Refresh pins for users upon new add

[dgatto]

We could either do refreshes based on zip codes, or based on the viewport. the users could give a zip code and then we do one request for that area, or we do it based on viewport and it would most likely work like below:

• Upon loading of the app (ionViewDidEnter) it kicks off a request for pins of the lat/lng of provided location.
  • If user zooms out, re-request pins with new lat/lng.
  • If user zooms in, do not request new pins.
  • If user is zoomed out too far, give a warning that they are viewing too large of an area.

[dgatto]

• upon adding a pin, an updatePins event is sent out to all listeners with the app currently open. if their app isn't open at that moment, there's no point in sending them that event.
  • would i have to disconnect the WS connection and reconnect every time they close and re-open the app? would it be less network-intensive to just have the connection sitting in the background? or can i possibly send an event from the client to say appIsClosed, and if any clients have that event tracked recently then they do not get new updatePins events sent.
  • the appIsClosed approach seems like it could be easily error prone?
  • first look in to WebSocket architecture and see if there's something about not sending events to clients that have the app in the background or closed. check in what cases the disconnect event is sent.
• Upon the client receiving the updatePins event, it will send a getPins event to the server, requesting all pins within the lat/lng of the (viewport??, or should it be an inputted zipcode).

[dgatto]

We should probably do everything based on the provided location from the user. Although, if they zoom out too far, then they should get a notification saying "hey, you've zoomed out a lot, provide a new location."

We could do viewport based, grab lat/lng and query based on that, but the logic would be a large amount of effort to take on. Maybe something to keep as a stretch item.

[dgatto]

So upon adding a pin, updatePins event is sent out to all listeners with a matching zip code.

Here's how we'll store clients in node:

new Client = {
    socketId: ObjectId,
    zipCode: string
}

If a client's zip code matches the zip code of the pin just added, emit a getPins(zipCode) event to them.

possibly store the clients in zip-code based dictionaries so i already know which ones to update?