Add interceptors for MITM

packages/safe-chain/src/registryProxy/interceptors/interceptorBuilder.js

@@ -0,0 +1,50 @@
+/**
+ * @typedef {import('./requestInterceptorBuilder.js').RequestInterceptorBuilder} RequestInterceptorBuilder
+ * @typedef {import('./requestInterceptorBuilder.js').RequestInterceptor} RequestInterceptor
+ *
+ * @typedef {Object} InterceptorBuilder
+ * @property {(requestFunc: (requestHandlerBuilder: RequestInterceptorBuilder) => Promise<void>) => void} onRequest
+ * @property {() => Interceptor} build
+ *
+ * @typedef {Object} Interceptor
+ * @property {(targetUrl: string) => Promise<RequestInterceptor>} handleRequest
+ */
+
+import { createRequestInterceptorBuilder } from "./requestInterceptorBuilder.js";
+
+/**
+ * @returns {InterceptorBuilder}
+ */
+export function createInterceptorBuilder() {
+  /**
+   * @type {Array<(requestHandlerBuilder: RequestInterceptorBuilder) => Promise<void>>}
+   */
+  const requestHandlers = [];
+
+  return {
+    onRequest(requestFunc) {
+      requestHandlers.push(requestFunc);
+    },
+    build() {
+      return buildInterceptor(requestHandlers);
+    },
+  };
+}
+
+/**
+ * @param {Array<(requestHandlerBuilder: RequestInterceptorBuilder) => Promise<void>>} requestHandlers
+ * @returns {Interceptor}
+ */
+function buildInterceptor(requestHandlers) {
+  return {
+    async handleRequest(targetUrl) {
+      const reqInterceptorBuilder = createRequestInterceptorBuilder(targetUrl);
+
+      for (const handler of requestHandlers) {
+        await handler(reqInterceptorBuilder);
+      }
+
+      return reqInterceptorBuilder.build();
+    },
+  };
+}