fix #5 and add local mode for testing

src/main/java/org/quiltmc/Constants.java

@@ -11,6 +11,7 @@ public final class Constants {
     static final String USER_AGENT = "update-quilt-meta/" + TOOL_VERSION;
 
     static final String GROUP = "org.quiltmc";
+    static final boolean TESTING = true;
 
     // Maven
     static final String BASE_MAVEN_URL = "https://maven.quiltmc.org/repository/release/";
@@ -21,12 +22,12 @@ public final class Constants {
 
     // Backblaze
     static final String B2_BUCKET = "meta-quiltmc-org";
-    static final String B2_APP_KEY_ID = System.getenv("B2_APP_KEY_ID");
-    static final String B2_APP_KEY = System.getenv("B2_APP_KEY");
+    static final String B2_APP_KEY_ID = getEnv("B2_APP_KEY_ID");
+    static final String B2_APP_KEY = getEnv("B2_APP_KEY");
 
     // Cloudflare
     static final String CF_ZONE_ID = "73c99d057aa12563eb4cad4ef14f0796";
-    static final String CF_KEY = System.getenv("CF_KEY");
+    static final String CF_KEY = getEnv("CF_KEY");
     static final URL CF_PURGE_FILES_ENDPOINT;
 
     static {
@@ -43,5 +44,10 @@ public final class Constants {
     // Internal
     static final String MANIFEST_FILE = "_manifest_01.gz";
 
+    private static String getEnv(String key) {
+        var env = System.getenv(key);
+        return env == null ? "" : env;
+    }
+
     private Constants() {}
 }

src/main/java/org/quiltmc/LoaderJson.java

@@ -0,0 +1,118 @@
+package org.quiltmc;
+
+import com.google.gson.Gson;
+import com.google.gson.JsonObject;
+import com.google.gson.annotations.SerializedName;
+
+import java.io.BufferedReader;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.net.URL;
+import java.net.URLConnection;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+@SuppressWarnings("unused")
+public class LoaderJson {
+	public int version;
+	@SerializedName("min_java_version")
+	public int minJavaVersion;
+	public Libraries libraries;
+	public MainClass mainClass;
+
+	public static void addSizeAndSignatures(JsonObject json, Gson gson, String mavenId, String url, String expectedExtension, String version) {
+		Library library = createFullyPopulatedLibrary(gson, mavenId, url, expectedExtension, version);
+
+		json.addProperty("md5", library.md5);
+		json.addProperty("sha1", library.sha1);
+		json.addProperty("sha256", library.sha256);
+		json.addProperty("sha512", library.sha512);
+		json.addProperty("size", library.size);
+	}
+
+	public static Library createFullyPopulatedLibrary(Gson gson, String mavenId, String url, String expectedExtension, String version) {
+		LoaderJson.Library asLibrary = new LoaderJson.Library(mavenId, url);
+		LoaderJson.addSizeAndSignatures(gson, asLibrary, expectedExtension, version);
+
+		return asLibrary;
+	}
+
+	public static void addSizeAndSignatures(Gson gson, Library library, String expectedExtension, String loaderVersion) {
+		AtomicBoolean fetchedModuleData = new AtomicBoolean(false);
+		String[] mavenLocation = library.name.split(":");
+		String mavenFolderUrl = library.url + mavenLocation[0].replace('.', '/') + '/' + mavenLocation[1] + '/' + mavenLocation[2] + '/';
+
+		try {
+			// fetch from gradle .module file on maven so we have to do less work
+			URL moduleUrl = new URL(mavenFolderUrl + mavenLocation[1] + '-' + mavenLocation[2] + ".module");
+
+			ModuleData moduleData = ModuleData.readModuleData(gson, moduleUrl);
+			ModuleData.findRuntimeFile(moduleData).ifPresent((file) -> {
+				library.md5 = file.md5;
+				library.sha1 = file.sha1;
+				library.sha256 = file.sha256;
+				library.sha512 = file.sha512;
+				library.size = file.size;
+
+				fetchedModuleData.set(true);
+			});
+		} catch (FileNotFoundException ignored) {
+		} catch (IOException e) {
+			throw new RuntimeException(e);
+		}
+
+		if (!fetchedModuleData.get()) {
+			String jarFileUrl = mavenFolderUrl + mavenLocation[1] + '-' + mavenLocation[2] + "." + expectedExtension;
+
+			try {
+				BufferedReader md5Reader = new BufferedReader(new InputStreamReader(new URL(jarFileUrl + ".md5").openStream()));
+				BufferedReader sha1 = new BufferedReader(new InputStreamReader(new URL(jarFileUrl + ".sha1").openStream()));
+				BufferedReader sha256 = new BufferedReader(new InputStreamReader(new URL(jarFileUrl + ".sha256").openStream()));
+				BufferedReader sha512 = new BufferedReader(new InputStreamReader(new URL(jarFileUrl + ".sha512").openStream()));
+
+				library.md5 = md5Reader.readLine();
+				library.sha1 = sha1.readLine();
+				library.sha256 = sha256.readLine();
+				library.sha512 = sha512.readLine();
+
+				URL url = new URL(jarFileUrl);
+				URLConnection conn = url.openConnection();
+				conn.connect();
+				library.size = conn.getContentLength();
+			} catch (IOException e) {
+				// this cannot be a hard crash because of a funny quirk: the json on quilt loader 0.17.5-beta.4 is completely broken and has ${version} instead of the real versions
+				System.out.println("[WARN] Could not append additional data for loader version: " + loaderVersion + " (artifact: " + mavenLocation[1] + ")");
+				e.printStackTrace();
+			}
+		}
+	}
+
+	public static class Libraries {
+		public List<Library> client;
+		public List<Library> server;
+		public List<Library> common;
+		public List<Library> development;
+	}
+
+	public static class Library {
+		public String name;
+		public String url;
+		public String md5;
+		public String sha1;
+		public String sha256;
+		public String sha512;
+		public int size;
+
+		public Library(String name, String url) {
+			this.name = name;
+			this.url = url;
+		}
+	}
+
+	public static class MainClass {
+		public String client;
+		public String server;
+		public String serverLauncher;
+	}
+}