Class: Grape::Middleware::Versioner::Header

Inherits:
Base
  • Object
show all
Defined in:
lib/grape/middleware/versioner/header.rb

Overview

This middleware sets various version related rack environment variables based on the HTTP Accept header with the pattern: application/vnd.:vendor-:version+:format

Example: For request header

Accept: application/vnd.mycompany-v1+json

The following rack env variables are set:

env['api.type']    => 'application'
env['api.subtype'] => 'vnd.mycompany-v1+json'
env['api.vendor]   => 'mycompany'
env['api.version]  => 'v1'
env['api.format]   => 'format'

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

Constant Summary

Constants inherited from Base

Base::CONTENT_TYPES

Instance Attribute Summary

Attributes inherited from Base

#app, #env, #options

Instance Method Summary collapse

Methods inherited from Base

#after, #call, #call!, #content_type, #content_types, #default_options, #initialize, #mime_types, #request, #response

Constructor Details

This class inherits a constructor from Grape::Middleware::Base

Instance Method Details

#before ⇒ Object 



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# File 'lib/grape/middleware/versioner/header.rb', line 29

def before
  header = Rack::Accept::MediaType.new env['HTTP_ACCEPT']

  if strict?
    # If no Accept header:
    if header.qvalues.empty?
      throw :error, :status => 406, :headers => {'X-Cascade' => 'pass'}, :message => 'Accept header must be set'
    end
    # Remove any acceptable content types with ranges.
    header.qvalues.reject! do |media_type,_|
      Rack::Accept::Header.parse_media_type(media_type).find{|s| s == '*'}
    end
    # If all Accept headers included a range:
    if header.qvalues.empty?
      throw :error, :status => 406, :headers => {'X-Cascade' => 'pass'}, :message => 'Accept header must not contain ranges ("*")'
    end
  end

  media_type = header.best_of available_media_types

  if media_type
    type, subtype = Rack::Accept::Header.parse_media_type media_type
    env['api.type']    = type
    env['api.subtype'] = subtype

    if /\Avnd\.([a-z0-9*.]+)(?:-([a-z0-9*\-.]+))?(?:\+([a-z0-9*\-.+]+))?\z/ =~ subtype
      env['api.vendor']  = $1
      env['api.version'] = $2
      env['api.format']  = $3  # weird that Grape::Middleware::Formatter also does this
    end
  # If none of the available content types are acceptable:
  elsif strict?
    throw :error, :status => 406, :headers => {'X-Cascade' => 'pass'}, :message => '406 Not Acceptable'
  # If all acceptable content types specify a vendor or version that doesn't exist:
  elsif header.values.all?{|media_type| has_vendor?(media_type) || has_version?(media_type)}
    throw :error, :status => 406, :headers => {'X-Cascade' => 'pass'}, :message => 'API vendor or version not found'
  end
end