GCF Cannot set property path of #<IncomingMessage>

[sanderhahn]

Deploying a minimal polka hello world in Google Cloud Functions will result in the following error. One workaround is to add a path setter to the req object (see example), but this feels a bit hacky :)

TypeError: Cannot set property path of #<IncomingMessage> which has only a getter
    at Polka.handler (/srv/functions/node_modules/polka/index.js:74:29)
    at process.nextTick (/srv/node_modules/@google-cloud/functions-framework/build/src/invoker.js:243:17)
    at process._tickCallback (internal/process/next_tick.js:61:11)

Example code with path setter:

// deploy using:
// gcloud functions deploy polka --runtime nodejs10 --trigger-http
const polka = require('polka');

const app = polka()
    .get('/', (req, res) => {
        res.end(`Hello world`);
    });

if (require.main === module) {
    app.listen(3000, err => {
        if (err) throw err;
        console.log(`> Running on http://localhost:3000`);
    });
}

exports.polka = (req, res) => {
    // define a path property setter on req
    var path = req.path;
    Object.defineProperty(req, 'path', {
        get: function () {
            return path;
        },
        set: function (newValue) {
            path = newValue;
        },
    });
    app.handler(req, res);
}

[lukeed]

Hi, thank you!

This is actually a duplicate of #86

There will be a GCF "adapter" come 1.0 that applies a workaround for (and only for) GCF applications. It's not worth including that change globally, for a few reasons.

Also, FYI, GCF is using Express under the hood already, so you gain no benefit in using Polka there 😓

Thank you for the detailed report though 🙌

[sanderhahn]

Sorry missed that issue... thanks for the quick response :)