Add @specified directive

This in an implementation for a spec proposal:

* Spec proposal: [[RFC] Custom Scalar Specification URIs](graphql/graphql-spec#649)
* Original issue: [[RFC] Custom Scalar Specification URIs](graphql/graphql-spec#635)

src/type/__tests__/introspection-test.js

@@ -61,6 +61,7 @@ describe('Introspection', () => {
               interfaces: [],
               enumValues: null,
               possibleTypes: null,
+              specifiedBy: null,
             },
             {
               kind: 'SCALAR',
@@ -70,6 +71,7 @@ describe('Introspection', () => {
               interfaces: null,
               enumValues: null,
               possibleTypes: null,
+              specifiedBy: null,
             },
             {
               kind: 'OBJECT',
@@ -163,6 +165,7 @@ describe('Introspection', () => {
               interfaces: [],
               enumValues: null,
               possibleTypes: null,
+              specifiedBy: null,
             },
             {
               kind: 'OBJECT',
@@ -205,6 +208,17 @@ describe('Introspection', () => {
                   isDeprecated: false,
                   deprecationReason: null,
                 },
+                {
+                  args: [],
+                  deprecationReason: null,
+                  isDeprecated: false,
+                  name: 'specifiedBy',
+                  type: {
+                    kind: 'SCALAR',
+                    name: 'String',
+                    ofType: null,
+                  },
+                },
                 {
                   name: 'fields',
                   args: [
@@ -336,6 +350,7 @@ describe('Introspection', () => {
               interfaces: [],
               enumValues: null,
               possibleTypes: null,
+              specifiedBy: null,
             },
             {
               kind: 'ENUM',
@@ -386,6 +401,7 @@ describe('Introspection', () => {
                 },
               ],
               possibleTypes: null,
+              specifiedBy: null,
             },
             {
               kind: 'SCALAR',
@@ -395,6 +411,7 @@ describe('Introspection', () => {
               interfaces: null,
               enumValues: null,
               possibleTypes: null,
+              specifiedBy: null,
             },
             {
               kind: 'OBJECT',
@@ -495,6 +512,7 @@ describe('Introspection', () => {
               interfaces: [],
               enumValues: null,
               possibleTypes: null,
+              specifiedBy: null,
             },
             {
               kind: 'OBJECT',
@@ -557,6 +575,7 @@ describe('Introspection', () => {
               interfaces: [],
               enumValues: null,
               possibleTypes: null,
+              specifiedBy: null,
             },
             {
               kind: 'OBJECT',
@@ -619,6 +638,7 @@ describe('Introspection', () => {
               interfaces: [],
               enumValues: null,
               possibleTypes: null,
+              specifiedBy: null,
             },
             {
               kind: 'OBJECT',
@@ -701,6 +721,7 @@ describe('Introspection', () => {
               interfaces: [],
               enumValues: null,
               possibleTypes: null,
+              specifiedBy: null,
             },
             {
               kind: 'ENUM',
@@ -806,6 +827,7 @@ describe('Introspection', () => {
                 },
               ],
               possibleTypes: null,
+              specifiedBy: null,
             },
           ],
           directives: [
@@ -847,6 +869,25 @@ describe('Introspection', () => {
                 },
               ],
             },
+            {
+              name: 'specified',
+              locations: ['SCALAR'],
+              args: [
+                {
+                  defaultValue: null,
+                  name: 'by',
+                  type: {
+                    kind: 'NON_NULL',
+                    name: null,
+                    ofType: {
+                      kind: 'SCALAR',
+                      name: 'String',
+                      ofType: null,
+                    },
+                  },
+                },
+              ],
+            },
             {
               name: 'deprecated',
               locations: ['FIELD_DEFINITION', 'ENUM_VALUE'],

src/type/definition.d.ts

@@ -409,6 +409,7 @@ export interface GraphQLObjectTypeConfig<
 > {
   name: string;
   description?: Maybe<string>;
+  specifiedBy?: string;
   interfaces?: Thunk<Maybe<GraphQLInterfaceType[]>>;
   fields: Thunk<GraphQLFieldConfigMap<TSource, TContext, TArgs>>;
   isTypeOf?: Maybe<GraphQLIsTypeOfFn<TSource, TContext>>;

src/type/directives.d.ts

@@ -54,6 +54,12 @@ export const GraphQLIncludeDirective: GraphQLDirective;
  */
 export const GraphQLSkipDirective: GraphQLDirective;
 
+/**
+ * Used to provide an RFC3986-compliant URI for specifying the behaviour of
+ * custom scalar definitions.
+ */
+export const GraphQLSpecifiedDirective: GraphQLDirective;
+
 /**
  * Constant string used for default reason for a deprecation.
  */

src/type/directives.js

@@ -167,6 +167,21 @@ export const GraphQLSkipDirective = new GraphQLDirective({
   },
 });
 
+/**
+ * Used to provide URL for specifying the behaviour of custom scalar definitions.
+ */
+export const GraphQLSpecifiedDirective = new GraphQLDirective({
+  name: 'specified',
+  description: 'Exposes a URL that specifies the behaviour of this scalar.',
+  locations: [DirectiveLocation.SCALAR],
+  args: {
+    by: {
+      type: GraphQLNonNull(GraphQLString),
+      description: 'The URL that specifies the behaviour of this scalar.',
+    },
+  },
+});
+
 /**
  * Constant string used for default reason for a deprecation.
  */
@@ -195,6 +210,7 @@ export const GraphQLDeprecatedDirective = new GraphQLDirective({
 export const specifiedDirectives = Object.freeze([
   GraphQLIncludeDirective,
   GraphQLSkipDirective,
+  GraphQLSpecifiedDirective,
   GraphQLDeprecatedDirective,
 ]);
 

src/type/introspection.js

@@ -8,9 +8,10 @@ import invariant from '../jsutils/invariant';
 import { print } from '../language/printer';
 import { DirectiveLocation } from '../language/directiveLocation';
 import { astFromValue } from '../utilities/astFromValue';
+import { getDirectiveValues } from '../execution/values';
 
 import { type GraphQLSchema } from './schema';
-import { type GraphQLDirective } from './directives';
+import { type GraphQLDirective, GraphQLSpecifiedDirective } from './directives';
 import { GraphQLString, GraphQLBoolean } from './scalars';
 import {
   type GraphQLType,
@@ -184,7 +185,7 @@ export const __DirectiveLocation = new GraphQLEnumType({
 export const __Type = new GraphQLObjectType({
   name: '__Type',
   description:
-    'The fundamental unit of any GraphQL Schema is the type. There are many kinds of types in GraphQL as represented by the `__TypeKind` enum.\n\nDepending on the kind of a type, certain fields describe information about that type. Scalar types provide no information beyond a name and description, while Enum types provide their values. Object and Interface types provide the fields they describe. Abstract types, Union and Interface, provide the Object types possible at runtime. List and NonNull types compose other types.',
+    'The fundamental unit of any GraphQL Schema is the type. There are many kinds of types in GraphQL as represented by the `__TypeKind` enum.\n\nDepending on the kind of a type, certain fields describe information about that type. Scalar types provide no information beyond a name, description and optional specifiedBy URL, while Enum types provide their values. Object and Interface types provide the fields they describe. Abstract types, Union and Interface, provide the Object types possible at runtime. List and NonNull types compose other types.',
   fields: () =>
     ({
       kind: {
@@ -221,6 +222,20 @@ export const __Type = new GraphQLObjectType({
         resolve: obj =>
           obj.description !== undefined ? obj.description : undefined,
       },
+      specifiedBy: {
+        type: GraphQLString,
+        resolve: type => {
+          if (!isScalarType(type) || !type.astNode) {
+            return null;
+          }
+
+          const specified = getDirectiveValues(
+            GraphQLSpecifiedDirective,
+            type.astNode,
+          );
+          return specified && specified.by;
+        },
+      },
       fields: {
         type: GraphQLList(GraphQLNonNull(__Field)),
         args: {

src/utilities/__tests__/buildASTSchema-test.js

@@ -15,6 +15,7 @@ import {
   assertDirective,
   GraphQLSkipDirective,
   GraphQLIncludeDirective,
+  GraphQLSpecifiedDirective,
   GraphQLDeprecatedDirective,
 } from '../../type/directives';
 import {
@@ -182,12 +183,15 @@ describe('Schema Builder', () => {
     expect(cycleSDL(sdl, { commentDescriptions: true })).to.equal(sdl);
   });
 
-  it('Maintains @skip & @include', () => {
+  it('Maintains @include, @skip & @specified', () => {
     const schema = buildSchema('type Query');
 
-    expect(schema.getDirectives()).to.have.lengthOf(3);
+    expect(schema.getDirectives()).to.have.lengthOf(4);
     expect(schema.getDirective('skip')).to.equal(GraphQLSkipDirective);
     expect(schema.getDirective('include')).to.equal(GraphQLIncludeDirective);
+    expect(schema.getDirective('specified')).to.equal(
+      GraphQLSpecifiedDirective,
+    );
     expect(schema.getDirective('deprecated')).to.equal(
       GraphQLDeprecatedDirective,
     );
@@ -197,27 +201,32 @@ describe('Schema Builder', () => {
     const schema = buildSchema(`
       directive @skip on FIELD
       directive @include on FIELD
+      directive @specified on FIELD_DEFINITION
       directive @deprecated on FIELD_DEFINITION
     `);
 
-    expect(schema.getDirectives()).to.have.lengthOf(3);
+    expect(schema.getDirectives()).to.have.lengthOf(4);
     expect(schema.getDirective('skip')).to.not.equal(GraphQLSkipDirective);
     expect(schema.getDirective('include')).to.not.equal(
       GraphQLIncludeDirective,
     );
+    expect(schema.getDirective('specified')).to.not.equal(
+      GraphQLSpecifiedDirective,
+    );
     expect(schema.getDirective('deprecated')).to.not.equal(
       GraphQLDeprecatedDirective,
     );
   });
 
-  it('Adding directives maintains @skip & @include', () => {
+  it('Adding directives maintains @include, @skip & @specified', () => {
     const schema = buildSchema(`
       directive @foo(arg: Int) on FIELD
     `);
 
-    expect(schema.getDirectives()).to.have.lengthOf(4);
+    expect(schema.getDirectives()).to.have.lengthOf(5);
     expect(schema.getDirective('skip')).to.not.equal(undefined);
     expect(schema.getDirective('include')).to.not.equal(undefined);
+    expect(schema.getDirective('specified')).to.not.equal(undefined);
     expect(schema.getDirective('deprecated')).to.not.equal(undefined);
   });
 

src/utilities/__tests__/findBreakingChanges-test.js

@@ -7,6 +7,7 @@ import { GraphQLSchema } from '../../type/schema';
 import {
   GraphQLSkipDirective,
   GraphQLIncludeDirective,
+  GraphQLSpecifiedDirective,
   GraphQLDeprecatedDirective,
 } from '../../type/directives';
 
@@ -790,7 +791,11 @@ describe('findBreakingChanges', () => {
     const oldSchema = new GraphQLSchema({});
 
     const newSchema = new GraphQLSchema({
-      directives: [GraphQLSkipDirective, GraphQLIncludeDirective],
+      directives: [
+        GraphQLSkipDirective,
+        GraphQLIncludeDirective,
+        GraphQLSpecifiedDirective,
+      ],
     });
 
     expect(findBreakingChanges(oldSchema, newSchema)).to.deep.equal([

src/utilities/__tests__/schemaPrinter-test.js

@@ -590,6 +590,12 @@ describe('Type System Printer', () => {
         if: Boolean!
       ) on FIELD | FRAGMENT_SPREAD | INLINE_FRAGMENT
 
+      """Exposes a URL that specifies the behaviour of this scalar."""
+      directive @specified(
+        """The URL that specifies the behaviour of this scalar."""
+        by: String!
+      ) on SCALAR
+
       """Marks an element of a GraphQL schema as no longer supported."""
       directive @deprecated(
         """
@@ -735,12 +741,13 @@ describe('Type System Printer', () => {
       """
       The fundamental unit of any GraphQL Schema is the type. There are many kinds of types in GraphQL as represented by the \`__TypeKind\` enum.
 
-      Depending on the kind of a type, certain fields describe information about that type. Scalar types provide no information beyond a name and description, while Enum types provide their values. Object and Interface types provide the fields they describe. Abstract types, Union and Interface, provide the Object types possible at runtime. List and NonNull types compose other types.
+      Depending on the kind of a type, certain fields describe information about that type. Scalar types provide no information beyond a name, description and optional specifiedBy URL, while Enum types provide their values. Object and Interface types provide the fields they describe. Abstract types, Union and Interface, provide the Object types possible at runtime. List and NonNull types compose other types.
       """
       type __Type {
         kind: __TypeKind!
         name: String
         description: String
+        specifiedBy: String
         fields(includeDeprecated: Boolean = false): [__Field!]
         interfaces: [__Type!]
         possibleTypes: [__Type!]
@@ -803,6 +810,12 @@ describe('Type System Printer', () => {
         if: Boolean!
       ) on FIELD | FRAGMENT_SPREAD | INLINE_FRAGMENT
 
+      # Exposes a URL that specifies the behaviour of this scalar.
+      directive @specified(
+        # The URL that specifies the behaviour of this scalar.
+        by: String!
+      ) on SCALAR
+
       # Marks an element of a GraphQL schema as no longer supported.
       directive @deprecated(
         # Explains why this element was deprecated, usually also including a suggestion for how to access supported similar data. Formatted using the Markdown syntax (as specified by [CommonMark](https://commonmark.org/).
@@ -927,11 +940,12 @@ describe('Type System Printer', () => {
 
       # The fundamental unit of any GraphQL Schema is the type. There are many kinds of types in GraphQL as represented by the \`__TypeKind\` enum.
       #
-      # Depending on the kind of a type, certain fields describe information about that type. Scalar types provide no information beyond a name and description, while Enum types provide their values. Object and Interface types provide the fields they describe. Abstract types, Union and Interface, provide the Object types possible at runtime. List and NonNull types compose other types.
+      # Depending on the kind of a type, certain fields describe information about that type. Scalar types provide no information beyond a name, description and optional specifiedBy URL, while Enum types provide their values. Object and Interface types provide the fields they describe. Abstract types, Union and Interface, provide the Object types possible at runtime. List and NonNull types compose other types.
       type __Type {
         kind: __TypeKind!
         name: String
         description: String
+        specifiedBy: String
         fields(includeDeprecated: Boolean = false): [__Field!]
         interfaces: [__Type!]
         possibleTypes: [__Type!]

src/utilities/buildASTSchema.js

@@ -55,6 +55,7 @@ import {
   GraphQLSkipDirective,
   GraphQLIncludeDirective,
   GraphQLDeprecatedDirective,
+  GraphQLSpecifiedDirective,
 } from '../type/directives';
 import {
   type GraphQLType,
@@ -170,6 +171,10 @@ export function buildASTSchema(
     directives.push(GraphQLIncludeDirective);
   }
 
+  if (!directives.some(directive => directive.name === 'specified')) {
+    directives.push(GraphQLSpecifiedDirective);
+  }
+
   if (!directives.some(directive => directive.name === 'deprecated')) {
     directives.push(GraphQLDeprecatedDirective);
   }

src/utilities/getIntrospectionQuery.js

@@ -34,6 +34,7 @@ export function getIntrospectionQuery(options?: IntrospectionOptions): string {
       kind
       name
       ${descriptions ? 'description' : ''}
+      specifiedBy
       fields(includeDeprecated: true) {
         name
         ${descriptions ? 'description' : ''}