Fix Ledger Privacy & Obfuscation by clates · Pull Request #29 · clates/lfl-booktracker

clates · 2025-12-21T20:23:38Z

Fixes Ledger List privacy issues by:

Using the correct DB_SECRET_KEY for admin operations.
Obfuscating user emails in the UI (e.g., tes...ser).
Implementing "Whimsical Location" (e.g., "Herndon") to hide precise coordinates for new sightings.

Also includes a regression test for the location privacy feature.

vercel · 2025-12-21T20:23:40Z

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Project	Deployment	Review	Updated (UTC)
lfl-booktracker	Ready	Preview, Comment	Dec 22, 2025 0:10am

Copilot

Pull request overview

This PR enhances privacy and security in the Ledger List feature by implementing three key improvements: correcting the admin client configuration to use DB_SECRET_KEY, obfuscating user emails in the UI, and introducing a "whimsical location" feature that replaces precise coordinates with general location names (e.g., "Herndon") using OpenStreetMap's Nominatim API.

Key Changes:

Admin client now prioritizes DB_SECRET_KEY for privileged operations
Email obfuscation changed from showing full username to showing first 3 and last 3 characters with ellipsis
New location privacy feature using Nominatim API to fetch suburb/town names instead of displaying raw coordinates

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
`lib/supabase-admin.ts`	Updated environment variable priority to use `DB_SECRET_KEY` first for admin operations
`lib/location-utils.ts`	New utility that integrates with Nominatim API to fetch "whimsical" location names for privacy
`app/page.tsx`	Enhanced email obfuscation to show only first 3 and last 3 characters of username
`app/api/books/generate/route.ts`	Integrated whimsical location feature and switched from admin client to route handler client
`__tests__/app/api/books/generate/route.test.ts`	Added mock for location utils in existing tests
`__tests__/api/generate-location.test.ts`	New comprehensive test suite for location privacy feature
`__tests__/api/generate-auth.test.ts`	Added location utils mock and headers to test requests

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Copilot · 2025-12-21T21:44:41Z

+      return `${lat.toFixed(2)}, ${lon.toFixed(2)}`
+    }
+
+    const data = await res.json()
+
+    // Extract just the suburb, neighborhood, or town as requested
+    // Fallback to "The Wilds" if nothing specific found, or coordinate-ish hint
+    const name =
+      data.address?.suburb ||
+      data.address?.town ||
+      data.address?.city ||
+      data.address?.village ||
+      data.address?.county ||
+      "The Wilds"
+
+    return name
+  } catch (error) {
+    console.error("Failed to fetch whimsical location:", error)
+    // Fallback to simplified coordinates
+    return `${lat.toFixed(2)}, ${lon.toFixed(2)}`


The fallback coordinate format uses toFixed(2) which provides 2 decimal places. This level of precision still reveals location within roughly 1km, which may not align with the privacy goals of using "whimsical locations". Consider reducing precision further (e.g., toFixed(1) or even toFixed(0)) in the fallback, or use a generic message like "Unknown Location" to maintain consistency with the privacy approach.

Copilot · 2025-12-21T21:44:41Z

+      {
+        headers: {
+          // Nominatim requires a User-Agent.
+          "User-Agent": "LFL-BookTracker/1.0",


The User-Agent string "LFL-BookTracker/1.0" should be updated to include contact information as per Nominatim's Usage Policy. The policy states: "Valid User-Agent identifying your application. Preferably a link to your application or an email address." Consider updating this to something like "LFL-BookTracker/1.0 (contact-email@domain.com)" or include a URL to the project.

Suggested change

"User-Agent": "LFL-BookTracker/1.0",

"User-Agent": "LFL-BookTracker/1.0 (contact@example.com)",

Copilot · 2025-12-21T21:44:42Z

+      }
+    )
+
+    if (!res.ok) {
+      console.warn("Nominatim API Error:", res.status, res.statusText)
+      return `${lat.toFixed(2)}, ${lon.toFixed(2)}`
+    }


The getWhimsicalLocation function is called during book generation, which is a synchronous operation in the request flow. If the Nominatim API is slow or times out, this will block the entire book generation process. Consider adding a timeout to the fetch request to prevent indefinite hanging. For example, use signal: AbortSignal.timeout(5000) to timeout after 5 seconds and fall back to the coordinate format.

Suggested change

}

)

if (!res.ok) {

console.warn("Nominatim API Error:", res.status, res.statusText)

return `${lat.toFixed(2)}, ${lon.toFixed(2)}`

}

signal: AbortSignal.timeout(5000),

}

)

if (!res.ok) {

console.warn("Nominatim API Error:", res.status, res.statusText)

return `${lat.toFixed(2)}, ${lon.toFixed(2)}`

Copilot · 2025-12-21T21:44:42Z

+      // Format: first 3 chars + ... + last 3 chars of username.
+      const username = fullEmail.split("@")[0]
+      const maskedEmail = `${username.slice(0, 3)}...${username.slice(-3)}`


The email obfuscation logic has a bug with short usernames. For usernames with 6 or fewer characters, the slice operations will produce overlapping or duplicate characters. For example:

A username "abc" would become "abc...abc" (duplicating all characters)

A username "test" would become "tes...est" (overlapping)

The logic should check the username length and handle short usernames appropriately, perhaps by showing them as "ab..." or similar for very short names.

Suggested change

// Format: first 3 chars + ... + last 3 chars of username.

const username = fullEmail.split("@")[0]

const maskedEmail = `${username.slice(0, 3)}...${username.slice(-3)}`

// For typical usernames (> 6 chars): first 3 chars + ... + last 3 chars of username.

const username = fullEmail.split("@")[0]

let maskedUsername: string

if (username.length <= 2) {

// Very short usernames: show first char only.

maskedUsername = `${username.slice(0, 1)}...`

} else if (username.length <= 6) {

// Short usernames: avoid overlapping/duplicating characters.

maskedUsername = `${username.slice(0, 2)}...${username.slice(-1)}`

} else {

maskedUsername = `${username.slice(0, 3)}...${username.slice(-3)}`

}

const maskedEmail = maskedUsername

Copilot · 2025-12-21T21:44:42Z

+export async function getWhimsicalLocation(lat: number, lon: number): Promise<string> {
+  try {
+    const res = await fetch(
+      `https://nominatim.openstreetmap.org/reverse?format=json&lat=${lat}&lon=${lon}&zoom=10`,


The zoom level of 10 in the Nominatim API request may not consistently return suburb/town level data for all locations. Zoom level 10 typically corresponds to city-level detail. For better consistency in getting neighborhood/suburb information, consider using zoom level 14-16. However, if the intention is to provide less precise information for privacy, the current level may be appropriate - just ensure this matches the privacy requirements.

Suggested change

`https://nominatim.openstreetmap.org/reverse?format=json&lat=${lat}&lon=${lon}&zoom=10`,

`https://nominatim.openstreetmap.org/reverse?format=json&lat=${lat}&lon=${lon}&zoom=14`,

Copilot · 2025-12-21T21:44:42Z

+    const res = await fetch(
+      `https://nominatim.openstreetmap.org/reverse?format=json&lat=${lat}&lon=${lon}&zoom=10`,
+      {
+        headers: {
+          // Nominatim requires a User-Agent.
+          "User-Agent": "LFL-BookTracker/1.0",
+        },
+        next: {
+          // Cache for a long time to avoid rate limits on known coords
+          revalidate: 86400,
+        },
+      }
+    )


The Nominatim Usage Policy requires no more than 1 request per second and recommends implementing proper caching. While the code implements caching with a 24-hour revalidation period, there's no rate limiting mechanism in place. If multiple books are generated simultaneously with different coordinates, this could violate the API's usage policy. Consider implementing a request queue or rate limiter to ensure compliance with the 1 request/second limit.

Not considering this high-priority; if we hit a rate limit I'll be impressed.

fix: ledger privacy, location obfuscation, and api key usage

79cd6f5

vercel Bot deployed to Preview December 21, 2025 20:24 View deployment

fix: resolved tests for generate api changes

88cdda2

clates requested a review from Copilot December 21, 2025 21:41

vercel Bot deployed to Preview December 21, 2025 21:41 View deployment

Copilot started reviewing on behalf of clates December 21, 2025 21:41 View session

Copilot AI reviewed Dec 21, 2025

View reviewed changes

fix: refined whimsical location formatting and fallback

62845a7

vercel Bot deployed to Preview December 22, 2025 00:06 View deployment

fix: typo in user-agent url

d90a2fe

vercel Bot deployed to Preview December 22, 2025 00:10 View deployment

clates merged commit d4dffd7 into main Dec 22, 2025
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Fix Ledger Privacy & Obfuscation - #29

Fix Ledger Privacy & Obfuscation#29
clates merged 4 commits into
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fix/userNameInSightings

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	"User-Agent": "LFL-BookTracker/1.0",
	"User-Agent": "LFL-BookTracker/1.0 (contact@example.com)",

-      // Format: first 3 chars + ... + last 3 chars of username.
-      const username = fullEmail.split("@")[0]
-      const maskedEmail = `${username.slice(0, 3)}...${username.slice(-3)}`
+      // For typical usernames (> 6 chars): first 3 chars + ... + last 3 chars of username.
+      const username = fullEmail.split("@")[0]
+      let maskedUsername: string
+      if (username.length <= 2) {
+        // Very short usernames: show first char only.
+        maskedUsername = `${username.slice(0, 1)}...`
+      } else if (username.length <= 6) {
+        // Short usernames: avoid overlapping/duplicating characters.
+        maskedUsername = `${username.slice(0, 2)}...${username.slice(-1)}`
+      } else {
+        maskedUsername = `${username.slice(0, 3)}...${username.slice(-3)}`
+      }
+      const maskedEmail = maskedUsername

	`https://nominatim.openstreetmap.org/reverse?format=json&lat=${lat}&lon=${lon}&zoom=10`,
	`https://nominatim.openstreetmap.org/reverse?format=json&lat=${lat}&lon=${lon}&zoom=14`,

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Pull request overview

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vercel Bot commented Dec 21, 2025 •

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