Class: SC::Rack::Proxy

Inherits:
Object show all
Defined in:
lib/sproutcore/rack/proxy.rb

Overview

Rack application proxies requests as needed for the given project.

Instance Method Summary collapse

Constructor Details

#initialize(project) ⇒ Proxy

Returns a new instance of Proxy.



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# File 'lib/sproutcore/rack/proxy.rb', line 85

def initialize(project)
  @project = project
  @proxies = project.buildfile.proxies
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/sproutcore/rack/proxy.rb', line 90

def call(env)
  path = env['PATH_INFO']

  @proxies.each do |proxy, value|
    # If the url matches a proxied url, handle it
    if path.match(/^#{Regexp.escape(proxy.to_s)}/)
      handle_proxy(value, proxy.to_s, env)

      # Don't block waiting for a response
      throw :async
    end
  end

  return [404, {}, "not found"]
end

#chunked?(headers) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/sproutcore/rack/proxy.rb', line 106

def chunked?(headers)
  headers['Transfer-Encoding'] == "chunked"
end

#handle_proxy(proxy, proxy_url, env) ⇒ Object 



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# File 'lib/sproutcore/rack/proxy.rb', line 110

def handle_proxy(proxy, proxy_url, env)

  if proxy[:secure] && !SC::HTTPS_ENABLED
    SC.logger << "~ WARNING: HTTPS is not supported on your system, using HTTP instead.\n"
    SC.logger << "    If you are using Ubuntu, you can run `apt-get install libopenssl-ruby`\n"
    proxy[:secure] = false
  end

  headers = request_headers(env, proxy)         # ex. {"Host"=>"localhost:4020", "Connection"=>"...
  path = env['PATH_INFO']                       # ex. /contacts
  params = env['QUERY_STRING']                  # ex. since=yesterday&unread=true

  # Switch to https if proxy[:secure] configured
  protocol = proxy[:secure] ? 'https' : 'http'

  # Adjust the path if proxy[:url] configured
  if proxy[:url]
    path = path.sub(/^#{Regexp.escape proxy_url}/, proxy[:url])
  end

  # The endpoint URL
  url = protocol + '://' + proxy[:to]
  url += path unless path.empty?
  url += '?' + params unless params.empty?

  if env['CONTENT_LENGTH'] || env['HTTP_TRANSFER_ENCODING']
    req_body = env['rack.input']
    req_body.rewind # May not be necessary but can't hurt

    req_body = req_body.read
  end

  # Options for the connection
  connect_options = {}
  if proxy[:inactivity_timeout] # allow the more verbose setting to take precedence
    connect_options[:inactivity_timeout] = proxy[:inactivity_timeout]
  elsif proxy[:timeout] # check the legacy and simpler setting
    connect_options[:inactivity_timeout] = proxy[:timeout]
  end
  connect_options[:connect_timeout] = proxy[:connect_timeout] if proxy[:connect_timeout]

  # Options for the request
  request_options = {}
  request_options[:head] = headers
  request_options[:body] = req_body if !!req_body
  request_options[:redirects] = 5 if proxy[:redirect] != false
  request_options[:decoding] = false  # don't decode gzipped content

  EventMachine.run {
    body = nil
    conn = EM::HttpRequest.new(url, connect_options)
    chunked = false
    headers = {}
    method = env['REQUEST_METHOD'].upcase
    status = 0
    conn.use RedirectHostHeaderKiller

    case method
      when 'GET'
        http = conn.get request_options
      when 'POST'
        http = conn.post request_options
      when 'PUT'
        http = conn.put request_options
      when 'DELETE'
        http = conn.delete request_options
      else
        http = conn.head request_options
      end

    # Received error
    http.errback {
      status = http.response_header.status
      path = env['PATH_INFO']
      url = http.last_effective_url
      SC.logger << "~ PROXY FAILED:  #{method} #{path} -> #{status} #{url}\n"

      # If a body has been sent use it, otherwise respond with generic message
      if !body
        body = "Unable to proxy to #{url}.  Received status: #{status}"
        size = body.respond_to?(:bytesize) ? body.bytesize : body.length
        headers = { 'Content-Length' => size.to_s }
        body = [body]
      end

      env['async.callback'].call [502, headers, body]
    }

    # Received response
    http.callback {

      # Too many redirects
      if redirect? status
        body = "Unable to proxy to #{url}.  Too many redirects."
        size = body.respond_to?(:bytesize) ? body.bytesize : body.length
        headers = { 'Content-Length' => size.to_s }

        env['async.callback'].call [502, headers, [body]]
      else
        # Terminate the deferred body (which may have been chunked)
        if body
          body.call ['']
          body.succeed
        end

        # Log the initial path and the final url
        path = env['PATH_INFO']
        url = http.last_effective_url
        SC.logger << "~ PROXY: #{method} #{path} -> #{status} #{url}\n"
     end
    }

    # Received headers
    http.headers { |hash|
      status = http.response_header.status

      headers = response_headers(hash)

      # Don't respond on redirection, but fail out on bad redirects
      if redirect? status

        if status == 304
          env["async.callback"].call [status, headers, ['']]
          SC.logger << "~ PROXY: #{method} #{path} -> #{status} #{url}\n"
        elsif !headers['Location']
          body = "Unable to proxy to #{url}. Received redirect with no Location."
          size = body.respond_to?(:bytesize) ? body.bytesize : body.length
          headers = { 'Content-Length' => size.to_s }

          http.close
        end

      else
        # Stream the body right across in the format it was sent
        chunked = chunked?(headers)
        body = DeferrableBody.new({ :chunked => chunked })

        # Start responding to the client immediately
        env["async.callback"].call [status, headers, body]
      end
    }

    # Received chunk of data
    http.stream { |chunk|
      # Ignore body of redirects
      if !redirect? status
        body.call [chunk]
      end
    }

    # If the client disconnects early, make sure we close our other connection too
    # TODO: this is waiting for changes not yet available in em-http
    # Test with: curl http://0.0.0.0:4020/stream.twitter.com/1/statuses/sample.json -uTWITTER_USERNAME:TWITTER_PASSWORD
    # env["async.close"].callback {
    #   conn.close
    # }

  }
end

#headerize(str) ⇒ Object

remove HTTP_, dasherize and titleize



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# File 'lib/sproutcore/rack/proxy.rb', line 337

def headerize(str)
  parts = str.gsub(/^HTTP_/, '').split('_')
  parts.map! { |p| p.capitalize }.join('-')
end

#redirect?(status) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/sproutcore/rack/proxy.rb', line 270

def redirect?(status)
  status >= 300 && status < 400
end

#request_headers(env, proxy) ⇒ Object

collect headers…



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# File 'lib/sproutcore/rack/proxy.rb', line 275

def request_headers(env, proxy)
  result = {}
  env.each do |key, value|
    next unless key =~ /^HTTP_/

    key = headerize(key)
    if !key.eql? "Version"
      result[key] = value
    end
  end

  # Rack documentation says CONTENT_TYPE and CONTENT_LENGTH aren't prefixed by HTTP_
  result['Content-Type'] = env['CONTENT_TYPE'] if env['CONTENT_TYPE']

  length = env['CONTENT_LENGTH']
  result['Content-Length'] = length if length

  # added 4/23/09 per Charles Jolley, corrects problem
  # when making requests to virtual hosts
  result['Host'] = proxy[:to]

  result
end

#response_headers(hash) ⇒ Object

construct and display specific response headers



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# File 'lib/sproutcore/rack/proxy.rb', line 300

def response_headers(hash)
  result = {}

  hash.each do |key, value|
    key = headerize(key)

    # Because Set-Cookie header can appear more the once in the response body,
    # but Rack only accepts a hash of headers, we store it in a line break separated string
    # for Ruby 1.9 and as an Array for Ruby 1.8
    # See http://groups.google.com/group/rack-devel/browse_thread/thread/e8759b91a82c5a10/a8dbd4574fe97d69?#a8dbd4574fe97d69
    if key.downcase == 'set-cookie'
      cookies = []

      case value
        when Array then value.each { |c| cookies << strip_domain(c) }
        when Hash  then value.each { |_, c| cookies << strip_domain(c) }
        else            cookies << strip_domain(value)
      end

      # Remove nil values
      result['Set-Cookie'] = [result['Set-Cookie'], cookies].compact

      if Thin.ruby_18?
        result['Set-Cookie'].flatten!
      else
        result['Set-Cookie'] = result['Set-Cookie'].join("\n")
      end
    end

    SC.logger << "   #{key}: #{value}\n"
    result[key] = value
  end

  ::Rack::Utils::HeaderHash.new(result)
end

#strip_domain(cookie) ⇒ Object

Strip out the domain of passed in cookie. This technically may break certain scenarios where services try to set cross-domain cookies, but those services should not be doing that anyway…



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# File 'lib/sproutcore/rack/proxy.rb', line 345

def strip_domain(cookie)
  cookie.to_s.gsub!(/domain=[^\;]+\;? ?/,'')
end