# RspecRailsApiDoc

> An RSpec plugin to test Rails api responses and generate swagger
> documentation

**This is a work in progress** but you're welcome to help, test, submit
issues, ...

## Installation

As the gem is not yet published, you have to specify its git repository
in order to test it.

Add this line to your application's Gemfile:

```rb
gem 'rspec-rails-api'
```

And then execute:

```sh
bundle
```

### Rails configuration

Configuration should be made manually for now:

**spec/acceptance_helper.rb**

```rb
require 'rails_helper'
require 'rspec_rails_api'

RSpec.configure do |config|
  config.include Rspec::Rails::Api::DSL::Example
end

renderer = RSpec::Rails::Api::OpenApiRenderer.new
renderer.api_servers = [{ url: 'https://example.com' }]
renderer.api_title = 'A nice API for a nice application'
renderer.api_version = '1'
renderer.api_description = 'Access update data in this project'
# renderer.api_tos = 'http://example.com/tos.html'
# renderer.api_contact = { name: 'Admin', email: 'admin@example.com', 'http://example.com/contact' } 
# renderer.api_license = { name: 'Apache', url: 'https://opensource.org/licenses/Apache-2.0' }

RSpec.configuration.after(:context, type: :acceptance) do |context|
  renderer.merge_context context.class.metadata[:rrad].to_h
end

RSpec.configuration.after(:suite) do
  # Default path is 'tmp/rspec_rails_api_output.json/yaml'
  renderer.write_files Rails.root.join('public', 'swagger_doc'), only: :json
end
```

**spec/rails_helper.rb**

```rb
# ...

RSpec::Rails::DIRECTORY_MAPPINGS[:acceptance] = %w[spec acceptance]

RSpec.configure do |config|
  # ...
  config.include RSpec::Rails::RequestExampleGroup, :type => :acceptance
end
```

## Configuration

TODO

## Usage

Write some spec files and run RSpec as you would usually do.

If you want to generate the documentation without testing the endpoints
(and thus, without examples in generated files), use the `DOC_ONLY`
environment variable:

```rb
DOC_ONLY=true bundle exec rails spec
```

For now, files are saved as `tmp/out.json` and `tmp/out.yml`.

There is nothing to customize the file headers (info, license, ...) yet.

## Writing specs

There is a [commented example](examples/commented.rb) available in
`doc/`.

The idea is to have a simple DSL, and declare things like:

**spec/acceptance/users_spec.rb**

```rb
require 'acceptance_helper'

RSpec.describe 'Users', type: :acceptance do
  resource 'Users', 'Manage users'

  entity :user,
         id:         { type: :integer, description: 'The id' },
         email:      { type: :string, description: 'The name' },
         role:       { type: :string, description: 'The name' },
         created_at: { type: :datetime, description: 'Creation date' },
         updated_at: { type: :datetime, description: 'Modification date' },
         url:        { type: :string, description: 'URL to this category' }

  on_get '/api/users/', 'Users list' do
    for_code 200, 'Success response' do |example|
      visit example
      expect(response).to have_many defined :user
    end
  end

  on_put '/api/users/:id', 'Users list' do
    path_param id: { type: :integer, description: 'User Id' }

    request_params user: {
      type: :object, required: true, properties: {
        name:  { type: :string, required: false, description: 'New name' },
        email: { type: :string, required: false, description: 'New email' },
        role:  { type: :string, required: false, description: 'New role' },
      }
    }

    for_code 200, 'Success response' do |example|
      visit example
      expect(response).to have_one defined :user
    end
  end
end
```

### DSL

#### Example groups

##### `resource(name, description)`

Starts a resource description.

- It must be called before any other documentation calls.
- It should be in the first `describe block`

##### `entity(name, fields)`

Describes an entity for the documentation. The name is not visible, so
you can put whatever fits (i.e: `:account`, `:user` if the content
differs)

They are ideally in the main `describe` block.

- `name` is a symbol
- `description` is a hash of attributes

```rb
{
  id: { type: :integer, desc: 'The resource identifier' },
  name: { type: :string, desc: 'The resource name' },
  # ...
}
```

An attribute should have the following form:

```
<field_name>: {type: <type>, desc: <description>}
```

- `type` can be any of the accepted
  [OpenAPI types](http://spec.openapis.org/oas/v3.0.2#dataTypeFormat):
  - `:integer`, `:int32`, `:int64`
  - `:number`, `:float`, `:double`
  - `:string`, `:byte`, `:binary`
  - `:boolean`
  - `:date`, `:datetime`
  - `:password`
  - `:object`, `:array`

- `description` should be some valid
  [CommonMark](https://commonmark.org/)

###### Objects and arrays

To describe complex structures, use `:object` with `:attributes` and
`:array` `:of` something:

```rb
entity :friend,
       name:    { type: :string, required: false, description: 'Friend name' }

entity :user,
       id:      { type: :number, required: false, description: 'Identifier' },
       name:    { type: :string, required: false, description: 'The name' },
       friends: { type: :array, of: :friend, required: false, description: 'Friends list'},
       dog:     { type: :object, required: false, description: 'The dog', attributes: :dog },
       cat:     {
         type: :object, required: false, description: 'The cat', attributes: {
           name: { type: :string, required: false, description: 'Cat name' },
         }
       }
```

In this example, there is an `:array, of: :friend`, which is a reference
to the `:friend` entity described above; an `:object` with `:dog`
attributes (reference too); and a cat object with its attributes defined
inline.

Both `:of` and `attributes` may be a hash of fields or a symbol. If they
are omitted, they will be documented, but responses won't be validated.

##### `on_<xxx>(url, description, &block)`

Defines an URL.

- `url` should be a relative URL to an existing endpoint (i.e.:
  `/api/users`)
- `description` should be some valid
  [CommonMark](https://commonmark.org/)

For now, only these methods are available:

- `on_get`
- `on_post`
- `on_put`
- `on_patch`
- `on_delete`

##### `path_params(<hash_of_attributes>)`

Defines the path parameters that are used in the URL.

```rb
on_get '/api/users/:id/posts/:post_slug?full=:full_post' do
  path_params id:        type: :integer, description: 'The user ID',
              post_slug: type: :string, description: 'The post slug',
              full_post: type: :boolean, required: false, description: 'Returns the full post if `true`, or only an excerpt',

  # ...
end
```

- `type` is the field type (check _entity definition_ for a list).
- `description` should be some valid
  [CommonMark](https://commonmark.org/)
- `required` is optional an defaults to `true`.

##### `request_params(<hash_of_attributes>)`

Defines the format of the JSON payload. Type `object` is supported, so
nested elements can be described:

```rb
on_post '/api/items' do
  request_params item: { type: :object, required: true, properties: {
                         name: { type: integer, description: 'The name of the new item', required: true },
                         notes: { type: string, description: 'Additional notes' }
                         },
                       }
  #...
end
```

An attribute should have the following form:

```
<attr_name>: {type: <type>, desc: <description>, required: <required>, properties: <another_hash> }
```

- `attr_name` is the attribute name (sic)
- `type` is the field type (check _entity definition_ for a list).
  `type` can be `:object` if the attribute contains other attributes.
- `required` is optional an defaults to `false`.
- `properties` is a hash of params and is only used if `type: :object`

##### `for_code(http_status, description, doc_only: false &block)`

Describes the desired output for a precedently defined URL.

Block takes one required argument, that should be passed to `visit`.
This argument will contain the block context and allow `visit` to access
the metadatas.

- `http_status` is an integer representing an
  [HTTP status](https://httpstat.us/)
- `description` should be some valid
  [CommonMark](https://commonmark.org/)
- `doc_only` can be set to true to temporarily disable block execution
  and only create the documentation (without examples).
- `block` where additional tests can be performed. If `visit()` is
  called within the block, its output will be used in documentation
  examples, and the response type and code will actually be tested.

If no block is passed, only the documentation will be generated, without
examples. This can be useful to document endpoints that are impossible
to test.

Once again, you have to pass an argument to the block if you use
`visit`.

```rb
# ...
  for_code 200 'A successful response' do |example|
    visit example
    # ...
  end
# ...
```

#### Examples

Example methods are available in `for_code` blocks

##### `visit(example, path_params: {}, payload: {}, headers: {})`

Visits the described URL and:

- Expects the response code to match the described one
- Expects the content type to be `application/json`

- `example` is required and should be the block context (yep, i'll never
  say it enough)
- `path_params`: a hash of overrides for path params (useful if a custom
  value is needed)
- `payload`: a hash of values to send. Ignored for GET and DELETE
  requests
- `headers`: a hash of custom headers.

```rb
for_code 200, 'Success' do |example|
  visit example
end
```

#### Matchers

##### `have_one(type)`

Expects the compared content to be a hash with the same keys as a
defined entity.

It should be compared against a hash or a `response` object:

```rb
#...
entity user:
       id:   { type: :integer, desc: 'The id' },
       name: { type: :string, desc: 'The name' }

#...

expect({name: 'John'}).to have_one defined :user # Fails because `id` is missing

# OR
expect(response).to have_one defined :user
```

`defined` will get the correct entity.

##### `have_many(type)`

Expects the compared content to be an array of hashes with the same keys
as a defined entity.

It should be compared against an array or a `response` object:

```rb
#...
entity user:
       id:   { type: :integer, desc: 'The id' },
       name: { type: :string, desc: 'The name }'

#...

expect([{id: 2, name: 'Jessica'}, {name: 'John'}]).to have_many defined :user # Fails because `id` is missing in the second entry

# OR
expect(response).to have_many defined :user
```

`defined` will get the correct entity.

## Limitations

### Contexts

Contexts will break the thing. This is due to how the gem builds its
metadata, relying on the parents metadata. You have to stick to the DSL.

```rb
RSpec.describe 'Categories', type: :request do
  describe 'Categories'

  context 'Authenticated' do
    on_get '/api/categories', 'List all categories' do
      # ...
    end
  end

  # or

  on_get '/api/categories', 'List all categories' do
    context 'Authenticated' do
      # ...
    end
  end

  # won't work as expected.
end
```

MRs to change this are welcome.

### Request parameters

Arrays of objects are not supported yet (i.e.: to describe nested
attributes of an `has_many` relation)

MRs to improve this are welcome.

### Files

There is no support for file fields yet.

## Development

After checking out the repo, run `bin/setup` to install dependencies.
Then, run `rake spec` to run the tests. You can also run `bin/console`
for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run `bundle exec rake
install`. To release a new version, update the version number in
`version.rb`, and then run `bundle exec rake release`, which will create
a git tag for the version, push git commits and tags, and push the
`.gem` file to [rubygems.org](https://rubygems.org).

## Contributing

Bug reports and pull requests are welcome on GitLab at
https://gitlab.com/experimentslabs/rspec-rails-api/issues. This
project is intended to be a safe, welcoming space for collaboration, and
contributors are expected to adhere to the
[Contributor Covenant](http://contributor-covenant.org) code of conduct.

## License

The gem is available as open source under the terms of the
[MIT License](https://opensource.org/licenses/MIT).

## Code of Conduct

Everyone interacting in the RspecRailsApiDoc project’s codebases, issue
trackers, chat rooms and mailing lists is expected to follow the
[code of conduct](https://gitlab.com/experimentslabs/rspec-rails-api/blob/master/CODE_OF_CONDUCT.md).