viewCount: integer("view_count").default(0).notNull(),
  maxViews: integer("max_views"),
  createdAt: timestamp("created_at").defaultNow().notNull(),
  revokedAt: timestamp("revoked_at"),
})
```

### Step 2: Export from `db/schema/index.ts`

Add this export to your existing `db/schema/index.ts`:

```typescript
export * from "./shared-links"
```

### Step 3: Create `lib/share-link/index.ts`

```typescript
import type { sharedLinks } from "@/db/schema"
import type { InferSelectModel } from "drizzle-orm"

export type ShareLink = InferSelectModel<typeof sharedLinks>

export function generateShareUrl(token: string): string {
  const base = process.env.NEXT_PUBLIC_APP_URL ?? ""
  return `${base}/share/${token}`
}

export function isExpired(link: ShareLink): boolean {
  if (!link.expiresAt) return false
  return link.expiresAt < new Date()
}

export function isRevoked(link: ShareLink): boolean {
  return link.revokedAt !== null
}

export function isOverLimit(link: ShareLink): boolean {
  if (link.maxViews === null || link.maxViews === undefined) return false
  return link.viewCount >= link.maxViews
}

export function isAccessible(link: ShareLink): boolean {
  return !isRevoked(link) && !isExpired(link) && !isOverLimit(link)
}
```

### Step 4: Create `app/api/share/route.ts`

```typescript
import { db } from "@/db"
import { sharedLinks } from "@/db/schema"
import { auth } from "@/lib/auth"
import { generateShareUrl } from "@/lib/share-link"
import { eq, and, isNull, or, gt } from "drizzle-orm"
import { headers } from "next/headers"
import { NextResponse } from "next/server"
import { randomBytes } from "node:crypto"

function generateToken(): string {
  return randomBytes(9).toString("base64url")
}

export async function POST(request: Request): Promise<NextResponse> {
  const session = await auth.api.getSession({ headers: await headers() })
  if (!session?.user) {
    return NextResponse.json({ error: "Unauthorized" }, { status: 401 })
  }

  let body: unknown
  try {
    body = await request.json()
  } catch {
    return NextResponse.json({ error: "Invalid JSON" }, { status: 400 })
  }

  const parsed = body as Record<string, unknown>

  if (
    typeof parsed.resourceType !== "string" ||
    typeof parsed.resourceId !== "string" ||
    parsed.resourceData === undefined
  ) {
    return NextResponse.json(
      { error: "resourceType, resourceId, and resourceData are required" },
      { status: 400 },
    )
  }

  const token = generateToken()
  const expiresAt =
    typeof parsed.expiresAt === "string" ? new Date(parsed.expiresAt) : null
  const maxViews =
    typeof parsed.maxViews === "number" ? parsed.maxViews : null
  const label =
    typeof parsed.label === "string" ? parsed.label : null

  const [row] = await db
    .insert(sharedLinks)
    .values({
      userId: session.user.id,
      token,
      resourceType: parsed.resourceType,
      resourceId: parsed.resourceId,
      resourceData: parsed.resourceData as Record<string, unknown>,
      label,
      expiresAt,
      maxViews,
    })
    .returning({
      id: sharedLinks.id,
      token: sharedLinks.token,
      expiresAt: sharedLinks.expiresAt,
    })

  return NextResponse.json({
    id: row.id,
    token: row.token,
    url: generateShareUrl(row.token),
    expiresAt: row.expiresAt,
  })
}

export async function GET(): Promise<NextResponse> {
  const session = await auth.api.getSession({ headers: await headers() })
  if (!session?.user) {
    return NextResponse.json({ error: "Unauthorized" }, { status: 401 })
  }

  const now = new Date()

  const links = await db
    .select()
    .from(sharedLinks)
    .where(
      and(
        eq(sharedLinks.userId, session.user.id),
        isNull(sharedLinks.revokedAt),
        or(isNull(sharedLinks.expiresAt), gt(sharedLinks.expiresAt, now)),
      ),
    )

  const result = links.map((link) => ({
    ...link,
    url: generateShareUrl(link.token),
  }))

  return NextResponse.json(result)
}
```

### Step 5: Create `app/api/share/[token]/route.ts`

```typescript
import { db } from "@/db"
import { sharedLinks } from "@/db/schema"
import { auth } from "@/lib/auth"
import { isAccessible, isExpired, isOverLimit, isRevoked } from "@/lib/share-link"
import { eq } from "drizzle-orm"
import { headers } from "next/headers"
import { NextResponse } from "next/server"

type RouteContext = {
  params: Promise<{ token: string }>
}

export async function GET(
  _request: Request,
  { params }: RouteContext,
): Promise<NextResponse> {
  const { token } = await params

  const [link] = await db
    .select()
    .from(sharedLinks)
    .where(eq(sharedLinks.token, token))
    .limit(1)

  if (!link) {
    return NextResponse.json({ error: "Not found" }, { status: 404 })
  }

  if (isRevoked(link) || isExpired(link)) {
    return NextResponse.json(
      { error: "This link has expired or been revoked" },
      { status: 410 },
    )
  }

  if (isOverLimit(link)) {
    return NextResponse.json(
      { error: "This link has reached its maximum view count" },
      { status: 429 },
    )
  }

  await db
    .update(sharedLinks)
    .set({ viewCount: (link.viewCount ?? 0) + 1 })
    .where(eq(sharedLinks.token, token))

  return NextResponse.json({
    resourceType: link.resourceType,
    resourceId: link.resourceId,
    resourceData: link.resourceData,
    label: link.label,
    viewCount: (link.viewCount ?? 0) + 1,
    createdAt: link.createdAt,
  })
}

export async function DELETE(
  _request: Request,
  { params }: RouteContext,
): Promise<NextResponse> {
  const session = await auth.api.getSession({ headers: await headers() })
  if (!session?.user) {
    return NextResponse.json({ error: "Unauthorized" }, { status: 401 })
  }

  const { token } = await params

  const [link] = await db
    .select()
    .from(sharedLinks)
    .where(eq(sharedLinks.token, token))
    .limit(1)

  if (!link) {
    return NextResponse.json({ error: "Not found" }, { status: 404 })
  }

  if (link.userId !== session.user.id) {
    return NextResponse.json({ error: "Forbidden" }, { status: 403 })
  }

  await db
    .update(sharedLinks)
    .set({ revokedAt: new Date() })
    .where(eq(sharedLinks.token, token))

  return NextResponse.json({ success: true })
}
```

### Step 6: Push the schema

```bash
bunx drizzle-kit push
```

## Usage

```typescript
// Create a share link (authenticated)
const res = await fetch("/api/share", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    resourceType: "storyboard",
    reso