Generate Markdown documentation from OpenAPI specifications.

Transducer is a Ruby gem that reads OpenAPI YAML specifications (versions 3.0.x and 3.1.x) and generates well-formatted, readable Markdown documentation.

Add this line to your application's Gemfile:

gem 'transducer'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install transducer

Generate Markdown documentation from an OpenAPI specification:

$ transducer generate input.yaml -o output.md

Options:

• -o, --output: Output file path (default: docs/openapi.md)
• -t, --template: Custom ERB template file path

You can customize the output format using ERB templates:

$ transducer generate input.yaml --template=custom.md.erb --output=api.md

Template variables available:

• data: Parsed OpenAPI specification hash
• formatter: Formatter instance for formatting endpoints, parameters, schemas, etc.

Example custom template:

# <%= data['info']['title'] %>

<% data['paths']&.each do |path, methods| %>
  <% methods.each do |method, details| %>
### <%= method.upcase %> <%= path %>
<%= formatter.format_endpoint(path, method, details) %>
  <% end %>
<% end %>

Display version information:

$ transducer version

Display help:

$ transducer help
$ transducer help generate

You can also use Transducer programmatically in your Ruby code:

require 'transducer'

# Parse OpenAPI specification
parser = Transducer::Parser.new('path/to/openapi.yaml')
data = parser.parse

# Generate Markdown with default template
generator = Transducer::Generator.new(data)
markdown = generator.generate

# Or use a custom template
generator = Transducer::Generator.new(data, template_path: 'custom.md.erb')
markdown = generator.generate

# Write to file
generator.to_file('output.md')

The generated Markdown documentation includes:

• API Title and Description: From the info section
• Version and Base URL: API version and server URL
• Table of Contents: Automatically generated with links to all sections
• Endpoints: All API endpoints with:
  • HTTP method and path
  • Description
  • Parameters (path, query, header)
  • Request body schema and examples
  • Response codes with schemas and examples
• Schemas: Component schemas with:
  • Type information
  • Property descriptions
  • Required fields
  • Examples

# Simple API

A simple API for testing

| | |
|---|---|
| Version | 1.0.0 |
| Base URL | https://api.example.com/v1 |

## Table of Contents

- [Endpoints](#endpoints)
  - [GET /users](#get-users)
  - [POST /users](#post-users)
- [Schemas](#schemas)
  - [User](#user)

## Endpoints

### GET /users

Returns a list of all users

**Parameters**:

| Name | Location | Type | Required | Description |
|------|----------|------|----------|-------------|
| limit | query | integer | No | Maximum number of users to return |

**Responses**:

#### 200 OK

Successful response
...

• OpenAPI 3.0.x
• OpenAPI 3.1.x

OpenAPI 2.0 (Swagger) is not currently supported.

After checking out the repo, run bundle install to install dependencies.

Run tests:

$ bundle exec rspec

Run RuboCop:

$ bundle exec rubocop

Run all checks (tests + RuboCop):

$ bundle exec rake

To install this gem onto your local machine:

$ bundle exec rake install

To release a new version:

1. Update the version number in lib/transducer/version.rb
2. Update CHANGELOG.md
3. Run bundle exec rake release

Bug reports and pull requests are welcome on GitHub at https://github.com/ydah/transducer.

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request

The gem is available as open source under the terms of the MIT License.