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Using Soulmate in Rails App

• Used to implement an autocomplete feature
• Add gem 'soulmate' to your GEMFILE and bundle install
• Will install redis as a dependency
• Need to add an after_save callback to your model object:

class Person
  after_save :load_into_soulmate
  
  def load_into_soulmate
    loader = Soulmate::Loader.new("person")
    loader.add("id" => id, "term" => name)
    # term will be the attribute you want to search for in autocomplete
  end
  
end

• If the following error occurs: Redis::CommandError: ERR value is not a valid float

  • FIX: Add score: 1 in the loader.add() parameter hash

• After that, run a task to update your model objects

Understanding how to structure the Redis DB

• When using soulmate to populate the db:

Soulmate::Loader.new(db_name).add({
  "term" => "value of field that will be sesrched on",
  "id" => "record.id" if using ActiceRecord,
  "value" => "string representation what to return to frontend" 
})

Redis-Server

• where you can write queries and obtain info about the redis db
• run keys * to obtain all keys in this current redis db
• Soulmate::Loader.new("person") will create the following keys:
  • soulmate-data:person: stores in a hash the attributes you added when you used loader.add
  • soulmate-index:person: stores a list of partial substrings of the term attribute
    • If a term was "dogsled", it would contain: "d", "do", "dog", ... "dogsled"

Useful Commands

• keys *
• keys soulmate-data:person *: retrieves all values in this key
• keys soulmate-index:person:sub_string*: retrieves all values in the DB that contain this sub_string
• hgetall soulmate-data:person
• hget soulmate-data:person 1: get value with id = 1
• select #: selects a db
• dbsize: returns the number of keys in that db
• Things to note:
  • Soulmate produces soulmate-index and soulmate-data keys
  • soulmate-index: is the collection of partial strings of the search term
  • soulmate-data: is the hash object formed when you produce the hash in the matches collection
• Verify the rank of a key:
  • zscore soulmate-index:cat:f7f 1643: contains the key of the db as well as the id (should be the same id of the product) of the key
  • Test the score by hitting the search again for that item and see if the score increased

Deleting Data in Redis DB

• Delete all keys from all Redis databases:
  • redis-cli FLUSHALL
• Delete all keys of the currently selected Redis database:
  • redis-cli FLUSHDB
• Delete all keys of the specified Redis database:
  • redis-cli -n <database_number> FLUSHDB