ApolloServer.ts

import { makeExecutableSchema, addMockFunctionsToSchema } from 'graphql-tools';
import { Server as HttpServer } from 'http';
import {
  execute,
  GraphQLSchema,
  subscribe,
  ExecutionResult,
  GraphQLError,
  GraphQLFieldResolver,
  ValidationContext,
  FieldDefinitionNode,
} from 'graphql';
import { GraphQLExtension } from 'graphql-extensions';
import { EngineReportingAgent } from 'apollo-engine-reporting';
import { InMemoryLRUCache } from 'apollo-server-caching';
import { ApolloServerPlugin } from 'apollo-server-plugin-base';

import {
  SubscriptionServer,
  ExecutionParams,
} from 'subscriptions-transport-ws';

import { formatApolloErrors } from 'apollo-server-errors';
import {
  GraphQLServerOptions as GraphQLOptions,
  PersistedQueryOptions,
} from './graphqlOptions';

import {
  Config,
  Context,
  ContextFunction,
  SubscriptionServerOptions,
  FileUploadOptions,
  PluginDefinition,
} from './types';

import { FormatErrorExtension } from './formatters';

import { gql } from './index';

import {
  createPlaygroundOptions,
  PlaygroundRenderPageOptions,
} from './playground';

import { generateSchemaHash } from './utils/schemaHash';
import {
  processGraphQLRequest,
  GraphQLRequestContext,
  GraphQLRequest,
} from './requestPipeline';

import { Headers } from 'apollo-server-env';

const NoIntrospection = (context: ValidationContext) => ({
  Field(node: FieldDefinitionNode) {
    if (node.name.value === '__schema' || node.name.value === '__type') {
      context.reportError(
        new GraphQLError(
          'GraphQL introspection is not allowed by Apollo Server, but the query contained __schema or __type. To enable introspection, pass introspection: true to ApolloServer in production',
          [node],
        ),
      );
    }
  },
});

function getEngineServiceId(engine: Config['engine']): string | undefined {
  const keyFromEnv = process.env.ENGINE_API_KEY || '';
  if (!(engine || (engine !== false && keyFromEnv))) {
    return;
  }

  let engineApiKey: string = '';

  if (typeof engine === 'object' && engine.apiKey) {
    engineApiKey = engine.apiKey;
  } else if (keyFromEnv) {
    engineApiKey = keyFromEnv;
  }

  if (engineApiKey) {
    return engineApiKey.split(':', 2)[1];
  }

  return;
}

export class ApolloServerBase {
  public subscriptionsPath?: string;
  public graphqlPath: string = '/graphql';
  public requestOptions: Partial<GraphQLOptions<any>> = Object.create(null);

  private context?: Context | ContextFunction;
  private engineReportingAgent?: EngineReportingAgent;
  private engineServiceId?: string;
  private extensions: Array<() => GraphQLExtension>;
  private schemaHash: string;
  protected plugins: ApolloServerPlugin[] = [];

  protected schema: GraphQLSchema;
  protected subscriptionServerOptions?: SubscriptionServerOptions;
  protected uploadsConfig?: FileUploadOptions;

  // set by installSubscriptionHandlers.
  private subscriptionServer?: SubscriptionServer;

  // the default version is specified in playground.ts
  protected playgroundOptions?: PlaygroundRenderPageOptions;

  // The constructor should be universal across all environments. All environment specific behavior should be set by adding or overriding methods
  constructor(config: Config) {
    if (!config) throw new Error('ApolloServer requires options.');
    const {
      context,
      resolvers,
      schema,
      schemaDirectives,
      typeDefs,
      introspection,
      mocks,
      mockEntireSchema,
      extensions,
      engine,
      subscriptions,
      uploads,
      playground,
      plugins,
      ...requestOptions
    } = config;

    // Plugins will be instantiated if they aren't already, and this.plugins
    // is populated accordingly.
    this.ensurePluginInstantiation(plugins);

    // While reading process.env is slow, a server should only be constructed
    // once per run, so we place the env check inside the constructor. If env
    // should be used outside of the constructor context, place it as a private
    // or protected field of the class instead of a global. Keeping the read in
    // the contructor enables testing of different environments
    const isDev = process.env.NODE_ENV !== 'production';

    // if this is local dev, introspection should turned on
    // in production, we can manually turn introspection on by passing {
    // introspection: true } to the constructor of ApolloServer
    if (
      (typeof introspection === 'boolean' && !introspection) ||
      (introspection === undefined && !isDev)
    ) {
      const noIntro = [NoIntrospection];
      requestOptions.validationRules = requestOptions.validationRules
        ? requestOptions.validationRules.concat(noIntro)
        : noIntro;
    }

    if (requestOptions.cacheControl !== false) {
      if (
        typeof requestOptions.cacheControl === 'boolean' &&
        requestOptions.cacheControl === true
      ) {
        // cacheControl: true means that the user needs the cache-control
        // extensions. This means we are running the proxy, so we should not
        // strip out the cache control extension and not add cache-control headers
        requestOptions.cacheControl = {
          stripFormattedExtensions: false,
          calculateHttpHeaders: false,
          defaultMaxAge: 0,
        };
      } else {
        // Default behavior is to run default header calculation and return
        // no cacheControl extensions
        requestOptions.cacheControl = {
          stripFormattedExtensions: true,
          calculateHttpHeaders: true,
          defaultMaxAge: 0,
          ...requestOptions.cacheControl,
        };
      }
    }

    if (!requestOptions.cache) {
      requestOptions.cache = new InMemoryLRUCache();
    }

    if (requestOptions.persistedQueries !== false) {
      if (!requestOptions.persistedQueries) {
        requestOptions.persistedQueries = {
          cache: requestOptions.cache!,
        };
      }
    } else {
      // the user does not want to use persisted queries, so we remove the field
      delete requestOptions.persistedQueries;
    }

    this.requestOptions = requestOptions as GraphQLOptions;
    this.context = context;

    if (uploads !== false) {
      if (this.supportsUploads()) {
        if (uploads === true || typeof uploads === 'undefined') {
          this.uploadsConfig = {};
        } else {
          this.uploadsConfig = uploads;
        }
        //This is here to check if uploads is requested without support. By
        //default we enable them if supported by the integration
      } else if (uploads) {
        throw new Error(
          'This implementation of ApolloServer does not support file uploads because the environmnet cannot accept multi-part forms',
        );
      }
    }

    if (schema) {
      this.schema = schema;
    } else {
      if (!typeDefs) {
        throw Error(
          'Apollo Server requires either an existing schema or typeDefs',
        );
      }

      let augmentedTypeDefs = Array.isArray(typeDefs) ? typeDefs : [typeDefs];

      // We augment the typeDefs with the @cacheControl directive and associated
      // scope enum, so makeExecutableSchema won't fail SDL validation
      augmentedTypeDefs.push(
        gql`
          enum CacheControlScope {
            PUBLIC
            PRIVATE
          }

          directive @cacheControl(
            maxAge: Int
            scope: CacheControlScope
          ) on FIELD_DEFINITION | OBJECT | INTERFACE
        `,
      );

      if (this.uploadsConfig) {
        const {
          GraphQLUpload,
        } = require('@apollographql/apollo-upload-server');
        if (resolvers && !resolvers.Upload) {
          resolvers.Upload = GraphQLUpload;
        }

        // We augment the typeDefs with the Upload scalar, so typeDefs that
        // don't include it won't fail
        augmentedTypeDefs.push(
          gql`
            scalar Upload
          `,
        );
      }

      this.schema = makeExecutableSchema({
        typeDefs: augmentedTypeDefs,
        schemaDirectives,
        resolvers,
      });
    }

    if (mocks || (typeof mockEntireSchema !== 'undefined' && mocks !== false)) {
      addMockFunctionsToSchema({
        schema: this.schema,
        mocks:
          typeof mocks === 'boolean' || typeof mocks === 'undefined'
            ? {}
            : mocks,
        preserveResolvers:
          typeof mockEntireSchema === 'undefined' ? false : !mockEntireSchema,
      });
    }

    // The schema hash is a string representation of the shape of the schema
    // it is used for reporting and can be used for a cache key if needed
    this.schemaHash = generateSchemaHash(this.schema);

    // Note: doRunQuery will add its own extensions if you set tracing,
    // or cacheControl.
    this.extensions = [];

    const debugDefault =
      process.env.NODE_ENV !== 'production' && process.env.NODE_ENV !== 'test';
    const debug =
      requestOptions.debug !== undefined ? requestOptions.debug : debugDefault;

    // Error formatting should happen after the engine reporting agent, so that
    // engine gets the unmasked errors if necessary
    this.extensions.push(
      () => new FormatErrorExtension(requestOptions.formatError, debug),
    );

    // In an effort to avoid over-exposing the API key itself, extract the
    // service ID from the API key for plugins which only needs service ID.
    // The truthyness of this value can also be used in other forks of logic
    // related to Engine, as is the case with EngineReportingAgent just below.
    this.engineServiceId = getEngineServiceId(engine);

    if (this.engineServiceId) {
      this.engineReportingAgent = new EngineReportingAgent(
        typeof engine === 'object' ? engine : Object.create(null),
        {
          schema: this.schema,
          schemaHash: this.schemaHash,
          engine: {
            serviceID: this.engineServiceId,
          },
        },
      );
      // Let's keep this extension second so it wraps everything, except error formatting
      this.extensions.push(() => this.engineReportingAgent!.newExtension());
    }

    if (extensions) {
      this.extensions = [...this.extensions, ...extensions];
    }

    if (subscriptions !== false) {
      if (this.supportsSubscriptions()) {
        if (subscriptions === true || typeof subscriptions === 'undefined') {
          this.subscriptionServerOptions = {
            path: this.graphqlPath,
          };
        } else if (typeof subscriptions === 'string') {
          this.subscriptionServerOptions = { path: subscriptions };
        } else {
          this.subscriptionServerOptions = {
            path: this.graphqlPath,
            ...subscriptions,
          };
        }
        // This is part of the public API.
        this.subscriptionsPath = this.subscriptionServerOptions.path;

        //This is here to check if subscriptions are requested without support. By
        //default we enable them if supported by the integration
      } else if (subscriptions) {
        throw new Error(
          'This implementation of ApolloServer does not support GraphQL subscriptions.',
        );
      }
    }

    this.playgroundOptions = createPlaygroundOptions(playground);
  }

  // used by integrations to synchronize the path with subscriptions, some
  // integrations do not have paths, such as lambda
  public setGraphQLPath(path: string) {
    this.graphqlPath = path;
  }

  protected async willStart() {
    await Promise.all(
      this.plugins.map(
        plugin =>
          plugin.serverWillStart &&
          plugin.serverWillStart({
            schema: this.schema,
            schemaHash: this.schemaHash,
            engine: {
              serviceID: this.engineServiceId,
            },
            persistedQueries: this.requestOptions.persistedQueries,
          }),
      ),
    );
  }

  public async stop() {
    if (this.subscriptionServer) await this.subscriptionServer.close();
    if (this.engineReportingAgent) {
      this.engineReportingAgent.stop();
      await this.engineReportingAgent.sendReport();
    }
  }

  public installSubscriptionHandlers(server: HttpServer) {
    if (!this.subscriptionServerOptions) {
      if (this.supportsSubscriptions()) {
        throw Error(
          'Subscriptions are disabled, due to subscriptions set to false in the ApolloServer constructor',
        );
      } else {
        throw Error(
          'Subscriptions are not supported, choose an integration, such as apollo-server-express that allows persistent connections',
        );
      }
    }

    const {
      onDisconnect,
      onConnect,
      keepAlive,
      path,
    } = this.subscriptionServerOptions;

    this.subscriptionServer = SubscriptionServer.create(
      {
        schema: this.schema,
        execute,
        subscribe,
        onConnect: onConnect
          ? onConnect
          : (connectionParams: Object) => ({ ...connectionParams }),
        onDisconnect: onDisconnect,
        onOperation: async (
          message: { payload: any },
          connection: ExecutionParams,
        ) => {
          connection.formatResponse = (value: ExecutionResult) => ({
            ...value,
            errors:
              value.errors &&
              formatApolloErrors([...value.errors], {
                formatter: this.requestOptions.formatError,
                debug: this.requestOptions.debug,
              }),
          });
          let context: Context = this.context ? this.context : { connection };

          try {
            context =
              typeof this.context === 'function'
                ? await this.context({ connection, payload: message.payload })
                : context;
          } catch (e) {
            throw formatApolloErrors([e], {
              formatter: this.requestOptions.formatError,
              debug: this.requestOptions.debug,
            })[0];
          }

          return { ...connection, context };
        },
        keepAlive,
      },
      {
        server,
        path,
      },
    );
  }

  protected supportsSubscriptions(): boolean {
    return false;
  }

  protected supportsUploads(): boolean {
    return false;
  }

  private ensurePluginInstantiation(plugins?: PluginDefinition[]): void {
    if (!plugins || !plugins.length) {
      return;
    }

    // FIXME: We also want to support default exports and possibly module names
    // but this requires adjustments to typing (see PluginDefinition type), and
    // I had to give up on that for now.
    this.plugins = plugins.map(plugin => {
      if (typeof plugin === 'function') {
        return new plugin();
      } else {
        return plugin as ApolloServerPlugin;
      }
    });
  }

  // This function is used by the integrations to generate the graphQLOptions
  // from an object containing the request and other integration specific
  // options
  protected async graphQLServerOptions(
    integrationContextArgument?: Record<string, any>,
  ) {
    let context: Context = this.context ? this.context : {};

    try {
      context =
        typeof this.context === 'function'
          ? await this.context(integrationContextArgument || {})
          : context;
    } catch (error) {
      // Defer context error resolution to inside of runQuery
      context = () => {
        throw error;
      };
    }

    return {
      schema: this.schema,
      plugins: this.plugins,
      extensions: this.extensions,
      context,
      // Allow overrides from options. Be explicit about a couple of them to
      // avoid a bad side effect of the otherwise useful noUnusedLocals option
      // (https://github.com/Microsoft/TypeScript/issues/21673).
      persistedQueries: this.requestOptions
        .persistedQueries as PersistedQueryOptions,
      fieldResolver: this.requestOptions.fieldResolver as GraphQLFieldResolver<
        any,
        any
      >,
      ...this.requestOptions,
    } as GraphQLOptions;
  }

  public async executeOperation(request: GraphQLRequest) {
    let options;

    try {
      options = await this.graphQLServerOptions();
    } catch (e) {
      e.message = `Invalid options provided to ApolloServer: ${e.message}`;
      throw new Error(e);
    }

    if (typeof options.context === 'function') {
      options.context = (options.context as () => never)();
    }

    const requestCtx: GraphQLRequestContext = {
      request,
      context: options.context || Object.create(null),
      cache: options.cache!,
      response: {
        http: {
          headers: new Headers(),
        },
      },
    };

    return processGraphQLRequest(options, requestCtx);
  }
}