Adds dynamic query cache-control

[tobias-tengler]

Allow to annotate the GraphQL schema with caching hints and add middleware that dynamically computes the cache expiration time on a per query basis. In this first iteration these cache hints are used to set the HTTP Cache-Control header, but I've also did some preparation work for custom user-space cache implementation for example using Redis. However there were some open questions around short-circuiting and cache key computation that were stalling the original PR, so I decided to leave them out.

Closes #2089

Examples

The examples below only show how to apply the @cacheControl directive on object type fields, but the directive can also be applied on object types, interfaces and union types. If a field returns a type that specifies a @cacheControl directive, the field will use the cache information from the type, unless the field itself specifies a @cacheControl directive.

Annotation-based

services.AddGraphQLServer()
    .AddHttpQueryCache()
    .UseQueryCachePipeline()
    .ModifyCacheControlOptions(options =>
    {
        options.Enable = true;
        options.ApplyDefaults = true;
        options.DefaultMaxAge = 0;
    })
    .AddQueryType<Query>();

public class Query
{
    [CacheControl(100, Scope = CacheControlScope.Private)]
    public string Foo() => "Bar";
}

Code-first

services.AddGraphQLServer()
    .AddHttpQueryCache()
    .UseQueryCachePipeline()
    .ModifyCacheControlOptions(options =>
    {
        options.Enable = true;
        options.ApplyDefaults = true;
        options.DefaultMaxAge = 0;
    })
    .AddQueryType<QueryType>();

public class QueryType : ObjectType
{
    protected override void Configure(IObjectTypeDescriptor descriptor)
    {
        descriptor.Field("foo")
            .Resolve("bar")
            .CacheControl(100, scope: CacheControlScope.Private);
    }
}

Schema-first

services.AddGraphQLServer()
    .AddHttpQueryCache()
    .UseQueryCachePipeline()
    .ModifyCacheControlOptions(options =>
    {
        options.Enable = true;
        options.ApplyDefaults = true;
        options.DefaultMaxAge = 0;
    })
    .AddDocumentFromString(@"
        type Query {
            foo: String @cacheControl(maxAge: 100 scope: PRIVATE)
        }
    ");

[michaelstaib]

Awesome Tobias, will go through it tonight

[sonarcloud]

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[sonarcloud]

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[zf-jsk]

@tobias-tengler Thanks. with this branch, can we try cacheControl directive. It would be great, if any usage snippets added here.
Also is this targeted with v13, kindly confirm. thanks.

[imranmomin]

@tobias-tengler @michaelstaib Thank you. It would be great if this can be targeted to v13

[tobias-tengler]

@zf-jsk You can try out the HTTP query cache by registering it like this:

services.AddGraphQLServer()
    .AddHttpQueryCache()
    .UseQueryCachePipeline()
    // optional:
    .ModifyCacheControlOptions(options => { })

You can then use the CacheControl() method in Code-first, the [CacheControl] attribute in Annotation-based or the @cacheControl directive in Schema-first to specify rules.

I haven't worked on this in a while, so I'm no longer sure what the current limitations are, but if I remember correctly it should cover basic use cases.

If custom caches are not part of the first iteration then I think this could go into v13. I'll try to spend some time on it to get it usable with HTTP Cache-Control. :)