Fhi.HelseId.Blazor 1.0.0-beta.1

Fhi.HelseId.Refit

This package contains code to simplify working with Blazor, Refit and HelseId.

Blazor does not currently let you interact with the HttpContext that is needed for normal HelseId funtionallity in a WebApi.

Some of the problems this code solves are

• HttpContext is not availible during most of the Blazor SPA lifetime
• The HelseId tokens are stored in the HttpContext which are not normally availible from most of the rendering tree in the Blazor code.
• The HelseId tokens are stored in the HttpContext which are not normally availible from a normal scoped or transient service when resolved with the ServiceProvider (DI).
• Refit uses HttpClientFactory, which creates transient DelegationHandlers, but they come from a singleton scope! This leads to us being unable to get the HelseId access token by the consumer of a Refit interface.
• We need to update cookies with new token data when refreshing HelseId token

This default setup will add a token handler to your Refit Interface in addition to letting you add multiple delegates if needed (f.ex. logging).

Usage

Include thhis code in your WebApi startup builder (remember to also call "builder.AddHelseIdWebAuthentication()"):

builder.AddHelseIdForBlazor()
    .AddRefitClient<IMyRefitClient>()

...

app.UseHelseIdForBlazor();
app.UseHelseIdForBlazorLogout();

You will also need to wrap your hole App.razor code with a CascadingStates-tag:

<CascadingStates>
    ... all your App.razor HTML ...
</CascadingStates>

If you want to add additional loggers add them before "AddRefitClient":

builder.AddHelseIdForBlazor()
    .AddHandler<MyLoggingDelegationHandler>()
    .AddRefitClient<IMyRefitClient>()

The code loads your configuration from IConfiguration using the section "HelseIdWebKonfigurasjon". If you want to override which section to use you can pass the correct section to AddHelseIdForBlazor:

builder.AddHelseIdForBlazor("HelseIdWebKonfigurasjon")
    .AddRefitClient<IMyRefitClient>()

The default RefitSettings we are using use SystemTextJsonContentSerializer, is case insensitive and use camelCasing. If you want to override the default RefitSettings to use you can pass the settings to AddHelseIdForBlazor:

builder.AddHelseIdForBlazor(new RefitSettings())
    .AddRefitClient<IMyRefitClient>();

Adding Correlation Id to all requests

Use "AddCorrelationId()" to add header propagation of the default FHI correlation id header.

builder.AddHelseIdForBlazor()
    .AddCorrelationId()
    .AddRefitClient<IMyRefitClient>();

A new correlation ID will be given to each request and response that does not contain the header when invoked. Remember to add usage of header propagation to your app startup code:

app.UseHeaderPropagation();

More usage

If you would like to reuse some of the code to access the HttpContext for dependency injection you can hook into the code with custom implementations of a IScopedState:

builder.AddStateHandlers().AddScopedState<UserState>();

An example of a implementation of UserState could be something like this.

public class UserState : IScopedState
{
    public string CorrelationId { get; set; }

    public UserState() // you can even use the constructor for normal dependency injection here!
    {
    }

    public async Task Populate(HttpContext httpContext)
    {
        var headerValue = string.Empty;

        if (httpContext.Request.Headers.TryGetValue("X-Correlation-ID", out var values))
        {
            headerValue = values.FirstOrDefault();
        }
        else if (httpContext.Response.Headers.TryGetValue("X-Correlation-ID", out values))
        {
            headerValue = values.FirstOrDefault();
        }

        CorrelationId = string.IsNullOrEmpty(headerValue) ? Guid.NewGuid().ToString() : headerValue;
    }
}