I have a server in go using gRPC and on the react client I'm using grpc web with grpcwebproxy and I've been trying to connect my client to the server but constantly get error Code 2, with the message: Response closed without headers. Has anybody else encountered this issue? I'm currently using improbable-eng implementation of grpc-web.
You probably need to configure grpcwebproxy for CORS, see this docs.
grpcwebproxy: might have read/write timeout and close your longPolling connection by timeout. Relevant for all client-server streaming calls.
server_http_max_read_timeout – HTTP server config, max read duration (default 10s).
server_http_max_write_timeout – HTTP server config, max write duration (default 10s).
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In http we have a method called CONNECT. I am trying to understand when it is used by the browser.
Is it used prior to every request or prior to every https request only?
Further, as we know - the http protocol makes persistent connection with the server. This connection gets closed after a certain period of inactivity or timeout. So does this concept influence when the CONNECT method is used by the browser? That is - whether CONNECT is used prior to each persistent connection or prior to each request within the persistent connection?
I need to operate with a SOAP service from Erlang. SOAP implementation is not a subject, I have a problem with HTTP requests at a client side.
I use IBrowse as a HTTP client. This SOAP service uses a specific authorization mechanism, which relates an opened session to a client connection (socket). So, the client should use only one persistent connection to server (socket), and if it try to send a request via another socket (e.g., connection from pool) - authorization will fail.
I use IBrowse in this way:
Spawn connection process to server (ibrowse:spawn_worker_process/1)
Send request to server via spawned process with {max_sessions, 1} and {max_pipeline_size, 0}.
If I understand the docs right, this should use one socket for server connection with disabled pipelining, also, I use Connection: Keep-Alive header and HTTP version explicitly set to 1.0. But my connection is always closed after the response is received.
How can I use IBrowse (or another http-client) the way I described above?
I think you could that with hackney by reusing a connection.
Also gun is quite nice http client, easy to use, keeping connection, but with little less connection control.
Can anyone provide an example of a simple HTTP server implemented using Netty, that supports persistent HTTP connections.
In other words, it won't close the connection until the client closes it, and can receive additional HTTP requests over the same connection?
This is exactly one of the things their sample http code demonstrates.
Should I use Timeouts in a HTTP Server implementation?
E.g. if I get a request and create a HTTP Connection to listen to requests with a separate Thread, should this thread use timeouts?
Currently I don't use Timeouts in Debug Code, only in Production code, as to find the lockups in the Server.
As long as you adheres the HTTP specification, I don't forsee problems.
I'm working on Comet support for CppCMS framework via long XMLHttpRequest polls. In many cases, such request is closed by client before any response from server was given -- for example the page is closed, user moves to other page or it is just refeshed.
At the server side I expect that I would recieve the notification that connection is dropped. I tested the application via 3 connectors: FastCGI, SCGI and simple HTTP Proxy.
From 3 major UNIX web servers, Apache2, lighttpd and Nginx, only the last one had closed
connection as expected allowing my application to remove the request from wait queue -- this worked for both FastCGI and HTTP Proxy connectors. (Nginx does not have scgi module by default).
Others, Apache and Lighttpd do not close connection or inform the backend about disconnected
clients, the proceed as if the client is still on line. This happens for all 3 supported APIs: FastCGI, SCGI and HTTP Proxy.
I had opened an issue for Lighttpd, but what
more conserns me is the fact that Apache -- mature and well supported web server as lighttpd
and does not discloses the server backend that client had gone.
Questions:
Is this a bug or this is a feature? Is there any reason not to close the connection between web server and application backend?
Are there real life Comet application working behind these servers via FastCGI/SCGI/HTTP-Proxy backends?
If the above true, how do they deal with this issue? I understand that I can timeout all connections every 10 seconds, but I would like to keep them idle as far as client listens -- because this allows easier scale up -- each connection is very cheep -- the cost is only the opended socket.
Thanks!
(1) Feature. Or, more specifically, fallout from an implementation detail.
A TCP/IP connection does not involve a constant flow of traffic back and forth. Thus, there is no way to know that a client is gone without (a) the client telling you it is closing the connection or (b) a timeout.
(2) I'm not specifically familiar with Comet or CppCMS. But, yes, there are all kinds of CMS servers running behind the mentioned web servers and they all have to deal with this issue (and, yes, it is a pain).
(3) Timeouts are the only way, but you can mitigate the pain, so to speak. Have the client ping the server across the connection every N seconds when there is otherwise no activity. Doesn't have to do anything and you can tack stuff on the reply; notifications of concurrent edits or whatever you need.
You are correct in that it is surprising that mod_fastcgi doesn't support telling the backend that Apache has detected the disconnect or the connection timed out. And you aren't the first to be dismayed.
The second patch on this page should fix that particular issue:
http://osdir.com/ml/web.fastcgi.devel/2006-02/msg00015.html
http://ncannasse.fr/blog/tora_comet
I don't have any concrete information for you, but this article does mention that they can detect when the client has disconnected from Apache. See tora.Queue. And it sounds like the source is available in the neko CVS, so you might be able to find some clues there. Good luck.