Add ability to parse JSON trusted setup to text format expected by C-KZG

bindings/node.js/.gitignore

@@ -2,3 +2,4 @@ build
 dist
 *.node
 node_modules
+testing_trusted_setups.txt

bindings/node.js/.npmignore

@@ -18,3 +18,4 @@ babel.config.js
 Dockerfile
 binding.dist.gyp
 Makefile
+testing_trusted_setups.txt

bindings/node.js/Dockerfile

@@ -4,7 +4,7 @@ FROM node:16
 
 COPY ./dist/ /app/dist/
 COPY test.ts /app
-COPY trusted_setup.txt /app
+COPY testing_trusted_setups.json /app
 COPY kzg.ts /app
 COPY kzg.cxx /app
 COPY package.json /app

bindings/node.js/Makefile

@@ -32,7 +32,5 @@ publish: bundle
 
 
 linux-test: bundle
-	cp ../../src/trusted_setup.txt .
 	docker build -t "linux-test" .
-	rm trusted_setup.txt
 	docker logs --follow `docker run -d linux-test`

bindings/node.js/kzg.cxx

@@ -86,7 +86,7 @@ Napi::Value LoadTrustedSetup(const Napi::CallbackInfo& info) {
 
   if (f == NULL) {
     free(kzg_settings);
-    Napi::Error::New(env, "Error opening trusted setup file").ThrowAsJavaScriptException();
+    Napi::Error::New(env, "Error opening trusted setup file: " + file_path).ThrowAsJavaScriptException();
     return env.Null();
   }
 

bindings/node.js/kzg.ts

@@ -3,6 +3,7 @@
  * https://github.com/ethereum/consensus-specs/blob/dev/specs/eip4844/polynomial-commitments.md#kzg
  */
 const kzg: KZG = require("./kzg.node");
+const fs = require("fs");
 
 export type BLSFieldElement = Uint8Array; // 32 bytes
 export type KZGProof = Uint8Array; // 48 bytes
@@ -44,6 +45,13 @@ type KZG = {
   ) => boolean;
 };
 
+type TrustedSetupJSON = {
+  setup_G1: string[];
+  setup_G2: string[];
+  setup_G1_lagrange: string[];
+  roots_of_unity: string[];
+};
+
 export const FIELD_ELEMENTS_PER_BLOB = kzg.FIELD_ELEMENTS_PER_BLOB;
 export const BYTES_PER_FIELD_ELEMENT = kzg.BYTES_PER_FIELD_ELEMENT;
 
@@ -57,12 +65,38 @@ function requireSetupHandle(): SetupHandle {
   return setupHandle;
 }
 
+export async function transformTrustedSetupJSON(
+  filePath: string,
+): Promise<string> {
+  const data: TrustedSetupJSON = JSON.parse(fs.readFileSync(filePath));
+
+  const textFilePath = filePath.replace(".json", "") + ".txt";
+
+  try {
+    fs.unlinkSync(textFilePath);
+  } catch {}
+
+  const file = fs.createWriteStream(textFilePath);
+  file.write(`${FIELD_ELEMENTS_PER_BLOB}\n65\n`);
+  file.write(data.setup_G1.map((p) => p.replace("0x", "")).join("\n"));
+  file.write(data.setup_G2.map((p) => p.replace("0x", "")).join("\n"));
+  file.end();
+
+  const p = new Promise((resolve) => {
+    file.close(resolve);
+  });
+
+  await p;
+  return textFilePath;
+}
+
 export function loadTrustedSetup(filePath: string): void {
   if (setupHandle) {
     throw new Error(
       "Call freeTrustedSetup before loading a new trusted setup.",
     );
   }
+
   setupHandle = kzg.loadTrustedSetup(filePath);
 }
 

bindings/node.js/test.ts

@@ -9,9 +9,10 @@ import {
   verifyAggregateKzgProof,
   BYTES_PER_FIELD_ELEMENT,
   FIELD_ELEMENTS_PER_BLOB,
+  transformTrustedSetupJSON,
 } from "./kzg";
 
-const setupFileName = "trusted_setup.txt";
+const setupFileName = "testing_trusted_setups.json";
 
 const SETUP_FILE_PATH = existsSync(setupFileName)
   ? setupFileName
@@ -22,8 +23,9 @@ const BLOB_BYTE_COUNT = FIELD_ELEMENTS_PER_BLOB * BYTES_PER_FIELD_ELEMENT;
 const generateRandomBlob = () => new Uint8Array(randomBytes(BLOB_BYTE_COUNT));
 
 describe("C-KZG", () => {
-  beforeAll(() => {
-    loadTrustedSetup(SETUP_FILE_PATH);
+  beforeAll(async () => {
+    const file = await transformTrustedSetupJSON(SETUP_FILE_PATH);
+    loadTrustedSetup(file);
   });
 
   afterAll(() => {