http2: add support for raw header arrays in h2Stream.respond()

doc/api/http2.md

@@ -1082,6 +1082,11 @@
     pr-url: https://github.com/nodejs/node/pull/58313
     description: Following the deprecation of priority signaling as of RFC 9113,
                  `weight` option is deprecated.
+  - version:
+      - v24.0.0
+      - v22.17.0
+    pr-url: https://github.com/nodejs/node/pull/57917
+    description: Allow passing headers in raw array format.
 -->
 
 * `headers` {HTTP/2 Headers Object|Array}
@@ -1856,14 +1861,18 @@
 <!-- YAML
 added: v8.4.0
 changes:
+  - version:
+    - REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/59455
+    description: Allow passing headers in raw array format.
   - version:
     - v14.5.0
     - v12.19.0
     pr-url: https://github.com/nodejs/node/pull/33160
     description: Allow explicitly setting date headers.
 -->
 
-* `headers` {HTTP/2 Headers Object}
+* `headers` {HTTP/2 Headers Object|Array}
 * `options` {Object}
   * `endStream` {boolean} Set to `true` to indicate that the response will not
     include payload data.

lib/internal/http2/core.js

@@ -2541,8 +2541,31 @@ function callStreamClose(stream) {
   stream.close();
 }
 
-function processHeaders(oldHeaders, options) {
-  assertIsObject(oldHeaders, 'headers');
+function prepareResponseHeaders(stream, headersParam, options) {
+  let headers;
+  let statusCode;
+
+  if (ArrayIsArray(headersParam)) {
+    ({
+      headers,
+      statusCode,
+    } = prepareResponseHeadersArray(headersParam, options));
+    stream[kRawHeaders] = headers;
+  } else {
+    ({
+      headers,
+      statusCode,
+    } = prepareResponseHeadersObject(headersParam, options));
+    stream[kSentHeaders] = headers;
+  }
+
+  const headersList = buildNgHeaderString(headers, assertValidPseudoHeaderResponse);
+
+  return { headers, headersList, statusCode };
+}
+
+function prepareResponseHeadersObject(oldHeaders, options) {
+  assertIsObject(oldHeaders, 'headers', ['Object', 'Array']);
   const headers = { __proto__: null };
 
   if (oldHeaders !== null && oldHeaders !== undefined) {
@@ -2563,23 +2586,58 @@ function processHeaders(oldHeaders, options) {
     headers[HTTP2_HEADER_DATE] ??= utcDate();
   }
 
+  validatePreparedResponseHeaders(headers, statusCode);
+
+  return {
+    headers,
+    statusCode: headers[HTTP2_HEADER_STATUS],
+  };
+}
+
+function prepareResponseHeadersArray(headers, options) {
+  let statusCode;
+  let isDateSet = false;
+
+  for (let i = 0; i < headers.length; i += 2) {
+    const header = headers[i].toLowerCase();
+    const value = headers[i + 1];
+
+    if (header === HTTP2_HEADER_STATUS) {
+      statusCode = value | 0;
+    } else if (header === HTTP2_HEADER_DATE) {
+      isDateSet = true;
+    }
+  }
+
+  if (!statusCode) {
+    statusCode = HTTP_STATUS_OK;
+    headers.unshift(HTTP2_HEADER_STATUS, statusCode);
+  }
+
+  if (!isDateSet && (options.sendDate == null || options.sendDate)) {
+    headers.push(HTTP2_HEADER_DATE, utcDate());
+  }
+
+  validatePreparedResponseHeaders(headers, statusCode);
+
+  return { headers, statusCode };
+}
+
+function validatePreparedResponseHeaders(headers, statusCode) {
   // This is intentionally stricter than the HTTP/1 implementation, which
   // allows values between 100 and 999 (inclusive) in order to allow for
   // backwards compatibility with non-spec compliant code. With HTTP/2,
   // we have the opportunity to start fresh with stricter spec compliance.
   // This will have an impact on the compatibility layer for anyone using
   // non-standard, non-compliant status codes.
   if (statusCode < 200 || statusCode > 599)
-    throw new ERR_HTTP2_STATUS_INVALID(headers[HTTP2_HEADER_STATUS]);
+    throw new ERR_HTTP2_STATUS_INVALID(statusCode);
 
   const neverIndex = headers[kSensitiveHeaders];
   if (neverIndex !== undefined && !ArrayIsArray(neverIndex))
     throw new ERR_INVALID_ARG_VALUE('headers[http2.neverIndex]', neverIndex);
-
-  return headers;
 }
 
-
 function onFileUnpipe() {
   const stream = this.sink[kOwner];
   if (stream.ownsFd)
@@ -2882,7 +2940,7 @@ class ServerHttp2Stream extends Http2Stream {
   }
 
   // Initiate a response on this Http2Stream
-  respond(headers, options) {
+  respond(headersParam, options) {
     if (this.destroyed || this.closed)
       throw new ERR_HTTP2_INVALID_STREAM();
     if (this.headersSent)
@@ -2907,15 +2965,16 @@ class ServerHttp2Stream extends Http2Stream {
       state.flags |= STREAM_FLAGS_HAS_TRAILERS;
     }
 
-    headers = processHeaders(headers, options);
-    const headersList = buildNgHeaderString(headers, assertValidPseudoHeaderResponse);
-    this[kSentHeaders] = headers;
+    const {
+      headers,
+      headersList,
+      statusCode,
+    } = prepareResponseHeaders(this, headersParam, options);
 
     state.flags |= STREAM_FLAGS_HEADERS_SENT;
 
     // Close the writable side if the endStream option is set or status
     // is one of known codes with no payload, or it's a head request
-    const statusCode = headers[HTTP2_HEADER_STATUS] | 0;
     if (!!options.endStream ||
         statusCode === HTTP_STATUS_NO_CONTENT ||
         statusCode === HTTP_STATUS_RESET_CONTENT ||
@@ -2945,7 +3004,7 @@ class ServerHttp2Stream extends Http2Stream {
   // regular file, here the fd is passed directly. If the underlying
   // mechanism is not able to read from the fd, then the stream will be
   // reset with an error code.
-  respondWithFD(fd, headers, options) {
+  respondWithFD(fd, headersParam, options) {
     if (this.destroyed || this.closed)
       throw new ERR_HTTP2_INVALID_STREAM();
     if (this.headersSent)
@@ -2982,8 +3041,11 @@ class ServerHttp2Stream extends Http2Stream {
     this[kUpdateTimer]();
     this.ownsFd = false;
 
-    headers = processHeaders(headers, options);
-    const statusCode = headers[HTTP2_HEADER_STATUS] |= 0;
+    const {
+      headers,
+      statusCode,
+    } = prepareResponseHeadersObject(headersParam, options);
+
     // Payload/DATA frames are not permitted in these cases
     if (statusCode === HTTP_STATUS_NO_CONTENT ||
         statusCode === HTTP_STATUS_RESET_CONTENT ||
@@ -3011,7 +3073,7 @@ class ServerHttp2Stream extends Http2Stream {
   // giving the user an opportunity to verify the details and set additional
   // headers. If statCheck returns false, the operation is aborted and no
   // file details are sent.
-  respondWithFile(path, headers, options) {
+  respondWithFile(path, headersParam, options) {
     if (this.destroyed || this.closed)
       throw new ERR_HTTP2_INVALID_STREAM();
     if (this.headersSent)
@@ -3042,8 +3104,11 @@ class ServerHttp2Stream extends Http2Stream {
     this[kUpdateTimer]();
     this.ownsFd = true;
 
-    headers = processHeaders(headers, options);
-    const statusCode = headers[HTTP2_HEADER_STATUS] |= 0;
+    const {
+      headers,
+      statusCode,
+    } = prepareResponseHeadersObject(headersParam, options);
+
     // Payload/DATA frames are not permitted in these cases
     if (statusCode === HTTP_STATUS_NO_CONTENT ||
         statusCode === HTTP_STATUS_RESET_CONTENT ||