OData Server

This is a rails plugin/engine to embue your application with OData features (so its data can be readily consumed by an OData client).

In OData, a service exposes a number of workspace. Each workspace is backed by a schema and contains a collection of entity collections. An entity collection is a related set of records.

Configure the plugin by adding a number of schema objects to OData::Edm::DataServices.schemas. Each schema is an instance of a subclass of OData::AbstractSchema::Base. We currently only support two implementations, and the specific implementation determines how to load the records, mapping the records' properties to/from Edm data types, and handling filtering, sorting, and data retrieval.

OData::ActiveRecordSchema::Base -- either you give it a list or it iterate over all your models exposing each as OData entities

and

OData::InMemorySchema::Base -- this takes in a list of objects which are exposed as OData entities

The accessible OData service will be a read-only provider.

This code is not heavily tested. It is alpha quality at best. Expect the API to change drastically over time.

Resources

Other repos

In case new commits can be pulled in, these are the repos this fork is primarily based on:

OData V4

Dependencies

Rails 4 or higher.

Installation

Put this line in your Gemfile:

gem 'odata_server'

Run the bundle command to install it.

Then add the following lines to an initializer (ex: odata_server.rb):

# ActiveRecordSchema

ar_schema = OData::ActiveRecordSchema::Base.new('AR', classes: Foo)
OData::Edm::DataServices.schemas << ar_schema

# OR

OData::Edm::DataServices.schemas << OData::ActiveRecordSchema::Base.new

By giving a list of classes to ActiveRecordSchema, it will represent only theses classes. Without classes option, all the models will be represented. ActiveRecordSchema can take a reflection option too (default is false): if true the models associations will be shown.

# InMemorySchema

class Foo
  attr_reader :foo, :bar, :baz

  def initialize(foo, bar, baz)
    @foo = foo
    @bar = bar
    @baz = baz
  end

  def sel.all
    (1..20).map do |n|
      Foo.new(n, "test", "test #{n}")
    end
  end
end

inmem = OData::InMemorySchema::Base.new("InMem", classes: Foo)
OData::Edm::DataServices.schemas << inmem

ActiveRecordSchema and InMemorySchema can either take a single classe or an array of classes.

Then, mount the OData::Engine in routes.rb:

mount OData::Engine, at: '/service/OData'

Restart your sever and you can visit the /service/Odata url that is the service base.

See https://github.com/lmcalpin/odata_provider_example_rb for an example application that uses this gem.

Other options

In addition to :classes and :reflection, you can use:

:transformers: Hash allowing the following data transformer hooks (ActiveRecord only for now):
- :root: Transform the JSON before output for /
- :metadata: Transform the schema before output to XML for /$metadata
- :feed: Transform the JSON before output for a resource feed, e.g. /Categories
- :entry: Transform the JSON before output for a resource entry, e.g. /Categories(1)
:skip_require: true if you want to skip automatically requiring each ActiveRecord class (for example if your app loads them itself)
:skip_add_entity_types: true if you want to skip automatically adding an EntityType for each ActiveRecord class (you must add them manually, which allows you to customize things like :name and :where)

TODOS

Update and add more tests
Review XML rendering
Update the core for OData v4
Add support for $search option

Development

To develop odata_server itself:

Setup

Install dependencies: bundle

Testing

rspec

synbioz/odata_server