Class: CommandTower::Username::Available

Inherits:
ServiceBase show all
Defined in:
app/services/command_tower/username/available.rb

Constant Summary collapse

REFRESH_KEY = 
"username.refresh_after"

Constants inherited from ServiceBase

ServiceBase::ON_ARGUMENT_VALIDATION

Instance Method Summary collapse

Methods inherited from ServiceBase

inherited, #internal_validate, #service_base_logging, #validate!

Methods included from ArgumentValidation

included

Methods included from ServiceLogging

#aletered_message, #class_name, #log, #log_error, #log_info, #log_prefix, #log_warn, #logger, #service_id

Constructor Details

#initialize ⇒ Available 



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# File 'app/services/command_tower/username/available.rb', line 12

def initialize(*)
  super

  @mutex = Mutex.new
end

Instance Method Details

#available? ⇒ Boolean 



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# File 'app/services/command_tower/username/available.rb', line 32

def available?
  !realtime.local_cache.exist?(username)
end

#call ⇒ Object 



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# File 'app/services/command_tower/username/available.rb', line 18

def call
  populate_local_cache! if refresh?

  context.available = available?
  context.valid = valid?
end

#populate_local_cache! ⇒ Object

this is a very terrible cache design at scale If we can use Redis, a bloom filter would be great



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# File 'app/services/command_tower/username/available.rb', line 38

def populate_local_cache!
  @mutex.synchronize do
    values = User.pluck(:username).map { [_1, 1] }.to_h rescue {}
    realtime.local_cache.write_multi(values)
    realtime.local_cache.write(REFRESH_KEY, realtime.local_cache_ttl.from_now)

    values
  end
end

#realtime ⇒ Object 



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# File 'app/services/command_tower/username/available.rb', line 60

def realtime
  CommandTower.config.username.realtime_username_check
end

#refresh? ⇒ Boolean 



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# File 'app/services/command_tower/username/available.rb', line 48

def refresh?
  return true if force_query

  refresh_by = realtime.local_cache.read(REFRESH_KEY)
  return true if refresh_by.nil?

  time = Time.at(refresh_by) rescue nil
  return true if time.nil?

  time < Time.now
end

#valid? ⇒ Boolean 



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# File 'app/services/command_tower/username/available.rb', line 25

def valid?
  return false if username.length < CommandTower.config.username.username_length_min
  return false if username.length > CommandTower.config.username.username_length_max

  !!username[CommandTower.config.username.username_regex]
end