I am testing my proxy server and have got a problem with connection close header from the client. If I try to response from the server with identity transfer-encoding it's limited with 390 bytes. After reading wireshark I decided that the my problem came from the limits of the tcp.reassembled.length and 390 payload is matches for the 512 of tcp.reassembled.length. Chunked responses doesn't work at all.
As I understand, if the client sends connection-close header the server should answer with only one packet and the sending payload is an undefined behaviour?
"As I understand, if the client sends connection-close header the server should answer with only one packet and the sending payload is an undefined behaviour?"
Not, it means that the server should send the full response and then close the connection.
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I want to send my response data to to client with "Transfer-Encoding:trunked".
But I do not find the way to do it with Golang.
Is there any example for this?
The net/http server does not allow the application to control the transfer encoding.
The net/http server automatically uses chunked encoding when the application does not set the Content-Length response header and the connection can be reused (http/1 client requested keep-alive or http/1.1 client did not request connection close).
I have two questions on HTTP Connection close:
If a client sends a HTTP request with Connection: close to HTTP Server, Is it the HTTP Server or client responsibility to send TCP FIN after response is received by client?
If a client sends a bad formatted HTTP request, and server sends a 400 BAD REQUEST, is it best practice to close the connection by server (even though the HTTP request has connection: keep-alive) or is it good practice to keep the connection still active?
Thanks in advance for answering my queries?
When the server receives a 400 Bad Request, it is going to send the response with the keep-alive header because if the client feels like sending another request, then they can use a pre-existing connection (this connection is shut down within a certain amount of time, it has an expiration date). The Keep-Alive Header is more about not saturating the network with TCP connection demands. You basically say "I am going to talk to you, for 2 minutes, whatever you send me, I'll answer you though this connection"
The server is only an object that receives commands from an user. You ask him, he does or not. The TCP FIN is something you send to the server to shut down the connection, but you choose when you don't want to communicate with him anymore. The client transmits the first FIN, and receives an ACK to ensure that the server got it. Then the server launches its own FIN, and waits for the ACK. If everything is okay, you and your server are no longer friends.
HTTP Protocol: http://greenbytes.de/tech/webdav/draft-ietf-httpbis-p2-semantics-26.html#header.expect
A server that responds with a final status code before reading the entire message body SHOULD indicate in that response whether it intends to close the connection or continue reading and discarding the request message
If the server wish to close the connection it will include "Connection: close" in his response. But how can it tell the client it wish to continue reading and discarding the body ? I don't know any header to do that.
And if it receive the body and discard it, this doesnt mean that "100-Continue" is useless ? That's the whole point of "100-Continue", not sending the body if it will be rejected anyway.
When the server sends its final reply, it has finished processing the request. If the server sends that reply while the client is still sending its data, the client should stop sending, and then the presense of an HTTP keep-alive (an explicit Connection: keep-alive header in an HTTP 1.0 reply, or a missing Connection: close header in an HTTP 1.1 reply) is the server's indication that it will be discarding any remaining data that is sent, since it needs to clear the socket of pending data before it can receive a new request on the same connection.
The 100-Continue is not useless. Think of what happens when the server sends 100 to let the client start sending, then later errors and decides to stop receiving and send a final reply reporting the error. The server did not know at the start of the request that it was going to error.
I know that, the http clients sends 0x10 0x13 bytes to inform the http server that the request data has finished.
But how the server informs the http clients that the response data has finished? (it sends -1 i.e. <EOF> correct)?
No. HTTP Clients do not send CRLF to the server to indicate that the request is complete, and servers do not send a particular byte sequence to the client to indicate completion. You should read this document: http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.4 to understand how clients and servers are able to determine when a request or response is complete. The short summary is that the Content-Length header, Chunked Transfer-encoding terminator, or TCP/IP connection closure are all used as signals.
I have a HTTP client that sets the Connection header to the following value when I make a request:
Connection: close
However when the server sends a response, it is setting the header to Keep-Alive:
Connection: Keep-Alive
This seems intuitively wrong to me, and I am wondering how the client should handle such a response from the server? Also why would a server respond with Keep-Alive, when the client has asked for the connection to be closed, is this valid?
According to the HTTP RFC:
"HTTP/1.1 defines the "close" connection option for the sender to signal that the connection will be closed after completion of the response. For example,
Connection: close
in either the request or the response header fields indicates that the connection SHOULD NOT be considered `persistent' (section 8.1) after the current request/response is complete."
That's fine. You are telling the server you don't support persistent connections and it's telling you it does. Either party is completely valid in closing the connection - it's more of a message about what both supports rather then a YOU MUST CLOSE THIS CONNECTION command.
The client says I will close the connection when the current request/response is finished,or in other words , said you don't support persisten connections. That is, it doesn't tell the server to close the connection. The server replies that it supports persistent connections(keep-alive).
As you've told the server that you don't support persistent connection, you should close the connection when you've read the response.