koaApollo.ts

import {
  GraphQLSchema,
  GraphQLResult,
} from 'graphql';

import { runQuery } from '../core/runQuery';

//import * as GraphiQL from '../modules/renderGraphiQL';

export interface KoaApolloOptions {
    schema: GraphQLSchema;
    formatError?: Function;
    rootValue?: any;
    context?: any;
    logFunction?: Function;
}

export function koaApollo(options: KoaApolloOptions): GraphQLResult {
  if (!options) {
    throw new Error('Apollo koa middleware requires options.');
  }
  if (arguments.length > 1) {
    throw new Error(`apolloServer expects exactly one argument, got ${arguments.length + 1}`);
  }
  return function *() {
    try {
      const query = getQueryString(this.request);
      const gqlResponse = yield runQuery({
        schema: options.schema,
        query: query,
        context: options.context || {},
      });
      this.body = gqlResponse;
    } catch (e) {
      this.body = { errors: [e.stack] };
    }
  };
}

function getQueryString(req) {
  if (req.method === 'POST') {
    return req.body.query;
  } else if (req.method === 'GET') {
    return req.query.query;
  }
  throw new Error(`HTTP method ${req.method} not supported`);
}