ev/pkg/gql/resolver/resolver.go

142 lines
3.6 KiB
Go

package resolver
import (
"context"
"fmt"
"net/http"
"os"
"reflect"
"runtime/debug"
"time"
"github.com/99designs/gqlgen/graphql"
"github.com/99designs/gqlgen/graphql/handler"
"github.com/99designs/gqlgen/graphql/handler/extension"
"github.com/99designs/gqlgen/graphql/handler/lru"
"github.com/99designs/gqlgen/graphql/handler/transport"
"github.com/vektah/gqlparser/v2/gqlerror"
"github.com/gorilla/websocket"
"github.com/ravilushqa/otelgqlgen"
"github.com/sour-is/ev/internal/lg"
"github.com/sour-is/ev/pkg/gql/graphiql"
"github.com/sour-is/ev/pkg/gql/playground"
)
type BaseResolver interface {
ExecutableSchema() graphql.ExecutableSchema
BaseResolver() IsResolver
}
type Resolver[T BaseResolver] struct {
res T
}
type IsResolver interface {
IsResolver()
}
func New[T BaseResolver](ctx context.Context, base T, resolvers ...IsResolver) (*Resolver[T], error) {
_, span := lg.Span(ctx)
defer span.End()
v := reflect.ValueOf(base)
v = reflect.Indirect(v)
noop := reflect.ValueOf(base.BaseResolver())
outer:
for _, idx := range reflect.VisibleFields(v.Type()) {
field := v.FieldByIndex(idx.Index)
for i := range resolvers {
rs := reflect.ValueOf(resolvers[i])
if field.IsNil() && rs.Type().Implements(field.Type()) {
span.AddEvent(fmt.Sprint("found ", field.Type().Name()))
field.Set(rs)
continue outer
}
}
span.AddEvent(fmt.Sprint("default ", field.Type().Name()))
field.Set(noop)
}
return &Resolver[T]{base}, nil
}
func (r *Resolver[T]) Resolver() T {
return r.res
}
// ChainMiddlewares will check all embeded resolvers for a GetMiddleware func and add to handler.
func (r *Resolver[T]) ChainMiddlewares(h http.Handler) http.Handler {
v := reflect.ValueOf(r) // Get reflected value of *Resolver
v = reflect.Indirect(v) // Get the pointed value (returns a zero value on nil)
n := v.NumField() // Get number of fields to iterate over.
for i := 0; i < n; i++ {
f := v.Field(i)
if !f.CanInterface() { // Skip non-interface types.
continue
}
if iface, ok := f.Interface().(interface {
GetMiddleware() func(http.Handler) http.Handler
}); ok {
h = iface.GetMiddleware()(h) // Append only items that fulfill the interface.
}
}
return h
}
func (r *Resolver[T]) RegisterHTTP(mux *http.ServeMux) {
gql := NewServer(r.res.ExecutableSchema())
gql.SetRecoverFunc(NoopRecover)
gql.Use(otelgqlgen.Middleware())
mux.Handle("/graphiql", graphiql.Handler("GraphiQL playground", "/gql"))
mux.Handle("/gql", lg.Htrace(r.ChainMiddlewares(gql), "gql"))
mux.Handle("/playground", playground.Handler("GraphQL playground", "/gql"))
}
func NoopRecover(ctx context.Context, err interface{}) error {
if err, ok := err.(string); ok && err == "not implemented" {
return gqlerror.Errorf("not implemented")
}
fmt.Fprintln(os.Stderr, err)
fmt.Fprintln(os.Stderr)
debug.PrintStack()
return gqlerror.Errorf("internal system error")
}
func NewServer(es graphql.ExecutableSchema) *handler.Server {
srv := handler.New(es)
srv.AddTransport(transport.Websocket{
Upgrader: websocket.Upgrader{
CheckOrigin: func(r *http.Request) bool {
switch r.Header.Get("Origin") {
case "https://ev.sour.is", "https://www.graphqlbin.com", "http://localhost:8080":
return true
default:
return false
}
},
},
KeepAlivePingInterval: 10 * time.Second,
})
srv.AddTransport(transport.Options{})
srv.AddTransport(transport.GET{})
srv.AddTransport(transport.POST{})
srv.AddTransport(transport.MultipartForm{})
srv.SetQueryCache(lru.New(1000))
srv.Use(extension.Introspection{})
srv.Use(extension.AutomaticPersistedQuery{
Cache: lru.New(100),
})
return srv
}