使用Ruby跟踪更新的信息？

Question

The script I am trying to build works like this.

1. User directs application to a webpage containing a number that represents total # of miles traveled
2. Application saves that number
3. User comes back 30 minutes later after traveling
4. Application returns miles per hour

Right now I can do step 1. I'm struggling to get my application to save the number the user obtained in step 1.

Ideally, this should work like a timer. The user starts the timer, goes for a drive, comes back, stops the timer, and his average speed is returned to him.

Is Ruby and Rails enough? Or will I need some sort of AJAX or JavaScript?

Answer 1

Ruby on Rails is enough. You can keep the starting time as data in step 1, and call that in step 3 or 4.

Answer 2

I think you're getting confused between how Rails, JS & Ajax work

Rails is backend; will handle your db & requests. JS / Ajax will process any front-end requests made directly by the client in the browser

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Make Another Model

What you're asking is actually quite simple if you break it into modular pieces

1. User doesn't have many miles; a User's Trip has many miles
2. Therefore, I'd introduce a new model call Trip
3. Each Trip will have many miles
4. You can create a new join model call TripMiles which you'll be able to store the miles in
5. Once you've got the miles in this model, you can use the created_at times to see how many miles per hour

Here are some examples:

#app/models/user.rb
Class User < ActiveRecord::Base
    has_many :trips
end

#app/models/trip.rb
Class Trip < ActiveRecord::Base
    belongs_to :user
    has_many :miles, :class_name => "TripMile"
end

#app/models/trip_mile.rb
Class TripMile < ActiveRecord::Base
    belongs_to :trip
end

trips
id | user_id | created_at | updated_at 

trip_miles
id | trip_id | created_at | updated_at

This will allow you to set the trip as a specific record, and then add as many miles to it through the trip_miles model. How you add these will depend on your front-end, but it will all be Rails