Profile Privacy & Visibility Controls

Profiles without visibility controls violate GDPR Art. 25 (data protection by design) and CCPA §1798.100 (consumer right to control their data). Under OWASP A01 (Broken Access Control) and CWE-284, any user whose profile is marked private but still returned to strangers has had their consent overridden by a code defect. Beyond compliance, exposed private profiles leak follower graphs, contact hints, and behavioral patterns to scrapers and stalkers — a direct user safety failure.

Gate every profile fetch through an access-control layer in lib/db.ts that checks the is_private flag and the viewer's follow status before returning any data. Never expose even partial profile fields to unauthorized viewers.

// lib/db.ts
export async function getUserProfile(userId: string, viewerId?: string) {
  const user = await db.user.findUnique({ where: { id: userId } })
  if (!user) return null
  if (!user.is_private) return user

  if (viewerId === userId) return user

  const isFollower = await db.follow.findFirst({
    where: { followingId: viewerId, followedId: userId }
  })
  return isFollower ? user : null
}

Also add is_private Boolean @default(false) to your Prisma User model if the field does not yet exist.