initial attempt

packages/wrap/src/transforms/TransformInputFields.ts

@@ -0,0 +1,194 @@
+import {
+  GraphQLSchema,
+  GraphQLType,
+  DocumentNode,
+  TypeInfo,
+  visit,
+  visitWithTypeInfo,
+  Kind,
+  FragmentDefinitionNode,
+  GraphQLInputObjectType,
+  ObjectValueNode,
+  ObjectFieldNode,
+} from 'graphql';
+
+import { Transform, Request, MapperKind, mapSchema } from '@graphql-tools/utils';
+import { InputFieldTransformer, InputFieldNodeTransformer, InputObjectNodeTransformer } from '../types';
+import { DelegationContext } from 'packages/delegate/src';
+
+export default class TransformInputFields implements Transform {
+  private readonly inputFieldTransformer: InputFieldTransformer;
+  private readonly inputFieldNodeTransformer: InputFieldNodeTransformer;
+  private readonly inputObjectNodeTransformer: InputObjectNodeTransformer;
+  private transformedSchema: GraphQLSchema;
+  private mapping: Record<string, Record<string, string>>;
+
+  constructor(
+    inputFieldTransformer: InputFieldTransformer,
+    inputFieldNodeTransformer?: InputFieldNodeTransformer,
+    inputObjectNodeTransformer?: InputObjectNodeTransformer
+  ) {
+    this.inputFieldTransformer = inputFieldTransformer;
+    this.inputFieldNodeTransformer = inputFieldNodeTransformer;
+    this.inputObjectNodeTransformer = inputObjectNodeTransformer;
+    this.mapping = {};
+  }
+
+  public transformSchema(originalSchema: GraphQLSchema): GraphQLSchema {
+    this.transformedSchema = mapSchema(originalSchema, {
+      [MapperKind.INPUT_OBJECT_TYPE]: (type: GraphQLInputObjectType) =>
+        this.transformFields(type, this.inputFieldTransformer),
+    });
+
+    return this.transformedSchema;
+  }
+
+  public transformRequest(originalRequest: Request, delegationContext: DelegationContext): Request {
+    const fragments = Object.create(null);
+    originalRequest.document.definitions
+      .filter(def => def.kind === Kind.FRAGMENT_DEFINITION)
+      .forEach(def => {
+        fragments[(def as FragmentDefinitionNode).name.value] = def;
+      });
+    const document = this.transformDocument(
+      originalRequest.document,
+      this.mapping,
+      this.inputFieldNodeTransformer,
+      this.inputObjectNodeTransformer,
+      delegationContext,
+      originalRequest
+    );
+    return {
+      ...originalRequest,
+      document,
+    };
+  }
+
+  private transformFields(type: GraphQLInputObjectType, inputFieldTransformer: InputFieldTransformer): any {
+    const config = type.toConfig();
+
+    const originalInputFieldConfigMap = config.fields;
+    const newInputFieldConfigMap = {};
+
+    Object.keys(originalInputFieldConfigMap).forEach(fieldName => {
+      const originalInputFieldConfig = originalInputFieldConfigMap[fieldName];
+      const transformedField = inputFieldTransformer(type.name, fieldName, originalInputFieldConfig);
+
+      if (transformedField === undefined) {
+        newInputFieldConfigMap[fieldName] = originalInputFieldConfig;
+      } else if (Array.isArray(transformedField)) {
+        const newFieldName = transformedField[0];
+        const newFieldConfig = transformedField[1];
+        newInputFieldConfigMap[newFieldName] = newFieldConfig;
+
+        if (newFieldName !== fieldName) {
+          const typeName = type.name;
+          if (!(typeName in this.mapping)) {
+            this.mapping[typeName] = {};
+          }
+          this.mapping[typeName][newFieldName] = fieldName;
+        }
+      } else if (transformedField != null) {
+        newInputFieldConfigMap[fieldName] = transformedField;
+      }
+    });
+
+    if (!Object.keys(newInputFieldConfigMap).length) {
+      return null;
+    }
+
+    return new GraphQLInputObjectType({
+      ...type.toConfig(),
+      fields: newInputFieldConfigMap,
+    });
+  }
+
+  private transformDocument(
+    document: DocumentNode,
+    mapping: Record<string, Record<string, string>>,
+    inputFieldNodeTransformer: InputFieldNodeTransformer,
+    inputObjectNodeTransformer: InputObjectNodeTransformer,
+    delegationContext: DelegationContext,
+    request: Request
+  ): DocumentNode {
+    const typeInfo = new TypeInfo(this.transformedSchema);
+    const newDocument: DocumentNode = visit(
+      document,
+      visitWithTypeInfo(typeInfo, {
+        leave: {
+          [Kind.OBJECT]: (node: ObjectValueNode): ObjectValueNode => {
+            const parentType: GraphQLType = typeInfo.getInputType() as GraphQLInputObjectType;
+            if (parentType != null) {
+              const parentTypeName = parentType.name;
+              const newInputFields: Array<ObjectFieldNode> = [];
+
+              node.fields.forEach(inputField => {
+                const newName = inputField.name.value;
+
+                const transformedInputField =
+                  inputFieldNodeTransformer != null
+                    ? inputFieldNodeTransformer(parentTypeName, newName, inputField, delegationContext, request)
+                    : inputField;
+
+                if (Array.isArray(transformedInputField)) {
+                  transformedInputField.forEach(individualTransformedInputField => {
+                    const typeMapping = mapping[parentTypeName];
+                    if (typeMapping == null) {
+                      newInputFields.push(individualTransformedInputField);
+                      return;
+                    }
+
+                    const oldName = typeMapping[newName];
+                    if (oldName == null) {
+                      newInputFields.push(individualTransformedInputField);
+                      return;
+                    }
+
+                    newInputFields.push({
+                      ...individualTransformedInputField,
+                      name: {
+                        ...individualTransformedInputField.name,
+                        value: oldName,
+                      },
+                    });
+                  });
+                  return;
+                }
+
+                const typeMapping = mapping[parentTypeName];
+                if (typeMapping == null) {
+                  newInputFields.push(transformedInputField);
+                  return;
+                }
+
+                const oldName = typeMapping[newName];
+                if (oldName == null) {
+                  newInputFields.push(transformedInputField);
+                  return;
+                }
+
+                newInputFields.push({
+                  ...transformedInputField,
+                  name: {
+                    ...transformedInputField.name,
+                    value: oldName,
+                  },
+                });
+              });
+
+              const newNode = {
+                ...node,
+                fields: newInputFields,
+              };
+
+              return inputObjectNodeTransformer != null
+                ? inputObjectNodeTransformer(parentTypeName, newNode, delegationContext, request)
+                : newNode;
+            }
+          },
+        },
+      })
+    );
+    return newDocument;
+  }
+}

packages/wrap/src/types.ts

@@ -2,12 +2,16 @@ import {
   GraphQLSchema,
   GraphQLFieldResolver,
   BuildSchemaOptions,
+  GraphQLInputFieldConfig,
   GraphQLFieldConfig,
   FieldNode,
   FragmentDefinitionNode,
   SelectionNode,
+  ObjectFieldNode,
+  ObjectValueNode,
 } from 'graphql';
-import { Executor, Subscriber } from '@graphql-tools/delegate';
+import { Executor, Subscriber, DelegationContext } from '@graphql-tools/delegate';
+import { Request } from '@graphql-tools/utils';
 
 export interface IMakeRemoteExecutableSchemaOptions {
   schema: GraphQLSchema | string;
@@ -17,6 +21,27 @@ export interface IMakeRemoteExecutableSchemaOptions {
   buildSchemaOptions?: BuildSchemaOptions;
 }
 
+export type InputFieldTransformer = (
+  typeName: string,
+  fieldName: string,
+  inputFieldConfig: GraphQLInputFieldConfig
+) => GraphQLInputFieldConfig | [string, GraphQLInputFieldConfig] | null | undefined;
+
+export type InputFieldNodeTransformer = (
+  typeName: string,
+  fieldName: string,
+  inputFieldNode: ObjectFieldNode,
+  delegationContext: DelegationContext,
+  request: Request
+) => ObjectFieldNode | Array<ObjectFieldNode>;
+
+export type InputObjectNodeTransformer = (
+  typeName: string,
+  inputObjectNode: ObjectValueNode,
+  delegationContext: DelegationContext,
+  request: Request
+) => ObjectValueNode;
+
 export type FieldTransformer = (
   typeName: string,
   fieldName: string,

packages/wrap/tests/transforms.test.ts

@@ -7,6 +7,8 @@ import {
   SelectionSetNode,
   print,
   parse,
+  GraphQLInputObjectType,
+  astFromValue,
 } from 'graphql';
 
 import { makeExecutableSchema } from '@graphql-tools/schema';
@@ -35,6 +37,7 @@ import {
 } from '@graphql-tools/delegate';
 
 import { propertySchema, bookingSchema } from './fixtures/schemas';
+import TransformInputFields from '../src/transforms/TransformInputFields';
 
 function createError<T>(message: string, extra?: T) {
   const error = new Error(message);
@@ -1368,4 +1371,72 @@ describe('replaces field with processed fragment node', () => {
       },
     });
   });
+
+  describe('transform input type', () => {
+    test('it works', async () => {
+      const schema = makeExecutableSchema({
+        typeDefs: `
+          input InputObject {
+            field1: String
+            field2: String
+          }
+
+          type OutputObject {
+            field1: String
+            field2: String
+          }
+
+          type Query {
+            test(argument: InputObject): OutputObject
+          }
+        `,
+        resolvers: {
+          Query: {
+            test: (_root, args) => {
+              return args.argument;
+            }
+          }
+        }
+      });
+
+      const transformedSchema = wrapSchema(schema, [
+        new TransformInputFields(
+          (typeName, fieldName) => {
+            if (typeName === 'InputObject' && fieldName === 'field2') {
+              return null;
+            }
+          },
+          undefined,
+          (typeName, inputObjectNode) => {
+            if (typeName === 'InputObject') {
+              return {
+                ...inputObjectNode,
+                fields: [...inputObjectNode.fields, {
+                  kind: Kind.OBJECT_FIELD,
+                  name: {
+                    kind: Kind.NAME,
+                    value: 'field2',
+                  },
+                  value: astFromValue('field2', (schema.getType('InputObject') as GraphQLInputObjectType).getFields()['field2'].type),
+                }],
+              };
+            }
+          }
+        )
+      ]);
+
+      const query = `{
+        test(argument: {
+          field1: "field1"
+        }) {
+          field1
+          field2
+        }
+      }`;
+
+      const result = await graphql(transformedSchema, query);
+      expect(result.data.test.field1).toBe('field1');
+      expect(result.data.test.field2).toBe('field2');
+    });
+  });
 });