launcher/launcher/src/main/java/sashegdev/zernmc/launcher/utils/DomainSelector.java

@@ -60,6 +60,13 @@ public final class DomainSelector {
             }
         }
 
+        if (best != null) {
+            // Make every candidate (incl. geo mirrors) available as a fallback proxy base.
+            for (String c : candidates) {
+                ZHttpClient.registerProxyBase(c);
+            }
+        }
+
         if (best == null) {
             // nothing reachable: keep whatever is configured
             System.err.println(ZAnsi.brightRed("DomainSelector: no reachable API domain"));

launcher/launcher/src/main/java/sashegdev/zernmc/launcher/utils/ZHttpClient.java

@@ -51,6 +51,24 @@ public class ZHttpClient {
 
     private static String BASE_URL = "https://api.zern.cc";
 
+    /**
+     * Alternate proxy endpoints (geo mirrors) used when BASE_URL's proxy fails with
+     * a connection error (e.g. CDN "Connection reset" from the current region).
+     * Stay in sync with LAUNCHER_MIRRORS in server/main.py.
+     */
+    private static final List<String> GEO_PROXY_BASES = List.of(
+            "https://api.zernmc.ru",
+            "https://api.zernmc.online",
+            "https://api.pl.zern.cc",
+            "https://api.swe.zern.cc"
+    );
+
+    /**
+     * Extra proxy bases discovered at runtime (e.g. mirrors fetched from
+     * /launcher/mirrors by DomainSelector). Kept in insertion order, deduplicated.
+     */
+    private static final List<String> extraProxyBases = new ArrayList<>();
+
     private static final AtomicBoolean useProxyMode = new AtomicBoolean(false);
     private static final AtomicBoolean proxyTested = new AtomicBoolean(false);
     private static final AtomicBoolean healthThreadStarted = new AtomicBoolean(false);
@@ -59,6 +77,38 @@ public class ZHttpClient {
         BASE_URL = url;
     }
 
+    /**
+     * Registers an additional proxy base URL (mirror/geo domain) that the smart
+     * proxy fallback may rotate through. No-op if already present.
+     */
+    public static void registerProxyBase(String url) {
+        if (url == null || url.isBlank()) return;
+        String normalized = url.endsWith("/") ? url.substring(0, url.length() - 1) : url;
+        synchronized (extraProxyBases) {
+            if (!extraProxyBases.contains(normalized)) {
+                extraProxyBases.add(normalized);
+            }
+        }
+    }
+
+    /**
+     * Ordered, deduplicated list of proxy endpoints to attempt: the primary
+     * BASE_URL first, then geo mirrors and any runtime-discovered mirrors.
+     */
+    private static List<String> getProxyBases() {
+        List<String> bases = new ArrayList<>();
+        bases.add(BASE_URL);
+        for (String geo : GEO_PROXY_BASES) {
+            if (!bases.contains(geo)) bases.add(geo);
+        }
+        synchronized (extraProxyBases) {
+            for (String m : extraProxyBases) {
+                if (!bases.contains(m)) bases.add(m);
+            }
+        }
+        return bases;
+    }
+
     public static String getBaseUrl() {
         return BASE_URL;
     }
@@ -418,11 +468,15 @@ public class ZHttpClient {
             }
         }
 
+        List<String> proxyBases = getProxyBases();
         int maxRetries = 3;
         for (int attempt = 1; attempt <= maxRetries; attempt++) {
+            // Rotate through every proxy base so one region's Connection Reset does not
+            // burn all retries on the same endpoint.
+            String proxyBase = proxyBases.get((attempt - 1) % proxyBases.size());
             try {
                 String encodedUrl = URLEncoder.encode(url, StandardCharsets.UTF_8);
-                String proxyUrl = BASE_URL + "/proxy/download?url=" + encodedUrl;
+                String proxyUrl = proxyBase + "/proxy/download?url=" + encodedUrl;
 
                 HttpRequest request = HttpRequest.newBuilder()
                         .uri(URI.create(proxyUrl))
@@ -442,8 +496,10 @@ public class ZHttpClient {
 
             } catch (Exception e) {
                 if (attempt == maxRetries || !isRetryableError(e)) {
-                    throw new IOException("Failed to fetch data directly or via proxy: " + e.getMessage(), e);
+                    throw new IOException("Failed to fetch data directly or via proxy (" + proxyBase + "): " + e.getMessage(), e);
                 }
+                LauncherLogger.warn("[NET] Proxy fetch attempt " + attempt + "/" + maxRetries
+                        + " via " + proxyBase + " failed (" + e.getMessage() + "), next proxy base");
                 try { Thread.sleep(1000 * attempt); } catch (InterruptedException ie) { break; }
             }
         }
@@ -452,6 +508,11 @@ public class ZHttpClient {
     }
 
     public static void downloadFileWithSmartProxy(String url, Path target) throws Exception {
+        Path tmp = target.resolveSibling(target.getFileName() + ".part");
+        try {
+            Files.deleteIfExists(tmp);
+        } catch (IOException ignored) {}
+
         if (!shouldUseProxyForUrl(url)) {
             try {
                 HttpRequest.Builder requestBuilder = HttpRequest.newBuilder()
@@ -469,12 +530,14 @@ public class ZHttpClient {
 
                 HttpRequest request = requestBuilder.build();
 
-                HttpResponse<Path> response = sendBounded(request, HttpResponse.BodyHandlers.ofFile(target), 45);
+                HttpResponse<Path> response = sendBounded(request, HttpResponse.BodyHandlers.ofFile(tmp), 45);
 
                 if (response.statusCode() == 200) {
+                    moveIntoPlace(tmp, target);
                     directSuccessCount++;
                     return;
                 }
+                // non-200 response: fall through to proxy below
             } catch (Exception e) {
                 if (isConnectionError(e)) {
                     directFailCount++;
@@ -486,11 +549,19 @@ public class ZHttpClient {
             }
         }
 
+        List<String> proxyBases = getProxyBases();
         int maxRetries = 3;
         for (int attempt = 1; attempt <= maxRetries; attempt++) {
+            // Rotate through every proxy base so one region's Connection Reset does not
+            // burn all retries on the same endpoint.
+            String proxyBase = proxyBases.get((attempt - 1) % proxyBases.size());
             try {
                 String encodedUrl = URLEncoder.encode(url, StandardCharsets.UTF_8);
-                String proxyUrl = BASE_URL + "/proxy/download?url=" + encodedUrl;
+                String proxyUrl = proxyBase + "/proxy/download?url=" + encodedUrl;
+
+                try {
+                    Files.deleteIfExists(tmp);
+                } catch (IOException ignored) {}
 
                 HttpRequest request = HttpRequest.newBuilder()
                         .uri(URI.create(proxyUrl))
@@ -499,24 +570,45 @@ public class ZHttpClient {
                         .GET()
                         .build();
 
-                HttpResponse<Path> response = sendBounded(request, HttpResponse.BodyHandlers.ofFile(target), 300);
+                HttpResponse<Path> response = sendBounded(request, HttpResponse.BodyHandlers.ofFile(tmp), 300);
 
                 if (response.statusCode() != 200) {
                     throw new IOException("Proxy download failed: HTTP " + response.statusCode());
                 }
 
+                moveIntoPlace(tmp, target);
                 proxySuccessCount++;
                 return;
 
             } catch (Exception e) {
+                try {
+                    Files.deleteIfExists(tmp);
+                } catch (IOException ignored) {}
                 if (attempt == maxRetries || !isRetryableError(e)) {
-                    throw new IOException("Proxy download failed: " + e.getMessage(), e);
+                    throw new IOException("Proxy download failed (" + proxyBase + "): " + e.getMessage(), e);
                 }
+                LauncherLogger.warn("[NET] Proxy download attempt " + attempt + "/" + maxRetries
+                        + " via " + proxyBase + " failed (" + e.getMessage() + "), next proxy base");
                 try { Thread.sleep(1000 * attempt); } catch (InterruptedException ie) { break; }
             }
         }
     }
 
+    /**
+     * Atomically replaces the destination with the fully-downloaded temp file.
+     * Prevents a Connection Reset mid-transfer from leaving a corrupt partial
+     * file at the final path that later "file exists" checks would treat as installed.
+     */
+    private static void moveIntoPlace(Path tmp, Path target) throws IOException {
+        Files.createDirectories(target.getParent());
+        try {
+            Files.move(tmp, target, java.nio.file.StandardCopyOption.REPLACE_EXISTING,
+                    java.nio.file.StandardCopyOption.ATOMIC_MOVE);
+        } catch (java.nio.file.AtomicMoveNotSupportedException e) {
+            Files.move(tmp, target, java.nio.file.StandardCopyOption.REPLACE_EXISTING);
+        }
+    }
+
     /**
      * Retries a request against the Zern server. The server proxies are slow on cold cache
      * and may return transient 502/5xx when upstreams are flaky, so a single failure should

launcher/pom.xml

@@ -19,8 +19,8 @@
     </modules>
 
     <properties>
-        <revision>1.0.16</revision>
+        <revision>1.1.0</revision>
-        <hotfix>21</hotfix>
+        <hotfix>0</hotfix>
         <maven.compiler.source>21</maven.compiler.source>
         <maven.compiler.target>21</maven.compiler.target>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>