Add support for inherit key on cacheControl.

packages/apollo-cache-control/CHANGELOG.md

@@ -1,5 +1,10 @@
 # Changelog
 
+### Unreleased
+
+* Add support for `inherited` key to skip setting a `maxAge` to 0 if a
+    type has no explicit `maxAge` set.
+
 ### v0.1.1
 
 * Fix `defaultMaxAge` feature (introduced in 0.1.0) so that `maxAge: 0` overrides the default, as previously documented.

packages/apollo-cache-control/src/__tests__/cacheControlDirective.ts

@@ -1,4 +1,5 @@
 import { buildSchema } from 'graphql';
+import { makeExecutableSchema } from 'graphql-tools';
 
 import { CacheScope } from '../';
 import { collectCacheControlHints } from './test-utils/helpers';
@@ -226,4 +227,114 @@ describe('@cacheControl directives', () => {
       scope: CacheScope.Private,
     });
   });
+
+  it('should use cache from parent if inherit is true', async () => {
+    const typeDefs = `
+      type Query {
+        droids(page: Int = 0): DroidList @cacheControl(maxAge: 10)
+      }
+
+      type DroidList @cacheControl(inherit: true) {
+        edges: [DroidEdge!]
+      }
+
+      type DroidEdge @cacheControl(inherit: true) {
+        node: Droid!
+      }
+
+      type Droid @cacheControl(inherit: true) {
+        id: ID!
+        name: String!
+      }
+    `;
+
+    const resolvers = {
+      Query: {
+        droids: (_source, _args, _context, { cacheControl }) => {
+          return {
+            edges: [{ node: { id: 1 } }],
+          };
+        },
+      },
+    };
+
+    const schema = makeExecutableSchema({ typeDefs, resolvers });
+
+    const hints = await collectCacheControlHints(
+      schema,
+      `
+        query {
+          droids {
+            edges {
+              node {
+                id
+              }
+            }
+          }
+        }
+      `,
+      { defaultMaxAge: 0 },
+    );
+
+    expect(hints).toEqual([{ maxAge: 10, path: ['droids'], scope: undefined }]);
+  });
+
+  it('should not use cache from parent if inherit is false', async () => {
+    const typeDefs = `
+      type Query {
+        droids(page: Int = 0): DroidList @cacheControl(maxAge: 10)
+      }
+
+      type DroidList @cacheControl(inherit: true) {
+        edges: [DroidEdge!]
+      }
+
+      type DroidEdge @cacheControl(inherit: false) {
+        node: Droid!
+      }
+
+      type Droid @cacheControl(inherit: true) {
+        id: ID!
+        name: String!
+      }
+    `;
+
+    const resolvers = {
+      Query: {
+        droids: (_source, _args, _context, { cacheControl }) => {
+          return {
+            edges: [{ node: { id: 1 } }],
+          };
+        },
+      },
+    };
+
+    const schema = makeExecutableSchema({ typeDefs, resolvers });
+
+    const hints = await collectCacheControlHints(
+      schema,
+      `
+        query {
+          droids {
+            edges {
+              node {
+                id
+              }
+            }
+          }
+        }
+      `,
+      { defaultMaxAge: 0 },
+    );
+
+    expect(hints).toEqual([
+      { inherit: undefined, maxAge: 10, path: ['droids'], scope: undefined },
+      {
+        inherit: false,
+        maxAge: 0,
+        path: ['droids', 'edges'],
+        scope: undefined,
+      },
+    ]);
+  });
 });

packages/apollo-cache-control/src/index.ts

@@ -18,6 +18,7 @@ export interface CacheControlFormat {
 export interface CacheHint {
   maxAge?: number;
   scope?: CacheScope;
+  inherit?: boolean;
 }
 
 export enum CacheScope {
@@ -86,12 +87,13 @@ export class CacheControlExtension<TContext = any>
 
     // If this resolver returns an object and we haven't seen an explicit maxAge
     // hint, set the maxAge to 0 (uncached) or the default if specified in the
-    // constructor.  (Non-object fields by default are assumed to inherit their
-    // cacheability from their parents.)
+    // constructor unless it inherits from parent. (Non-object fields by default
+    // are assumed to inherit their cacheability from their parents.)
     if (
       (targetType instanceof GraphQLObjectType ||
         targetType instanceof GraphQLInterfaceType) &&
-      hint.maxAge === undefined
+      hint.maxAge === undefined &&
+      !hint.inherit
     ) {
       hint.maxAge = this.defaultMaxAge;
     }
@@ -149,6 +151,9 @@ function cacheHintFromDirectives(
   const scopeArgument = cacheControlDirective.arguments.find(
     argument => argument.name.value === 'scope',
   );
+  const inheritArgument = cacheControlDirective.arguments.find(
+    argument => argument.name.value === 'inherit',
+  );
 
   // TODO: Add proper typechecking of arguments
   return {
@@ -164,6 +169,12 @@ function cacheHintFromDirectives(
       scopeArgument.value.kind === 'EnumValue'
         ? (scopeArgument.value.value as CacheScope)
         : undefined,
+    inherit:
+      inheritArgument &&
+      inheritArgument.value &&
+      inheritArgument.value.kind === 'BooleanValue'
+        ? (inheritArgument.value.value as boolean)
+        : undefined,
   };
 }
 
@@ -176,5 +187,6 @@ function mergeHints(
   return {
     maxAge: otherHint.maxAge !== undefined ? otherHint.maxAge : hint.maxAge,
     scope: otherHint.scope || hint.scope,
+    inherit: otherHint.inherit,
   };
 }