Deploying behind a reverse proxy

When a Lagoon application is deployed behind a reverse proxy or a gateway, HTTP header forwarding must be enabled.

Enabling HTTP header forwarding

Add the following configuration to appsettings.json:

{
  "Lagoon": {
    "UseForwardedHeaders": true
  }
}

The UseForwardedHeaders middleware is automatically added by Lagoon with the ForwardedHeaders.All option.

For more information, see the Microsoft documentation:

• https://learn.microsoft.com/en-us/dotnet/api/microsoft.aspnetcore.builder.forwardedheadersextensions.useforwardedheaders?view=aspnetcore-8.0
• https://learn.microsoft.com/en-us/dotnet/api/microsoft.aspnetcore.httpoverrides.forwardedheaders?view=aspnetcore-8.0
• https://learn.microsoft.com/fr-fr/aspnet/core/host-and-deploy/proxy-load-balancer?view=aspnetcore-8.0

The OnConfigureForwardedHeaders method lets you customize header forwarding.

"OpenID Connect request cannot be retrieved" error

If GET /connect/authorize returns the The OpenID Connect request cannot be retrieved exception, it is probably because the HTTP request's host name does not match the PublicUrl defined in appsettings.json.

Check that:

• the URL set as PublicUrl is correct;
• the UseForwardedHeaders option is set to true in the configuration file.

Azure Application Gateway

Azure Application Gateway does not send the X-Forwarded-Host header, but the X-Original-Host header instead.

The application configuration must be updated by adding the following method to the Main.cs file of the Server project:

///<inheritdoc/>
protected override void OnConfigureForwardedHeaders(ForwardedHeadersOptions options)
{
    base.OnConfigureForwardedHeaders(options);
    options.ForwardedHostHeaderName = "X-Original-Host";
}

Note

For more flexibility, the value can be read from the configuration.