From 46544dd96a0be596fbfd5a2b681ef235eef453b7 Mon Sep 17 00:00:00 2001
From: Roman Tsisyk <roman@tsisyk.com>
Date: Thu, 1 Sep 2022 15:53:44 +0300
Subject: [PATCH] Handle old versions properly

---
 src/index.ts | 77 ++++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 57 insertions(+), 20 deletions(-)

diff --git a/src/index.ts b/src/index.ts
index d592bc0..678136e 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -2,17 +2,42 @@ export { };
 
 // TODO: Implement automated version checks from this metaserver script.
 // It should check by cron if actual files are really available on all servers.
-const LAST_AVAILABLE_VERSION = 220103;
-const BEFORE_LAST_AVAILABLE_VERSION = 220204;
-
 const SERVER = {
-  backblaze: 'https://cdn-us1.organicmaps.app/', // BackBlaze + CloudFlare (US-West) unmetered.
-  uk1: 'https://cdn-uk1.organicmaps.app/',       // Mythic Beasts VPS (London, UK) 200TB/mo.
-  nl1: 'https://cdn-nl1.organicmaps.app/',       // Mythic Beasts VPS (Amsterdam, NL) 200TB/mo.
-  planet: 'https://cdn.organicmaps.app/',        // Hetzner BareMetal (Falkenstein, Germany) unmetered
-  fi1: 'https://cdn-fi1.organicmaps.app/',       // Hetzner Cloud (Helsinki, Finland), 20TB/mo
-  de1: 'https://cdn-eu2.organicmaps.app/',       // Hetzner Cloud (Falkenstein, Germany), 20TB/mo
-  us2: 'https://cdn-us2.organicmaps.app/',       // Hetzner Cloud (Asburn, US East), 20TB/mo
+  backblaze: {
+    // BackBlaze + CloudFlare (US-West) unmetered.
+    url: 'https://cdn-us1.organicmaps.app/',
+    dataVersions: [210529, 210703, 210729, 210825, 211002, 211022, 211122, 220103, 220204, 220314, 220415, 220515, 220613, 220718, 220816]
+  },
+  uk1: {
+    // Mythic Beasts VPS (London, UK) 200TB/mo.
+    url: 'https://cdn-uk1.organicmaps.app/',
+    dataVersions: [220613, 220718, 220816]
+  },
+  nl1: {
+    // // Mythic Beasts VPS (Amsterdam, NL) 200TB/mo.
+    url: 'https://cdn-nl1.organicmaps.app/',
+    dataVersions: [220613, 220718, 220816]
+  },
+  planet: {
+    // Hetzner BareMetal (Falkenstein, Germany) unmetered
+    url: 'https://cdn.organicmaps.app/',
+    dataVersions: [220103, 220204, 220314, 220415, 220515, 220613, 220718, 220816]
+  },
+  fi1: {
+    // Hetzner Cloud (Helsinki, Finland), 20TB/mo
+    url: 'https://cdn-fi1.organicmaps.app/',
+    dataVersions: [220718, 220816]
+  },
+  de1: {
+    // Hetzner Cloud (Falkenstein, Germany), 20TB/mo
+    url: 'https://cdn-eu2.organicmaps.app/',
+    dataVersions: [220718, 220816]
+  },
+  us2: {
+    // Hetzner Cloud (Asburn, US East), 20TB/mo
+    url: 'https://cdn-us2.organicmaps.app/',
+    dataVersions: [220718, 220816]
+  }
 };
 
 // Main entry point.
@@ -24,7 +49,7 @@ addEventListener('fetch', (event) => {
 // of their current maps data version, for example, "211022" (October 22, 2021).
 // It is lowercased by Cloudflare.
 // Returns 0 if data version is absent or invalid, or a valid integer version.
-function extractDataVersion(request: Request): Number {
+function extractDataVersion(request: Request): number {
   const strDataVersion = request.headers.get('x-om-dataversion');
   if (strDataVersion) {
     const dataVersion = parseInt(strDataVersion);
@@ -43,23 +68,35 @@ async function handleRequest(request: Request) {
     case '/servers': {  // Private for map files.
       let servers;
       const dataVersion = extractDataVersion(request);
-      if (dataVersion < LAST_AVAILABLE_VERSION) {
-        // Old maps versions are available only on BackBlaze.
-        servers = [SERVER.backblaze];
-      } else if (dataVersion < BEFORE_LAST_AVAILABLE_VERSION) {
-        // Some servers have one additional version available.
-        servers = [SERVER.uk1, SERVER.nl1, SERVER.backblaze];
+      if (dataVersion == 0) {
+        servers = [SERVER.backblaze]
       } else switch (request.cf?.continent) {
         // See https://developers.cloudflare.com/firewall/cf-firewall-language/fields for a list of all continents.
         case 'NA': // North America
         case 'SA': // South America
         case 'OC': // Oceania
-          servers = [SERVER.backblaze, SERVER.us2, SERVER.uk1, SERVER.nl1, SERVER.planet];
+          servers = [SERVER.backblaze, SERVER.us2, SERVER.uk1, SERVER.nl1, SERVER.planet]
+            .filter(server => server.dataVersions.includes(dataVersion))
+          if (servers.length == 0) {
+            servers = [SERVER.planet]
+          }
           break;
         default: // Every other continent + Tor networks.
-          servers = [SERVER.planet, SERVER.uk1, SERVER.nl1, SERVER.fi1, SERVER.de1];
+          servers = [SERVER.planet, SERVER.uk1, SERVER.nl1, SERVER.fi1, SERVER.de1]
+            .filter(server => server.dataVersions.includes(dataVersion))
+          if (servers.length == 0) {
+            if (SERVER.backblaze.dataVersions.includes(dataVersion)) {
+              servers = [SERVER.backblaze]
+            } else {
+              servers = [SERVER.planet]
+            }
+          }
       }
-      return new Response(JSON.stringify(servers), {
+
+      let donation
+
+      const response = servers.map(server => server.url)
+      return new Response(JSON.stringify(response), {
         headers: { 'Content-Type': 'application/json' },
       });
     }