@babblevoice/babble-drachtio-presence/lib/uassubscribe.js

A presence agent which will work with other modules in this family.

/*
This next section listen for SUBSCRIBE requests which we will auth then accept.
We then need to maintain a list of targets the request is asking for events for.

We allow a subscriber to subscribe to anything, but they simply may not get notifies
about stuff which is unnotifiable.

When we receive a SUBSCRIBE it will request a subscription against a resource.
The resource could be another user (and their REGISTERED state etc) or something like
a parking lot, call queue etc.

The UAC also might be SUBSCRIBing to itself to receive information regarding voicemail.
*/

const uassubscription = require( "./uassubscription.js" )
const uasstore = require( "./uasstore.js" )


module.exports.use = ( options ) => {

  options.em.on( "presence.voicemail.out", ( v ) => {
    const subs = uasstore.get( v.entity )
    if( !subs ) return

    subs.forEach( ( sub ) => {
      sub.notifyvoicemail( v )
    } )
  } )

  options.em.on( "presence.checksync.out", ( v ) => {
    const subs = uasstore.get( v.entity )
    if( !subs ) return

    subs.forEach( ( sub ) => {
      sub.notifychecksync()
    } )

  } )


  options.em.on( "presence.registration.out", ( v ) => {

    if( v.callid ) {
      const subs = uasstore.get( v.callid )
      if( !subs ) return
      subs.notifyregistration( v )
      return
    }

    const subs = uasstore.get( v.entity )
    if( !subs ) return
    subs.forEach( ( sub ) => {
      sub.notifyregistration( v )
    } )
  } )

  options.em.on( "presence.dialog.out", ( v ) => {
    if( v.callid ) {
      const subs = uasstore.get( v.callid )
      if( !subs ) return
      subs.notifydialog( v )
      return
    }

    const subs = uasstore.get( v.entity )
    if( subs ) {
      subs.forEach( ( sub ) => {
        sub.notifydialog( v )
      } )
    }
  } )

  /**
   * @param { object } req 
   * @param { object } res
   * @param { object } next
   */
  return ( req, res, next ) => {
    if ( "SUBSCRIBE" !== req.method ) return next()

    const fqcallid = uassubscription.getfqcallid( req )
    let s
    try {
      s = uasstore.get( fqcallid )
      if( s ) {
        return s._update( req, res )
      }

      uassubscription.create( req, res, options )
    } catch( e ) {
      console.error( e )
      if( s ) {
        try{
          res.send( 400 )
          s.destroy()
        } catch ( e ) {
          console.error( e )
        }
      }
    }
  }
}