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 21
def before
  potential_version = (env['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

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

    env['api.version'] = potential_version
  end
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 54
def cascade?
  options[:version_options] && options[:version_options].has_key?(:cascade) ? 
    !! options[:version_options][:cascade] : 
    true
end
error_headers() click to toggle source
# File lib/grape/middleware/versioner/accept_version_header.rb, line 60
def error_headers
  cascade? ? { 'X-Cascade' => 'pass' } : {}
end
strict?() click to toggle source
# File lib/grape/middleware/versioner/accept_version_header.rb, line 47
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 43
def versions
  options[:versions] || []
end