http2: respondWith* to the new error handling

Fixes: nodejs#14963

doc/api/http2.md

@@ -1118,6 +1118,8 @@ added: v8.4.0
 * `headers` {[Headers Object][]}
 * `options` {Object}
   * `statCheck` {Function}
+  * `onError` {Function} Callback function invoked in the case of an
+    Error before send
   * `getTrailers` {Function} Callback function invoked to collect trailer
     headers.
   * `offset` {number} The offset position at which to begin reading
@@ -1146,6 +1148,16 @@ server.on('stream', (stream) => {
   function statCheck(stat, headers) {
     headers['last-modified'] = stat.mtime.toUTCString();
   }
+
+  function onError(err) {
+    if (err.code === 'ENOENT') {
+      stream.respond({ ':status': 404 });
+    } else {
+      stream.respond({ ':status': 500 });
+    }
+    stream.end();
+  }
+
   stream.respondWithFile('/some/file',
                          { 'content-type': 'text/plain' },
                          { statCheck });
@@ -1178,6 +1190,10 @@ The `offset` and `length` options may be used to limit the response to a
 specific range subset. This can be used, for instance, to support HTTP Range
 requests.
 
+The `options.onError` function may also be used to handle all the errors
+that could happen before the delivery of the file is initiated. The
+default behavior is to destroy the stream.
+
 When set, the `options.getTrailers()` function is called immediately after
 queuing the last chunk of payload data to be sent. The callback is passed a
 single object (with a `null` prototype) that the listener may used to specify

lib/internal/http2/core.js

@@ -1640,13 +1640,24 @@ function doSendFileFD(session, options, fd, headers, getTrailers, err, stat) {
     abort(this);
     return;
   }
+  const onError = options.onError;
+
   if (err) {
-    process.nextTick(() => this.emit('error', err));
+    if (onError) {
+      onError(err);
+    } else {
+      this.destroy(err);
+    }
     return;
   }
+
   if (!stat.isFile()) {
     err = new errors.Error('ERR_HTTP2_SEND_FILE');
-    process.nextTick(() => this.emit('error', err));
+    if (onError) {
+      onError(err);
+    } else {
+      this.destroy(err);
+    }
     return;
   }
 
@@ -1683,12 +1694,17 @@ function doSendFileFD(session, options, fd, headers, getTrailers, err, stat) {
 
 function afterOpen(session, options, headers, getTrailers, err, fd) {
   const state = this[kState];
+  const onError = options.onError;
   if (this.destroyed || session.destroyed) {
     abort(this);
     return;
   }
   if (err) {
-    process.nextTick(() => this.emit('error', err));
+    if (onError) {
+      onError(err);
+    } else {
+      this.destroy(err);
+    }
     return;
   }
   state.fd = fd;

test/parallel/test-http2-respond-file-404.js

@@ -0,0 +1,48 @@
+// Flags: --expose-http2
+'use strict';
+
+const common = require('../common');
+if (!common.hasCrypto)
+  common.skip('missing crypto');
+const http2 = require('http2');
+const assert = require('assert');
+const path = require('path');
+
+const {
+  HTTP2_HEADER_CONTENT_TYPE
+} = http2.constants;
+
+const server = http2.createServer();
+server.on('stream', (stream) => {
+  const file = path.join(process.cwd(), 'not-a-file');
+  stream.respondWithFile(file, {
+    [HTTP2_HEADER_CONTENT_TYPE]: 'text/plain'
+  }, {
+    onError(err) {
+      common.expectsError({
+        code: 'ENOENT',
+        type: Error,
+        message: `ENOENT: no such file or directory, open '${file}'`
+      })(err);
+
+      stream.respond({ ':status': 404 });
+      stream.end();
+    },
+    statCheck: common.mustNotCall()
+  });
+});
+server.listen(0, () => {
+
+  const client = http2.connect(`http://localhost:${server.address().port}`);
+  const req = client.request();
+
+  req.on('response', common.mustCall((headers) => {
+    assert.strictEqual(headers[':status'], 404);
+  }));
+  req.on('data', common.mustNotCall());
+  req.on('end', common.mustCall(() => {
+    client.destroy();
+    server.close();
+  }));
+  req.end();
+});

test/parallel/test-http2-respond-file-error-dir.js

@@ -0,0 +1,46 @@
+// Flags: --expose-http2
+'use strict';
+
+const common = require('../common');
+if (!common.hasCrypto)
+  common.skip('missing crypto');
+const http2 = require('http2');
+const assert = require('assert');
+
+const {
+  HTTP2_HEADER_CONTENT_TYPE
+} = http2.constants;
+
+const server = http2.createServer();
+server.on('stream', (stream) => {
+  stream.respondWithFile(process.cwd(), {
+    [HTTP2_HEADER_CONTENT_TYPE]: 'text/plain'
+  }, {
+    onError(err) {
+      common.expectsError({
+        code: 'ERR_HTTP2_SEND_FILE',
+        type: Error,
+        message: 'Only regular files can be sent'
+      })(err);
+
+      stream.respond({ ':status': 404 });
+      stream.end();
+    },
+    statCheck: common.mustNotCall()
+  });
+});
+server.listen(0, () => {
+
+  const client = http2.connect(`http://localhost:${server.address().port}`);
+  const req = client.request();
+
+  req.on('response', common.mustCall((headers) => {
+    assert.strictEqual(headers[':status'], 404);
+  }));
+  req.on('data', common.mustNotCall());
+  req.on('end', common.mustCall(() => {
+    client.destroy();
+    server.close();
+  }));
+  req.end();
+});