fabric: validate launcher jar and use HTTP/2 (#616)

itzg · web-flow · commit f976f6d9376b · 2025-08-09T17:27:05.000-05:00
diff --git a/src/main/java/me/itzg/helpers/McImageHelper.java b/src/main/java/me/itzg/helpers/McImageHelper.java
@@ -150,6 +150,8 @@ private static void setLevel(boolean enabled, Level level) {
             if (Level.TRACE.isGreaterOrEqual(level)) {
                 ((Logger) LoggerFactory.getLogger("org.apache.hc.client5.http")).setLevel(
                     enabled ? level : Level.INFO);
+                ((Logger) LoggerFactory.getLogger("reactor.netty.http.client.HttpClient")).setLevel(
+                    enabled ? level : Level.INFO);
             }
         }
 
diff --git a/src/main/java/me/itzg/helpers/errors/InvalidContentException.java b/src/main/java/me/itzg/helpers/errors/InvalidContentException.java
@@ -0,0 +1,13 @@
+package me.itzg.helpers.errors;
+
+import java.io.IOException;
+
+public class InvalidContentException extends IOException {
+
+    public InvalidContentException(String message) {
+        super(message);
+    }
+    public InvalidContentException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}
diff --git a/src/main/java/me/itzg/helpers/fabric/FabricLauncherInstaller.java b/src/main/java/me/itzg/helpers/fabric/FabricLauncherInstaller.java
@@ -8,6 +8,7 @@
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.Properties;
+import lombok.AccessLevel;
 import lombok.Getter;
 import lombok.NonNull;
 import lombok.RequiredArgsConstructor;
@@ -42,6 +43,12 @@ public class FabricLauncherInstaller {
     @Getter @Setter
     private boolean forceReinstall;
 
+    /**
+     * For testing purposes.
+     */
+    @Getter @Setter(AccessLevel.PACKAGE)
+    private boolean skipValidation;
+
     public void installUsingVersions(
         Options sharedFetchOptions, @NonNull String minecraftVersion,
         @Nullable String loaderVersion,
@@ -97,7 +104,8 @@ private Mono<FabricManifest> downloadResolvedLauncher(FabricMetaClient fabricMet
         if (needsInstall) {
             return fabricMetaClient.downloadLauncher(
                     outputDir, minecraftVersion, loaderVersion, installerVersion,
-                    Fetch.loggingDownloadStatusHandler(log)
+                    Fetch.loggingDownloadStatusHandler(log),
+                    skipValidation
                 )
                 .publishOn(Schedulers.boundedElastic())
                 .flatMap(launcherPath ->
diff --git a/src/main/java/me/itzg/helpers/fabric/FabricMetaClient.java b/src/main/java/me/itzg/helpers/fabric/FabricMetaClient.java
@@ -1,20 +1,28 @@
 package me.itzg.helpers.fabric;
 
+import java.io.BufferedReader;
 import java.io.IOException;
+import java.nio.file.Files;
 import java.nio.file.Path;
 import java.time.Duration;
 import java.util.List;
+import java.util.Properties;
 import java.util.function.Predicate;
 import lombok.Setter;
+import lombok.extern.slf4j.Slf4j;
 import me.itzg.helpers.errors.GenericException;
+import me.itzg.helpers.errors.InvalidContentException;
+import me.itzg.helpers.files.IoStreams;
 import me.itzg.helpers.http.FileDownloadStatusHandler;
 import me.itzg.helpers.http.SharedFetch;
 import me.itzg.helpers.http.UriBuilder;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import reactor.core.publisher.Mono;
+import reactor.core.scheduler.Schedulers;
 import reactor.util.retry.Retry;
 
+@Slf4j
 public class FabricMetaClient {
 
     private final SharedFetch sharedFetch;
@@ -32,7 +40,7 @@ public class FabricMetaClient {
     private Duration retryMinBackoff = Duration.ofMillis(500);
 
     @Setter
-    private int downloadRetryMaxAttempts = 5;
+    private int downloadRetryMaxAttempts = 10;
     @Setter
     private Duration downloadRetryMinBackoff = Duration.ofMillis(500);
 
@@ -134,7 +142,8 @@ public Mono<String> resolveInstallerVersion(String installerVersion) {
 
     public Mono<Path> downloadLauncher(
         Path outputDir, String minecraftVersion, String loaderVersion, String installerVersion,
-        FileDownloadStatusHandler statusHandler
+        FileDownloadStatusHandler statusHandler,
+        boolean skipValidation
     ) {
         return sharedFetch.fetch(
                 uriBuilder.resolve(
@@ -146,9 +155,56 @@ public Mono<Path> downloadLauncher(
             .handleStatus(statusHandler)
             .assemble()
             .retryWhen(Retry.backoff(downloadRetryMaxAttempts, downloadRetryMinBackoff).filter(IOException.class::isInstance))
+            .flatMap(path -> skipValidation ? Mono.just(path) : validateLauncherJar(path))
+            .doOnError(InvalidContentException.class, e -> log.warn("Invalid launcher jar, will try again", e))
+            .retryWhen(Retry.backoff(downloadRetryMaxAttempts, downloadRetryMinBackoff).filter(InvalidContentException.class::isInstance))
             .checkpoint("downloadLauncher");
     }
 
+    private Mono<Path> validateLauncherJar(Path path) {
+        return Mono.fromCallable(() -> {
+                log.debug("Validating Fabric launcher file {}", path);
+
+                if (!path.toFile().isFile()) {
+                    throw new InvalidContentException("Downloaded launcher jar is not a file");
+                }
+                try {
+                    final Properties installProperties = IoStreams.readFileFromZip(path, "install.properties", in -> {
+                            Properties p = new Properties();
+                            p.load(in);
+                            return p;
+                        }
+                    );
+                    if (installProperties == null) {
+                        debugDownloadedContent(path);
+                        throw new InvalidContentException("Downloaded launcher jar does not contain an install.properties");
+                    }
+                    if (!installProperties.containsKey("game-version")) {
+                        debugDownloadedContent(path);
+                        throw new InvalidContentException("Downloaded launcher jar does not contain a valid install.properties");
+                    }
+                } catch (IOException e) {
+                    debugDownloadedContent(path);
+                    throw new InvalidContentException("Downloaded launcher jar could not be read as a jar/zip", e);
+                }
+
+                return path;
+            })
+            .subscribeOn(Schedulers.boundedElastic());
+    }
+
+    private static void debugDownloadedContent(Path path) {
+        if (log.isDebugEnabled()) {
+            try (BufferedReader reader = Files.newBufferedReader(path)) {
+                final char[] buf = new char[100];
+                final int amount = reader.read(buf);
+                log.debug("Downloaded launcher jar content starts with: {}", new String(buf, 0, amount));
+            } catch (IOException e) {
+                throw new GenericException("Failed to read downloaded launcher jar for debugging", e);
+            }
+        }
+    }
+
     @NotNull
     private static Mono<String> findFirst(List<VersionEntry> versionEntries, Predicate<VersionEntry> condition
     ) {
diff --git a/src/main/java/me/itzg/helpers/http/OutputToDirectoryFetchBuilder.java b/src/main/java/me/itzg/helpers/http/OutputToDirectoryFetchBuilder.java
@@ -231,6 +231,10 @@ else if (skipUpToDate) {
                         return failedRequestMono(resp, byteBufFlux.aggregate(), "Downloading file");
                     }
 
+                    if (log.isTraceEnabled()) {
+                        resp.responseHeaders().forEach(header -> log.trace("Response header: {}={}", header.getKey(), header.getValue()));
+                    }
+
                     return copyBodyInputStreamToFile(byteBufFlux, outputFile);
                 })
                 .last()
diff --git a/src/main/java/me/itzg/helpers/http/SharedFetch.java b/src/main/java/me/itzg/helpers/http/SharedFetch.java
@@ -12,9 +12,11 @@
 import lombok.extern.slf4j.Slf4j;
 import me.itzg.helpers.McImageHelper;
 import me.itzg.helpers.errors.GenericException;
-import reactor.netty.http.Http11SslContextSpec;
+import reactor.netty.http.Http2SslContextSpec;
+import reactor.netty.http.HttpProtocol;
 import reactor.netty.http.client.HttpClient;
 import reactor.netty.resources.ConnectionProvider;
+import reactor.netty.tcp.SslProvider.GenericSslContextSpec;
 
 /**
  * Provides an efficient way to make multiple web requests since a single client
@@ -58,6 +60,8 @@ public SharedFetch(String forCommand, Options options) {
 
         reactiveClient = HttpClient.create(connectionProvider)
             .proxyWithSystemProperties()
+            // https://projectreactor.io/docs/netty/release/reference/http-client.html#HTTP2
+            .protocol(HttpProtocol.HTTP11, HttpProtocol.H2)
             .headers(headers -> {
                     headers
                         .set(HttpHeaderNames.USER_AGENT.toString(), userAgent)
@@ -69,11 +73,14 @@ public SharedFetch(String forCommand, Options options) {
             )
             // Reference https://projectreactor.io/docs/netty/release/reference/index.html#response-timeout
             .responseTimeout(options.getResponseTimeout())
-            // Reference https://projectreactor.io/docs/netty/release/reference/index.html#ssl-tls-timeout
             .secure(spec ->
-                spec.sslContext(Http11SslContextSpec.forClient())
+                // Http2 SSL supports both HTTP/2 and HTTP/1.1
+                spec.sslContext((GenericSslContextSpec<?>) Http2SslContextSpec.forClient())
+                // Reference https://projectreactor.io/docs/netty/release/reference/index.html#ssl-tls-timeout
                 .handshakeTimeout(options.getTlsHandshakeTimeout())
-            );
+            )
+
+        ;
 
         headers.put("x-fetch-session", fetchSessionId);
 
diff --git a/src/main/java/me/itzg/helpers/modrinth/ModrinthApiClient.java b/src/main/java/me/itzg/helpers/modrinth/ModrinthApiClient.java
@@ -20,7 +20,6 @@
 import me.itzg.helpers.errors.InvalidParameterException;
 import me.itzg.helpers.http.FailedRequestException;
 import me.itzg.helpers.http.Fetch;
-import me.itzg.helpers.http.FileDownloadedHandler;
 import me.itzg.helpers.http.SharedFetch;
 import me.itzg.helpers.http.SharedFetch.Options;
 import me.itzg.helpers.http.UriBuilder;
@@ -266,10 +265,10 @@ public void close() {
         sharedFetch.close();
     }
 
-    public Mono<Path> downloadFileFromUrl(Path outputFile, URI uri, FileDownloadedHandler fileDownloadedHandler) {
+    public Mono<Path> downloadFileFromUrl(Path outputFile, URI uri) {
         return sharedFetch.fetch(uri)
             .toFile(outputFile)
-            .handleDownloaded(fileDownloadedHandler)
+            .handleStatus(Fetch.loggingDownloadStatusHandler(log))
             .skipExisting(true)
             .assemble();
     }
diff --git a/src/main/java/me/itzg/helpers/modrinth/ModrinthHttpPackFetcher.java b/src/main/java/me/itzg/helpers/modrinth/ModrinthHttpPackFetcher.java
@@ -22,9 +22,7 @@ public class ModrinthHttpPackFetcher implements ModrinthPackFetcher {
     @Override
     public Mono<FetchedPack> fetchModpack(ModrinthModpackManifest prevManifest) {
         return apiClient.downloadFileFromUrl(
-                destFilePath, modpackUri,
-                (uri, file, contentSizeBytes) ->
-                    log.info("Downloaded {}", destFilePath)
+                destFilePath, modpackUri
             )
             .map(mrPackFile -> new FetchedPack(mrPackFile, "custom", deriveVersionId(), deriveVersionName()));
     }
diff --git a/src/main/java/me/itzg/helpers/modrinth/ModrinthPackInstaller.java b/src/main/java/me/itzg/helpers/modrinth/ModrinthPackInstaller.java
@@ -118,6 +118,8 @@ public Mono<Installation> processModpack(SharedFetch sharedFetch) {
                 ));
         }
 
+        log.info("Processing modpack files for {} {}", modpackIndex.getName(), modpackIndex.getVersionId());
+
         return processModFiles(modpackIndex)
             .collectList()
             .map(modFiles ->
@@ -168,9 +170,7 @@ private Flux<Path> processModFiles(ModpackIndex modpackIndex) {
 
                 return this.apiClient.downloadFileFromUrl(
                     outFilePath,
-                    modpackFile.getDownloads().get(0),
-                    (uri, file, contentSizeBytes) ->
-                        log.info("Downloaded {}", modpackFilePath)
+                    modpackFile.getDownloads().get(0)
                 );
             }, maxConcurrentDownloads);
     }
diff --git a/src/test/java/me/itzg/helpers/fabric/FabricLauncherInstallerTest.java b/src/test/java/me/itzg/helpers/fabric/FabricLauncherInstallerTest.java
@@ -56,6 +56,7 @@ void testInstallUsingVersions_onlyGameVersion(WireMockRuntimeInfo wmRuntimeInfo)
         final FabricLauncherInstaller installer = new FabricLauncherInstaller(
             tempDir
         )
+            .setSkipValidation(true)
             .setResultsFile(resultsFile);
         installer.setFabricMetaBaseUrl(wmRuntimeInfo.getHttpBaseUrl());
 
@@ -106,6 +107,7 @@ void testWithProvidedUri(WireMockRuntimeInfo wmRuntimeInfo) throws IOException {
 
         final Path expectedResultsPath = tempDir.resolve("results.env");
         final FabricLauncherInstaller installer = new FabricLauncherInstaller(tempDir)
+            .setSkipValidation(true)
             .setResultsFile(expectedResultsPath);
         final URI loaderUri = URI.create(wmRuntimeInfo.getHttpBaseUrl() + "/fabric-launcher.jar");
 
@@ -142,7 +144,8 @@ void testWithProvidedUri_contentDisposition(WireMockRuntimeInfo wmRuntimeInfo) t
                 )
         );
 
-        final FabricLauncherInstaller installer = new FabricLauncherInstaller(tempDir);
+        final FabricLauncherInstaller installer = new FabricLauncherInstaller(tempDir)
+            .setSkipValidation(true);
         installer.installUsingUri(
             Options.builder().build(), URI.create(wmRuntimeInfo.getHttpBaseUrl() + "/server")
         );
@@ -157,6 +160,7 @@ void testWithProvidedUri_contentDisposition(WireMockRuntimeInfo wmRuntimeInfo) t
     void testWithLocalLauncherFile() throws IOException {
         final Path expectedResultsPath = tempDir.resolve("results.env");
         final FabricLauncherInstaller installer = new FabricLauncherInstaller(tempDir)
+            .setSkipValidation(true)
             .setResultsFile(expectedResultsPath);
 
         final Path launcherFile = Paths.get("src/test/resources/__files/fabric-empty-launcher.jar");
@@ -179,7 +183,8 @@ void testUpgradeFromVersionToVersion(WireMockRuntimeInfo wmRuntimeInfo) {
 
         final FabricLauncherInstaller installer = new FabricLauncherInstaller(
             tempDir
-        );
+        )
+            .setSkipValidation(true);
         installer.setFabricMetaBaseUrl(wmRuntimeInfo.getHttpBaseUrl());
 
         installer.installUsingVersions(
@@ -213,7 +218,8 @@ void testNoNetworkUsageWhenVersionMatches(WireMockRuntimeInfo wmRuntimeInfo) {
 
         final FabricLauncherInstaller installer = new FabricLauncherInstaller(
             tempDir
-        );
+        )
+            .setSkipValidation(true);
         installer.setFabricMetaBaseUrl(wmRuntimeInfo.getHttpBaseUrl());
 
         installer.installUsingVersions(
@@ -255,6 +261,7 @@ void testNoNetworkUsageWhenVersionMatches(WireMockRuntimeInfo wmRuntimeInfo) {
     void forRecordingVersionDiscovery() {
         final Path resultsFile = tempDir.resolve("results.env");
         final FabricLauncherInstaller installer = new FabricLauncherInstaller(tempDir)
+            .setSkipValidation(true)
             .setResultsFile(resultsFile);
         installer.setFabricMetaBaseUrl("http://localhost:8080");
 

Original file line number	Diff line number	Diff line change
`@@ -150,6 +150,8 @@ private static void setLevel(boolean enabled, Level level) {`
`150`	`150`	`if (Level.TRACE.isGreaterOrEqual(level)) {`
`151`	`151`	`((Logger) LoggerFactory.getLogger("org.apache.hc.client5.http")).setLevel(`
`152`	`152`	`enabled ? level : Level.INFO);`
	`153`	`+ ((Logger) LoggerFactory.getLogger("reactor.netty.http.client.HttpClient")).setLevel(`
	`154`	`+ enabled ? level : Level.INFO);`
`153`	`155`	`}`
`154`	`156`	`}`
`155`	`157`
Original file line number	Diff line number	Diff line change
`@@ -22,9 +22,7 @@ public class ModrinthHttpPackFetcher implements ModrinthPackFetcher {`
`22`	`22`	`@Override`
`23`	`23`	`public Mono<FetchedPack> fetchModpack(ModrinthModpackManifest prevManifest) {`
`24`	`24`	`return apiClient.downloadFileFromUrl(`
`25`		`- destFilePath, modpackUri,`
`26`		`- (uri, file, contentSizeBytes) ->`
`27`		`- log.info("Downloaded {}", destFilePath)`
	`25`	`+ destFilePath, modpackUri`
`28`	`26`	`)`
`29`	`27`	`.map(mrPackFile -> new FetchedPack(mrPackFile, "custom", deriveVersionId(), deriveVersionName()));`
`30`	`28`	`}`