fdoc: Documentation format and verification

High-quality documentation is extremely useful, but maintaining it is often a pain. We aim to create a tool to facilitate easy creation and maintenance of API documentation.

In a Rails or Sinatra app, fdoc can help document an API as well as verify that requests and responses adhere to their appropriate schemata.

Outside a Rails or Sinatra app, fdoc can provide a common format for API documentation, as well as the ability to generate basic HTML pages for humans to consume.

fdoc is short for Farnsdocs. They are named for everybody's favorite, good news-bearing, crotchety old man, Professor Farnsworth.

Professor Farnsworth

Usage

In a Rails app

Add fdoc to your Gemfile.

gem 'fdoc'

Tell fdoc where to look for .fdoc files. By default, fdoc will look in docs/fdoc, but you can change this behavior to look anywhere. This fits best in something like a spec_helper file.

require 'fdoc'

Fdoc.service_path = "path/to/your/fdocs"

# Configure how Fdoc decides a successful response
Fdoc.decide_success_with do |response, status|
 status.to_i < 400
end

fdoc is built to work around controller specs in rspec, and provides Fdoc::SpecWatcher as a mixin. Make sure to include it inside your top level describe.

require 'fdoc/spec_watcher'

describe MembersController do
  include Fdoc::SpecWatcher
  # ...
end

To enable fdoc for an endpoint, add the fdoc option with the path to the endpoint. fdoc will intercept all calls to get, post, put, and delete and verify those parameters accordingly.

context "#show", :fdoc => 'members/list' do
  # ...
end

fdoc also has a scaffolding mode, where it attemps to infer the schema of a request based on sample responses. The interface is exactly the same as verifying, just set the environment variable FDOC_SCAFFOLD=true.

FDOC_SCAFFOLD=true bundle exec rspec spec/controllers

For more information on scaffolding, please see the more in-depth fdoc scaffolding example.

In a Sinatra app

Add fdoc to your Gemfile.

gem 'fdoc'

Tell fdoc where to look for .fdoc files. By default, fdoc will look in docs/fdoc, but you can change this behavior to look anywhere. This fits best in something like a spec_helper file.

require 'fdoc'

Fdoc.service_path = "path/to/your/fdocs"

fdoc is built to work around your Sinatra app specs in rspec, and provides Fdoc::SpecWatcher as a mixin. Make sure to include it inside your top level describe.

require 'fdoc/spec_watcher'

describe Sinatra::Application do
  include Rack::Test::Methods
  include Fdoc::SpecWatcher

  def app
    Sinatra::Application
  end
end

Outside a Rails App

fdoc provides the fdoc convert script to transform a directory of .fdoc files into more human-readable HTML.

In this repo, try running:

bin/fdoc convert ./spec/fixtures --output=./html

Options:
  -o, [--output=OUTPUT]                # Output path
  -u, [--url-base-path=URL_BASE_PATH]  # URL base path
  -f, [--format=FORMAT]                # Format in html or markdown, defaults to html
                                       # Default: html
  -t, [--templates=TEMPLATES]          # Directory with override templates

Example

.fdoc files are YAML files based on JSON schema to describe API endpoints. They derive their endpoint path and verb from their filename.

For more information on fdoc file naming conventions, please see the fdoc file conventions guide.
For more information on how fdoc uses JSON schema, please see the json schema usage document.

Here is docs/fdoc/members/list-GET.fdoc:

description: The list of members.
requestParameters:
  properties:
    limit:
      type: integer
      required: no
      default: 50
      description: Limits the number of results returned, used for paging.
responseParameters:
  properties:
    members:
      type: array
      items:
        title: member
        description: Representation of a member
        type: object
        properties:
          name:
            description: Member's name
            type: string
            required: yes
            example: Captain Smellypants
responseCodes:
- status: 200 OK
  successful: yes
  description: A list of current members
- status: 400 Bad Request
  successful: no
  description: Indicates malformed parameters

If we run a test against our members controller with an undocumented parameter, offset, we'll get an error.

Our spec file, spec/controllers/members_controller_spec.rb looks like:

require 'fdoc/spec_watcher'

describe MembersController do
  context "#show", :fdoc => "members/list" do
    it "can take an offset" do
      get :show, {
        :offset => 5
      }
    end
  end
end

We run:

bundle exec rspec spec/controllers/members_controller_spec.rb

And since offset is undocumented, fdoc will fail the test:

Failures:

  1) MembersController#show can take an offset
     Failure/Error: get :show, { :offset => 5 }
     JSON::Schema::ValidationError:
       The property '#/' contains additional properties ["offset"] outside of the schema when none are allowed in schema 8fcac6c4-294b-56a2-a3de-9342e2e729da#
     # ./spec/controllers/members_controller_spec.rb:5:in `block (3 levels) in <top (required)>'

If we run the same spec in scaffold mode, it passes and fdoc will write changes to the correspoding .fdoc file:

FDOC_SCAFFOLD=true bundle exec spec/controllers/members_controller_spec.rb

The diff looks like:

diff --git a/docs/fdoc/members/list-GET.fdoc b/docs/fdoc/members/list-GET.fdoc b2e3656..dfa363a 100644
--- a/docs/fdoc/members/list-GET.fdoc
+++ b/docs/fdoc/members/list-GET.fdoc
+    offset:
+      description: ???
+      required: ???
+      type: integer
+      example: 5

Notice how it infers a type, and copies an example, but leaves description and required blank. These fields are best left to humans to decide.

Goals

Client engineers should be able to participate in documenting an API and keeping it up to date.
Server engineers should be able to test their implementations.
The documentation should be as close to the code as possible.
- Branches, reviews, and merges are the appropriate way to update the docs.
- Experimental drafts should just live on branches and never get merged into master.
Specification alone is not enough, there needs to be room for discussion.

Contributing

Just fork and make a pull request! You will need to sign the Individual Contributor License Agreement (CLA) before we can merge your code.