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.
# 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
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
# File lib/grape/middleware/versioner/accept_version_header.rb, line 60 def error_headers cascade? ? { 'X-Cascade' => 'pass' } : {} end
# File lib/grape/middleware/versioner/accept_version_header.rb, line 47 def strict? options[:version_options] && options[:version_options][:strict] end
# File lib/grape/middleware/versioner/accept_version_header.rb, line 43 def versions options[:versions] || [] end