create a cache key based on location - ruby-on-rails

Question

All,
I am trying to use cache to avoid request over http when the request is made for a specific area.
For example, your are in Los Angeles and 3 persons around you ( appx 1miles) make a google search about gas station nearby.
Instead of requesting each time, it's faster to allow people who are close to you and making the same search to get the result already cached.
In a previous method, I am caching using Redis and build a key using the parameters but to re-use it, you need an exact match as the key created was based on "gas_station__"
def set_cache key, val
return if blank?( key ) || blank?( val )
connection.set key, val
connection.expire key, EXPIRY
end
def get_cache key
connection.get( key ) if present?( key )
end
now I have used the Ruby Gem geocode api and when giving a coordinate and distance, it give me back a range of lat/lon
Geocoder::Calculations.bounding_box(location, distance)
and using the api below:
def isLocationInRange(location, area)
if location[0].between?(area[0], area[2]) && location[1].between?(area[1], area[3])
return true
end
false
end
I am able to know if the location gave in isLocationInRange is inside the "area"
the issue now is to connect this logic to Redis and use it to re-use the cache.
the best should be to generate a Redis key and look for it but it's not easy as I do not want to parse each key stored and check one by one the lat/lon params defined to see if that match an already known range of location.

Answer 1

Gemfile
gem 'redis'
Run bundle install
config/redis.yml
default: &default
host: localhost
port: 6379
db: 15
development:
<<: *default
test:
<<: *default
production:
<<: *default
config/initializers/redis.rb
redis_config = HashWithIndifferentAccess.new(Rails.application.config_for(:redis))
REDIS = Redis.new(host: redis_config[:host], port: redis_config[:port], db: redis_config[:db])
Now REDIS variable is available throughout your application since initializer files are loaded on app load.
REDIS.set("gas_station__#{some_location}", latitude_values here)
REDIS.get("gas_station_#{some_location}")
References: https://github.com/redis/redis-rb