添加deflate gzip模块到apache2服务器

$> ./configure --prefix=/usr/local/apache2 --enable-so --enable-mods-shared=all --enable-modules=all
Configuring Apache Portable Runtime Utility library...

checking for APR-util... yes
configure: error: Cannot use an external APR-util with the bundled APR

如果编译过程中发现APR-util的错误，可以加上--with-included-apr这个参数，如下：
$> ./configure --prefix=/usr/local/apache2 --enable-so --enable-mods-shared=all --enable-modules=all --with-included-apr
$> make
$> cp ./modules/filters/.libs/mod_deflate.so /usr/local/apache2/modules
$> vi /usr/local/apache2/conf/httpd.conf
# append 2 line to httpd.conf
LoadModule deflate_module modules/mod_deflate.so
AddOutputFilterByType DEFLATE text/html text/plain text/xml text/css text/javascript application/x-json application/x-javascript
$> /usr/local/apache2/bin/apachectl graceful

更多关于deflate module的设置可参考官方说明：http://httpd.apache.org/docs/2.0/mod/mod_deflate.html

Reference:
http://yuweijun.blogspot.com/2007/09/apache22module.html

Rails output compress plugin

source code from: http://blog.craz8.com/files/compress.rb

require 'stringio'
require 'zlib'

class OutputCompressionFilter

  def self.filter(controller)
    return if controller.response.headers['Content-Encoding'] || controller.request.env['HTTP_ACCEPT_ENCODING'].nil?
    begin
      controller.request.env['HTTP_ACCEPT_ENCODING'].split(/\s*,\s*/).each do |encoding|
        # TODO: use "q" values to determine user agent encoding preferences
        case encoding
          when /\Agzip\b/
            StringIO.open('', 'w') do |strio|
              begin
                gz = Zlib::GzipWriter.new(strio)
                gz.write(controller.response.body)
                controller.response.body = strio.string
              ensure
                gz.close if gz
              end
            end
          when /\Adeflate\b/
            controller.response.body = Zlib::Deflate.deflate(controller.response.body, Zlib::BEST_COMPRESSION)
          when /\Aidentity\b/
            # do nothing for identity
          else
            next # the encoding is not supported, try the next one
        end
        controller.logger.info "Response body was encoded with #{encoding}" 
        controller.response.headers['Content-Encoding'] = encoding
        break    # the encoding is supported, stop
      end
    end
    controller.response.headers['Content-Length'] = controller.response.body.length
    if controller.response.headers['Vary'] != '*'
      controller.response.headers['Vary'] = 
        controller.response.headers['Vary'].to_s.split(',').push('Accept-Encoding').uniq.join(',')
    end
  end

end