Debugging complex GraphQL queries with shortlinks to GraphiQL

const express = require('express')
const graphqlHTTP = require('express-graphql')
const { buildSchema } = require('graphql')
const hash = require('object-hash')
const bodyParser = require('body-parser')
const querystring = require('querystring')

// Construct a schema, using GraphQL schema language
const schema = buildSchema(`
  type Query {
    hello: String
  }
`)

// The root provides a resolver function for each API endpoint
const root = {
  hello: () => {
    return 'Hello world!'
  }
}

const app = express()

// parses incoming json post requests, and
// makes it available on req.body.
app.use(bodyParser.json());

/**
 * Enable shortlinks in the terminal  which will automatically
 * take you to graphiql editor pre-filled with data.
 */
if (process.env.NODE_ENV === 'development') {

  const queryLog = {}

  // parses shortlinks and redirects to the GraphiQL editor
  app.use('/goto', (req, res) => {
    const { id } = req.query
    if (!queryLog[id]) {
      console.error('Failed to find a stored query')
      return res.status(404).end()
    }
    return res.redirect(queryLog[id])
  })

  // peeks at incoming /graphql requests and builds shortlinks
  app.use('/graphql', (req, res, next) => {
    const { query, variables } = req.body
    const queryParams = querystring.stringify({
      query,
      variables: JSON.stringify(variables)
    })
    // hash query into id so that identical queries occupy
    // the same space in the queryLog map.
    const id = hash({ query, variables })
    queryLog[id] = `http://localhost:4000/graphql?${queryParams}`
    console.log(
      'Query was made, inspect:',
      `http://localhost:4000/goto?id=${id}`
    )
    // finally pass requests to the actual /graphql endpoint
    next()
  })
}

app.use(
  '/graphql',
  graphqlHTTP({
    schema: schema,
    rootValue: root,
    graphiql: true
  })
)

app.listen(4000)
console.log('Running a GraphQL API server at http://localhost:4000/graphql')