289 lines
6.1 KiB
Markdown
289 lines
6.1 KiB
Markdown
# Rating
|
||
|
||
[](https://travis-ci.org/wbotelhos/rating)
|
||
[](https://badge.fury.io/rb/rating)
|
||
[](https://codeclimate.com/github/wbotelhos/rating/maintainability)
|
||
[](https://liberapay.com/wbotelhos)
|
||
|
||
A true Bayesian rating system with scope and cache enabled.
|
||
|
||
## JS Rating?
|
||
|
||
This is **Raty**: https://github.com/wbotelhos/raty :star2:
|
||
|
||
## Description
|
||
|
||
Rating uses the know as "True Bayesian Estimate" inspired on [IMDb rating](http://www.imdb.com/help/show_leaf?votestopfaq) with the following formula:
|
||
|
||
```
|
||
(WR) = (v ÷ (v + m)) × R + (m ÷ (v + m)) × C
|
||
```
|
||
|
||
**IMDb Implementation:**
|
||
|
||
`WR`: weighted rating
|
||
|
||
`R`: average for the movie (mean) = (Rating)
|
||
|
||
`v`: number of votes for the movie = (votes)
|
||
|
||
`m`: minimum votes required to be listed in the Top 250
|
||
|
||
`C`: the mean vote across the whole report
|
||
|
||
**Rating Implementation:**
|
||
|
||
`WR`: weighted rating
|
||
|
||
`R`: average for the resource
|
||
|
||
`v`: number of votes for the resource
|
||
|
||
`m`: average of the number of votes
|
||
|
||
`C`: the average rating based on all resources
|
||
|
||
## Install
|
||
|
||
Add the following code on your `Gemfile` and run `bundle install`:
|
||
|
||
```ruby
|
||
gem 'rating'
|
||
```
|
||
|
||
Run the following task to create a Rating migration:
|
||
|
||
```bash
|
||
rails g rating:install
|
||
```
|
||
|
||
Then execute the migrations to create the to create tables `rating_rates` and `rating_ratings`:
|
||
|
||
```bash
|
||
rake db:migrate
|
||
```
|
||
|
||
## Usage
|
||
|
||
Just add the callback `rating` to your model:
|
||
|
||
```ruby
|
||
class Author < ApplicationRecord
|
||
rating
|
||
end
|
||
```
|
||
|
||
Now this model can vote or receive votes.
|
||
|
||
### rate
|
||
|
||
You can vote on some resource:
|
||
|
||
```ruby
|
||
author = Author.last
|
||
resource = Article.last
|
||
|
||
author.rate(resource, 3)
|
||
```
|
||
|
||
### rating
|
||
|
||
A voted resource exposes a cached data about it state:
|
||
|
||
```ruby
|
||
resource = Article.last
|
||
|
||
resource.rating
|
||
```
|
||
|
||
It will return a `Rating` object that keeps:
|
||
|
||
`average`: the normal mean of votes;
|
||
|
||
`estimate`: the true Bayesian estimate mean value (you should use this over average);
|
||
|
||
`sum`: the sum of votes for this resource;
|
||
|
||
`total`: the total of votes for this resource.
|
||
|
||
### rate_for
|
||
|
||
You can retrieve the rate of some author gave to some resource:
|
||
|
||
```ruby
|
||
author = Author.last
|
||
resource = Article.last
|
||
|
||
author.rate_for resource
|
||
```
|
||
|
||
It will return a `Rate` object that keeps:
|
||
|
||
`author`: the author of vote;
|
||
|
||
`resource`: the resource that received the vote;
|
||
|
||
`value`: the value of the vote.
|
||
|
||
### rated?
|
||
|
||
Maybe you want just to know if some author already rated some resource and receive `true` or `false`:
|
||
|
||
```ruby
|
||
author = Author.last
|
||
resource = Article.last
|
||
|
||
author.rated? resource
|
||
```
|
||
|
||
### rates
|
||
|
||
You can retrieve all rates received by some resource:
|
||
|
||
```ruby
|
||
resource = Article.last
|
||
|
||
resource.rates
|
||
```
|
||
|
||
It will return a collection of `Rate` object.
|
||
|
||
### rated
|
||
|
||
In the same way you can retrieve all rates that some author received:
|
||
|
||
```ruby
|
||
author = Author.last
|
||
|
||
author.rated
|
||
```
|
||
|
||
It will return a collection of `Rate` object.
|
||
|
||
### order_by_rating
|
||
|
||
You can list resource ordered by rating data:
|
||
|
||
```ruby
|
||
Article.order_by_rating
|
||
```
|
||
|
||
It will return a collection of resource ordered by `estimate desc` as default.
|
||
The order column and direction can be changed:
|
||
|
||
```ruby
|
||
Article.order_by_rating :average, :asc
|
||
```
|
||
|
||
It will return a collection of resource ordered by `Rating` table data.
|
||
|
||
### Scope
|
||
|
||
All methods support scope query, since you may want to vote on items of a resource instead the resource itself.
|
||
Let's say an article belongs to one or more categories and you want to vote on some categories of this article.
|
||
|
||
```ruby
|
||
category_1 = Category.first
|
||
category_2 = Category.second
|
||
author = Author.last
|
||
resource = Article.last
|
||
```
|
||
|
||
In this situation you should scope the vote of article with some category:
|
||
|
||
**rate**
|
||
|
||
```ruby
|
||
author.rate resource, 3, scopeable: category_1
|
||
author.rate resource, 5, scopeable: category_2
|
||
```
|
||
|
||
Now `resource` has a rating for `category_1` and another one for `category_2`.
|
||
|
||
**rating**
|
||
|
||
Recovering the rating values for resource, we have:
|
||
|
||
```ruby
|
||
resource.rating
|
||
# nil
|
||
```
|
||
|
||
But using the scope to make the right query:
|
||
|
||
```ruby
|
||
resource.rating scope: category_1
|
||
# { average: 3, estimate: 3, sum: 3, total: 1 }
|
||
|
||
resource.rating scope: category_2
|
||
# { average: 5, estimate: 5, sum: 5, total: 1 }
|
||
```
|
||
|
||
**rated**
|
||
|
||
On the same way you can find your rates with a scoped query:
|
||
|
||
```ruby
|
||
author.rated scope: category_1
|
||
# { value: 3, scopeable: category_1 }
|
||
```
|
||
|
||
**rates**
|
||
|
||
The resource still have the power to consult its rates:
|
||
|
||
```ruby
|
||
article.rates scope: category_1
|
||
# { value: 3, scopeable: category_1 }
|
||
|
||
article.rates scope: category_2
|
||
# { value: 3, scopeable: category_2 }
|
||
```
|
||
|
||
**order_by_rating**
|
||
|
||
To order the rating you do the same thing:
|
||
|
||
```ruby
|
||
Article.order_by_rating scope: category_1
|
||
```
|
||
|
||
### Records
|
||
|
||
Maybe you want to recover all records with or without scope, so you can add the suffix `_records` on relations:
|
||
|
||
```ruby
|
||
category_1 = Category.first
|
||
category_2 = Category.second
|
||
author = Author.last
|
||
resource = Article.last
|
||
|
||
author.rate resource, 1
|
||
author.rate resource, 3, scopeable: category_1
|
||
author.rate resource, 5, scopeable: category_2
|
||
|
||
author.rating_records
|
||
# { average: 1, estimate: 1, scopeable: nil , sum: 1, total: 1 },
|
||
# { average: 3, estimate: 3, scopeable: category_1, sum: 3, total: 1 },
|
||
# { average: 5, estimate: 5, scopeable: category_2, sum: 5, total: 1 }
|
||
|
||
author.rated_records
|
||
# { value: 1 }, { value: 3, scopeable: category_1 }, { value: 5, scopeable: category_2 }
|
||
|
||
article.rates_records
|
||
# { value: 1 }, { value: 3, scopeable: category_1 }, { value: 5, scopeable: category_2 }
|
||
```
|
||
|
||
### As
|
||
|
||
If you have a model that will only be able to rate but not to receive a rate, configure it as `author`.
|
||
An author model still can be rated, but won't genarate a Rating record with all values as zero to warm up the cache.
|
||
|
||
```ruby
|
||
rating as: :author
|
||
```
|
||
|
||
## Love it!
|
||
|
||
Via [PayPal](https://www.paypal.com/cgi-bin/webscr?cmd=_donations&business=X8HEP2878NDEG&item_name=rating) or [Support](https://liberapay.com/wbotelhos). Thanks! (:
|