notes on adding tls to matrix appservice bridge

info.txt

Tracing from matrix-appservice-imessage on down through the turtle stack:

The call bridge.run(port, config) makes the server listen:

https://github.com/kfatehi/matrix-appservice-imessage/blob/master/index.js#L181

bridge.run, as defined in matrix-appservice-bridge, calls `appService.listen(port)`:

https://github.com/matrix-org/matrix-appservice-bridge/blob/master/lib/bridge.js#L253

`AppService` is defined in matrix-appservice-node and calls `app.listen(port, ...)`:

https://github.com/matrix-org/matrix-appservice-node/blob/master/lib/app-service.js#L184

`app` is an express instance:

https://github.com/matrix-org/matrix-appservice-node/blob/master/lib/app-service.js#L21

When you just run `app.listen` express uses `require('http')` under the hood. In order to use tls, you need to do the following:


```
var fs = require('fs');
var https = require('https');
var app = require('express')(); // XXX you have this already
var options = {
   key  : fs.readFileSync('server.key'),
   cert : fs.readFileSync('server.crt')
};

https.createServer(options, app).listen(3000, function () {
   console.log('Started!');
});
```

The only thing that's curious is the number of arguments being passed into the express `listen` method, and how that would translate over to this.

According to the docs

https://expressjs.com/en/api.html#app.listen

> This method is identical to Node’s http.Server.listen().

For more on that you can look at

https://nodejs.org/api/https.html#https_class_https_server