feat(parser): implement hashing

bun.lock

@@ -18,7 +18,7 @@
     },
     "packages/parser": {
       "name": "@packwizjs/parser",
-      "version": "1.0.2",
+      "version": "1.0.4",
       "dependencies": {
         "@types/semver": "^7.5.8",
         "semver": "^7.7.1",

packages/parser/package.json

@@ -1,7 +1,7 @@
 {
   "name": "@packwizjs/parser",
   "module": "src/index.ts",
-  "version": "1.0.4",
+  "version": "1.1.0",
   "type": "module",
   "description": "A simple library for parsing Packwiz TOML files",
   "author": {

packages/parser/src/enums/hash-format.ts

@@ -1,3 +1,6 @@
+import { createHash } from "crypto";
+//import { murmur2 } from "murmurhash2";
+
 /**
  * The hash formats allowed by Packwiz.
  */
@@ -37,3 +40,22 @@ export function isValidHashFormat(hashFormat: string): HashFormat {
     throw new Error(`Invalid index file hash format: ${hashFormat}`);
   }
 }
+
+export function doHashesMatch(
+  hash: string,
+  hashFormat: HashFormat,
+  data: Buffer,
+): boolean {
+  let computedHash;
+  if (hashFormat === HashFormat.murmur2) {
+    console.log(
+      "WARNING: Murmur2 hash checking is not implemented yet! Skipping hash checking.",
+    );
+    return true;
+    //computedHash = murmur2(data.toString(), 0).toString(16);
+  } else {
+    computedHash = createHash(hashFormat).update(data).digest("hex");
+  }
+  console.log(`Comparing ${hashFormat} hashes: ${hash} vs ${computedHash}`);
+  return hash === computedHash;
+}

packages/parser/src/index.ts

@@ -14,4 +14,8 @@ export {
   CurseForgeProvider,
 } from "./provider";
 export { Side, isValidSide } from "./enums/side";
-export { HashFormat, isValidHashFormat } from "./enums/hash-format";
+export {
+  HashFormat,
+  isValidHashFormat,
+  doHashesMatch,
+} from "./enums/hash-format";

packages/parser/src/parser.ts

@@ -6,7 +6,11 @@ import {
   CurseForgeProvider,
   GitHubProvider,
 } from "./provider";
-import { HashFormat, isValidHashFormat } from "./enums/hash-format";
+import {
+  HashFormat,
+  isValidHashFormat,
+  doHashesMatch,
+} from "./enums/hash-format";
 import { isValidSide, type Side } from "./enums/side";
 import * as semver from "semver";
 
@@ -90,6 +94,16 @@ export class IndexFileEntry {
       );
     }
     const fileContent = await this.file.fetchContents();
+    if (!fileContent) {
+      throw new Error("Unable to fetch metafile contents!");
+    }
+
+    if (!doHashesMatch(this.hash, this.hashFormat, Buffer.from(fileContent))) {
+      throw new Error(
+        `Hash of metafile ${this.file.toString()} does not match!`,
+      );
+    }
+
     const parsed = toml.parse(fileContent);
     const side = isValidSide(parsed.side);
 
@@ -254,6 +268,19 @@ export async function parsePackwiz(filePath: string): Promise<Packwiz> {
   const parsedPackwizFile = toml.parse(await packwizFile.fetchContents());
 
   const indexFile = packwizFile.parent.join(parsedPackwizFile.index.file);
+
+  if (
+    !doHashesMatch(
+      parsedPackwizFile.index.hash,
+      parsedPackwizFile.index["hash-format"],
+      Buffer.from(await indexFile.fetchContents()),
+    )
+  ) {
+    throw new Error(
+      `Hash of index file ${indexFile.toString()} does not match!`,
+    );
+  }
+
   const parsedIndexFile = toml.parse(await indexFile.fetchContents());
   const indexHashFormat = isValidHashFormat(parsedIndexFile["hash-format"]);