server.js

// External dependencies
const fs = require("fs")
const yaml = require("js-yaml")
const express = require("express")
const { createWebhooksApi } = require("@octokit/webhooks")
const { createAppAuth } = require("@octokit/auth-app")
const { graphql } = require("@octokit/graphql")

// Local dependencies
const smeeClient = require("./smee")
const emojify = require("./emojify")
const hasCommand = require("./command")
const updateBodyMutationFor = require("./mutations")

// Setup
const port = 64897
const app = express()
const privateKey = fs.readFileSync("gh-app.pem", "utf8")
const config = require('../config.json')
var emojifierConfig = yaml.safeLoad(fs.readFileSync("emojifier-default.yml", "utf8"))

const smee = smeeClient(config.webproxy_url, port)
smee.start()

const webhooks = new createWebhooksApi({ secret: "mysecret", path: "/webhooks" })
app.use(webhooks.middleware)

// App

webhooks.on(["issue_comment.created", "issues.opened", "pull_request.opened"], async (event) => {
  const { payload } = event
  const auth = createAppAuth({
    id: config.github_app_id,
    privateKey: privateKey,
    installationId: payload.installation.id
  })

  const { token } = await auth({ type: "installation" });
  const graphqlWithAuth = graphql.defaults({
    headers: {
      authorization: `token ${token}`
    }
  })

  const { comment, issue, pullRequest } = payload
  const body = (comment || issue || pullRequest).body
  const nodeId = (comment || issue || pullRequest).node_id

  const getEmojifierConfig = `
    query($repoName:String!, $repoOwner:String!) {
      repository(name: $repoName, owner: $repoOwner) {
        object(expression: "master:.emojifier.yml") {
          ... on Blob {
            text
          }
        }
      }
    }
  `

  try {
    const queryResponse = await graphqlWithAuth(getEmojifierConfig, {
      repoName: payload.repository.name,
      repoOwner: payload.repository.owner.login
    })

    if (queryResponse.repository.object != null) {
      emojifierConfig = yaml.safeLoad(queryResponse.repository.object.text)
    }
  } catch (e) {
    console.log(e)
  }

  if (hasCommand("emojify", body)) {
    const newBody = emojify(body, emojifierConfig.editMode, emojifierConfig.emojiLimit)

    try {
      await graphqlWithAuth(updateBodyMutationFor(event.name), {
        newBody: newBody,
        id: nodeId
      })
      return
    } catch (err) {
      console.log(err)
    }
  } else {
    console.log("Command not found in body")
  }
})

webhooks.on("error", (error) => {
  console.log(`Error occured in "${error.event.name} handler: ${error.stack}"`)
})

const listener = app.listen(port, () => {
  console.log("Your app is listening on port " + listener.address().port)
})