add example GraphQL server and client that use @defer experimental feature

Author: Gabriel Saliev

examples/defer-example/README.md

@@ -0,0 +1,17 @@
+# Example usage
+
+This is the bare minimum that one needs in order to setup GraphQL server that supports @defer and a client that consumes it.
+
+## Server setup
+
+1. cd to /server
+2. use ``npm install``
+3. start the server with `` node server.js ``
+
+## Client setup
+
+1. cd to /client
+2. use ``node client.js`` to execute the example deferred query
+
+Have fun!
+

examples/defer-example/client/client.js

@@ -0,0 +1,44 @@
+import http from 'http';
+
+const data = `query defer_test {
+  deferTest {
+    text
+    ... on GraphQLDeferTest @defer {
+      defferedText
+    }
+  }
+}`
+
+const options = {
+  hostname: 'localhost',
+  port: 4040,
+  path: '/graphql',
+  method: 'POST',
+  headers: {
+    'Content-Type': 'application/graphql',
+    'Content-Length': Buffer.byteLength(data)
+  }
+};
+
+const req = http.request(options, (res) => {
+  console.log(`STATUS: ${res.statusCode}`);
+  console.log(`HEADERS: ${JSON.stringify(res.headers)}`);
+  
+  res.setEncoding('utf8');
+
+  res.on('data', (chunk) => {
+    console.log(`BODY: ${chunk}`);
+  });
+
+  res.on('end', () => {
+    console.log('No more data in response.');
+  });
+});
+
+req.on('error', (e) => {
+  console.error(`problem with request: ${e.message}`);
+});
+
+// Write data to request body
+req.write(data);
+req.end();

examples/defer-example/server/package.json

@@ -0,0 +1,7 @@
+{
+  "dependencies": {
+    "express": "^4.17.1",
+    "express-graphql": "0.12.0-experimental-stream-defer.1",
+    "graphql": "15.4.0-experimental-stream-defer.1"
+  }
+}

examples/defer-example/server/server.js

@@ -0,0 +1,50 @@
+const express  = require('express');
+const { graphqlHTTP } = require('express-graphql');
+const { buildSchema } = require('graphql');
+
+// Construct a schema, using GraphQL schema language
+var schema = buildSchema(`
+  type Query {
+    hello: String
+    deferTest: GraphQLDeferTest
+  }
+
+  type GraphQLDeferTest {
+    text: String
+    defferedText: String
+  }
+`);
+
+const sleep = (t = 1000) => new Promise((res) => setTimeout(res, t));
+
+// Model
+class GraphQLDeferTest {
+  constructor() {}
+
+  async text() {
+    return "Peter Parker"
+  }
+
+  async defferedText() {
+    await sleep(5000)
+
+    return 'Took a long time, he?'
+  }
+}
+
+// Query resolvers
+var root = {
+  hello: () => 'Hello World',
+  deferTest: async () => new GraphQLDeferTest(),
+};
+
+var app = express();
+
+app.use('/graphql', graphqlHTTP({
+  schema: schema,
+  rootValue: root,
+  graphiql: true,
+}));
+
+app.listen(4040)
+console.log('Running a GraphQL API server at http://localhost:4040/graphql');

examples/index.ts

@@ -3,16 +3,40 @@ import { buildSchema } from 'graphql';
 
 import { graphqlHTTP } from '../src';
 
+// Model
+class GraphQLDeferTest {
+  constructor() {}
+
+  // Child resolvers
+  async text() {
+    return "Peter Parker"
+  }
+
+  async defferedText() {
+    await sleep(5000)
+
+    return 'Took a long time, he?'
+  }
+}
+
+
 // Construct a schema, using GraphQL schema language
 const schema = buildSchema(`
   type Query {
     hello: String
+    deferTest: GraphQLDeferTest
+  }
+
+  type GraphQLDeferTest {
+    text: String
+    defferedText: String
   }
 `);
 
 // The root provides a resolver function for each API endpoint
 const rootValue = {
   hello: () => 'Hello world!',
+  deferTest: async () => new GraphQLDeferTest(),
 };
 
 const app = express();