fix(fetch): skip HTTP/2 pseudo-headers in toFetchHeaders

packages/fetch/src/headers.test.ts

@@ -49,3 +49,19 @@ it('toFetchHeaders', () => {
     ['x-custom-header', 'custom-value'],
   ])
 })
+
+it('toFetchHeaders skips http2 pseudo-headers', () => {
+  const standardHeaders: StandardHeaders = {
+    ':method': 'POST',
+    ':path': '/hello?foo=bar',
+    ':scheme': 'https',
+    ':authority': 'example.com',
+    'content-type': 'application/json',
+  }
+
+  const fetchHeaders = toFetchHeaders(standardHeaders)
+
+  expect([...fetchHeaders]).toEqual([
+    ['content-type', 'application/json'],
+  ])
+})

packages/fetch/src/headers.ts

@@ -25,11 +25,19 @@ export function toStandardHeaders(headers: Headers): StandardHeaders {
 
 /**
  * Convert standard headers to fetch headers.
+ *
+ * HTTP/2 pseudo-headers (`:method`, `:path`, ...), which node's http2 request
+ * headers carry, are skipped: they are not header fields (RFC 9113 §8.3) and
+ * fetch rejects their names.
  */
 export function toFetchHeaders(standardHeaders: StandardHeaders): Headers {
   const headers = new Headers()
 
   for (const key of Object.keys(standardHeaders)) {
+    if (key.startsWith(':')) {
+      continue
+    }
+
     const value = standardHeaders[key]
     if (Array.isArray(value)) {
       for (const v of value) {

tests/data-transfer.test.ts

@@ -1,4 +1,5 @@
 import { ErrorEvent, unwrapEvent, withEventMeta } from '@standard-server/core'
+import { toFetchHeaders } from '@standard-server/fetch'
 import { isAsyncIteratorObject, sleep } from '@standard-server/shared'
 import { expectPeerMessages } from './client-server'
 import { createExpressjsClientServerTest } from './client-server.expressjs'
@@ -87,6 +88,8 @@ describe.each([
       ...headers,
       'x-from': 'client',
     })
+    // node http2 request headers carry pseudo-headers, which fetch rejects
+    expect(toFetchHeaders(request.headers).get('x-from')).toEqual('client')
   })
 
   it.each([