Step 6: Sending Responses

5.9 Step 6: Sending Responses

Web servers face similar issues sending data across connections as they do receiving. The server may have many connections to many clients, some idle, some sending data to the server, and some carrying response data back to the clients.

The server needs to keep track of the connection state and handle persistent connections with special care. For nonpersistent connections, the server is expected to close its side of the connection when the entire message is sent.

For persistent connections, the connection may stay open, in which case the server needs to be extra cautious to compute the Content-Length header correctly, or the client will have no way of knowing when a response ends (see Chapter 4).