# class Rack::URLMap

`Rack::URLMap` takes a hash mapping urls or paths to apps, and dispatches accordingly. Support for HTTP/1.1 host names exists if the URLs start with `http://` or `https://`.

`URLMap` modifies the SCRIPT_NAME and PATH_INFO such that the part relevant for dispatch is in the SCRIPT_NAME, and the rest in the PATH_INFO. This should be taken care of when you need to reconstruct the URL in order to create links.

`URLMap` dispatches in such a way that the longest paths are tried first, since they are most specific.

### Public Class Methods

new(map = {}) click to toggle source

    # File lib/rack/urlmap.rb, line 19
    def initialize(map = {})
      remap(map)
    end

### Public Instance Methods

call(env) click to toggle source

    # File lib/rack/urlmap.rb, line 46
    def call(env)
      path        = env[PATH_INFO]
      script_name = env[SCRIPT_NAME]
      http_host   = env[HTTP_HOST]
      server_name = env[SERVER_NAME]
      server_port = env[SERVER_PORT]

      is_same_server = casecmp?(http_host, server_name) ||
                       casecmp?(http_host, "#{server_name}:#{server_port}")

      is_host_known = @known_hosts.include? http_host

      @mapping.each do |host, location, match, app|
        unless casecmp?(http_host, host) \
            || casecmp?(server_name, host) \
            || (!host && is_same_server) \
            || (!host && !is_host_known) # If we don't have a matching host, default to the first without a specified host
          next
        end

        next unless m = match.match(path.to_s)

        rest = m[1]
        next unless !rest || rest.empty? || rest[0] == ?/

        env[SCRIPT_NAME] = (script_name + location)
        env[PATH_INFO] = rest

        return app.call(env)
      end

      [404, { CONTENT_TYPE => "text/plain", "X-Cascade" => "pass" }, ["Not Found: #{path}"]]

    ensure
      env[PATH_INFO]   = path
      env[SCRIPT_NAME] = script_name
    end

remap(map) click to toggle source

    # File lib/rack/urlmap.rb, line 23
    def remap(map)
      @known_hosts = Set[]
      @mapping = map.map { |location, app|
        if location =~ %r{\Ahttps?://(.*?)(/.*)}
          host, location = $1, $2
          @known_hosts << host
        else
          host = nil
        end

        unless location[0] == ?/
          raise ArgumentError, "paths need to start with /"
        end

        location = location.chomp('/')
        match = Regexp.new("^#{Regexp.quote(location).gsub('/', '/+')}(.*)", Regexp::NOENCODING)

        [host, location, match, app]
      }.sort_by do |(host, location, _, _)|
        [host ? -host.size : Float::INFINITY, -location.size]
      end
    end

### Private Instance Methods

casecmp?(v1, v2) click to toggle source

    # File lib/rack/urlmap.rb, line 85
    def casecmp?(v1, v2)
      # if both nil, or they're the same string
      return true if v1 == v2

      # if either are nil... (but they're not the same)
      return false if v1.nil?
      return false if v2.nil?

      # otherwise check they're not case-insensitive the same
      v1.casecmp(v2).zero?
    end