Implement a proxy blocking tarball requests for packages containing malware.

packages/safe-chain/src/registryProxy/parsePackageFromUrl.js

@@ -0,0 +1,48 @@
+export const knownRegistries = ["registry.npmjs.org", "registry.yarnpkg.com"];
+
+export function parsePackageFromUrl(url) {
+  let packageName, version, registry;
+
+  for (const knownRegistry of knownRegistries) {
+    if (url.includes(knownRegistry)) {
+      registry = knownRegistry;
+      break;
+    }
+  }
+
+  if (!registry || !url.endsWith(".tgz")) {
+    return { packageName, version };
+  }
+
+  const registryIndex = url.indexOf(registry);
+  const afterRegistry = url.substring(registryIndex + registry.length + 1); // +1 to skip the slash
+
+  const separatorIndex = afterRegistry.indexOf("/-/");
+  if (separatorIndex === -1) {
+    return { packageName, version };
+  }
+
+  packageName = afterRegistry.substring(0, separatorIndex);
+  const filename = afterRegistry.substring(
+    separatorIndex + 3,
+    afterRegistry.length - 4
+  ); // Remove /-/ and .tgz
+
+  // Extract version from filename
+  // For scoped packages like @babel/core, the filename is core-7.21.4.tgz
+  // For regular packages like lodash, the filename is lodash-4.17.21.tgz
+  if (packageName.startsWith("@")) {
+    const scopedPackageName = packageName.substring(
+      packageName.lastIndexOf("/") + 1
+    );
+    if (filename.startsWith(scopedPackageName + "-")) {
+      version = filename.substring(scopedPackageName.length + 1);
+    }
+  } else {
+    if (filename.startsWith(packageName + "-")) {
+      version = filename.substring(packageName.length + 1);
+    }
+  }
+
+  return { packageName, version };
+}