WhereYouAre

I'm going to take an "Open-Design Software" approach to this project, please feel free to send me your two cents if you have an opinion.

Analysis

It would be useful, and should be easy, to provide an app that shows where your friends are. Many of these apps already exist, but they all break down when it comes to reaching critical mass: it's just too much trouble to get all your friends registered and receive their locations when you need them. Everyone is not going to run the app at the same time, which just leaves push communication to the phone. Can we solve this problem well enough to make an app worth having?

Requirements

• Free and easy to configure
• Quickly start to track existing friends
• Provide tracking for all, one, and groups of friends
• Make fast privacy and priority adjustments
• Obtain best-in-class location information

Design

• Map view for traditional location display
• Arrow view for sexy fun location display
• Contacts view for fast privacy/prioritization changes

Implementation

REST API

   map features:
       touch user to open details
   arrow features:
       touch user to open details
   contacts features:
       open details...
           show pic, phone, ip, last timestamp
           adjust...
               track		follow just this user
               meetup		track, + use push to harass, etc. for meetup
               ignore		do not show this user no matter what
               stealth		show this user but prevent them from seeing me
               ping/msg	send a push to the wya user
               groups		change friend's groups
   settings features:
       go completely offline
       go completely stealth
       select current group
       manage groups including priority
       adjust total number of friends shown on arrows
       adjust total number of friends shown on map
       toggle [show my location] on map
       turn off focus (if on)
       turn off meetup (if on)

   Use cases
   -------------
   1 user starts app
   User gets updated friend locations
   User closes app
   2 user goes offline (in app, prevents notifications)
   3 user goes stealthmode
   4 user changes friends priority (make this easy to do!)
   5 user changes # tracked friends
   6 user sets friend to ignore on/off
   7 user sets friend to meetup on/off
   8 user sets friend to stealth on/off
   9 user pings friend
   10 user adds friend
   11 user deletes friend
   12 import friends?

   wya API requirements
   ------------------------------------------
   https put "my friends subscription" (on startup)
   https put "my location" every 15 seconds (may be "stealthmode") \ 
   https get "my friends' locations" with ages (may be "stealthed")/ combine?
   https post "my new friend" with phone number and stealthstatus
   https put "my friend" with phone number and updated stealthstatus
   https delete "my friend" with phone number
   https put "ping this friend" with phone number
   https put "logoff"

   NOT needed...
   -------------
   put "i am running the app" (implied by [put my location])
   put "my friend" (the server only tracks phone number, no editing available)
   any meetup or ignore state
      ignore is done by deleting friend
      meetup is done by client requesting pings

   wya server requirements
   -------------------
   track activeuser {phone,stealthmode,friendarray{phone,stealthed}} array
   collect nonstealthed friend locations "by any means necessary"
      priority: active app users, inactive app users, nonusers
   reply to API requests
      only report locations if not stealthed
      only report locations if under a day old?
   ping app users for meetups (if not ignored or stealthmoded)
   use TTL of 6 heartbeats, kill activeuser after that

   wya client requirements
   -------------------
   maintain complete friends list (even ignored) with prioritization
   ping server with location every 15 seconds
   adjust tracking to include "top n" friends
   "ignore all" mode (similar to "logoff server")

   (round1)

   all f's of all users running app need constant location ping
      f's must be shared with phone# as key
      server must track users' flist
      server must constantly work on getting f updates

   user starts up app
      user logs in to server and sends friendlist
      server adds user to userlist, merges friendlist into totalfriendlist (w/refcount?)
      server should do its best to get all friends' locations
          ** this is a separate task from communicating with user **
      user pings server with location, gets f updates
          ping every 15 seconds?
          only send updates if they have not been received by user?  (how to get best performance?)
      user shuts down app (or times out)
      user is logged out of server

   server f location collector
      use external services to poll for location for all f that are not running app	
          ping every 15 seconds?
          users that are running app are all sending locations, no need to collect them

      include occasional push check:
          if f owns app
              if f is not running app
                  if f is in meetup
                      push request to f1

   <iph>			<tdm_rest>		<tdm_pusher>		<apl>			<loc_server>
   -----			-----			-----			-----			-----
   

REST Examples

1. The best example I have to follow is the Twitter API. It *obviously* scales. It uses Basic Authentication, which sucks (everything is plaintext, holy shit). BETTER force it to use SSL. They are moving towards a more-robust authentication based on OAuth.
2. The other excellent example is the Amazon S3 API. Authentication is brilliant - it uses a SHA1 signature of the request, which MUST include a timestamp within the last 15 minutes. There is a set of rules for turning the request URL into the request string that is signed.

Signature = Base64( HMAC-SHA1( UTF-8-Encoding-Of( YourSecretAccessKeyID, StringToSign ) ) );