How to fix Error: HTTP/2 stream closed (cannot send on closed stream) in Node.js

const http2 = require('http2');
const server = http2.createSecureServer((req, res) => {
  // Check if stream is still writable
  if (!res.writableEnded) {
    res.writeHead(200, { 'Content-Type': 'application/json' });
    res.write(JSON.stringify({ status: 'ok' }));
    res.end();
  } else {
    console.log('Stream already closed, cannot write response');
  }
});

server.listen(443);

const http2 = require('http2');

const server = http2.createSecureServer((req, res) => {
  let canWrite = true;

  // Mark stream as closed when it closes
  res.on('close', () => {
    console.log('Stream closed');
    canWrite = false;
  });

  res.on('error', (err) => {
    console.error('Stream error:', err);
    canWrite = false;
  });

  // Only write if stream is still open
  setTimeout(() => {
    if (canWrite && !res.writableEnded) {
      res.writeHead(200);
      res.end('Response');
    } else {
      console.log('Cannot write, stream is closed');
    }
  }, 100);
});

server.listen(443);

const http2 = require('http2');

const server = http2.createSecureServer((req, res) => {
  // WRONG: Writing headers twice
  // res.writeHead(200);
  // res.writeHead(404);  // Error! Headers already sent

  // CORRECT: Write headers once, then write data
  res.writeHead(200, { 'Content-Type': 'text/plain' });
  res.write('Hello, ');
  res.write('World!');
  res.end();  // Complete the stream properly
});

server.listen(443);

const http2 = require('http2');

const server = http2.createSecureServer((req, res) => {
  res.writeHead(200, { 'Content-Type': 'application/json' });

  const sendData = (data) => {
    try {
      if (!res.writableEnded && !res.destroyed) {
        res.write(JSON.stringify(data));
      }
    } catch (err) {
      if (err.code === 'ERR_HTTP2_STREAM_CLOSED') {
        console.log('Stream was closed, cannot send data');
      } else {
        console.error('Write error:', err);
      }
    }
  };

  // Safe to call multiple times
  sendData({ message: 'First message' });

  setTimeout(() => {
    sendData({ message: 'Second message' });
  }, 1000);

  setTimeout(() => {
    if (!res.writableEnded) {
      res.end();
    }
  }, 2000);
});

server.listen(443);

const http2 = require('http2');

const server = http2.createSecureServer((req, res) => {
  res.writeHead(200);

  // Simulate writing large data
  let canWrite = true;

  const write = (data) => {
    if (!canWrite) {
      console.log('Write buffer full, waiting for drain');
      return;
    }

    try {
      // write returns false if buffer is full
      canWrite = res.write(data);
    } catch (err) {
      console.error('Write error:', err);
      canWrite = false;
    }
  };

  // Resume writing when buffer is drained
  res.on('drain', () => {
    console.log('Buffer drained, can write more');
    canWrite = true;
    // Resume sending data...
  });

  // Close when done
  res.on('close', () => {
    console.log('Stream closed');
  });

  // Write initial chunk
  write('Starting data...\n');
  write('More data...\n');
});

server.listen(443);

const http2 = require('http2');

const server = http2.createSecureServer((req, res) => {
  // Listen for reset from client
  req.on('error', (err) => {
    if (err.code === 'ERR_HTTP2_STREAM_RESET') {
      console.log('Client reset the stream');
    } else {
      console.error('Request error:', err);
    }
  });

  res.on('error', (err) => {
    if (err.code === 'ERR_HTTP2_STREAM_CLOSED') {
      console.log('Cannot write, stream is closed');
    } else {
      console.error('Response error:', err);
    }
  });

  // Safe to attempt write, errors are caught
  try {
    res.writeHead(200);
    res.write('Data');
    res.end();
  } catch (err) {
    console.log('Write failed:', err.code);
  }
});

server.listen(443);