ASP .Net Core Access the DistributedRedisCache in the JWTBearerOptions.Events OnTokenValidated Event - asp.net

Question

I have an ASP .Net Core API Project. In this project I am using JWTBearer Authentication. I am also using the AddDistributedRedisCache feature of the .Net Core Dependency Injection. (Both shown below)
We have a need to blacklist the tokens on occasion (Admin user removing rights, logout, etc) so that these can take immediate effect. Essentially forcing a user to log back in before the next call can be made.
We are adding the JWT Tokens to the redis cache as well as removing them from the client side cache on logout. But a user could (in theory) store the JWT token, and still gain access until the token expires, unless we intercept the call and check it against the blacklist.
How can I access the distributed cache object in the "OnTokenValidated" event in the code below? Do I have to manually create a new connection each time? We are only checking valid tokens, as that will stop invalid requests from even being checked against the blacklist.
Bearer Token Config:
services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
.AddJwtBearer(options =>
{
options.TokenValidationParameters = new TokenValidationParameters
{
ValidateIssuer = true,
ValidateAudience = true,
ValidateLifetime = true,
ValidateIssuerSigningKey = true,
ValidIssuer = "localhost:5000",
ValidAudience = "localhost:5000",
IssuerSigningKey = new SymmetricSecurityKey(
Encoding.UTF8.GetBytes(Configuration.GetValue<string>("SigningKey"))),
};
options.Events = new JwtBearerEvents
{
OnTokenValidated = context => {
//context.Fail("User has been logged out");
return Task.CompletedTask;
}
};
});
Redis Cache Config:
services.AddDistributedRedisCache(option =>
{
option.Configuration = Configuration.GetValue<string>("RedisCacheAddress");
option.InstanceName = Configuration.GetValue<string>("RedisCacheInstance");
});

Answer 1

You can access services in DI utilizing the HttpContext available there:
OnTokenValidated = ctx =>
{
var cache = ctx.HttpContext.RequestServices.GetRequiredService<IDistributedCache>();
return Task.CompletedTask;
}
GetRequiredService will throw an exception if the service is not found. You can use GetService<T>() if you want the service to be optional.