Notice that your generated /src-ssr contains a file named production-export.js. This file defines how your SSR webserver is served. You can start listening to a port or provide a handler for your serverless infrastructure to use. It’s up to you.

Whatever this function returns (if anything) will be exported from your built dist/ssr/index.js.

Anatomy

The /src-ssr/production-export.[js|ts] file is a simple JavaScript file which boots up your SSR webserver and defines what your webserver exports (if exporting anything).

// import something here (serverless packages?)

export default ({
  app, port, isReady, ssrHandler,
  resolve, publicPath, folders, render, serve
}) => {
  // something to do with the server "app"
  // return whatever you want your webserver to export (handler for serverless function?)
}

You can wrap the returned function with ssrProductionExport helper to get a better IDE autocomplete experience (Quasar v2.3.1+ required):

import { ssrProductionExport } from 'quasar/wrappers'

export default ssrProductionExport(({
  app, port, isReady, ssrHandler,
  resolve, publicPath, folders, render, serve
}) => {
  // something to do with the server "app"
  // return whatever you want your webserver to export (handler for serverless?)
})

Parameters

We are referring here to the Object received as parameter by the default exported function of the production-export file.

export default ({
  app, port, isReady, ssrHandler,
  resolve, publicPath, folders, render, serve
}) => {

Detailing the Object:

{
  app,     // Expressjs app instance

  port,    // process.env.PORT or quasar.config.js > ssr > prodPort

  isReady, // Function to call returning a Promise
           // when app is ready to serve clients

  ssrHandler, // Prebuilt app handler if your serverless service
              // doesn't require a specific way to provide it.
              // Form: ssrHandler (req, res, next)
              // Tip: it uses isReady() under the hood already

  // all of the following are the same as
  // for the SSR middlewares (check its docs page);
  // normally you don't need these here
  // (use a real SSR middleware instead)
  resolve: {
    urlPath(path)
    root(arg1, arg2),
    public(arg1, arg2)
  },
  publicPath, // String
  folders: {
    root,     // String
    public    // String
  },
  render(ssrContext),
  serve: {
    static(path, opts),
    error({ err, req, res })
  }
}

Default content

The following is the default content of /src-ssr/production-export.js when you add SSR support in a Quasar CLI project:

import { ssrProductionExport } from 'quasar/wrappers'

export default ssrProductionExport(({ app, port, isReady }) => {
  return isReady().then(() => {
    app.listen(port, () => {
      console.log('Server listening at port ' + port)
    })
  })
})

Usage

Listen on a port

This is the default option that you get when adding SSR support in a Quasar CLI project. It starts listening on the configured port (process.env.PORT or quasar.config.js > ssr > prodPort).

// src-ssr/production-export.[js|ts]

import { ssrProductionExport } from 'quasar/wrappers'

export default ssrProductionExport(({ app, port, isReady }) => {
  // we wait for app to be ready (including running all SSR middlewares)
  return isReady().then(() => {
    // then we start listening on a port
    app.listen(port, () => {
      // we're ready to serve clients
      console.log('Server listening at port ' + port)
    })
  })
})

Serverless

If you have a serverless infrastructure, then you generally need to export a handler instead of starting to listen to a port.

Say that your serverless service requires you to:

module.exports.handler = __your_handler__

Then what you’d need to do is:

// src-ssr/production-export.[js|ts]

import { ssrProductionExport } from 'quasar/wrappers'

export default ssrProductionExport(({ ssrHandler }) => {
  // "ssrHandler" is a prebuilt handler which already
  // waits for all the middlewares to run before serving clients

  // whatever you return here is equivalent to module.exports.<key> = <value>
  return { handler: ssrHandler }
})

Please note that the provided ssrHandler is a Function of form: (req, res, next) => void. Should you require to export a handler of form (event, context, callback) => void then you will most likely want to use the serverless-http package (see below).

Example: serverless-http

// src-ssr/production-export.[js|ts]

import serverless from 'serverless-http'
import { ssrProductionExport } from 'quasar/wrappers'

export default ssrProductionExport(({ ssrHandler }) => {
  return { handler: serverless(ssrHandler) }
})

Example: Firebase function

// src-ssr/production-export.[js|ts]

import * as functions from 'firebase-functions'
import { ssrProductionExport } from 'quasar/wrappers'

export default ssrProductionExport(({ ssrHandler }) => {
  return {
    handler: functions.https.onRequest(ssrHandler)
  }
})