ASP.NET
Core SignalR
Linux
▌Problems
We
encountered some issues while dockerizing ASP.NET Core with SignalR on Linux
containers:
1. Websocket connection from client to server will be blocked by using
self-signed SSL certificate.
2. Websocket connection fails when using Nginx reverse proxy
▌Environment
▋ASP.NET Core 2.2.301
▋Microsoft.AspNetCore.SignalR.Client
1.1.0
▌Solutions
▋(Client) Ignore validating insecure SSL cert
To solve the issue:
「Websocket connection from
client to server will be blocked by using self-signed SSL certificate」, we have to bypass validating
the certificate of server by always set validation to success in client side:
HubConnection connection = new HubConnectionBuilder()
.WithUrl(new Uri(this.hubHost), options =>
{
var httpClientHandler = new HttpClientHandler
{
ClientCertificateOptions = ClientCertificateOption.Manual,
ServerCertificateCustomValidationCallback = (httpRequestMessage, cert, cetChain, policyErrors) =>
{
// If this is a development app, you could just return true always
// In production you should ALWAYS either use a trusted cert or check the thumbprint of the cert matches one you expect.
return true;
}
};
options.HttpMessageHandlerFactory = _ => httpClientHandler;
})
.Build();
await connection.StartAsync();
▋(Server) Prevent from buffering asynchronous responses on Nginx
We
have to disable buffering asynchronous response(s) for ONLY SignarlR events in
Nginx.
To
do so, just set proxy_buffering
to off.
Here
is a configuration sample,
▋nginx.conf
http {
sendfile on;
access_log ./nginx_access.log;
error_log ./nginx_error.log;
server{
listen 9999 ssl;
ssl on;
ssl_certificate /etc/certs/docker.crt;
ssl_certificate_key /etc/certs/docker.key;
location / {
proxy_set_header Host $http_host;
proxy_set_header X-Real-IP \$remote_addr;
proxy_set_header X-Forwarded-For \$proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto \$scheme;
proxy_read_timeout 600s;
proxy_pass https://xxx:9999/;
}
location /keyEventHub {
proxy_set_header Host $http_host;
proxy_set_header X-Real-IP \$remote_addr;
proxy_set_header X-Forwarded-For \$proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto \$scheme;
proxy_read_timeout 2m;
proxy_connect_timeout 1m;
proxy_send_timeout 1m;
keepalive_requests 1000;
keepalive_timeout 2m;
send_timeout 1m;
proxy_buffering off;
proxy_pass https://xxx:9999/MyEventHub;
}
}
}
▌Reference
