fix(remote schemas): must add __typename to remote query to properly …

…resolve interfaces. Error will occur only when querying directly on the remote schema, as delegateToSchema automatically adds type names. addTypenameToAbstract is necessary for resolveType to work in the parent schema just as checkResultAndHandleErrors is necessary for resolve to work!
ardatan · Sep 24, 2019 · db9307d · db9307d
1 parent 98b0986
commit db9307d
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Showing 4 changed files with 113 additions and 62 deletions.
diff --git a/src/stitching/addTypenameToAbstract.ts b/src/stitching/addTypenameToAbstract.ts
@@ -0,0 +1,56 @@
+import {
+  GraphQLType,
+  DocumentNode,
+  TypeInfo,
+  visit,
+  visitWithTypeInfo,
+  SelectionSetNode,
+  Kind,
+  FieldNode,
+  GraphQLInterfaceType,
+  GraphQLUnionType,
+} from 'graphql';
+import { GraphQLSchemaWithTransforms } from '../Interfaces';
+
+export function addTypenameToAbstract(
+  targetSchema: GraphQLSchemaWithTransforms,
+  document: DocumentNode,
+): DocumentNode {
+  const typeInfo = new TypeInfo(targetSchema);
+  return visit(
+    document,
+    visitWithTypeInfo(typeInfo, {
+      [Kind.SELECTION_SET](
+        node: SelectionSetNode,
+      ): SelectionSetNode | null | undefined {
+        const parentType: GraphQLType = typeInfo.getParentType();
+        let selections = node.selections;
+        if (
+          parentType &&
+          (parentType instanceof GraphQLInterfaceType ||
+            parentType instanceof GraphQLUnionType) &&
+          !selections.find(
+            _ =>
+              (_ as FieldNode).kind === Kind.FIELD &&
+              (_ as FieldNode).name.value === '__typename',
+          )
+        ) {
+          selections = selections.concat({
+            kind: Kind.FIELD,
+            name: {
+              kind: Kind.NAME,
+              value: '__typename',
+            },
+          });
+        }
+
+        if (selections !== node.selections) {
+          return {
+            ...node,
+            selections,
+          };
+        }
+      },
+    }),
+  );
+}
diff --git a/src/stitching/makeRemoteExecutableSchema.ts b/src/stitching/makeRemoteExecutableSchema.ts
@@ -8,10 +8,12 @@ import {
   buildSchema,
   Kind,
   GraphQLResolveInfo,
-  BuildSchemaOptions
+  BuildSchemaOptions,
+  DocumentNode,
 } from 'graphql';
 import linkToFetcher, { execute } from './linkToFetcher';
 import { Fetcher, Operation } from '../Interfaces';
+import { addTypenameToAbstract } from './addTypenameToAbstract';
 import { checkResultAndHandleErrors } from './checkResultAndHandleErrors';
 import { observableToAsyncIterable } from './observableToAsyncIterable';
 import mapAsyncIterator from './mapAsyncIterator';
@@ -79,12 +81,15 @@ export default function makeRemoteExecutableSchema({
 export function createResolver(fetcher: Fetcher): GraphQLFieldResolver<any, any> {
   return async (root, args, context, info) => {
     const fragments = Object.keys(info.fragments).map(fragment => info.fragments[fragment]);
-    const document = {
+    let query: DocumentNode = {
       kind: Kind.DOCUMENT,
       definitions: [info.operation, ...fragments]
     };
+
+    query = addTypenameToAbstract(info.schema, query);
+
     const result = await fetcher({
-      query: document,
+      query,
       variables: info.variableValues,
       context: { graphqlContext: context }
     });
@@ -95,13 +100,15 @@ export function createResolver(fetcher: Fetcher): GraphQLFieldResolver<any, any>
 function createSubscriptionResolver(link: ApolloLink): ResolverFn {
   return (root, args, context, info) => {
     const fragments = Object.keys(info.fragments).map(fragment => info.fragments[fragment]);
-    const document = {
+    let query: DocumentNode = {
       kind: Kind.DOCUMENT,
       definitions: [info.operation, ...fragments]
     };
 
+    query = addTypenameToAbstract(info.schema, query);
+
     const operation = {
-      query: document,
+      query,
       variables: info.variableValues,
       context: { graphqlContext: context }
     };

diff --git a/src/test/testMakeRemoteExecutableSchema.ts b/src/test/testMakeRemoteExecutableSchema.ts
@@ -2,15 +2,57 @@
 
 import { expect } from 'chai';
 import { forAwaitEach } from 'iterall';
-import { GraphQLSchema, ExecutionResult, subscribe, parse } from 'graphql';
+import { GraphQLSchema, ExecutionResult, subscribe, parse, graphql } from 'graphql';
 import {
+  propertySchema,
   subscriptionSchema,
   subscriptionPubSubTrigger,
   subscriptionPubSub,
   makeSchemaRemoteFromLink
 } from '../test/testingSchemas';
 import { makeRemoteExecutableSchema } from '../stitching';
 
+describe('remote queries', () => {
+  let schema: GraphQLSchema;
+  before(async () => {
+    const remoteSchemaExecConfig = await makeSchemaRemoteFromLink(propertySchema);
+    schema = makeRemoteExecutableSchema({
+      schema: remoteSchemaExecConfig.schema,
+      link: remoteSchemaExecConfig.link
+    });
+  });
+
+  it('should work', async () => {
+    const query = `
+      {
+        interfaceTest(kind: ONE) {
+          kind
+          testString
+          ...on TestImpl1 {
+            foo
+          }
+          ...on TestImpl2 {
+            bar
+          }
+        }
+      }
+    `;
+
+    const expected = {
+      data: {
+        interfaceTest: {
+          foo: 'foo',
+          kind: 'ONE',
+          testString: 'test',
+        },
+      },
+    };
+
+    const result = await graphql(schema, query);
+    expect(result).to.deep.equal(expected);
+  });
+});
+
 describe('remote subscriptions', () => {
   let schema: GraphQLSchema;
   before(async () => {

diff --git a/src/transforms/AddTypenameToAbstract.ts b/src/transforms/AddTypenameToAbstract.ts
@@ -1,18 +1,7 @@
-import {
-  DocumentNode,
-  FieldNode,
-  GraphQLInterfaceType,
-  GraphQLSchema,
-  GraphQLType,
-  GraphQLUnionType,
-  Kind,
-  SelectionSetNode,
-  TypeInfo,
-  visit,
-  visitWithTypeInfo,
-} from 'graphql';
+import { GraphQLSchema } from 'graphql';
 import { Request } from '../Interfaces';
 import { Transform } from './transforms';
+import { addTypenameToAbstract } from '../stitching/addTypenameToAbstract';
 
 export default class AddTypenameToAbstract implements Transform {
   private targetSchema: GraphQLSchema;
@@ -32,46 +21,3 @@ export default class AddTypenameToAbstract implements Transform {
     };
   }
 }
-
-function addTypenameToAbstract(
-  targetSchema: GraphQLSchema,
-  document: DocumentNode,
-): DocumentNode {
-  const typeInfo = new TypeInfo(targetSchema);
-  return visit(
-    document,
-    visitWithTypeInfo(typeInfo, {
-      [Kind.SELECTION_SET](
-        node: SelectionSetNode,
-      ): SelectionSetNode | null | undefined {
-        const parentType: GraphQLType = typeInfo.getParentType();
-        let selections = node.selections;
-        if (
-          parentType &&
-          (parentType instanceof GraphQLInterfaceType ||
-            parentType instanceof GraphQLUnionType) &&
-          !selections.find(
-            _ =>
-              (_ as FieldNode).kind === Kind.FIELD &&
-              (_ as FieldNode).name.value === '__typename',
-          )
-        ) {
-          selections = selections.concat({
-            kind: Kind.FIELD,
-            name: {
-              kind: Kind.NAME,
-              value: '__typename',
-            },
-          });
-        }
-
-        if (selections !== node.selections) {
-          return {
-            ...node,
-            selections,
-          };
-        }
-      },
-    }),
-  );
-}