ohm-sorted

ohm-sorted

Sorted indices for Ohm

Setup

1. Include the Callbacks and Sorted modules in your model:

    include Ohm::Callbacks 
    include Ohm::Sorted
   

2. Add the sorted indices you want to your model:

• If you want a complete index:

  sorted :created_at
  

• If you want to partition the index based on an attribute:

  sorted :created_at, :group_by => :site_id
  

You can use both indices for the same attribute, as the partition keys are namespaced by the group_by attribute.

You will need to resave every model if they already exist for the index to get built.

The ranking attribute must be of a type that responds to to_f.

Usage

To query the sorted index, use the sorted_find class method.

>> Post.sorted_find(:created_at, site_id: "ar")

This returns an Ohm::SortedSet, similiar to an Ohm::Set but backed by a sorted set.

To limit the results to a certain score range, use the between method. This and the following methods return a new copy of the set object, but data is not read until it is necessary.

>> Post.sorted_find(:created_at, site_id: "ar").between(start_time, end_time)

To take a slice of the results, use the slice method. This returns a new copy of the set which will pass its offset and count parameters to Redis.

>> Post.sorted_find(:created_at, site_id: "ar").slice(2, 4)

Requirements

This plugin works with Ohm versions higher than 0.1.3.

Acknowledgements

Many thanks to Damian Janowski (https://github.com/djanowski)