From 5cefe245affc55312abbf7e4547aba20b62634b6 Mon Sep 17 00:00:00 2001
From: Derrick Hammer <derrick@derrickhammer.com>
Date: Sun, 31 Jul 2022 23:00:17 -0400
Subject: [PATCH] *Use custom json flatten algorithm to ensure deterministic
 hashing

---
 package.json    |  1 -
 src/rpcQuery.ts | 11 ++++++-----
 src/util.ts     | 51 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 57 insertions(+), 6 deletions(-)
 create mode 100644 src/util.ts

diff --git a/package.json b/package.json
index 7c32f40..7dccfeb 100644
--- a/package.json
+++ b/package.json
@@ -15,7 +15,6 @@
     },
     "dependencies": {
         "@hyperswarm/dht": "^6.0.1",
-        "json-stable-stringify": "^1.0.1",
         "libskynet": "^0.0.61",
         "msgpackr": "^1.6.1"
     }
diff --git a/src/rpcQuery.ts b/src/rpcQuery.ts
index 97feddd..6f3ca9f 100644
--- a/src/rpcQuery.ts
+++ b/src/rpcQuery.ts
@@ -4,8 +4,7 @@ import { pack, unpack } from "msgpackr";
 import { RPCRequest, RPCResponse } from "./types";
 import { Buffer } from "buffer";
 import { blake2b } from "libskynet";
-
-import jsonStringify from "json-stable-stringify";
+import { flatten } from "./util.js";
 
 export default class RpcQuery {
   private _network: RpcNetwork;
@@ -100,22 +99,24 @@ export default class RpcQuery {
 
   private checkResponses() {
     const responseStore = this._responses;
-
     const responseStoreData = Object.values(responseStore);
 
     type ResponseGroup = { [response: string]: number };
 
     const responseObjects = responseStoreData.reduce((output: any, item) => {
+      const itemFlattened = flatten(item?.data).sort();
+
       const hash = Buffer.from(
-        blake2b(Buffer.from(jsonStringify(item?.data)))
+        blake2b(Buffer.from(JSON.stringify(itemFlattened)))
       ).toString("hex");
       output[hash] = item?.data;
       return output;
     }, {});
     const responses: ResponseGroup = responseStoreData.reduce(
       (output: ResponseGroup, item) => {
+        const itemFlattened = flatten(item?.data).sort();
         const hash = Buffer.from(
-          blake2b(Buffer.from(jsonStringify(item?.data)))
+          blake2b(Buffer.from(JSON.stringify(itemFlattened)))
         ).toString("hex");
         output[hash] = output[hash] ?? 0;
         output[hash]++;
diff --git a/src/util.ts b/src/util.ts
new file mode 100644
index 0000000..4a10b97
--- /dev/null
+++ b/src/util.ts
@@ -0,0 +1,51 @@
+function isBuffer(obj: any): boolean {
+  return (
+    obj &&
+    obj.constructor &&
+    typeof obj.constructor.isBuffer === "function" &&
+    obj.constructor.isBuffer(obj)
+  );
+}
+/*
+Forked from https://github.com/hughsk/flat
+ */
+export function flatten(target: any, opts: any = {}): any[] {
+  opts = opts || {};
+
+  const delimiter = opts.delimiter || ".";
+  const maxDepth = opts.maxDepth;
+  const transformKey =
+    opts.transformKey || ((key: any) => (isNaN(parseInt(key)) ? key : ""));
+  const output: any[] = [];
+
+  function step(object: any, prev?: any, currentDepth?: any) {
+    currentDepth = currentDepth || 1;
+    Object.keys(object).forEach(function (key) {
+      const value = object[key];
+      const isarray = opts.safe && Array.isArray(value);
+      const type = Object.prototype.toString.call(value);
+      const isbuffer = isBuffer(value);
+      const isobject = type === "[object Object]" || type === "[object Array]";
+
+      const newKey = prev
+        ? prev + delimiter + transformKey(key)
+        : transformKey(key);
+
+      if (
+        !isarray &&
+        !isbuffer &&
+        isobject &&
+        Object.keys(value).length &&
+        (!opts.maxDepth || currentDepth < maxDepth)
+      ) {
+        return step(value, newKey, currentDepth + 1);
+      }
+
+      output.push(`${newKey}=${value}`);
+    });
+  }
+
+  step(target);
+
+  return output;
+}