Add an example for getting the selection sets from ctx

example/selection/models_gen.go

@@ -0,0 +1,21 @@
+// This file was generated by github.com/vektah/gqlgen, DO NOT EDIT
+
+package selection
+
+import (
+	time "time"
+)
+
+type Event interface{}
+type Like struct {
+	Reaction  string
+	Sent      time.Time
+	Selection []string
+	Collected []string
+}
+type Post struct {
+	Message   string
+	Sent      time.Time
+	Selection []string
+	Collected []string
+}

example/selection/readme.md

@@ -0,0 +1,10 @@
+### todo app
+
+This is the simplest example of a graphql server.
+
+to run this server
+```bash
+go run ./example/todo/server/server.go
+```
+
+and open http://localhost:8081 in your browser

example/selection/schema.graphql

@@ -0,0 +1,24 @@
+interface Event {
+    selection: [String!]
+    collected: [String!]
+}
+
+type Post implements Event {
+    message: String!
+    sent: Time!
+    selection: [String!]
+    collected: [String!]
+}
+
+type Like implements Event {
+    reaction: String!
+    sent: Time!
+    selection: [String!]
+    collected: [String!]
+}
+
+type Query {
+    events: [Event]
+}
+
+scalar Time

example/selection/selection.go

@@ -0,0 +1,62 @@
+//go:generate gorunpkg github.com/vektah/gqlgen -out generated.go
+
+package selection
+
+import (
+	context "context"
+	"fmt"
+	"time"
+
+	"github.com/vektah/gqlgen/graphql"
+	query "github.com/vektah/gqlgen/neelance/query"
+)
+
+type SelectionResolver struct{}
+
+func (r *SelectionResolver) Query_events(ctx context.Context) ([]Event, error) {
+	var sels []string
+
+	reqCtx := graphql.GetRequestContext(ctx)
+	fieldSelections := graphql.GetResolverContext(ctx).Field.Selections
+	for _, sel := range fieldSelections {
+		switch sel := sel.(type) {
+		case *query.Field:
+			sels = append(sels, fmt.Sprintf("%s as %s", sel.Name.Name, sel.Alias.Name))
+		case *query.InlineFragment:
+			sels = append(sels, fmt.Sprintf("inline fragment on %s", sel.On.Name))
+		case *query.FragmentSpread:
+			fragment := reqCtx.Doc.Fragments.Get(sel.Name.Name)
+			sels = append(sels, fmt.Sprintf("named fragment %s on %s", sel.Name.Name, fragment.On.Name))
+		}
+	}
+
+	var events []Event
+	for i := 0; i < 10; i++ {
+		if i%2 == 0 {
+			events = append(events, &Like{
+				Selection: sels,
+				Collected: formatCollected(graphql.CollectFieldsCtx(ctx, []string{"Like"})),
+				Reaction:  ":=)",
+				Sent:      time.Now(),
+			})
+		} else {
+			events = append(events, &Post{
+				Selection: sels,
+				Collected: formatCollected(graphql.CollectFieldsCtx(ctx, []string{"Post"})),
+				Message:   "Hey",
+				Sent:      time.Now(),
+			})
+		}
+	}
+
+	return events, nil
+}
+
+func formatCollected(cf []graphql.CollectedField) []string {
+	var res []string
+
+	for _, f := range cf {
+		res = append(res, fmt.Sprintf("%s as %s", f.Name, f.Alias))
+	}
+	return res
+}

example/selection/selection_test.go

@@ -0,0 +1,58 @@
+package selection
+
+import (
+	"net/http/httptest"
+	"testing"
+
+	"github.com/vektah/gqlgen/client"
+
+	"github.com/stretchr/testify/require"
+	"github.com/vektah/gqlgen/handler"
+)
+
+func TestSelection(t *testing.T) {
+	srv := httptest.NewServer(handler.GraphQL(MakeExecutableSchema(&SelectionResolver{})))
+	c := client.New(srv.URL)
+
+	query := `{
+			events {
+				selection
+				collected
+
+				... on Post {
+					message
+					sent
+				}
+
+				...LikeFragment
+			}
+		}
+		fragment LikeFragment on Like { reaction sent }
+		`
+
+	var resp struct {
+		Events []struct {
+			Selection []string
+			Collected []string
+
+			Message  string
+			Reaction string
+			Sent     string
+		}
+	}
+	c.MustPost(query, &resp)
+
+	require.Equal(t, []string{
+		"selection as selection",
+		"collected as collected",
+		"inline fragment on Post",
+		"named fragment LikeFragment on Like",
+	}, resp.Events[0].Selection)
+
+	require.Equal(t, []string{
+		"selection as selection",
+		"collected as collected",
+		"reaction as reaction",
+		"sent as sent",
+	}, resp.Events[0].Collected)
+}

example/selection/server/server.go

@@ -0,0 +1,15 @@
+package main
+
+import (
+	"log"
+	"net/http"
+
+	"github.com/vektah/gqlgen/example/selection"
+	"github.com/vektah/gqlgen/handler"
+)
+
+func main() {
+	http.Handle("/", handler.Playground("Selection Demo", "/query"))
+	http.Handle("/query", handler.GraphQL(selection.MakeExecutableSchema(&selection.SelectionResolver{})))
+	log.Fatal(http.ListenAndServe(":8086", nil))
+}

graphql/context.go

@@ -49,5 +49,12 @@ func GetResolverContext(ctx context.Context) *ResolverContext {
 }
 
 func WithResolverContext(ctx context.Context, rc *ResolverContext) context.Context {
-	return context.WithValue(ctx, request, rc)
+	return context.WithValue(ctx, resolver, rc)
+}
+
+// This is just a convenient wrapper method for CollectFields
+func CollectFieldsCtx(ctx context.Context, satisfies []string) []CollectedField {
+	reqctx := GetRequestContext(ctx)
+	resctx := GetResolverContext(ctx)
+	return CollectFields(reqctx.Doc, resctx.Field.Selections, satisfies, reqctx.Variables)
 }