fix: json compliance layer simplified a little bit (#4630)

Signed-off-by: Mariusz Jasuwienas <[email protected]>

Author: jasuwienas

packages/server/src/compliance.ts

@@ -3,96 +3,57 @@
 import { ConfigService } from '@hashgraph/json-rpc-config-service/dist/services';
 import { ParameterizedContext } from 'koa';
 
-interface JsonRpcSuccess {
-  jsonrpc: unknown;
-  id: string | number | unknown;
-  result: unknown;
-}
-
-interface JsonRpcError {
-  jsonrpc: unknown;
-  id: string | number | unknown;
-  error?: {
-    code?: number;
-    message: unknown;
-    data?: unknown;
-  };
-}
-
-type JsonRpcResponse = JsonRpcSuccess | JsonRpcError;
-type JsonRpcBatch = JsonRpcResponse[];
-type JsonRpcBody = JsonRpcResponse | JsonRpcBatch;
-
 const VALID_JSON_RPC_HTTP_REQUESTS_STATUS_CODE = ConfigService.get('VALID_JSON_RPC_HTTP_REQUESTS_STATUS_CODE');
 
-const isCorrectSuccess = (res: JsonRpcResponse, httpStatus: unknown) =>
-  httpStatus === 200 &&
-  res.jsonrpc === '2.0' &&
-  hasValidId(res.id) &&
-  Object.prototype.hasOwnProperty.call(res, 'result');
-
-const hasValidId = (id: unknown) => Boolean(id !== undefined && id !== null);
-
-const isCorrectError = (res: JsonRpcResponse, httpStatus: unknown) =>
-  httpStatus !== 200 &&
-  res.jsonrpc === '2.0' &&
-  hasValidId(res.id) &&
-  Object.prototype.hasOwnProperty.call(res, 'error') &&
-  typeof (res as JsonRpcError).error?.message === 'string';
-
-const hasCorrectResponseBody = (res: JsonRpcResponse, httpStatus: unknown) =>
-  isCorrectSuccess(res, httpStatus) || isCorrectError(res, httpStatus);
-
-const fixResponseBody = (res: Partial<JsonRpcResponse> | undefined, httpStatus: unknown) => {
-  const id = hasValidId(res?.id) ? (res!.id as string | number) : null;
-  if (httpStatus === 200) {
-    return {
-      jsonrpc: '2.0',
-      id,
-      result: Object.prototype.hasOwnProperty.call(res ?? {}, 'result') ? (res as JsonRpcSuccess).result : '0x',
-    };
-  }
-  const errorObj =
-    'error' in (res ?? {}) && (res as JsonRpcError).error
-      ? {
-          code: (res as JsonRpcError).error!.code ?? -32603,
-          message: (res as JsonRpcError).error!.message,
-        }
-      : {
-          code: -32603,
-          message: 'Internal error',
-        };
+const FALLBACK_RESPONSE_BODY = {
+  jsonrpc: '2.0',
+  id: null,
+  error: { code: -32600, message: 'Request body is empty; expected a JSON-RPC 2.0 request' },
+};
 
-  return {
-    jsonrpc: '2.0',
-    id,
-    error: errorObj,
-  };
+export const INVALID_METHOD_RESPONSE_BODY = {
+  ...FALLBACK_RESPONSE_BODY,
+  error: { code: -32600, message: 'Invalid HTTP method: only POST is allowed' },
 };
 
 /**
  * Ensures a JSON-RPC response uses a valid JSON-RPC 2.0 structure.
  * Normalizes missing or invalid fields for both single and batch responses.
  * May update HTTP status depending on VALID_JSON_RPC_HTTP_REQUESTS_STATUS_CODE.
  *
- * This function must be invoked in any place where Koa's `next()` might not run,
- * or where the response may bypass normal middleware cleanup - so it's not implemented as a KOA's middleware.
- *
  * @param {ParameterizedContext} ctx - Koa context containing status and body.
  */
-export const jsonRpcComplianceLayer = async (ctx: ParameterizedContext) => {
-  const body = ctx.body as JsonRpcBody | undefined;
-  if (!body) {
-    ctx.body = fixResponseBody(undefined, ctx.status);
-    ctx.status = VALID_JSON_RPC_HTTP_REQUESTS_STATUS_CODE ? 200 : 400;
+export const jsonRpcComplianceLayer = async (
+  ctx: {
+    body: {
+      jsonrpc: unknown;
+      id: unknown;
+      result?: unknown;
+      error?: { code: unknown; message: unknown };
+    };
+    status: number | undefined;
+  } & ParameterizedContext,
+) => {
+  if (!ctx.body) {
+    ctx.status = 400;
+    ctx.body = FALLBACK_RESPONSE_BODY;
     return;
   }
-  if (Array.isArray(body)) {
-    // Regardless of the mode the batch requests will always return 200;
+
+  // Always return 200 for array requests.
+  if (Array.isArray(ctx.body)) {
     ctx.status = 200;
     return;
   }
+  if (typeof ctx.body !== 'object') {
+    ctx.status = 400;
+    ctx.body = FALLBACK_RESPONSE_BODY;
+    return;
+  }
 
-  if (!hasCorrectResponseBody(body, ctx.status)) ctx.body = fixResponseBody(body, ctx.status);
+  if (!ctx.body.jsonrpc) ctx.body.jsonrpc = FALLBACK_RESPONSE_BODY.jsonrpc;
+  if (!ctx.body.id) ctx.body.id = FALLBACK_RESPONSE_BODY.id;
+  if (ctx.status === 200 && !ctx.body.result) ctx.body.result = '0x';
+  if (ctx.status === 400 && (!ctx.body.error || !ctx.body.error.code)) ctx.body.error = FALLBACK_RESPONSE_BODY.error;
   if (ctx.status === 400 && VALID_JSON_RPC_HTTP_REQUESTS_STATUS_CODE) ctx.status = 200;
 };

packages/server/src/server.ts

@@ -6,14 +6,13 @@ import { ConfigService } from '@hashgraph/json-rpc-config-service/dist/services'
 import { Relay } from '@hashgraph/json-rpc-relay/dist';
 import { RedisClientManager } from '@hashgraph/json-rpc-relay/dist/lib/clients/redisClientManager';
 import fs from 'fs';
-import { ParameterizedContext } from 'koa';
 import cors from 'koa-cors';
 import path from 'path';
 import pino from 'pino';
 import { collectDefaultMetrics, Histogram, Registry } from 'prom-client';
 import { v4 as uuid } from 'uuid';
 
-import { jsonRpcComplianceLayer } from './compliance';
+import { INVALID_METHOD_RESPONSE_BODY, jsonRpcComplianceLayer } from './compliance';
 import { formatRequestIdMessage } from './formatters';
 import KoaJsonRpc from './koaJsonRpc';
 import { spec } from './koaJsonRpc/lib/RpcError';
@@ -276,8 +275,8 @@ export async function initializeServer() {
       await next();
       return;
     }
-    ctx.status = 400;
-    await jsonRpcComplianceLayer(ctx);
+    ctx.status = 403;
+    ctx.body = INVALID_METHOD_RESPONSE_BODY;
   });
 
   app.use((ctx, next) => {
@@ -306,11 +305,13 @@ export async function initializeServer() {
 
   const rpcApp = koaJsonRpc.rpcApp();
 
-  app.use(async (ctx) => {
+  app.use(async (ctx, next) => {
     await rpcApp(ctx);
-    await jsonRpcComplianceLayer(ctx);
+    await next();
   });
 
+  app.use(jsonRpcComplianceLayer);
+
   process.on('unhandledRejection', (reason, p) => {
     logger.error(`Unhandled Rejection at: Promise: ${JSON.stringify(p)}, reason: ${reason}`);
   });