interagent/heroics

Heroics

Ruby HTTP client generator for APIs represented with JSON schema.

Installation

Add this line to your application's Gemfile:

gem 'heroics'

And then execute:

$ bundle

Or install it yourself as:

$ gem install heroics

Usage

Configuration File

If you don't want to pass config to the CLI, you can provide a Ruby config file to the heroics-generate script as a single parameter.

The form of this configuration file is shown below.

require 'heroics'

Heroics.default_configuration do |config|
  config.base_url = 'https://example.com'
  config.module_name = 'ExampleClient'
  config.schema_filepath = 'schema.json'

  config.headers = { 'Accept' => 'application/vnd.example+json; version=1' }

  # Note: Don't use doublequotes below -- we want to interpolate at runtime,
  # not when the client is generated
  config.cache_path = '#{Dir.home}/.heroics/example'
end

Optional configuration

base_url, module_name, and schema_filepath are required for a proper configuration.

The following keys are optional:

• headers
• cache_path
• ruby_name_replacements a hash of replacement patterns for converting endpoint paths to Ruby method names, such as:

{ /[\s-]+/ => '_' }

For further details on config file usage, see the example/ directory in this repo.

Generating a client

Heroics generates an HTTP client from a JSON schema that describes your API. Look at prmd for tooling to help write a JSON schema. When you have a JSON schema prepared you can generate a client for your API:

heroics-generate MyApp schema.json https://api.myapp.com > client.rb

If you are using a configuration file, per above, just pass the path to it:

heroics-generate my-config-file.rb > client.rb

Passing custom headers

If your client needs to pass custom headers with each request these can be specified using -H:

heroics-generate \
  -H "Accept: application/vnd.myapp+json; version=3" \
  MyApp \
  schema.json \
  https://api.myapp.com > client.rb

Pass multiple -H options if you need more than one custom header.

Client-side caching

The generated client sends and caches ETags received from the server. By default, this data is cached in memory and is only used during the lifetime of a single instance. You can specify a directory for cache data:

heroics-generate \
  -c "~/.heroics/myapp" \
  MyApp \
  schema.json \
  https://api.myapp.com > client.rb

~ will automatically be expanded to the user's home directory. Be sure to wrap such paths in quotes to avoid the shell expanding it to the directory you built the client in.

Generating API documentation

The generated client has Yard-compatible docstrings. You can generate documentation using yardoc:

yard doc -m markdown client.rb

This will generate HTML in the docs directory. Note that Yard creates an _index.html page won't be served by Jekyll on GitHub Pages. Add a .nojekyll file to your project to prevent GitHub from passing the content through Jekyll.

Handling failures

The client uses Excon under the hood and raises Excon errors when failures occur.

begin
  client.app.create({'name' => 'example'})
rescue Excon::Errors::Forbidden => error
  puts error
end

Contributing

1. Fork the repository
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