From f1e93e0475aeac2ebd2c841dcac42be1f0054abf Mon Sep 17 00:00:00 2001 From: cliffhall Date: Wed, 17 Sep 2025 14:45:58 -0400 Subject: [PATCH] * In server/index.ts - in createCustomFetch function - convert finalHeaders to headers object for node-fetch compatibility - for SSE streams, convert node stream to response body to web ReadableStream since EventSource polyfill expects web-compatible stream * In package-lock.json and package.json - add node-fetch as a dependency This fixes #600 --- package-lock.json | 92 +++++++++++++++++++++++++++++++++++++++++++++ package.json | 1 + server/src/index.ts | 72 +++++++++++++++++++++++++++++++++-- 3 files changed, 161 insertions(+), 4 deletions(-) diff --git a/package-lock.json b/package-lock.json index d422148bb..92a40ccf4 100644 --- a/package-lock.json +++ b/package-lock.json @@ -19,6 +19,7 @@ "@modelcontextprotocol/inspector-server": "^0.16.7", "@modelcontextprotocol/sdk": "^1.18.0", "concurrently": "^9.2.0", + "node-fetch": "^3.3.2", "open": "^10.2.0", "shell-quote": "^1.8.3", "spawn-rx": "^5.1.2", @@ -5103,6 +5104,15 @@ "devOptional": true, "license": "MIT" }, + "node_modules/data-uri-to-buffer": { + "version": "4.0.1", + "resolved": "https://registry.npmjs.org/data-uri-to-buffer/-/data-uri-to-buffer-4.0.1.tgz", + "integrity": "sha512-0R9ikRb668HB7QDxT1vkpuUBtqc53YyAwMwGeUFKRojY/NWKvdZ+9UYtRfGmhqNbRkTSVpMbmyhXipFFv2cb/A==", + "license": "MIT", + "engines": { + "node": ">= 12" + } + }, "node_modules/data-urls": { "version": "3.0.2", "resolved": "https://registry.npmjs.org/data-urls/-/data-urls-3.0.2.tgz", @@ -5970,6 +5980,29 @@ "bser": "2.1.1" } }, + "node_modules/fetch-blob": { + "version": "3.2.0", + "resolved": "https://registry.npmjs.org/fetch-blob/-/fetch-blob-3.2.0.tgz", + "integrity": "sha512-7yAQpD2UMJzLi1Dqv7qFYnPbaPx7ZfFK6PiIxQ4PfkGPyNyl2Ugx+a/umUonmKqjhM4DnfbMvdX6otXq83soQQ==", + "funding": [ + { + "type": "github", + "url": "https://github.com/sponsors/jimmywarting" + }, + { + "type": "paypal", + "url": "https://paypal.me/jimmywarting" + } + ], + "license": "MIT", + "dependencies": { + "node-domexception": "^1.0.0", + "web-streams-polyfill": "^3.0.3" + }, + "engines": { + "node": "^12.20 || >= 14.13" + } + }, "node_modules/file-entry-cache": { "version": "8.0.0", "resolved": "https://registry.npmjs.org/file-entry-cache/-/file-entry-cache-8.0.0.tgz", @@ -6154,6 +6187,18 @@ "node": ">= 0.6" } }, + "node_modules/formdata-polyfill": { + "version": "4.0.10", + "resolved": "https://registry.npmjs.org/formdata-polyfill/-/formdata-polyfill-4.0.10.tgz", + "integrity": "sha512-buewHzMvYL29jdeQTVILecSaZKnt/RJWjoZCF5OW60Z67/GmSLBkOFM7qh1PI3zFNtJbaZL5eQu1vLfazOwj4g==", + "license": "MIT", + "dependencies": { + "fetch-blob": "^3.1.2" + }, + "engines": { + "node": ">=12.20.0" + } + }, "node_modules/forwarded": { "version": "0.2.0", "resolved": "https://registry.npmjs.org/forwarded/-/forwarded-0.2.0.tgz", @@ -8716,6 +8761,44 @@ "node": ">= 0.6" } }, + "node_modules/node-domexception": { + "version": "1.0.0", + "resolved": "https://registry.npmjs.org/node-domexception/-/node-domexception-1.0.0.tgz", + "integrity": "sha512-/jKZoMpw0F8GRwl4/eLROPA3cfcXtLApP0QzLmUT/HuPCZWyB7IY9ZrMeKw2O/nFIqPQB3PVM9aYm0F312AXDQ==", + "deprecated": "Use your platform's native DOMException instead", + "funding": [ + { + "type": "github", + "url": "https://github.com/sponsors/jimmywarting" + }, + { + "type": "github", + "url": "https://paypal.me/jimmywarting" + } + ], + "license": "MIT", + "engines": { + "node": ">=10.5.0" + } + }, + "node_modules/node-fetch": { + "version": "3.3.2", + "resolved": "https://registry.npmjs.org/node-fetch/-/node-fetch-3.3.2.tgz", + "integrity": "sha512-dRB78srN/l6gqWulah9SrxeYnxeddIG30+GOqK/9OlLVyLg3HPnr6SqOWTWOXKRwC2eGYCkZ59NNuSgvSrpgOA==", + "license": "MIT", + "dependencies": { + "data-uri-to-buffer": "^4.0.0", + "fetch-blob": "^3.1.4", + "formdata-polyfill": "^4.0.10" + }, + "engines": { + "node": "^12.20.0 || ^14.13.1 || >=16.0.0" + }, + "funding": { + "type": "opencollective", + "url": "https://opencollective.com/node-fetch" + } + }, "node_modules/node-int64": { "version": "0.4.0", "resolved": "https://registry.npmjs.org/node-int64/-/node-int64-0.4.0.tgz", @@ -11504,6 +11587,15 @@ "makeerror": "1.0.12" } }, + "node_modules/web-streams-polyfill": { + "version": "3.3.3", + "resolved": "https://registry.npmjs.org/web-streams-polyfill/-/web-streams-polyfill-3.3.3.tgz", + "integrity": "sha512-d2JWLCivmZYTSIoge9MsgFCZrt571BikcWGYkjC1khllbTeDlGqZ2D8vD8E/lJa8WGWbb7Plm8/XJYV7IJHZZw==", + "license": "MIT", + "engines": { + "node": ">= 8" + } + }, "node_modules/webidl-conversions": { "version": "7.0.0", "resolved": "https://registry.npmjs.org/webidl-conversions/-/webidl-conversions-7.0.0.tgz", diff --git a/package.json b/package.json index 48609a207..a1f704a27 100644 --- a/package.json +++ b/package.json @@ -52,6 +52,7 @@ "@modelcontextprotocol/inspector-server": "^0.16.7", "@modelcontextprotocol/sdk": "^1.18.0", "concurrently": "^9.2.0", + "node-fetch": "^3.3.2", "open": "^10.2.0", "shell-quote": "^1.8.3", "spawn-rx": "^5.1.2", diff --git a/server/src/index.ts b/server/src/index.ts index 7e966d34a..88954ebc5 100644 --- a/server/src/index.ts +++ b/server/src/index.ts @@ -3,6 +3,11 @@ import cors from "cors"; import { parseArgs } from "node:util"; import { parse as shellParseArgs } from "shell-quote"; +import nodeFetch, { Headers as NodeHeaders } from "node-fetch"; + +// Type-compatible wrappers for node-fetch to work with browser-style types +const fetch = nodeFetch; +const Headers = NodeHeaders; import { SSEClientTransport, @@ -231,13 +236,37 @@ const authMiddleware = ( next(); }; +/** + * Converts a Node.js ReadableStream to a web-compatible ReadableStream + * This is necessary for the EventSource polyfill which expects web streams + */ +const createWebReadableStream = (nodeStream: any): ReadableStream => { + return new ReadableStream({ + start(controller) { + nodeStream.on("data", (chunk: any) => { + controller.enqueue(chunk); + }); + nodeStream.on("end", () => { + controller.close(); + }); + nodeStream.on("error", (err: any) => { + controller.error(err); + }); + }, + }); +}; + /** * Creates a `fetch` function that merges dynamic session headers with the * headers from the actual request, ensuring that request-specific headers like - * `Content-Type` are preserved. + * `Content-Type` are preserved. For SSE requests, it also converts Node.js + * streams to web-compatible streams. */ const createCustomFetch = (headerHolder: { headers: HeadersInit }) => { - return (input: RequestInfo | URL, init?: RequestInit): Promise => { + return async ( + input: RequestInfo | URL, + init?: RequestInit, + ): Promise => { // Determine the headers from the original request/init. // The SDK may pass a Request object or a URL and an init object. const originalHeaders = @@ -252,8 +281,43 @@ const createCustomFetch = (headerHolder: { headers: HeadersInit }) => { finalHeaders.set(key, value); }); - // This works for both `fetch(url, init)` and `fetch(request)` style calls. - return fetch(input, { ...init, headers: finalHeaders }); + // Convert Headers to a plain object for node-fetch compatibility + const headersObject: Record = {}; + finalHeaders.forEach((value, key) => { + headersObject[key] = value; + }); + + // Get the response from node-fetch (cast input and init to handle type differences) + const response = await fetch( + input as any, + { ...init, headers: headersObject } as any, + ); + + // Check if this is an SSE request by looking at the Accept header + const acceptHeader = finalHeaders.get("Accept"); + const isSSE = acceptHeader?.includes("text/event-stream"); + + if (isSSE && response.body) { + // For SSE requests, we need to convert the Node.js stream to a web ReadableStream + // because the EventSource polyfill expects web-compatible streams + const webStream = createWebReadableStream(response.body); + + // Create a new response with the web-compatible stream + // Convert node-fetch headers to plain object for web Response compatibility + const responseHeaders: Record = {}; + response.headers.forEach((value: string, key: string) => { + responseHeaders[key] = value; + }); + + return new Response(webStream, { + status: response.status, + statusText: response.statusText, + headers: responseHeaders, + }) as Response; + } + + // For non-SSE requests, return the response as-is (cast to handle type differences) + return response as unknown as Response; }; };