React Fetch Google Cloud Function http cors req.method OPTIONS, POST

Question

save time and skip to answer

What's wrong with my axios 'GET' this.props.profile.id logs into the console correctly from react-redux-firebase, but that's another story.

...

const response = await axios.get(
  "https://us-central1-thumbprint-1c31n.cloudfunctions.net/listCharts",
  { 'seatsioid': this.props.profile.id }
);

Or cloud functions header?

const functions = require('firebase-functions');
//const admin = require('firebase-admin');
const { SeatsioClient } = require('seatsio')
const cors = require('cors')
//admin.initializeApp(functions.config().firebase);


// // Create and Deploy Your First Cloud Functions
// // https://firebase.google.com/docs/functions/write-firebase-functions
//
exports.listCharts = functions.https.onRequest(async(req, res) => {
  cors(req, res, async () => {
    res.set('Access-Control-Allow-Origin', 'https://1c31n.csb.app');
    //res.set('Access-Control-Allow-Credentials', 'true');

    res.set('Access-Control-Allow-Methods', 'GET');
    res.set('Access-Control-Allow-Headers', 'Content-Type', 'X-Requested-Width', 'Accept', 'seatsioid')
    res.set('Access-Control-Max-Age', '60');
  var allowedOrigins = ['https://1c31n.csb.app', 'https://1c31n.codesandbox.io'];
  var origin = req.headers.origin;
  if(allowedOrigins.indexOf(origin) > -1){}
  const seatsioid = **req.get('seatsioid')
  let clientAdmin = new SeatsioClient('<THIS_IS_MY_ADMIN_SEATSIO_secretKey>')
  let subaccountInfo = await clientAdmin.subaccounts.retrieve(seatsioid);
  let secretKey = subaccountInfo.secretKey
  let clientDesignerKey = subaccountInfo.designerKey
  let charts = []
  let clientUser = new SeatsioClient(secretKey)
  for await(let chart of clientUser.charts.listAll()){
    charts.push(`chart":"${chart.key}`)
    }
    let couple = {
      charts,
      clientDesignerKey
    }
    res.send(couple)
})
})

Thank you

Answer 1

This took dayssss for me. hopefully this helps readers

express' cors middleware : https://expressjs.com/en/resources/middleware/cors.html

Google Cloud Function abstraction for cors middleware : https://cloud.google.com/functions/docs/writing/http

Call GCFunctions thru http (for fetch) : https://firebase.google.com/docs/functions/http-events

React fetch(URL, {})

async componentDidMount() {
    //console.log(this.props.profile)
    //this.setState({ posterOptions: this.props.profile.pages.unshift('post as myself')})
    //const seatsioid = this.props.profile.id;
    await fetch(
      "https://us-central1-foldername.cloudfunctions.net/function",
      {
        method: "POST",
        credentials: "include",
        headers: {
          "Content-Type": "Application/JSON",
          "Access-Control-Request-Method": "POST"
        },
        body: JSON.stringify({ seatsioid: this.props.profile.id }),
        maxAge: 3600
        //"mode": "cors",
      }
    )
      .then(response => response.json())
      .then(body => {
        console.log(body);
        //const reader = response.body.getReader()
        //reader.read().then(value => {
        //console.log(value);
        this.setState({
          allCharts: body.couple[0].charts,
          secretKey: body.couple[0].secretKey
        });
      })
      .catch(err => console.log(err));
}

Google Cloud Function

const functions = require("firebase-functions");
const { SeatsioClient } = require("seatsio");
const cors = require("cors")({
  origin: true,
  allowedHeaders: [
    "Access-Control-Allow-Origin",
    "Access-Control-Allow-Methods",
    "Content-Type",
    "Origin",
    "X-Requested-With",
    "Accept"
  ],
  methods: ["POST", "OPTIONS"],
  credentials: true
});

exports.listCharts = functions.https.onRequest((req, res) => {
  // Google Cloud Function res.methods
  res.set("Access-Control-Allow-Headers", "Content-Type");
  res.set("Content-Type", "Application/JSON");
  // CORS-enabled req.methods, res.methods
  return cors(req, res, async () => {
    res.set("Content-Type", "Application/JSON");
    var origin = req.get("Origin");
    var allowedOrigins = [
      "https://www.yoursite.blah",
      "https://yoursite2.blah"
    ];
    if (allowedOrigins.indexOf(origin) > -1) {
      // Origin Allowed!!
      res.set("Access-Control-Allow-Origin", origin);
      if (req.method === "OPTIONS") {
        // Method accepted for next request
        res.set("Access-Control-Allow-Methods", "POST");
        //SEND or end
        return res.status(200).send({});
      } else {
          // After req.method === 'OPTIONS' set ["Access-Control-Allow-Methods": "POST"]
          // req.method === 'POST' with req.body.{name} => res.body.{name}
          // req.method === 'PUT' with req.body.{name}, no res.body.{name}
        let couple = [];
        if (req.body.seatsioid) {
          const seatsioid = req.body.seatsioid;
          let clientAdmin = new SeatsioClient("YOUR_ADMIN_KEY");
          let subaccountInfo = await clientAdmin.subaccounts.retrieve(seatsioid);
          let secretKey = subaccountInfo.secretKey;
          let charts = [];
          let clientUser = new SeatsioClient(secretKey);
          for await (let chart of clientUser.charts.listAll()) {
            charts.push(`chart":"${chart.key}`);
          }
          couple = [
            {
              charts: charts,
              secretKey: secretKey
            }
          ];
          //SEND or end
          res.status(200).send({ couple });
        } else {
          //SEND or end
          res.status(400).send("No seatsioid defined!");
        }
      }
    } else {
      //Origin Bad!!
      //SEND or end
      return res.status(400).send("no access for this origin");
    }
  });
});

Someone with 1500 rep points should maybe add the seatsio tag in replace of reactjs or javascript for their other users, thanks

Answer 2

Normally, in the Cloud Functions index.js file, you should declare cors as follows:

const cors = require('cors')({
    origin: true
});

This is the way to allow current request origin, or, in other words "to reflect the request origin", see https://expressjs.com/en/resources/middleware/cors.html

Also see the Firebase documentation: https://firebase.google.com/docs/functions/http-events