Add ProhibitIntrospectionQueriesRule

.vscode/settings.json

@@ -0,0 +1,3 @@
+{
+  "javascript.validate.enable": false
+}

src/validation/__tests__/ProhibitIntrospectionQueriesRule-test.js

@@ -0,0 +1,146 @@
+// @flow strict
+
+import { describe, it } from 'mocha';
+
+import { ProhibitIntrospectionQueriesRule } from '../rules/optional/ProhibitIntrospectionQueriesRule';
+
+import {
+  GraphQLSchema,
+  GraphQLObjectType,
+  GraphQLString,
+  __Schema,
+} from '../../type/index';
+
+import { expectValidationErrorsWithSchema } from './harness';
+
+const schema = new GraphQLSchema({
+  query: new GraphQLObjectType({
+    name: 'Query',
+    fields: {
+      someQuery: {
+        type: new GraphQLObjectType({
+          name: 'SomeType',
+          fields: {
+            someField: { type: GraphQLString },
+            introspectionField: { type: __Schema },
+          },
+        }),
+      },
+    },
+  }),
+});
+
+function expectErrors(queryStr) {
+  return expectValidationErrorsWithSchema(
+    schema,
+    ProhibitIntrospectionQueriesRule,
+    queryStr,
+  );
+}
+
+function expectValid(queryStr) {
+  expectErrors(queryStr).to.deep.equal([]);
+}
+
+describe('Validate: Prohibit introspection queries', () => {
+  it('ignores valid fields including __typename', () => {
+    expectValid(`
+      {
+        someQuery {
+          __typename
+          someField
+        }
+      }
+    `);
+  });
+
+  it('ignores fields not in the schema', () => {
+    expectValid(`
+      {
+        __introspect
+      }
+    `);
+  });
+
+  it('reports error when a field with introspection type is requested', () => {
+    expectErrors(`
+      {
+        __schema {
+          queryType {
+            name
+          }
+        }
+      }
+    `).to.deep.equal([
+      {
+        locations: [
+          {
+            column: 9,
+            line: 3,
+          },
+        ],
+        message:
+          'GraphQL introspection has been disabled, but the requested query contained the field "__schema".',
+      },
+      {
+        locations: [
+          {
+            column: 11,
+            line: 4,
+          },
+        ],
+        message:
+          'GraphQL introspection has been disabled, but the requested query contained the field "queryType".',
+      },
+    ]);
+  });
+
+  it('reports error when a field with an introspection type is requested and aliased', () => {
+    expectErrors(`
+      {
+        s: __schema {
+          queryType {
+            name
+          }
+        }
+      }
+      `).to.deep.equal([
+      {
+        locations: [
+          {
+            column: 9,
+            line: 3,
+          },
+        ],
+        message:
+          'GraphQL introspection has been disabled, but the requested query contained the field "__schema".',
+      },
+      {
+        locations: [
+          {
+            column: 11,
+            line: 4,
+          },
+        ],
+        message:
+          'GraphQL introspection has been disabled, but the requested query contained the field "queryType".',
+      },
+    ]);
+  });
+
+  it('reports error for non-standard introspection fields', () => {
+    expectErrors(`
+      {
+        someQuery {
+          introspectionField
+        }
+      }
+    `).to.deep.equal([
+      {
+        message:
+          'GraphQL introspection has been disabled, but the requested query contained the field "introspectionField".',
+        locations: [{ line: 4, column: 11 }],
+      },
+    ]);
+  });
+});

src/validation/index.js

@@ -94,3 +94,6 @@ export { UniqueEnumValueNamesRule } from './rules/UniqueEnumValueNamesRule';
 export { UniqueFieldDefinitionNamesRule } from './rules/UniqueFieldDefinitionNamesRule';
 export { UniqueDirectiveNamesRule } from './rules/UniqueDirectiveNamesRule';
 export { PossibleTypeExtensionsRule } from './rules/PossibleTypeExtensionsRule';
+
+// Optional rules not defined by the GraphQL Specification
+export { ProhibitIntrospectionQueriesRule } from './rules/optional/ProhibitIntrospectionQueriesRule';

src/validation/rules/optional/ProhibitIntrospectionQueriesRule.d.ts

@@ -0,0 +1,16 @@
+import { ASTVisitor } from '../../../language/visitor';
+import { ValidationContext } from '../../ValidationContext';
+
+/**
+ * Prohibit introspection queries
+ *
+ * A GraphQL document is only valid if all fields selected are not fields that
+ * return an introspection type.
+ *
+ * Note: This rule is optional and is not part of the Validation section of the
+ * GraphQL Specification. This rule effectively disables introspection, which
+ * does not reflect best practices and should only be done if absolutely necessary.
+ */
+export function ProhibitIntrospectionQueriesRule(
+  context: ValidationContext,
+): ASTVisitor;

src/validation/rules/optional/ProhibitIntrospectionQueriesRule.js

@@ -0,0 +1,41 @@
+// @flow strict
+
+import { GraphQLError } from '../../../error/GraphQLError';
+
+import { type FieldNode } from '../../../language/ast';
+import { type ASTVisitor } from '../../../language/visitor';
+
+import { type ValidationContext } from '../../ValidationContext';
+
+import { getNamedType } from '../../../type/definition';
+import { isIntrospectionType } from '../../../type/introspection';
+
+/**
+ * Prohibit introspection queries
+ *
+ * A GraphQL document is only valid if all fields selected are not fields that
+ * return an introspection type.
+ *
+ * Note: This rule is optional and is not part of the Validation section of the
+ * GraphQL Specification. This rule effectively disables introspection, which
+ * does not reflect best practices and should only be done if absolutely necessary.
+ */
+export function ProhibitIntrospectionQueriesRule(
+  context: ValidationContext,
+): ASTVisitor {
+  return {
+    Field(node: FieldNode) {
+      const fieldType = context.getType();
+      if (fieldType) {
+        if (isIntrospectionType(getNamedType(fieldType))) {
+          context.reportError(
+            new GraphQLError(
+              `GraphQL introspection has been disabled, but the requested query contained the field "${node.name.value}".`,
+              node,
+            ),
+          );
+        }
+      }
+    },
+  };
+}