[RFC] Initial pass at adding subscription to executor

src/execution/__tests__/executor.js

@@ -433,7 +433,7 @@ describe('Execute: Handles basic execution tasks', () => {
   });
 
   it('uses the query schema for queries', async () => {
-    var doc = `query Q { a } mutation M { c }`;
+    var doc = `query Q { a } mutation M { c } subscription S { a }`;
     var data = { a: 'b', c: 'd' };
     var ast = parse(doc);
     var schema = new GraphQLSchema({
@@ -448,6 +448,12 @@ describe('Execute: Handles basic execution tasks', () => {
         fields: {
           c: { type: GraphQLString },
         }
+      }),
+      subscription: new GraphQLObjectType({
+        name: 'S',
+        fields: {
+          a: { type: GraphQLString },
+        }
       })
     });
 
@@ -480,6 +486,30 @@ describe('Execute: Handles basic execution tasks', () => {
     expect(mutationResult).to.deep.equal({ data: { c: 'd' } });
   });
 
+  it('uses the subscription schema for subscriptions', async () => {
+    var doc = `query Q { a } subscription S { a }`;
+    var data = { a: 'b', c: 'd' };
+    var ast = parse(doc);
+    var schema = new GraphQLSchema({
+      query: new GraphQLObjectType({
+        name: 'Q',
+        fields: {
+          a: { type: GraphQLString },
+        }
+      }),
+      subscription: new GraphQLObjectType({
+        name: 'S',
+        fields: {
+          a: { type: GraphQLString },
+        }
+      })
+    });
+
+    var subscriptionResult = await execute(schema, ast, data, {}, 'S');
+
+    expect(subscriptionResult).to.deep.equal({ data: { a: 'b' } });
+  });
+
   it('correct field ordering despite execution order', async () => {
     var doc = `{
       a,

src/execution/execute.js

@@ -240,9 +240,18 @@ function getOperationRootType(
         );
       }
       return mutationType;
+    case 'subscription':
+      var subscriptionType = schema.getSubscriptionType();
+      if (!subscriptionType) {
+        throw new GraphQLError(
+          'Schema is not configured for subscriptions',
+          [ operation ]
+        );
+      }
+      return subscriptionType;
     default:
       throw new GraphQLError(
-        'Can only execute queries and mutations',
+        'Can only execute queries, mutations and subscriptions',
         [ operation ]
       );
   }

src/language/__tests__/kitchen-sink.graphql

@@ -34,6 +34,19 @@ mutation likeStory {
   }
 }
 
+subscription StoryLikeSubscription($input: StoryLikeSubscribeInput) {
+  storyLikeSubscribe(input: $input) {
+    story {
+      likers {
+        count
+      }
+      likeSentence {
+        text
+      }
+    }
+  }
+}
+
 fragment frag on Friend {
   foo(size: $size, bar: $b, obj: {key: "value"})
 }

src/language/__tests__/parser.js

@@ -163,6 +163,7 @@ fragment MissingOn Type
       'fragment',
       'query',
       'mutation',
+      'subscription',
       'true',
       'false'
     ];
@@ -185,22 +186,38 @@ fragment ${fragmentName} on Type {
     });
   });
 
-  it('parses experimental subscription feature', () => {
+  it('parses anonymous mutation operations', () => {
     expect(() => parse(`
-      subscription Foo {
+      mutation {
+        mutationField
+      }
+    `)).to.not.throw();
+  });
+
+  it('parses anonymous subscription operations', () => {
+    expect(() => parse(`
+      subscription {
         subscriptionField
       }
     `)).to.not.throw();
   });
 
-  it('parses anonymous operations', () => {
+  it('parses named mutation operations', () => {
     expect(() => parse(`
-      mutation {
+      mutation Foo {
         mutationField
       }
     `)).to.not.throw();
   });
 
+  it('parses named subscription operations', () => {
+    expect(() => parse(`
+      subscription Foo {
+        subscriptionField
+      }
+    `)).to.not.throw();
+  });
+
   it('parse creates ast', () => {
 
     var source = new Source(`{

src/language/__tests__/printer.js

@@ -76,6 +76,19 @@ mutation likeStory {
   }
 }
 
+subscription StoryLikeSubscription($input: StoryLikeSubscribeInput) {
+  storyLikeSubscribe(input: $input) {
+    story {
+      likers {
+        count
+      }
+      likeSentence {
+        text
+      }
+    }
+  }
+}
+
 fragment frag on Friend {
   foo(size: $size, bar: $b, obj: {key: "value"})
 }

src/language/__tests__/visitor.js

@@ -385,7 +385,63 @@ describe('Visitor', () => {
       [ 'leave', 'Field', 0, undefined ],
       [ 'leave', 'SelectionSet', 'selectionSet', 'OperationDefinition' ],
       [ 'leave', 'OperationDefinition', 1, undefined ],
-      [ 'enter', 'FragmentDefinition', 2, undefined ],
+      [ 'enter', 'OperationDefinition', 2, undefined ],
+      [ 'enter', 'Name', 'name', 'OperationDefinition' ],
+      [ 'leave', 'Name', 'name', 'OperationDefinition' ],
+      [ 'enter', 'VariableDefinition', 0, undefined ],
+      [ 'enter', 'Variable', 'variable', 'VariableDefinition' ],
+      [ 'enter', 'Name', 'name', 'Variable' ],
+      [ 'leave', 'Name', 'name', 'Variable' ],
+      [ 'leave', 'Variable', 'variable', 'VariableDefinition' ],
+      [ 'enter', 'NamedType', 'type', 'VariableDefinition' ],
+      [ 'enter', 'Name', 'name', 'NamedType' ],
+      [ 'leave', 'Name', 'name', 'NamedType' ],
+      [ 'leave', 'NamedType', 'type', 'VariableDefinition' ],
+      [ 'leave', 'VariableDefinition', 0, undefined ],
+      [ 'enter', 'SelectionSet', 'selectionSet', 'OperationDefinition' ],
+      [ 'enter', 'Field', 0, undefined ],
+      [ 'enter', 'Name', 'name', 'Field' ],
+      [ 'leave', 'Name', 'name', 'Field' ],
+      [ 'enter', 'Argument', 0, undefined ],
+      [ 'enter', 'Name', 'name', 'Argument' ],
+      [ 'leave', 'Name', 'name', 'Argument' ],
+      [ 'enter', 'Variable', 'value', 'Argument' ],
+      [ 'enter', 'Name', 'name', 'Variable' ],
+      [ 'leave', 'Name', 'name', 'Variable' ],
+      [ 'leave', 'Variable', 'value', 'Argument' ],
+      [ 'leave', 'Argument', 0, undefined ],
+      [ 'enter', 'SelectionSet', 'selectionSet', 'Field' ],
+      [ 'enter', 'Field', 0, undefined ],
+      [ 'enter', 'Name', 'name', 'Field' ],
+      [ 'leave', 'Name', 'name', 'Field' ],
+      [ 'enter', 'SelectionSet', 'selectionSet', 'Field' ],
+      [ 'enter', 'Field', 0, undefined ],
+      [ 'enter', 'Name', 'name', 'Field' ],
+      [ 'leave', 'Name', 'name', 'Field' ],
+      [ 'enter', 'SelectionSet', 'selectionSet', 'Field' ],
+      [ 'enter', 'Field', 0, undefined ],
+      [ 'enter', 'Name', 'name', 'Field' ],
+      [ 'leave', 'Name', 'name', 'Field' ],
+      [ 'leave', 'Field', 0, undefined ],
+      [ 'leave', 'SelectionSet', 'selectionSet', 'Field' ],
+      [ 'leave', 'Field', 0, undefined ],
+      [ 'enter', 'Field', 1, undefined ],
+      [ 'enter', 'Name', 'name', 'Field' ],
+      [ 'leave', 'Name', 'name', 'Field' ],
+      [ 'enter', 'SelectionSet', 'selectionSet', 'Field' ],
+      [ 'enter', 'Field', 0, undefined ],
+      [ 'enter', 'Name', 'name', 'Field' ],
+      [ 'leave', 'Name', 'name', 'Field' ],
+      [ 'leave', 'Field', 0, undefined ],
+      [ 'leave', 'SelectionSet', 'selectionSet', 'Field' ],
+      [ 'leave', 'Field', 1, undefined ],
+      [ 'leave', 'SelectionSet', 'selectionSet', 'Field' ],
+      [ 'leave', 'Field', 0, undefined ],
+      [ 'leave', 'SelectionSet', 'selectionSet', 'Field' ],
+      [ 'leave', 'Field', 0, undefined ],
+      [ 'leave', 'SelectionSet', 'selectionSet', 'OperationDefinition' ],
+      [ 'leave', 'OperationDefinition', 2, undefined ],
+      [ 'enter', 'FragmentDefinition', 3, undefined ],
       [ 'enter', 'Name', 'name', 'FragmentDefinition' ],
       [ 'leave', 'Name', 'name', 'FragmentDefinition' ],
       [ 'enter', 'NamedType', 'typeCondition', 'FragmentDefinition' ],
@@ -426,8 +482,8 @@ describe('Visitor', () => {
       [ 'leave', 'Argument', 2, undefined ],
       [ 'leave', 'Field', 0, undefined ],
       [ 'leave', 'SelectionSet', 'selectionSet', 'FragmentDefinition' ],
-      [ 'leave', 'FragmentDefinition', 2, undefined ],
-      [ 'enter', 'OperationDefinition', 3, undefined ],
+      [ 'leave', 'FragmentDefinition', 3, undefined ],
+      [ 'enter', 'OperationDefinition', 4, undefined ],
       [ 'enter', 'SelectionSet', 'selectionSet', 'OperationDefinition' ],
       [ 'enter', 'Field', 0, undefined ],
       [ 'enter', 'Name', 'name', 'Field' ],
@@ -450,8 +506,7 @@ describe('Visitor', () => {
       [ 'leave', 'Name', 'name', 'Field' ],
       [ 'leave', 'Field', 1, undefined ],
       [ 'leave', 'SelectionSet', 'selectionSet', 'OperationDefinition' ],
-      [ 'leave', 'OperationDefinition', 3, undefined ],
-      [ 'leave', 'Document', undefined, undefined ]
-    ]);
+      [ 'leave', 'OperationDefinition', 4, undefined ],
+      [ 'leave', 'Document', undefined, undefined ] ]);
   });
 });

src/type/__tests__/definition.js

@@ -81,6 +81,16 @@ var BlogMutation = new GraphQLObjectType({
   }
 });
 
+var BlogSubscription = new GraphQLObjectType({
+  name: 'Subscription',
+  fields: {
+    articleSubscribe: {
+      args: { id: { type: GraphQLString } },
+      type: BlogArticle
+    }
+  }
+});
+
 var ObjectType = new GraphQLObjectType({
   name: 'Object',
   isTypeOf: () => true
@@ -143,6 +153,21 @@ describe('Type System: Example', () => {
 
   });
 
+  it('defines a subscription schema', () => {
+    var BlogSchema = new GraphQLSchema({
+      query: BlogQuery,
+      subscription: BlogSubscription
+    });
+
+    expect(BlogSchema.getSubscriptionType()).to.equal(BlogSubscription);
+
+    var sub = BlogSubscription.getFields()[('articleSubscribe' : string)];
+    expect(sub && sub.type).to.equal(BlogArticle);
+    expect(sub && sub.type.name).to.equal('Article');
+    expect(sub && sub.name).to.equal('articleSubscribe');
+
+  });
+
   it('includes nested input objects in the map', () => {
     var NestedInputObject = new GraphQLInputObjectType({
       name: 'NestedInputObject',
@@ -161,9 +186,19 @@ describe('Type System: Example', () => {
         }
       }
     });
+    var SomeSubscription = new GraphQLObjectType({
+      name: 'SomeSubscription',
+      fields: {
+        subscribeToSomething: {
+          type: BlogArticle,
+          args: { input: { type: SomeInputObject } }
+        }
+      }
+    });
     var schema = new GraphQLSchema({
       query: BlogQuery,
       mutation: SomeMutation,
+      subscription: SomeSubscription
     });
     expect(schema.getTypeMap().NestedInputObject).to.equal(NestedInputObject);
   });

src/type/__tests__/enumType.js

@@ -70,7 +70,22 @@ describe('Type System: Enum Values', () => {
     }
   });
 
-  var schema = new GraphQLSchema({ query: QueryType, mutation: MutationType });
+  var SubscriptionType = new GraphQLObjectType({
+    name: 'Subscription',
+    fields: {
+      subscribeToEnum: {
+        type: ColorType,
+        args: { color: { type: ColorType } },
+        resolve(value, { color }) { return color; }
+      }
+    }
+  });
+
+  var schema = new GraphQLSchema({
+    query: QueryType,
+    mutation: MutationType,
+    subscription: SubscriptionType
+  });
 
   it('accepts enum literals as input', async () => {
     expect(
@@ -173,6 +188,21 @@ describe('Type System: Enum Values', () => {
     });
   });
 
+  it('accepts enum literals as input arguments to subscriptions', async () => {
+    expect(
+      await graphql(
+        schema,
+        'subscription x($color: Color!) { subscribeToEnum(color: $color) }',
+        null,
+        { color: 'GREEN' }
+      )
+    ).to.deep.equal({
+      data: {
+        subscribeToEnum: 'GREEN'
+      }
+    });
+  });
+
   it('does not accept internal value as enum variable', async () => {
     expect(
       await graphql(