ruby : Add no_speech_thold (#2641)

* Remove Whisper::Model.[]

* Fix Whisper::Model::URI#request

* Make Whisper::Context#initialize accept pre-converted model name

* Use downloading pre-converted model feature for testing

* Update README

* Remove unnecessary task

* Move whisper/model.rb -> whisper/model/uri.rb

* Update document comment of Whisper::Context#initialize

* Don't show download progress when not tty

* Pass String to raise

* Use cache model file if download fails

* Add test for auto download

* Specify required Ruby version

* Fix a typo

* Remove unnecessary flags

* Initialize Whisper::Params#diarize explicitely

* Remove redundant code from README for simplicity

* Add Whisper::Params#no_speech_thold attribute

* Add test for Whisper::Params#no_speech_thold

bindings/ruby/lib/whisper/model/uri.rb

@@ -0,0 +1,157 @@
+require "whisper.so"
+require "uri"
+require "net/http"
+require "time"
+require "pathname"
+require "io/console/size"
+
+class Whisper::Model
+  class URI
+    def initialize(uri)
+      @uri = URI(uri)
+    end
+
+    def to_path
+      cache
+      cache_path.to_path
+    end
+
+    def clear_cache
+      path = cache_path
+      path.delete if path.exist?
+    end
+
+    private
+
+    def cache_path
+      base_cache_dir/@uri.host/@uri.path[1..]
+    end
+
+    def base_cache_dir
+      base = case RUBY_PLATFORM
+             when /mswin|mingw/
+               ENV.key?("LOCALAPPDATA") ? Pathname(ENV["LOCALAPPDATA"]) : Pathname(Dir.home)/"AppData/Local"
+             when /darwin/
+               Pathname(Dir.home)/"Library/Caches"
+             else
+               ENV.key?("XDG_CACHE_HOME") ? ENV["XDG_CACHE_HOME"] : Pathname(Dir.home)/".cache"
+             end
+      base/"whisper.cpp"
+    end
+
+    def cache
+      path = cache_path
+      headers = {}
+      headers["if-modified-since"] = path.mtime.httpdate if path.exist?
+      request @uri, headers
+      path
+    end
+
+    def request(uri, headers)
+      Net::HTTP.start uri.host, uri.port, use_ssl: uri.scheme == "https" do |http|
+        request = Net::HTTP::Get.new(uri, headers)
+        http.request request do |response|
+          case response
+          when Net::HTTPNotModified
+            # noop
+          when Net::HTTPOK
+            download response
+          when Net::HTTPRedirection
+            request URI(response["location"]), headers
+          else
+            return if headers.key?("if-modified-since") # Use cache file
+
+            raise "#{response.code} #{response.message}\n#{response.body}"
+          end
+        end
+      end
+    end
+
+    def download(response)
+      path = cache_path
+      path.dirname.mkpath unless path.dirname.exist?
+      downloading_path = Pathname("#{path}.downloading")
+      size = response.content_length
+      downloading_path.open "wb" do |file|
+        downloaded = 0
+        response.read_body do |chunk|
+          file << chunk
+          downloaded += chunk.bytesize
+          show_progress downloaded, size
+        end
+      end
+      downloading_path.rename path
+    end
+
+    def show_progress(current, size)
+      return unless $stderr.tty?
+      return unless size
+
+      unless @prev
+        @prev = Time.now
+        $stderr.puts "Downloading #{@uri}"
+      end
+
+      now = Time.now
+      return if now - @prev < 1 && current < size
+
+      progress_width = 20
+      progress = current.to_f / size
+      arrow_length = progress * progress_width
+      arrow = "=" * (arrow_length - 1) + ">" + " " * (progress_width - arrow_length)
+      line = "[#{arrow}] (#{format_bytesize(current)} / #{format_bytesize(size)})"
+      padding = ' ' * ($stderr.winsize[1] - line.size)
+      $stderr.print "\r#{line}#{padding}"
+      $stderr.puts if current >= size
+      @prev = now
+    end
+
+    def format_bytesize(bytesize)
+      return "0.0 B" if bytesize.zero?
+
+      units = %w[B KiB MiB GiB TiB]
+      exp = (Math.log(bytesize) / Math.log(1024)).to_i
+      format("%.1f %s", bytesize.to_f / 1024 ** exp, units[exp])
+    end
+  end
+
+  @pre_converted_models = {}
+  %w[
+    tiny
+    tiny.en
+    tiny-q5_1
+    tiny.en-q5_1
+    tiny-q8_0
+    base
+    base.en
+    base-q5_1
+    base.en-q5_1
+    base-q8_0
+    small
+    small.en
+    small.en-tdrz
+    small-q5_1
+    small.en-q5_1
+    small-q8_0
+    medium
+    medium.en
+    medium-q5_0
+    medium.en-q5_0
+    medium-q8_0
+    large-v1
+    large-v2
+    large-v2-q5_0
+    large-v2-q8_0
+    large-v3
+    large-v3-q5_0
+    large-v3-turbo
+    large-v3-turbo-q5_0
+    large-v3-turbo-q8_0
+  ].each do |name|
+    @pre_converted_models[name] = URI.new("https://huggingface.co/ggerganov/whisper.cpp/resolve/main/ggml-#{name}.bin")
+  end
+
+  class << self
+    attr_reader :pre_converted_models
+  end
+end