# class Gem::RemoteFetcher

`RemoteFetcher` handles the details of fetching gems and gem information from a remote source.

### Constants

BASE64_URI_TRANSLATE

### Attributes

headers[RW]

### Public Class Methods

fetcher() click to toggle source

Cached `RemoteFetcher` instance.

    # File lib/rubygems/remote_fetcher.rb, line 57
    def self.fetcher
      @fetcher ||= self.new Gem.configuration[:http_proxy]
    end

fetcher=(fetcher) click to toggle source

    # File lib/rubygems/test_utilities.rb, line 162
    def self.fetcher=(fetcher)
      @fetcher = fetcher
    end

new(proxy=nil, dns=nil, headers={}) click to toggle source

Initialize a remote fetcher using the source `URI` and possible proxy information.

`proxy`

- [String]: explicit specification of proxy; overrides any environment

      variable setting

- nil: respect environment variables (HTTP_PROXY, HTTP_PROXY_USER,

      HTTP_PROXY_PASS)

- `:no_proxy`: ignore environment variables and _don't_ use a proxy

`headers`: A set of additional HTTP headers to be sent to the server when

    fetching the gem.

    # File lib/rubygems/remote_fetcher.rb, line 77
    def initialize(proxy=nil, dns=nil, headers={})
      require 'net/http'
      require 'stringio'
      require 'time'
      require 'uri'

      Socket.do_not_reverse_lookup = true

      @proxy = proxy
      @pools = {}
      @pool_lock = Mutex.new
      @cert_files = Gem::Request.get_cert_files

      @headers = headers
    end

### Public Instance Methods

cache_update_path(uri, path = nil, update = true) click to toggle source

Downloads `uri` to `path` if necessary. If no path is given, it just passes the data.

    # File lib/rubygems/remote_fetcher.rb, line 295
    def cache_update_path(uri, path = nil, update = true)
      mtime = path && File.stat(path).mtime rescue nil

      data = fetch_path(uri, mtime)

      if data == nil # indicates the server returned 304 Not Modified
        return Gem.read_binary(path)
      end

      if update and path
        Gem.write_binary(path, data)
      end

      data
    end

close_all() click to toggle source

    # File lib/rubygems/remote_fetcher.rb, line 348
    def close_all
      @pools.each_value {|pool| pool.close_all}
    end

correct_for_windows_path(path) click to toggle source

    # File lib/rubygems/remote_fetcher.rb, line 320
    def correct_for_windows_path(path)
      if path[0].chr == '/' && path[1].chr =~ /[a-z]/i && path[2].chr == ':'
        path[1..-1]
      else
        path
      end
    end

download(spec, source_uri, install_dir = Gem.dir) click to toggle source

Moves the gem `spec` from `source_uri` to the cache dir unless it is already there. If the source_uri is local the gem cache dir copy is always replaced.

    # File lib/rubygems/remote_fetcher.rb, line 115
    def download(spec, source_uri, install_dir = Gem.dir)
      cache_dir =
        if Dir.pwd == install_dir  # see fetch_command
          install_dir
        elsif File.writable? install_dir
          File.join install_dir, "cache"
        else
          File.join Gem.user_dir, "cache"
        end

      gem_file_name = File.basename spec.cache_file
      local_gem_path = File.join cache_dir, gem_file_name

      FileUtils.mkdir_p cache_dir rescue nil unless File.exist? cache_dir

      # Always escape URI's to deal with potential spaces and such
      # It should also be considered that source_uri may already be
      # a valid URI with escaped characters. e.g. "{DESede}" is encoded
      # as "%7BDESede%7D". If this is escaped again the percentage
      # symbols will be escaped.
      unless source_uri.is_a?(URI::Generic)
        begin
          source_uri = URI.parse(source_uri)
        rescue
          source_uri = URI.parse(URI::DEFAULT_PARSER.escape(source_uri.to_s))
        end
      end

      scheme = source_uri.scheme

      # URI.parse gets confused by MS Windows paths with forward slashes.
      scheme = nil if scheme =~ /^[a-z]$/i

      # REFACTOR: split this up and dispatch on scheme (eg download_http)
      # REFACTOR: be sure to clean up fake fetcher when you do this... cleaner
      case scheme
      when 'http', 'https', 's3' then
        unless File.exist? local_gem_path
          begin
            verbose "Downloading gem #{gem_file_name}"

            remote_gem_path = source_uri + "gems/#{gem_file_name}"

            self.cache_update_path remote_gem_path, local_gem_path
          rescue Gem::RemoteFetcher::FetchError
            raise if spec.original_platform == spec.platform

            alternate_name = "#{spec.original_name}.gem"

            verbose "Failed, downloading gem #{alternate_name}"

            remote_gem_path = source_uri + "gems/#{alternate_name}"

            self.cache_update_path remote_gem_path, local_gem_path
          end
        end
      when 'file' then
        begin
          path = source_uri.path
          path = File.dirname(path) if File.extname(path) == '.gem'

          remote_gem_path = correct_for_windows_path(File.join(path, 'gems', gem_file_name))

          FileUtils.cp(remote_gem_path, local_gem_path)
        rescue Errno::EACCES
          local_gem_path = source_uri.to_s
        end

        verbose "Using local gem #{local_gem_path}"
      when nil then # TODO test for local overriding cache
        source_path = if Gem.win_platform? && source_uri.scheme &&
                         !source_uri.path.include?(':')
                        "#{source_uri.scheme}:#{source_uri.path}"
                      else
                        source_uri.path
                      end

        source_path = Gem::UriFormatter.new(source_path).unescape

        begin
          FileUtils.cp source_path, local_gem_path unless
            File.identical?(source_path, local_gem_path)
        rescue Errno::EACCES
          local_gem_path = source_uri.to_s
        end

        verbose "Using local gem #{local_gem_path}"
      else
        raise ArgumentError, "unsupported URI scheme #{source_uri.scheme}"
      end

      local_gem_path
    end

download_to_cache(dependency) click to toggle source

Given a name and requirement, downloads this gem into cache and returns the filename. Returns nil if the gem cannot be located.

    # File lib/rubygems/remote_fetcher.rb, line 100
    def download_to_cache(dependency)
      found, _ = Gem::SpecFetcher.fetcher.spec_for_dependency dependency

      return if found.empty?

      spec, source = found.max_by { |(s,_)| s.version }

      download spec, source.uri.to_s
    end

fetch_file(uri, *_) click to toggle source

`File` Fetcher. Dispatched by `fetch_path`. Use it instead.

    # File lib/rubygems/remote_fetcher.rb, line 212
    def fetch_file(uri, *_)
      Gem.read_binary correct_for_windows_path uri.path
    end

fetch_http(uri, last_modified = nil, head = false, depth = 0) click to toggle source

HTTP Fetcher. Dispatched by `fetch_path`. Use it instead.

    # File lib/rubygems/remote_fetcher.rb, line 219
    def fetch_http(uri, last_modified = nil, head = false, depth = 0)
      fetch_type = head ? Net::HTTP::Head : Net::HTTP::Get
      response   = request uri, fetch_type, last_modified do |req|
        headers.each { |k,v| req.add_field(k,v) }
      end

      case response
      when Net::HTTPOK, Net::HTTPNotModified then
        response.uri = uri if response.respond_to? :uri
        head ? response : response.body
      when Net::HTTPMovedPermanently, Net::HTTPFound, Net::HTTPSeeOther,
           Net::HTTPTemporaryRedirect then
        raise FetchError.new('too many redirects', uri) if depth > 10

        unless location = response['Location']
          raise FetchError.new("redirecting but no redirect location was given", uri)
        end
        location = URI.parse response['Location']

        if https?(uri) && !https?(location)
          raise FetchError.new("redirecting to non-https resource: #{location}", uri)
        end

        fetch_http(location, last_modified, head, depth + 1)
      else
        raise FetchError.new("bad response #{response.message} #{response.code}", uri)
      end
    end

Also aliased as: fetch_https
fetch_https(uri, last_modified = nil, head = false, depth = 0)
Alias for: fetch_http
fetch_path(uri, mtime = nil, head = false) click to toggle source

Downloads `uri` and returns it as a `String`.

    # File lib/rubygems/remote_fetcher.rb, line 253
    def fetch_path(uri, mtime = nil, head = false)
      uri = URI.parse uri unless URI::Generic === uri

      raise ArgumentError, "bad uri: #{uri}" unless uri

      unless uri.scheme
        raise ArgumentError, "uri scheme is invalid: #{uri.scheme.inspect}"
      end

      data = send "fetch_#{uri.scheme}", uri, mtime, head

      if data and !head and uri.to_s =~ /\.gz$/
        begin
          data = Gem::Util.gunzip data
        rescue Zlib::GzipFile::Error
          raise FetchError.new("server did not return a valid file", uri.to_s)
        end
      end

      data
    rescue FetchError
      raise
    rescue Timeout::Error
      raise UnknownHostError.new('timed out', uri.to_s)
    rescue IOError, SocketError, SystemCallError,
      *(OpenSSL::SSL::SSLError if defined?(OpenSSL)) => e
      if e.message =~ /getaddrinfo/
        raise UnknownHostError.new('no such name', uri.to_s)
      else
        raise FetchError.new("#{e.class}: #{e}", uri.to_s)
      end
    end

fetch_s3(uri, mtime = nil, head = false) click to toggle source

    # File lib/rubygems/remote_fetcher.rb, line 286
    def fetch_s3(uri, mtime = nil, head = false)
      public_uri = sign_s3_url(uri)
      fetch_https public_uri, mtime, head
    end

fetch_size(uri) click to toggle source

Returns the size of `uri` in bytes.

    # File lib/rubygems/remote_fetcher.rb, line 314
    def fetch_size(uri) # TODO: phase this out
      response = fetch_path(uri, nil, true)

      response['content-length'].to_i
    end

https?(uri) click to toggle source

    # File lib/rubygems/remote_fetcher.rb, line 344
    def https?(uri)
      uri.scheme.downcase == 'https'
    end

request(uri, request_class, last_modified = nil) { |req| ... } click to toggle source

Performs a `Net::HTTP` request of type `request_class` on `uri` returning a `Net::HTTP` response object. request maintains a table of persistent connections to reduce connect overhead.

    # File lib/rubygems/remote_fetcher.rb, line 333
    def request(uri, request_class, last_modified = nil)
      proxy = proxy_for @proxy, uri
      pool  = pools_for(proxy).pool_for uri

      request = Gem::Request.new uri, request_class, last_modified, pool

      request.fetch do |req|
        yield req if block_given?
      end
    end

### Protected Instance Methods

s3_expiration() click to toggle source

    # File lib/rubygems/remote_fetcher.rb, line 371
    def s3_expiration
      (Time.now + 3600).to_i # one hour from now
    end

sign_s3_url(uri, expiration = nil) click to toggle source

we have our own signing code here to avoid a dependency on the aws-sdk gem fortunately, a simple GET request isn't too complex to sign properly

    # File lib/rubygems/remote_fetcher.rb, line 356
    def sign_s3_url(uri, expiration = nil)
      require 'base64'
      require 'openssl'

      id, secret = s3_source_auth uri

      expiration ||= s3_expiration
      canonical_path = "/#{uri.host}#{uri.path}"
      payload = "GET\n\n\n#{expiration}\n#{canonical_path}"
      digest = OpenSSL::HMAC.digest('sha1', secret, payload)
      # URI.escape is deprecated, and there isn't yet a replacement that does quite what we want
      signature = Base64.encode64(digest).gsub("\n", '').gsub(/[\+\/=]/) { |c| BASE64_URI_TRANSLATE[c] }
      URI.parse("https://#{uri.host}.s3.amazonaws.com#{uri.path}?AWSAccessKeyId=#{id}&Expires=#{expiration}&Signature=#{signature}")
    end

### Private Instance Methods

pools_for(proxy) click to toggle source

    # File lib/rubygems/remote_fetcher.rb, line 383
    def pools_for(proxy)
      @pool_lock.synchronize do
        @pools[proxy] ||= Gem::Request::ConnectionPools.new proxy, @cert_files
      end
    end

proxy_for(proxy, uri) click to toggle source

    # File lib/rubygems/remote_fetcher.rb, line 379
    def proxy_for(proxy, uri)
      Gem::Request.proxy_uri(proxy || Gem::Request.get_proxy_from_env(uri.scheme))
    end

s3_source_auth(uri) click to toggle source

    # File lib/rubygems/remote_fetcher.rb, line 389
    def s3_source_auth(uri)
      return [uri.user, uri.password] if uri.user && uri.password

      s3_source = Gem.configuration[:s3_source] || Gem.configuration['s3_source']
      host = uri.host
      raise FetchError.new("no s3_source key exists in .gemrc", "s3://#{host}") unless s3_source

      auth = s3_source[host] || s3_source[host.to_sym]
      raise FetchError.new("no key for host #{host} in s3_source in .gemrc", "s3://#{host}") unless auth

      id = auth[:id] || auth['id']
      secret = auth[:secret] || auth['secret']
      raise FetchError.new("s3_source for #{host} missing id or secret", "s3://#{host}") unless id and secret

      [id, secret]
    end