Supply binding interface in .env

[windware-ono]

Summary

.env file needs an entry to supply the binding interface for 'listen'.
It currently forces to listen on all interfaces exposing port 3000 globally without a firewall blocking it.

Also, you should check to make sure APP_PORT is an integer or else it starts out as listening on port NaN and the process stays alive.

Steps to Reproduce

1. Install as normal
2. node app

Additional info

• Postleaf version: 1.0.0-beta.1
• Node version: 8.9.4
• Affected browsers:
• Operating system: Ubuntu 16.04

[claviska]

Would you care to give an example? I.E. what's your preferred method to resolve this?

[windware-ono]

Perhaps, provide

APP_BIND=127.0.0.1

in .env and simply

app.listen(process.env.APP_PORT, () => {

becomes

app.listen(process.env.APP_PORT, process.env.APP_BIND, () => {

[claviska]

Ok. I'll be happy to accept a PR that looks for the APP_HOST environmental variable. If present, it binds to that host. Otherwise, the current behavior stays the same.

I'm suggesting APP_HOST in lieu of APP_BIND because its also the argument name for server.listen() in the docs and may be more clear to users.

[claviska]

Fixed in #77. Only thing left here:

• Add APP_HOST to docs