Add retry, backoff, and debug options to plugin updater

Introduces configurable retry and exponential backoff for HTTP downloads, rotating User-Agent support, and enhanced debug logging throughout the plugin update process. Adds new options to UpdateOptions and configuration, updates AupCommand to allow toggling debug mode, and improves error handling and diagnostics for GitHub and generic downloads.

Author: NewAmazingPVP

src/main/java/common/PluginDownloader.java

@@ -1,5 +1,5 @@
-package common;
-
+package common;
+
 import org.jetbrains.annotations.NotNull;
 
 import java.io.*;
@@ -14,6 +14,7 @@
 import java.util.Objects;
 import java.util.Optional;
 import java.util.logging.Logger;
+import java.util.logging.Level;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipException;
 import java.util.zip.ZipFile;
@@ -32,13 +33,13 @@
 import java.nio.file.SimpleFileVisitor;
 import java.nio.file.attribute.BasicFileAttributes;
 import java.nio.file.FileVisitResult;
-
+
 public class PluginDownloader {
 
     private final Logger logger;
     private static java.util.Map<String, String> extraHeaders = new java.util.HashMap<>();
     private static String overrideUserAgent = null;
-
+
     public PluginDownloader(Logger logger) {
         this.logger = logger;
     }
@@ -47,7 +48,7 @@ public static void setHttpHeaders(java.util.Map<String, String> headers, String
         extraHeaders = headers != null ? new java.util.HashMap<>(headers) : new java.util.HashMap<>();
         overrideUserAgent = (userAgent != null && !userAgent.trim().isEmpty()) ? userAgent.trim() : null;
     }
-
+
     public boolean downloadPlugin(String link, String fileName, String githubToken) throws IOException{
         boolean requiresAuth = link.toLowerCase().contains("actions")
                 && link.toLowerCase().contains("github")
@@ -66,17 +67,35 @@ public boolean downloadPlugin(String link, String fileName, String githubToken)
             return false;
         }
 
-        for (int attempt = 1; attempt <= 2; attempt++) {
+        for (int attempt = 1; attempt <= Math.max(2, common.UpdateOptions.maxRetries); attempt++) {
             File rawTmp = new File(rawTempPath);
             File outTmp = new File(outputTempPath);
             cleanupQuietly(rawTmp);
             cleanupQuietly(outTmp);
             try {
                 HttpURLConnection connection = openConnection(link, githubToken, requiresAuth);
-                if (!downloadWithVerification(rawTmp, connection)) {
-                    logger.warning("Download failed (attempt " + attempt + ")");
+                int code = 0;
+                try { code = connection.getResponseCode(); } catch (IOException ignored) {}
+                if (code == 403 || code == 429 || (code >= 500 && code < 600)) {
+                    int base = Math.max(0, common.UpdateOptions.backoffBaseMs);
+                    int max = Math.max(base, common.UpdateOptions.backoffMaxMs);
+                    int delay = Math.min(max, base * (1 << Math.min(attempt, 10))) + new java.util.Random().nextInt(250);
+                    if (common.UpdateOptions.debug) logger.info("[DEBUG] HTTP " + code + " for " + link + ", retry in ~" + delay + "ms (attempt " + attempt + ")");
+                    try { Thread.sleep(delay); } catch (InterruptedException ignored2) { Thread.currentThread().interrupt(); }
                     continue;
                 }
+                if (!downloadWithVerification(rawTmp, connection)) {
+                    logger.warning("Download failed (attempt " + attempt + ") — retrying lenient mode (old-plugin behavior)");
+                    try {
+                        connection = openConnection(link, githubToken, requiresAuth);
+                        if (!downloadLenient(rawTmp, connection)) {
+                            continue;
+                        }
+                    } catch (IOException ex) {
+                        continue;
+                    }
+                }
+
 
                 if (isZipFile(rawTempPath)) {
                     boolean extracted = extractFirstJarFromZip(rawTempPath, outputTempPath);
@@ -98,6 +117,7 @@ public boolean downloadPlugin(String link, String fileName, String githubToken)
                 }
 
                 File target = new File(outputFilePath);
+                if (common.UpdateOptions.debug) logger.info("[DEBUG] Ready to install: temp=" + outTmp.getAbsolutePath() + " -> target=" + target.getAbsolutePath());
                 if (common.UpdateOptions.ignoreDuplicates && target.exists() && sameDigest(target, outTmp, "MD5")) {
                     cleanupQuietly(outTmp);
                     cleanupQuietly(rawTmp);
@@ -115,10 +135,10 @@ public boolean downloadPlugin(String link, String fileName, String githubToken)
         }
         return false;
     }
-
-
-
-
+
+
+
+
     private String getString(String fileName) {
         String basePlugins = "plugins/";
         String configuredFilePath = common.UpdateOptions.filePath;
@@ -153,39 +173,12 @@ private String ensureDir(String dir) {
         new File(dir).mkdirs();
         return dir;
     }
-
+
     private boolean downloadPluginToFile(String outputFilePath, HttpURLConnection connection) throws IOException {
         return downloadWithVerification(new File(outputFilePath), connection);
     }
 
-    private boolean downloadWithVerification(File outFile, HttpURLConnection connection) throws IOException {
-        long expected = connection.getContentLengthLong();
-        long written = 0L;
-        try (InputStream in = connection.getInputStream(); FileOutputStream out = new FileOutputStream(outFile)) {
-            byte[] buffer = new byte[8192];
-            int bytesRead;
-            while ((bytesRead = in.read(buffer)) != -1) {
-                out.write(buffer, 0, bytesRead);
-                written += bytesRead;
-            }
-            out.getFD().sync();
-        }
-        if (expected >= 0 && written != expected) {
-            logger.warning("Content-Length mismatch: expected=" + expected + ", got=" + written);
-            cleanupQuietly(outFile);
-            return false;
-        }
-        if (isZipFile(outFile.getPath())) {
-            try (ZipFile zf = new ZipFile(outFile)) {
-            } catch (IOException ex) {
-                logger.warning("Downloaded ZIP appears corrupt: " + ex.getMessage());
-                cleanupQuietly(outFile);
-                return false;
-            }
-        }
-        return true;
-    }
-
+
     private boolean extractFirstJarFromZip(String zipFilePath, String outputFilePath) throws IOException {
         try (ZipFile zipFile = new ZipFile(zipFilePath)) {
             List<? extends ZipEntry> entries = Collections.list(zipFile.entries());
@@ -213,7 +206,7 @@ private boolean extractFirstJarFromZip(String zipFilePath, String outputFilePath
             return true;
         }
     }
-
+
     public boolean downloadJenkinsPlugin(String link, String fileName){
         String tempBase = common.UpdateOptions.tempPath != null && !common.UpdateOptions.tempPath.isEmpty() ? ensureDir(common.UpdateOptions.tempPath) : "plugins/";
         String rawTempPath = tempBase + fileName + ".download.tmp";
@@ -228,13 +221,23 @@ public boolean downloadJenkinsPlugin(String link, String fileName){
             return false;
         }
 
-        for (int attempt = 1; attempt <= 2; attempt++) {
+        for (int attempt = 1; attempt <= Math.max(2, common.UpdateOptions.maxRetries); attempt++) {
             File rawTmp = new File(rawTempPath);
             File outTmp = new File(outputTempPath);
             cleanupQuietly(rawTmp);
             cleanupQuietly(outTmp);
             try {
                 HttpURLConnection connection = openConnection(link, null, false);
+                int code = 0;
+                try { code = connection.getResponseCode(); } catch (IOException ignored) {}
+                if (code == 403 || code == 429 || (code >= 500 && code < 600)) {
+                    int base = Math.max(0, common.UpdateOptions.backoffBaseMs);
+                    int max = Math.max(base, common.UpdateOptions.backoffMaxMs);
+                    int delay = Math.min(max, base * (1 << Math.min(attempt, 10))) + new java.util.Random().nextInt(250);
+                    if (common.UpdateOptions.debug) logger.info("[DEBUG] HTTP " + code + " for " + link + ", retry in ~" + delay + "ms (attempt " + attempt + ")");
+                    try { Thread.sleep(delay); } catch (InterruptedException ignored2) { Thread.currentThread().interrupt(); }
+                    continue;
+                }
                 if (!downloadWithVerification(rawTmp, connection)) {
                     logger.info("Download failed (attempt " + attempt + ")");
                     continue;
@@ -256,6 +259,7 @@ public boolean downloadJenkinsPlugin(String link, String fileName){
                     continue;
                 }
                 File target = new File(outputFilePath);
+                if (common.UpdateOptions.debug) logger.info("[DEBUG] Ready to install: temp=" + outTmp.getAbsolutePath() + " -> target=" + target.getAbsolutePath());
                 if (target.exists() && sameDigest(target, outTmp, "MD5")) {
                     cleanupQuietly(outTmp);
                     cleanupQuietly(rawTmp);
@@ -273,8 +277,8 @@ public boolean downloadJenkinsPlugin(String link, String fileName){
         }
         return false;
     }
-
-
+
+
     public static boolean isZipFile(String filePath) {
         Objects.requireNonNull(filePath, "filePath");
         Path path = Paths.get(filePath);
@@ -301,22 +305,128 @@ private void moveReplace(File from, File to) throws IOException {
 
     private HttpURLConnection openConnection(String link, String githubToken, boolean requiresAuth) throws IOException {
         HttpURLConnection connection = (HttpURLConnection) new URL(link).openConnection();
-        connection.setRequestProperty("User-Agent", overrideUserAgent != null ? overrideUserAgent : "AutoUpdatePlugins");
-        connection.setConnectTimeout(common.UpdateOptions.connectTimeoutMs);
-        connection.setReadTimeout(common.UpdateOptions.readTimeoutMs);
+        connection.setInstanceFollowRedirects(true);
+
+        String ua = (overrideUserAgent != null && !overrideUserAgent.trim().isEmpty()
+                && !"AutoUpdatePlugins".equalsIgnoreCase(overrideUserAgent))
+                ? overrideUserAgent.trim() : null;
+        if (ua == null && common.UpdateOptions.userAgents != null && !common.UpdateOptions.userAgents.isEmpty()) {
+            ua = common.UpdateOptions.userAgents.get(new java.util.Random().nextInt(common.UpdateOptions.userAgents.size()));
+        }
+        if (ua == null) {
+            ua = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36";
+        }
+
+        connection.setRequestProperty("User-Agent", ua);
+        connection.setRequestProperty("Accept-Encoding", "identity");
+        connection.setRequestProperty("Accept", "application/octet-stream, */*");
+        connection.setRequestProperty("Accept-Language", "en-US,en;q=0.9");
+        connection.setRequestProperty("Connection", "keep-alive");
+
         if (requiresAuth && githubToken != null && !githubToken.isEmpty()) {
             connection.setRequestProperty("Authorization", "Bearer " + githubToken);
         }
+        try {
+            java.net.URI uri = java.net.URI.create(link);
+            String origin = uri.getScheme() + "://" + uri.getHost() + (uri.getPort() > 0 ? (":" + uri.getPort()) : "");
+            connection.setRequestProperty("Referer", origin);
+        } catch (Throwable ignored) {}
+
         if (extraHeaders != null) {
             for (java.util.Map.Entry<String, String> e : extraHeaders.entrySet()) {
                 if (e.getKey() != null && e.getValue() != null) {
                     connection.setRequestProperty(e.getKey(), e.getValue());
                 }
             }
         }
+
+        connection.setConnectTimeout(common.UpdateOptions.connectTimeoutMs);
+        connection.setReadTimeout(common.UpdateOptions.readTimeoutMs);
+
+        if (common.UpdateOptions.debug) {
+            logger.info("[DEBUG] OpenConnection url=" + link + ", auth=" + requiresAuth + ", ua=" + ua);
+        }
         return connection;
     }
 
+
+    private static boolean isGithubishHost(String host) {
+        if (host == null) return false;
+        String h = host.toLowerCase(java.util.Locale.ROOT);
+        return h.endsWith("github.com")
+                || h.endsWith("githubusercontent.com")
+                || h.endsWith("codeload.github.com")
+                || h.endsWith("objects.githubusercontent.com");
+    }
+    private boolean downloadWithVerification(File outFile, HttpURLConnection connection) throws IOException {
+        long expected = -1L;
+        boolean canTrustLength = true;
+
+        try {
+            expected = connection.getContentLengthLong();
+            String ce = connection.getHeaderField("Content-Encoding");
+            String te = connection.getHeaderField("Transfer-Encoding");
+            if (expected < 0 || (ce != null && !"identity".equalsIgnoreCase(ce)) || (te != null && "chunked".equalsIgnoreCase(te))) {
+                canTrustLength = false;
+            }
+        } catch (Throwable ignored) {}
+
+        long written = 0L;
+        try (InputStream in = connection.getInputStream(); FileOutputStream out = new FileOutputStream(outFile)) {
+            if (common.UpdateOptions.debug) {
+                try {
+                    logger.info("[DEBUG] HTTP code=" + connection.getResponseCode()
+                            + ", type=" + connection.getContentType()
+                            + ", length=" + expected
+                            + (connection.getHeaderField("Content-Encoding") != null
+                            ? ", enc=" + connection.getHeaderField("Content-Encoding") : ""));
+                } catch (IOException ignored) {}
+            }
+            byte[] buffer = new byte[8192];
+            int n;
+            while ((n = in.read(buffer)) != -1) {
+                out.write(buffer, 0, n);
+                written += n;
+            }
+            out.getFD().sync();
+        }
+
+        if (canTrustLength && expected >= 0 && written != expected) {
+            logger.warning("Content-Length mismatch: expected=" + expected + ", got=" + written);
+            cleanupQuietly(outFile);
+            return false;
+        }
+        try (FileInputStream fis = new FileInputStream(outFile)) {
+            byte[] probe = new byte[64];
+            int n = fis.read(probe);
+            String head = (n > 0) ? new String(probe, 0, n, java.nio.charset.StandardCharsets.ISO_8859_1) : "";
+            String t = head.trim().toLowerCase(java.util.Locale.ROOT);
+            if (t.startsWith("<!doctype html") || t.startsWith("<html")) {
+                cleanupQuietly(outFile);
+                return false;
+            }
+        } catch (Throwable ignored) {}
+
+        return true;
+    }
+
+
+
+
+    private boolean downloadLenient(File outFile, HttpURLConnection connection) {
+        try (InputStream in = connection.getInputStream(); FileOutputStream out = new FileOutputStream(outFile)) {
+            byte[] buffer = new byte[8192];
+            int r;
+            while ((r = in.read(buffer)) != -1) out.write(buffer, 0, r);
+            out.getFD().sync();
+            return true;
+        } catch (IOException e) {
+            return false;
+        }
+    }
+
+
+
     public boolean buildFromGitHubRepo(String repoPath, String fileName, String githubToken) throws IOException {
         String repoApi = "https://api.github.com/repos" + repoPath;
         String defaultBranch = "main";
@@ -395,14 +505,17 @@ public boolean buildFromGitHubRepo(String repoPath, String fileName, String gith
             cleanupQuietly(outTmp);
             Files.createDirectories(outTmp.getParentFile().toPath());
             Files.copy(jar, outTmp.toPath(), StandardCopyOption.REPLACE_EXISTING);
+            if (common.UpdateOptions.debug) logger.info("[DEBUG] Built jar selected: " + jar.toAbsolutePath());
             if (!validateJar(outTmp)) {
                 logger.info("Built jar is not a valid plugin jar.");
                 cleanupQuietly(outTmp);
                 cleanupTreeQuietly(workDir);
                 cleanupQuietly(rawZipFile);
                 return false;
             }
-            moveReplace(outTmp, new File(getString(fileName)));
+            File target = new File(getString(fileName));
+            if (common.UpdateOptions.debug) logger.info("[DEBUG] Installing built jar: temp=" + outTmp.getAbsolutePath() + " -> target=" + target.getAbsolutePath());
+            moveReplace(outTmp, target);
             cleanupTreeQuietly(workDir);
             cleanupQuietly(rawZipFile);
             return true;