redo region routing

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Project	Deployment	Preview	Comments	Updated (UTC)
priv-gemini-browser	Ready	Preview	Comment	Oct 7, 2025 0:10am

[vercel]

The timezone region mapping is completely broken - the client sends timezone identifiers like "America/New_York" but the server now expects timezone abbreviations like "EST". This will cause all sessions to default to "us-west-2" regardless of user location.

View Details

📝 Patch Details

diff --git a/app/api/session/route.ts b/app/api/session/route.ts
index 569427d..7d0c303 100644
--- a/app/api/session/route.ts
+++ b/app/api/session/route.ts
@@ -7,7 +7,84 @@ type BrowserbaseRegion =
   | "eu-central-1"
   | "ap-southeast-1";
 
-// Timezone abbreviation to region mapping
+// IANA timezone identifier to region mapping
+const exactTimezoneMap: Record<string, BrowserbaseRegion> = {
+  // US East Coast
+  "America/New_York": "us-east-1",
+  "America/Detroit": "us-east-1",
+  "America/Kentucky/Louisville": "us-east-1",
+  "America/Kentucky/Monticello": "us-east-1",
+  "America/Indiana/Indianapolis": "us-east-1",
+  "America/Indiana/Vincennes": "us-east-1",
+  "America/Indiana/Winamac": "us-east-1",
+  "America/Indiana/Marengo": "us-east-1",
+  "America/Indiana/Petersburg": "us-east-1",
+  "America/Indiana/Vevay": "us-east-1",
+  "America/Toronto": "us-east-1",
+  "America/Montreal": "us-east-1",
+  "America/Halifax": "us-east-1",
+
+  // US West Coast
+  "America/Los_Angeles": "us-west-2",
+  "America/Vancouver": "us-west-2",
+  "America/Tijuana": "us-west-2",
+
+  // Europe
+  "Europe/London": "eu-central-1",
+  "Europe/Paris": "eu-central-1",
+  "Europe/Berlin": "eu-central-1",
+  "Europe/Rome": "eu-central-1",
+  "Europe/Madrid": "eu-central-1",
+  "Europe/Amsterdam": "eu-central-1",
+  "Europe/Brussels": "eu-central-1",
+  "Europe/Vienna": "eu-central-1",
+  "Europe/Prague": "eu-central-1",
+  "Europe/Warsaw": "eu-central-1",
+  "Europe/Budapest": "eu-central-1",
+  "Europe/Stockholm": "eu-central-1",
+  "Europe/Oslo": "eu-central-1",
+  "Europe/Copenhagen": "eu-central-1",
+  "Europe/Helsinki": "eu-central-1",
+  "Europe/Zurich": "eu-central-1",
+  "Europe/Dublin": "eu-central-1",
+  "Europe/Lisbon": "eu-central-1",
+  "Europe/Athens": "eu-central-1",
+  "Europe/Istanbul": "eu-central-1",
+  "Europe/Moscow": "eu-central-1",
+
+  // Asia-Pacific
+  "Asia/Tokyo": "ap-southeast-1",
+  "Asia/Seoul": "ap-southeast-1",
+  "Asia/Shanghai": "ap-southeast-1",
+  "Asia/Hong_Kong": "ap-southeast-1",
+  "Asia/Singapore": "ap-southeast-1",
+  "Asia/Bangkok": "ap-southeast-1",
+  "Asia/Jakarta": "ap-southeast-1",
+  "Asia/Manila": "ap-southeast-1",
+  "Asia/Kuala_Lumpur": "ap-southeast-1",
+  "Asia/Kolkata": "ap-southeast-1",
+  "Asia/Dubai": "ap-southeast-1",
+  "Australia/Sydney": "ap-southeast-1",
+  "Australia/Melbourne": "ap-southeast-1",
+  "Australia/Brisbane": "ap-southeast-1",
+  "Australia/Perth": "ap-southeast-1",
+  "Australia/Adelaide": "ap-southeast-1",
+  "Pacific/Auckland": "ap-southeast-1",
+};
+
+// Prefix-based region mapping for fallback
+const prefixToRegion: Record<string, BrowserbaseRegion> = {
+  America: "us-west-2",
+  US: "us-west-2",
+  Canada: "us-west-2",
+  Europe: "eu-central-1",
+  Africa: "eu-central-1",
+  Asia: "ap-southeast-1",
+  Australia: "ap-southeast-1",
+  Pacific: "ap-southeast-1",
+};
+
+// Timezone abbreviation to region mapping (for legacy support)
 const timezoneAbbreviationMap: Record<string, BrowserbaseRegion> = {
   // US East Coast
   EST: "us-east-1",
@@ -93,19 +170,52 @@ function selectRegionWithProbability(
   return baseRegion;
 }
 
-function getRegionFromTimezoneAbbr(timezoneAbbr?: string): BrowserbaseRegion {
+function getClosestRegion(timezone?: string): BrowserbaseRegion {
   try {
-    if (!timezoneAbbr) {
+    if (!timezone) {
       return "us-west-2"; // Default if no timezone provided
     }
 
-    // Direct lookup from timezone abbreviation
-    const region = timezoneAbbreviationMap[timezoneAbbr.toUpperCase()];
-    if (region) {
-      return region;
+    // Check exact IANA timezone identifier matches first
+    if (timezone in exactTimezoneMap) {
+      return exactTimezoneMap[timezone];
+    }
+
+    // Check timezone abbreviation matches (legacy support)
+    const abbreviationRegion = timezoneAbbreviationMap[timezone.toUpperCase()];
+    if (abbreviationRegion) {
+      return abbreviationRegion;
+    }
+
+    // Check prefix matches for IANA identifiers
+    const prefix = timezone.split("/")[0];
+    if (prefix in prefixToRegion) {
+      return prefixToRegion[prefix];
+    }
+
+    // Use offset-based fallback for unknown timezones
+    try {
+      const date = new Date();
+      // Create a date formatter for the given timezone
+      const formatter = new Intl.DateTimeFormat("en-US", { timeZone: timezone });
+      // Get the timezone offset by comparing formatted times
+      const utcDate = new Date(date.toISOString().slice(0, -1));
+      const localDate = new Date(formatter.format(date) + " UTC");
+      const hourOffset = (localDate.getTime() - utcDate.getTime()) / (1000 * 60 * 60);
+
+      // Map offset ranges to regions
+      if (hourOffset >= -12 && hourOffset <= -4) {
+        return "us-west-2"; // US West Coast and Pacific
+      } else if (hourOffset >= -3 && hourOffset <= 4) {
+        return "eu-central-1"; // Europe and Africa
+      } else if (hourOffset >= 5 && hourOffset <= 12) {
+        return "ap-southeast-1"; // Asia-Pacific
+      }
+    } catch {
+      // If offset calculation fails, fall through to default
     }
 
-    // Fallback to us-west-2 for unknown abbreviations
+    // Fallback to us-west-2 for unknown timezones
     return "us-west-2";
   } catch {
     return "us-west-2";
@@ -128,12 +238,12 @@ async function createSession(timezone?: string) {
     advancedStealth: true
   };
 
-  // Use timezone abbreviation to determine base region
-  const closestRegion = getRegionFromTimezoneAbbr(timezone);
+  // Use timezone identifier to determine base region
+  const closestRegion = getClosestRegion(timezone);
   // Apply probability routing for potential load balancing
   const finalRegion = selectRegionWithProbability(closestRegion);
 
-  console.log("timezone abbreviation:", timezone);
+  console.log("timezone:", timezone);
   console.log("mapped to region:", closestRegion);
   console.log("final region after probability routing:", finalRegion);
 

Analysis

Timezone region mapping broken for IANA identifiers in session creation

What fails: getRegionFromTimezoneAbbr() only handles timezone abbreviations like "EST" but client sends IANA timezone identifiers like "America/New_York", causing all sessions to default to "us-west-2"

How to reproduce:

// Client sends IANA identifier from browser:
Intl.DateTimeFormat().resolvedOptions().timeZone; // Returns "America/New_York"

// Server function only matches abbreviations:
getRegionFromTimezoneAbbr("America/New_York"); // Returns "us-west-2" (fallback)

Result: All users with IANA timezone identifiers (default browser behavior) get routed to us-west-2 instead of their geographic region

Expected: "America/New_York" should map to "us-east-1", "Europe/London" to "eu-central-1", per Intl.DateTimeFormat docs which return IANA timezone names