class Grape::Middleware::Versioner::AcceptVersionHeader

This middleware sets various version related rack environment variables based on the HTTP Accept-Version header

Example: For request header

Accept-Version: v1

The following rack env variables are set:

env['api.version']  => 'v1'

If version does not match this route, then a 406 is raised with X-Cascade header to alert Rack::Mount to attempt the next matched route.

Public Instance Methods

before() click to toggle source
# File lib/grape/middleware/versioner/accept_version_header.rb, line 20
def before
  potential_version = (env[Grape::Http::Headers::HTTP_ACCEPT_VERSION] || '').strip

  if strict?
    # If no Accept-Version header:
    if potential_version.empty?
      throw :error, status: 406, headers: error_headers, message: 'Accept-Version header must be set.'
    end
  end

  return if potential_version.empty?

  # If the requested version is not supported:
  throw :error, status: 406, headers: error_headers, message: 'The requested version is not supported.' unless versions.any? { |v| v.to_s == potential_version }

  env[Grape::Env::API_VERSION] = potential_version
end

Private Instance Methods

cascade?() click to toggle source

By default those errors contain an `X-Cascade` header set to `pass`, which allows nesting and stacking of routes (see [Rack::Mount](github.com/josh/rack-mount) for more information). To prevent this behavior, and not add the `X-Cascade` header, one can set the `:cascade` option to `false`.

# File lib/grape/middleware/versioner/accept_version_header.rb, line 51
def cascade?
  if options[:version_options] && options[:version_options].key?(:cascade)
    !!options[:version_options][:cascade]
  else
    true
  end
end
error_headers() click to toggle source
# File lib/grape/middleware/versioner/accept_version_header.rb, line 59
def error_headers
  cascade? ? { Grape::Http::Headers::X_CASCADE => 'pass' } : {}
end
strict?() click to toggle source
# File lib/grape/middleware/versioner/accept_version_header.rb, line 44
def strict?
  options[:version_options] && options[:version_options][:strict]
end
versions() click to toggle source
# File lib/grape/middleware/versioner/accept_version_header.rb, line 40
def versions
  options[:versions] || []
end