mongrel.rb

来自「Amarok是一款在LINUX或其他类UNIX操作系统中运行的音频播放器软件。 」· RB 代码 · 共 807 行 · 第 1/2 页

# Copyright (c) 2005 Zed A. Shaw 
# You can redistribute it and/or modify it under the same terms as Ruby.
#
# Additional work donated by contributors.  See http://mongrel.rubyforge.org/attributions.html 
# for more information.

$mongrel_debug_client = false

require 'rubygems'
require 'socket'
require 'http11'
require 'tempfile'
begin
  require 'fastthread'
rescue RuntimeError => e
  warn "fastthread not loaded: #{ e.message }"
rescue LoadError
ensure
  require 'thread'
end
require 'stringio'
require 'mongrel/cgi'
require 'mongrel/handlers'
require 'mongrel/command'
require 'mongrel/tcphack'
require 'yaml'
require 'mongrel/configurator'
require 'time'
require 'etc'
require 'uri'


# Mongrel module containing all of the classes (include C extensions) for running
# a Mongrel web server.  It contains a minimalist HTTP server with just enough
# functionality to service web application requests fast as possible.
module Mongrel

  class URIClassifier
    attr_reader :handler_map

    # Returns the URIs that have been registered with this classifier so far.
    # The URIs returned should not be modified as this will cause a memory leak.
    # You can use this to inspect the contents of the URIClassifier.
    def uris
      @handler_map.keys
    end

    # Simply does an inspect that looks like a Hash inspect.
    def inspect
      @handler_map.inspect
    end
  end


  # Used to stop the HttpServer via Thread.raise.
  class StopServer < Exception; end


  # Thrown at a thread when it is timed out.
  class TimeoutError < Exception; end


  # Every standard HTTP code mapped to the appropriate message.  These are
  # used so frequently that they are placed directly in Mongrel for easy
  # access rather than Mongrel::Const.
  HTTP_STATUS_CODES = {  
    100  => 'Continue', 
    101  => 'Switching Protocols', 
    200  => 'OK', 
    201  => 'Created', 
    202  => 'Accepted', 
    203  => 'Non-Authoritative Information', 
    204  => 'No Content', 
    205  => 'Reset Content', 
    206  => 'Partial Content', 
    300  => 'Multiple Choices', 
    301  => 'Moved Permanently', 
    302  => 'Moved Temporarily', 
    303  => 'See Other', 
    304  => 'Not Modified', 
    305  => 'Use Proxy', 
    400  => 'Bad Request', 
    401  => 'Unauthorized', 
    402  => 'Payment Required', 
    403  => 'Forbidden', 
    404  => 'Not Found', 
    405  => 'Method Not Allowed', 
    406  => 'Not Acceptable', 
    407  => 'Proxy Authentication Required', 
    408  => 'Request Time-out', 
    409  => 'Conflict', 
    410  => 'Gone', 
    411  => 'Length Required', 
    412  => 'Precondition Failed', 
    413  => 'Request Entity Too Large', 
    414  => 'Request-URI Too Large', 
    415  => 'Unsupported Media Type', 
    500  => 'Internal Server Error', 
    501  => 'Not Implemented', 
    502  => 'Bad Gateway', 
    503  => 'Service Unavailable', 
    504  => 'Gateway Time-out', 
    505  => 'HTTP Version not supported'
  }


  # Frequently used constants when constructing requests or responses.  Many times
  # the constant just refers to a string with the same contents.  Using these constants
  # gave about a 3% to 10% performance improvement over using the strings directly.
  # Symbols did not really improve things much compared to constants.
  #
  # While Mongrel does try to emulate the CGI/1.2 protocol, it does not use the REMOTE_IDENT,
  # REMOTE_USER, or REMOTE_HOST parameters since those are either a security problem or 
  # too taxing on performance.
  module Const
    DATE = "Date".freeze

    # This is the part of the path after the SCRIPT_NAME.  URIClassifier will determine this.
    PATH_INFO="PATH_INFO".freeze

    # This is the initial part that your handler is identified as by URIClassifier.
    SCRIPT_NAME="SCRIPT_NAME".freeze

    # The original URI requested by the client.  Passed to URIClassifier to build PATH_INFO and SCRIPT_NAME.
    REQUEST_URI='REQUEST_URI'.freeze
    REQUEST_PATH='REQUEST_PATH'.freeze

    MONGREL_VERSION="1.0.1".freeze

    MONGREL_TMP_BASE="mongrel".freeze

    # The standard empty 404 response for bad requests.  Use Error4040Handler for custom stuff.
    ERROR_404_RESPONSE="HTTP/1.1 404 Not Found\r\nConnection: close\r\nServer: Mongrel #{MONGREL_VERSION}\r\n\r\nNOT FOUND".freeze

    CONTENT_LENGTH="CONTENT_LENGTH".freeze

    # A common header for indicating the server is too busy.  Not used yet.
    ERROR_503_RESPONSE="HTTP/1.1 503 Service Unavailable\r\n\r\nBUSY".freeze

    # The basic max request size we'll try to read.
    CHUNK_SIZE=(16 * 1024)

    # This is the maximum header that is allowed before a client is booted.  The parser detects
    # this, but we'd also like to do this as well.
    MAX_HEADER=1024 * (80 + 32)

    # Maximum request body size before it is moved out of memory and into a tempfile for reading.
    MAX_BODY=MAX_HEADER

    # A frozen format for this is about 15% faster
    STATUS_FORMAT = "HTTP/1.1 %d %s\r\nConnection: close\r\n".freeze
    CONTENT_TYPE = "Content-Type".freeze
    LAST_MODIFIED = "Last-Modified".freeze
    ETAG = "ETag".freeze
    SLASH = "/".freeze
    REQUEST_METHOD="REQUEST_METHOD".freeze
    GET="GET".freeze
    HEAD="HEAD".freeze
    # ETag is based on the apache standard of hex mtime-size-inode (inode is 0 on win32)
    ETAG_FORMAT="\"%x-%x-%x\"".freeze
    HEADER_FORMAT="%s: %s\r\n".freeze
    LINE_END="\r\n".freeze
    REMOTE_ADDR="REMOTE_ADDR".freeze
    HTTP_X_FORWARDED_FOR="HTTP_X_FORWARDED_FOR".freeze
    HTTP_IF_MODIFIED_SINCE="HTTP_IF_MODIFIED_SINCE".freeze
    HTTP_IF_NONE_MATCH="HTTP_IF_NONE_MATCH".freeze
    REDIRECT = "HTTP/1.1 302 Found\r\nLocation: %s\r\nConnection: close\r\n\r\n".freeze
    HOST = "HOST".freeze
  end


  # Basically a Hash with one extra parameter for the HTTP body, mostly used internally.
  class HttpParams < Hash
    attr_accessor :http_body
  end


  # When a handler is found for a registered URI then this class is constructed
  # and passed to your HttpHandler::process method.  You should assume that 
  # *one* handler processes all requests.  Included in the HttpRequest is a
  # HttpRequest.params Hash that matches common CGI params, and a HttpRequest.body
  # which is a string containing the request body (raw for now).
  #
  # The HttpRequest.initialize method will convert any request that is larger than
  # Const::MAX_BODY into a Tempfile and use that as the body.  Otherwise it uses 
  # a StringIO object.  To be safe, you should assume it works like a file.
  #
  # The HttpHandler.request_notify system is implemented by having HttpRequest call
  # HttpHandler.request_begins, HttpHandler.request_progress, HttpHandler.process during
  # the IO processing.  This adds a small amount of overhead but lets you implement
  # finer controlled handlers and filters.
  class HttpRequest
    attr_reader :body, :params

    # You don't really call this.  It's made for you.
    # Main thing it does is hook up the params, and store any remaining
    # body data into the HttpRequest.body attribute.
    def initialize(params, socket, dispatchers)
      @params = params
      @socket = socket
      @dispatchers = dispatchers
      content_length = @params[Const::CONTENT_LENGTH].to_i
      remain = content_length - @params.http_body.length
      
      # tell all dispatchers the request has begun
      @dispatchers.each do |dispatcher|
        dispatcher.request_begins(@params) 
      end unless @dispatchers.nil? || @dispatchers.empty?

      # Some clients (like FF1.0) report 0 for body and then send a body.  This will probably truncate them but at least the request goes through usually.
      if remain <= 0
        # we've got everything, pack it up
        @body = StringIO.new
        @body.write @params.http_body
        update_request_progress(0, content_length)
      elsif remain > 0
        # must read more data to complete body
        if remain > Const::MAX_BODY
          # huge body, put it in a tempfile
          @body = Tempfile.new(Const::MONGREL_TMP_BASE)
          @body.binmode
        else
          # small body, just use that
          @body = StringIO.new 
        end

        @body.write @params.http_body
        read_body(remain, content_length)
      end

      @body.rewind if @body
    end

    # updates all dispatchers about our progress
    def update_request_progress(clen, total)
      return if @dispatchers.nil? || @dispatchers.empty?
      @dispatchers.each do |dispatcher|
        dispatcher.request_progress(@params, clen, total) 
      end 
    end
    private :update_request_progress

    # Does the heavy lifting of properly reading the larger body requests in 
    # small chunks.  It expects @body to be an IO object, @socket to be valid,
    # and will set @body = nil if the request fails.  It also expects any initial
    # part of the body that has been read to be in the @body already.
    def read_body(remain, total)
      begin
        # write the odd sized chunk first
        @params.http_body = read_socket(remain % Const::CHUNK_SIZE)

        remain -= @body.write(@params.http_body)

        update_request_progress(remain, total)

        # then stream out nothing but perfectly sized chunks
        until remain <= 0 or @socket.closed?
          # ASSUME: we are writing to a disk and these writes always write the requested amount
          @params.http_body = read_socket(Const::CHUNK_SIZE)
          remain -= @body.write(@params.http_body)

          update_request_progress(remain, total)
        end
      rescue Object
        STDERR.puts "ERROR reading http body: #$!"
        $!.backtrace.join("\n")
        # any errors means we should delete the file, including if the file is dumped
        @socket.close rescue Object
        @body.delete if @body.class == Tempfile
        @body = nil # signals that there was a problem
      end
    end
 
    def read_socket(len)
      if !@socket.closed?
        data = @socket.read(len)
        if !data
          raise "Socket read return nil"
        elsif data.length != len
          raise "Socket read returned insufficient data: #{data.length}"
        else
          data
        end
      else
        raise "Socket already closed when reading."
      end
    end

    # Performs URI escaping so that you can construct proper
    # query strings faster.  Use this rather than the cgi.rb
    # version since it's faster.  (Stolen from Camping).
    def self.escape(s)
      s.to_s.gsub(/([^ a-zA-Z0-9_.-]+)/n) {
        '%'+$1.unpack('H2'*$1.size).join('%').upcase
      }.tr(' ', '+') 
    end


    # Unescapes a URI escaped string. (Stolen from Camping).
    def self.unescape(s)
      s.tr('+', ' ').gsub(/((?:%[0-9a-fA-F]{2})+)/n){
        [$1.delete('%')].pack('H*')
      } 
    end

    # Parses a query string by breaking it up at the '&' 
    # and ';' characters.  You can also use this to parse
    # cookies by changing the characters used in the second
    # parameter (which defaults to '&;'.
    def self.query_parse(qs, d = '&;')
      params = {}
      (qs||'').split(/[#{d}] */n).inject(params) { |h,p|
        k, v=unescape(p).split('=',2)
        if cur = params[k]
          if cur.class == Array
            params[k] << v
          else
            params[k] = [cur, v]
          end
        else
          params[k] = v
        end
      }

      return params
    end
  end


  # This class implements a simple way of constructing the HTTP headers dynamically
  # via a Hash syntax.  Think of it as a write-only Hash.  Refer to HttpResponse for
  # information on how this is used.
  #
  # One consequence of this write-only nature is that you can write multiple headers
  # by just doing them twice (which is sometimes needed in HTTP), but that the normal
  # semantics for Hash (where doing an insert replaces) is not there.
  class HeaderOut
    attr_reader :out
    attr_accessor :allowed_duplicates

    def initialize(out)
      @sent = {}
      @allowed_duplicates = {"Set-Cookie" => true, "Set-Cookie2" => true,
        "Warning" => true, "WWW-Authenticate" => true}
      @out = out
    end

    # Simply writes "#{key}: #{value}" to an output buffer.
    def[]=(key,value)
      if not @sent.has_key?(key) or @allowed_duplicates.has_key?(key)
        @sent[key] = true
        @out.write(Const::HEADER_FORMAT % [key, value])
      end
    end
  end


  # Writes and controls your response to the client using the HTTP/1.1 specification.
  # You use it by simply doing:
  #
  #  response.start(200) do |head,out|
  #    head['Content-Type'] = 'text/plain'
  #    out.write("hello\n")
  #  end
  #
  # The parameter to start is the response code--which Mongrel will translate for you
  # based on HTTP_STATUS_CODES.  The head parameter is how you write custom headers.
  # The out parameter is where you write your body.  The default status code for 
  # HttpResponse.start is 200 so the above example is redundant.
  # 
  # As you can see, it's just like using a Hash and as you do this it writes the proper
  # header to the output on the fly.  You can even intermix specifying headers and 
  # writing content.  The HttpResponse class with write the things in the proper order
  # once the HttpResponse.block is ended.
  #
  # You may also work the HttpResponse object directly using the various attributes available
  # for the raw socket, body, header, and status codes.  If you do this you're on your own.
  # A design decision was made to force the client to not pipeline requests.  HTTP/1.1 
  # pipelining really kills the performance due to how it has to be handled and how 
  # unclear the standard is.  To fix this the HttpResponse gives a "Connection: close"
  # header which forces the client to close right away.  The bonus for this is that it
  # gives a pretty nice speed boost to most clients since they can close their connection
  # immediately.
  #
  # One additional caveat is that you don't have to specify the Content-length header
  # as the HttpResponse will write this for you based on the out length.
  class HttpResponse
    attr_reader :socket
    attr_reader :body
    attr_writer :body
    attr_reader :header
    attr_reader :status
    attr_writer :status
    attr_reader :body_sent
    attr_reader :header_sent
    attr_reader :status_sent

    def initialize(socket)
      @socket = socket
      @body = StringIO.new
      @status = 404
      @header = HeaderOut.new(StringIO.new)
      @header[Const::DATE] = Time.now.httpdate
      @body_sent = false