Class: Rack::Rewrite

Inherits:
Object
  • Object
show all
Defined in:
lib/rack/rewrite.rb,
lib/rack/rewrite/rule.rb

Overview

A rack middleware for defining and applying rewrite rules. In many cases you
can get away with rack-rewrite instead of writing Apache mod_rewrite rules.

Defined Under Namespace

Classes: Rule, RuleSet

Instance Method Summary collapse

Constructor Details

#initialize(app, given_options = {}) ⇒ Rewrite

Returns a new instance of Rewrite.



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# File 'lib/rack/rewrite.rb', line 9

def initialize(app, given_options = {}, &)
  options = {
    klass: RuleSet,
    options: {}
  }.merge(given_options)
  @app = app
  @rule_set = options[:klass].new(options[:options])
  @logger = options[:logger] || ::Logger.new($stdout)
  @redis = options[:redis]
  @rule_set.instance_eval(&) if block_given?
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/rack/rewrite.rb', line 21

def call(env)
  if (matched_rule = find_first_matching_rule(env))
    rack_response = matched_rule.apply!(env)
    rule_key = matched_rule.from.inspect
    rule_details = { rule_type: matched_rule.rule_type, from: rule_key, to: matched_rule.to }
    significant_options = matched_rule.options.dup.delete(:'Cache-Control')
    rule_details[:options] = significant_options if significant_options.present?
    unless redis.nil?
      redis_match = JSON.parse(redis.get(rule_key) || {})
      # Log referring agent for bots for further analysis
      # Test by uncommenting this
      # ua = "Mozilla/5.0 (Linux; Android 6.0.1; Nexus 5X Build/MMB29P) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/86.0.4240.79 Mobile Safari/537.36 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)"
      if (ua ||= env['HTTP_USER_AGENT']).present?
        require 'device_detector'
        # Ensure all header values are strings to prevent nil gsub errors in device_detector
        safe_headers = (env || {}).select { |k, v| k.start_with?('HTTP_') }.transform_values { |v| v.nil? ? '' : v.to_s }
        dd = DeviceDetector.new(ua, safe_headers)
        # log bots
        if dd.bot?
          bn = dd.bot_name
          rule_details['bots'] = redis_match['bots'] || []
          rule_details['bots'] << bn unless rule_details['bots'].include?(bn)
          rule_details['bots'].sort!
        end
      end
      # Log Referring page
      # Test by uncommenting this
      # ref = "http://www.somepage.com/referring_page"
      if (ref ||= env['HTTP_REFERER']).present?
        rule_details['ref'] = redis_match['ref'] || []
        rule_details['ref'] << ref unless rule_details['ref'].include?(ref)
        rule_details['ref'].sort!
      end
      # Log original request path and query string
      if (uri = env['REQUEST_URI']).present?
        rule_details['uri'] = redis_match['uri'] || []
        rule_details['uri'] << uri unless rule_details['uri'].include?(uri)
        rule_details['uri'].sort!
      end
      rule_details['counter'] = redis_match.fetch('counter', 0).to_i + 1
      rule_details['last_use'] = Time.current.to_s
      redis.set(rule_key, rule_details.to_json)
    end
    # logger&.info "[REDIRECT] #{rule_details.inspect}"
    # Stringify the keys in our rack response to prevent puma from choking
    # https://medium.com/@ssscripting/puma-typeerror-no-implicit-conversion-of-symbol-into-string-d58df06a780b
    rack_response[1]&.stringify_keys! if rack_response[1].respond_to?(:stringify_keys!)
    # Don't invoke the app if applying the rule returns a rack response
    return rack_response unless rack_response === true
  end
  @app.call(env)
end