Merge pull request #21 from sogko/sogko/master

Updated IDFetcherFn and GlobalIDFetcherFn to allow user to return error

examples/starwars/schema.go

@@ -1,6 +1,7 @@
 package starwars
 
 import (
+	"errors"
 	"github.com/graphql-go/graphql"
 	"github.com/graphql-go/relay"
 	"golang.org/x/net/context"
@@ -103,15 +104,18 @@ func init() {
 	 * way we resolve an object that implements node to its type.
 	 */
 	nodeDefinitions = relay.NewNodeDefinitions(relay.NodeDefinitionsConfig{
-		IDFetcher: func(id string, info graphql.ResolveInfo, ctx context.Context) interface{} {
+		IDFetcher: func(id string, info graphql.ResolveInfo, ctx context.Context) (interface{}, error) {
 			// resolve id from global id
 			resolvedID := relay.FromGlobalID(id)
 
 			// based on id and its type, return the object
-			if resolvedID.Type == "Faction" {
-				return GetFaction(resolvedID.ID)
-			} else {
-				return GetShip(resolvedID.ID)
+			switch resolvedID.Type {
+			case "Faction":
+				return GetFaction(resolvedID.ID), nil
+			case "Ship":
+				return GetShip(resolvedID.ID), nil
+			default:
+				return nil, errors.New("Unknown node type")
 			}
 		},
 		TypeResolve: func(value interface{}, info graphql.ResolveInfo) *graphql.Object {

node.go

@@ -18,8 +18,8 @@ type NodeDefinitionsConfig struct {
 	IDFetcher   IDFetcherFn
 	TypeResolve graphql.ResolveTypeFn
 }
-type IDFetcherFn func(id string, info graphql.ResolveInfo, ctx context.Context) interface{}
-type GlobalIDFetcherFn func(obj interface{}, info graphql.ResolveInfo, ctx context.Context) string
+type IDFetcherFn func(id string, info graphql.ResolveInfo, ctx context.Context) (interface{}, error)
+type GlobalIDFetcherFn func(obj interface{}, info graphql.ResolveInfo, ctx context.Context) (string, error)
 
 /*
  Given a function to map from an ID to an underlying object, and a function
@@ -62,8 +62,7 @@ func NewNodeDefinitions(config NodeDefinitionsConfig) *NodeDefinitions {
 			if iid, ok := p.Args["id"]; ok {
 				id = fmt.Sprintf("%v", iid)
 			}
-			fetchedID := config.IDFetcher(id, p.Info, p.Context)
-			return fetchedID, nil
+			return config.IDFetcher(id, p.Info, p.Context)
 		},
 	}
 	return &NodeDefinitions{
@@ -121,8 +120,11 @@ func GlobalIDField(typeName string, idFetcher GlobalIDFetcherFn) *graphql.Field
 		Resolve: func(p graphql.ResolveParams) (interface{}, error) {
 			id := ""
 			if idFetcher != nil {
-				fetched := idFetcher(p.Source, p.Info, p.Context)
+				fetched, err := idFetcher(p.Source, p.Info, p.Context)
 				id = fmt.Sprintf("%v", fetched)
+				if err != nil {
+					return id, err
+				}
 			} else {
 				// try to get from p.Source (data)
 				var objMap interface{}

node_global_test.go

@@ -1,6 +1,7 @@
 package relay_test
 
 import (
+	"errors"
 	"fmt"
 	"github.com/graphql-go/graphql"
 	"github.com/graphql-go/graphql/testutil"
@@ -30,15 +31,19 @@ var globalIDTestUserType *graphql.Object
 var globalIDTestPhotoType *graphql.Object
 
 var globalIDTestDef = relay.NewNodeDefinitions(relay.NodeDefinitionsConfig{
-	IDFetcher: func(globalID string, info graphql.ResolveInfo, ctx context.Context) interface{} {
+	IDFetcher: func(globalID string, info graphql.ResolveInfo, ctx context.Context) (interface{}, error) {
 		resolvedGlobalID := relay.FromGlobalID(globalID)
 		if resolvedGlobalID == nil {
-			return nil
+			return nil, errors.New("Unknown node id")
 		}
-		if resolvedGlobalID.Type == "User" {
-			return globalIDTestUserData[resolvedGlobalID.ID]
-		} else {
-			return globalIDTestPhotoData[resolvedGlobalID.ID]
+
+		switch resolvedGlobalID.Type {
+		case "User":
+			return globalIDTestUserData[resolvedGlobalID.ID], nil
+		case "Photo":
+			return globalIDTestPhotoData[resolvedGlobalID.ID], nil
+		default:
+			return nil, errors.New("Unknown node type")
 		}
 	},
 	TypeResolve: func(value interface{}, info graphql.ResolveInfo) *graphql.Object {
@@ -84,12 +89,12 @@ func init() {
 		},
 		Interfaces: []*graphql.Interface{globalIDTestDef.NodeInterface},
 	})
-	photoIDFetcher := func(obj interface{}, info graphql.ResolveInfo, ctx context.Context) string {
+	photoIDFetcher := func(obj interface{}, info graphql.ResolveInfo, ctx context.Context) (string, error) {
 		switch obj := obj.(type) {
 		case *photo2:
-			return fmt.Sprintf("%v", obj.PhotoId)
+			return fmt.Sprintf("%v", obj.PhotoId), nil
 		}
-		return ""
+		return "", errors.New("Not a photo")
 	}
 	globalIDTestPhotoType = graphql.NewObject(graphql.ObjectConfig{
 		Name: "Photo",

node_test.go

@@ -1,8 +1,11 @@
 package relay_test
 
 import (
+	"errors"
 	"fmt"
 	"github.com/graphql-go/graphql"
+	"github.com/graphql-go/graphql/gqlerrors"
+	"github.com/graphql-go/graphql/language/location"
 	"github.com/graphql-go/graphql/testutil"
 	"github.com/graphql-go/relay"
 	"golang.org/x/net/context"
@@ -34,14 +37,14 @@ var nodeTestUserType *graphql.Object
 var nodeTestPhotoType *graphql.Object
 
 var nodeTestDef = relay.NewNodeDefinitions(relay.NodeDefinitionsConfig{
-	IDFetcher: func(id string, info graphql.ResolveInfo, ctx context.Context) interface{} {
+	IDFetcher: func(id string, info graphql.ResolveInfo, ctx context.Context) (interface{}, error) {
 		if user, ok := nodeTestUserData[id]; ok {
-			return user
+			return user, nil
 		}
 		if photo, ok := nodeTestPhotoData[id]; ok {
-			return photo
+			return photo, nil
 		}
-		return nil
+		return nil, errors.New("Unknown node")
 	},
 	TypeResolve: func(value interface{}, info graphql.ResolveInfo) *graphql.Object {
 		switch value.(type) {
@@ -266,11 +269,18 @@ func TestNodeInterfaceAndFields_AllowsRefetching_ReturnsNullForBadIDs(t *testing
 		Data: map[string]interface{}{
 			"node": nil,
 		},
+		Errors: []gqlerrors.FormattedError{
+			{
+				Message:   "Unknown node",
+				Locations: []location.SourceLocation{},
+			},
+		},
 	}
 	result := graphql.Do(graphql.Params{
 		Schema:        nodeTestSchema,
 		RequestString: query,
 	})
+
 	if !reflect.DeepEqual(result, expected) {
 		t.Fatalf("wrong result, graphql result diff: %v", testutil.Diff(expected, result))
 	}