Module 12: Creating an Uber Clone
Transcript
next we’ll go into the underlying business logic portion of the hailing process on the client up until now i kept hailing as a vague process i think uber probably has a far more elaborate system than the one i developed in an hour but this should work fine for most cases healing includes the following phases we mark what we are interested that we are interested in hailing in the location service websocket code the server checks which drivers are available in the area and returns to us their push keys we send push notifications to the available drivers as time moves on we expand the circle of search for drivers in order to do this i had to make some changes to the websocket protocol in the location service class but first we need some additional variables in the globals class i’ll go into more details on those values in the next chapter but for now we need the variables only all of these apis require developer keys which you can obtain from their respective websites i’ve edited the globals class to include these new keys required by the three apis right now we can leave these all blank and get to them later let’s move to the location service class and the variables i had to add when a driver accepts our hail the server sends a special message indicating that the hail was accepted previously we had two modes for polling the server for searching and not searching i added a third mode that allows us to disable hailing i’ve made the location service into a singleton this these represent whether we are hailing and if so to what radius we use a motion object to get a growing radius that will stretch over time to encapsulate a wider region for hailing our source and destination values which we need to broadcast a hail when we send a push notification to a car we need to make sure we didn’t already notify it the unique id of the driver we’ve found this is the callback we invoke when a driver is found now that these are out of the way let’s look at the other things that need doing we changed the way we handle communication protocol by and we added some additional details first we need to ignore location changes when doing hailing which we can do by adding that condition next we need to change the protocol a little bit this was previously limited to 0 only and now we check if we are in hailing mode during hailing mode the radius of search grows over time we send the from two values as utf-8 encoded strings which allows us to communicate locale specific locations when we turn off healing in the server it’s a one-time thing after it’s off we can go back to the regular mode this isn’t likely as this is a ram based stream we also need to handle message reception code this is a new special case that provides us with details on the driver that picked up the right we are provided with the driver id card and name notice we need the final user variable since car might change and the value that can change can’t be passed to an inner class or lambda in java this is a list of push keys who we should not notify i added a push token to the driver details so we can send a push message to a specific driver if the car wasn’t notified yet add it to the list of cars that we should notify we send the push message in a batch to speed this up we send push type 3 which includes a data payload the first section and a visual payload which you can see after the semicolon before we can compile that code we need to add a push token attribute to the user class finally we have the hail ride method which is relatively simple there isn’t much we need to cover here it just initializes the variables and starts the motion object for the expanding radius this should conclude the client side of the hailing process and now we need to address the server side