class Gem::SpecFetcher

SpecFetcher handles metadata updates from remote gem repositories.

Public Class Methods

fetcher ()

Default fetcher instance. Use this instead of ::new to reduce object allocation.

# File lib/rubygems/spec_fetcher.rb, line 42
def self.fetcher
  @fetcher ||= new
end

new (sources = nil)

Creates a new SpecFetcher. Ordinarily you want to use the default fetcher from Gem::SpecFetcher::fetcher which uses the Gem.sources.

If you need to retrieve specifications from a different source, you can send it as an argument.

# File lib/rubygems/spec_fetcher.rb, line 57
def initialize(sources = nil)
  @sources = sources || Gem.sources

  @update_cache =
    begin
      File.stat(Gem.user_home).uid == Process.uid
    rescue Errno::EACCES, Errno::ENOENT
      false
    end

  @specs = {}
  @latest_specs = {}
  @prerelease_specs = {}

  @caches = {
    latest: @latest_specs,
    prerelease: @prerelease_specs,
    released: @specs,
  }

  @fetcher = Gem::RemoteFetcher.fetcher
end

Public Instance Methods

available_specs (type)

Returns a list of gems available for each source in Gem::sources.

type can be one of 3 values: :released => Return the list of all released specs :complete => Return the list of all specs :latest => Return the list of only the highest version of each gem :prerelease => Return the list of all prerelease only specs

# File lib/rubygems/spec_fetcher.rb, line 204
def available_specs(type)
  errors = []
  list = {}

  @sources.each_source do |source|
    names = case type
            when :latest
              tuples_for source, :latest
            when :released
              tuples_for source, :released
            when :complete
              names =
                tuples_for(source, :prerelease, true) +
                tuples_for(source, :released)

              names.sort
            when :abs_latest
              names =
                tuples_for(source, :prerelease, true) +
                tuples_for(source, :latest)

              names.sort
            when :prerelease
              tuples_for(source, :prerelease)
            else
              raise Gem::Exception, "Unknown type - :#{type}"
    end
  rescue Gem::RemoteFetcher::FetchError => e
    errors << Gem::SourceFetchProblem.new(source, e)
  else
    list[source] = names
  end

  [list, errors]
end

detect (type=:complete) { |tup| ... }

Return all gem name tuples who’s names match obj

# File lib/rubygems/spec_fetcher.rb, line 133
def detect(type=:complete)
  tuples = []

  list, _ = available_specs(type)
  list.each do |source, specs|
    specs.each do |tup|
      if yield(tup)
        tuples << [tup, source]
      end
    end
  end

  tuples
end

search_for_dependency (dependency, matching_platform=true)

Find and fetch gem name tuples that match dependency.

If matching_platform is false, gems for all platforms are returned.

# File lib/rubygems/spec_fetcher.rb, line 86
def search_for_dependency(dependency, matching_platform=true)
  found = {}

  rejected_specs = {}

  list, errors = available_specs(dependency.identity)

  list.each do |source, specs|
    if dependency.name.is_a?(String) && specs.respond_to?(:bsearch)
      start_index = (0...specs.length).bsearch {|i| specs[i].name >= dependency.name }
      end_index   = (0...specs.length).bsearch {|i| specs[i].name > dependency.name }
      specs = specs[start_index...end_index] if start_index && end_index
    end

    found[source] = specs.select do |tup|
      if dependency.match?(tup)
        if matching_platform && !Gem::Platform.match_gem?(tup.platform, tup.name)
          pm = (
            rejected_specs[dependency] ||= \
              Gem::PlatformMismatch.new(tup.name, tup.version))
          pm.add_platform tup.platform
          false
        else
          true
        end
      end
    end
  end

  errors += rejected_specs.values

  tuples = []

  found.each do |source, specs|
    specs.each do |s|
      tuples << [s, source]
    end
  end

  tuples = tuples.sort_by {|x| x[0].version }

  [tuples, errors]
end

spec_for_dependency (dependency, matching_platform=true)

Find and fetch specs that match dependency.

If matching_platform is false, gems for all platforms are returned.

# File lib/rubygems/spec_fetcher.rb, line 153
def spec_for_dependency(dependency, matching_platform=true)
  tuples, errors = search_for_dependency(dependency, matching_platform)

  specs = []
  tuples.each do |tup, source|
    spec = source.fetch_spec(tup)
  rescue Gem::RemoteFetcher::FetchError => e
    errors << Gem::SourceFetchProblem.new(source, e)
  else
    specs << [spec, source]
  end

  [specs, errors]
end

suggest_gems_from_name (gem_name, type = :latest, num_results = 5)

Suggests gems based on the supplied gem_name. Returns an array of alternative gem names.

# File lib/rubygems/spec_fetcher.rb, line 172
def suggest_gems_from_name(gem_name, type = :latest, num_results = 5)
  gem_name        = gem_name.downcase.tr("_-", "")
  max             = gem_name.size / 2
  names           = available_specs(type).first.values.flatten(1)

  matches = names.map do |n|
    next unless n.match_platform?
    distance = levenshtein_distance gem_name, n.name.downcase.tr("_-", "")
    next if distance >= max
    return [n.name] if distance == 0
    [n.name, distance]
  end.compact

  matches = if matches.empty? && type != :prerelease
    suggest_gems_from_name gem_name, :prerelease
  else
    matches.uniq.sort_by {|_name, dist| dist }
  end

  matches.map {|name, _dist| name }.uniq.first(num_results)
end