gqlgen-cache-control-plugin

README

Cache control plugin for GQLGEN

Plugin for gqlgen (https://gqlgen.com/) to write cache-control directives. With this plugin, you can write a cache-control HTTP header and cache-control extension, following Apollo's rules. Refs:

• https://www.apollographql.com/docs/apollo-server/performance/caching/
• https://github.com/apollographql/apollo-server/tree/d5015f4ea00cadb2a74b09956344e6f65c084629/packages/apollo-cache-control

Installation

Install Go module:

$ go get github.com/landrade/gqlgen-cache-control-plugin

Configuring the plugin

package main
import (
	"github.com/landrade/gqlgen-cache-control-plugin/cache"
	"github.com/99designs/gqlgen/graphql/handler"
)
func main() {
	// Building your server
	cfg := generated.Config{Resolvers: &graph.Resolver{}}
	srv := handler.NewDefaultServer(generated.NewExecutableSchema(cfg))
	// Enable cache extensions
	srv.Use(cache.Extension{}) // <----
	//...
}

Set cache hints

After you enable cache.Extension, you can set cache hints using cache.SetHint function in your resolvers.

import (
	"github.com/landrade/gqlgen-cache-control-plugin/cache"
	// ...
)
func (r *commentResolver) Post(ctx context.Context, obj *model.Comment) (*model.Post, error) {
    post, err := // getting post by comment
    if err != nil {
        return nil, err
	}
	// Set a CacheHint
	cache.SetHint(ctx, cache.ScopePublic, 10*time.Second)
	return post, nil
}

CDN Caching

It's possible to enable the Gqlgen to provide a Cache-Control header based on your cache hints in GET or POST requests. To do it you need wrap your server using cache.Middleware function. It will add Cache-Control header to all responses that have set cache.

func main() {
	// ... setup server
	srv = cache.Middleware(srv)
	// ... do more things
}

Doing it, Gqlgen write the lowest max-age defined in cacheControl extensions.

For more informations, see _example folder.