重构，修正了许多的空指针异常

app/helpers/system_log_helper.rb

@@ -2,9 +2,11 @@ module SystemLogHelper
     class SystemLog
       class << self
         # 分页（支持多关键字查询）
-        def logo_data(page,per,search)
-          logs = find_all_logs
-
+        def logo_data(page,per,search,day)
+          logs = find_all_logs day
+          if logs.empty? #如果返回的是空數組，就說明日誌文件不存在
+            return logs
+          end
           # 根据search参数来决定是否需要查询
           keywords = search
           if keywords && !keywords.strip.blank?
@@ -14,6 +16,7 @@ module SystemLogHelper
             logs = logs.find_all do |log|
               keywords.all? { |r| log =~ r }
             end
+            #用Kaminari分页
             logs = Kaminari.paginate_array(logs).page(page).per(per).collect! {|log| parse(log)}
             logs.collect! do |log|
               keywords.each { |r| log.gsub!(r, '<span class="search_results">\0</span>')}
@@ -26,31 +29,127 @@ module SystemLogHelper
         end
 
         #清除日誌
-        def clear
-          File.open(logfile_path, 'w') do |f|
+        def clear day
+          if File::exists?(logfile_path day)
+            File.open(logfile_path(day), 'w') do |f|
               f.print ''
             end
+          else
+          end
         end
 
         #讀取日誌
         private
-        def find_all_logs
-          File.open(logfile_path) do |f|
+        def find_all_logs day
+          if File::exists?(logfile_path day)
+            File.open(logfile_path day) do |f|
               #打开文件，并按照正则表达式切分，逆序，最新一个记录可以扔掉（因为最新的记录永远都是访问System_log)
               f.read.split("Processing").reverse[1..-1]
             end
+          else
+            []
+          end
         end
 
         # 日志文件的路径，一般在Rails.root/log下，根据环境配置
         # 依次记录到product.log development.log test.log中
-        def logfile_path
+        def logfile_path day
+          #将日期处理成2015-01-01的形式
+          unless day.nil?
+          dayArr = day.split('-')
+          if dayArr[1].length == 1
+            dayArr[1] = "0" + dayArr[1]
+          end
+          if dayArr[2].length == 1
+            dayArr[2] = "0" + dayArr[2]
+          end
+          day = dayArr.join('-')
+          end
+          #如果不是當天，則需要加後綴
+          if !day.nil? && !day.strip.blank? && day != Time.now.strftime("%Y-%m-%d")
+            File.join(Rails.root, "log", "#{Rails.env}.log.#{day.gsub('-','')}")
+          else
             File.join(Rails.root, "log", "#{Rails.env}.log")
           end
+        end
 
         #替換換行符
         def parse(log)
           ERB::Util.html_escape(log.gsub(/\e\[[\d;m]+/, '')).gsub("\n", "<br/>")
         end
+
+        #定义响应正则表达式 2015-01-20 11:31:13 INFO -- Completed 200 OK in 125ms (Views: 81.0ms | ActiveRecord: 2.0ms)
+        def response_regex
+          'Completed \d+ \w+ in (\d+)ms \(Views: (\d+\.\d+)?ms \| ActiveRecord: (\d+\.\d+)?ms\)'
+        end
+
+        #将一条记录中的地址主机等都分析出来
+        def get_status(paragraph)
+          request_regex = 'Started GET \"(\/.*)\" for ([\d]+\.[\d]+\.[\d]+\.[\d]+) at [\d]*-([\d]*-[\d]* [\d]*:[\d]*:[\d]*)'
+          controller_regex = 'Processing by ([\w]+#[\w]+)'
+          page_time_regex = 'Views: \d+(\.\d+)?ms'
+          activeRecord_time_regex = 'ActiveRecord: \d+(\.\d+)?ms'
+
+          if paragraph.match(request_regex) != nil
+            request_url = paragraph.match(request_regex)[1] #正则表达式中的括号能够截取成数组
+            request_host = paragraph.match(request_regex)[2]
+            request_at =  paragraph.match(request_regex)[3]
+          end
+
+          if paragraph.match(controller_regex) != nil
+            controller_name = paragraph.match(controller_regex)[1]
+          end
+
+          if paragraph.match(response_regex) != nil
+            #print(paragraph.match(response_regex))
+            total_time = paragraph.match(response_regex)[1]
+            page_time = paragraph.match(response_regex)[2]
+            activeRecord_time = paragraph.match(response_regex)[3]
+            page_time_percent = page_time.to_f/(total_time.to_f)
+            activeRecord_time_percent = activeRecord_time.to_f/(total_time.to_f)
+          else
+          end
+          request_status = [request_url, request_host, request_at,
+                            controller_name, total_time,page_time,page_time_percent,activeRecord_time,activeRecord_time_percent]
+          request_status
+        end
+
+        #分析日志
+        public
+        def analysis day
+          csv = Array.new
+          #如果文件不存在，则直接返回空数组
+          if File::exists?(logfile_path day)
+           File.open(logfile_path(day), "r:utf-8") do |file|
+              paragraph = ""
+              begin_flag = false
+              # 对每一行进行判断
+              file.each do |line|
+                # 以"Started GET "开头为一个paragraph
+                #print(line.match('[\d]*-([\d]*-[\d]* [\d]*:[\d]*:[\d]*) INFO -- Started GET ') == nil)
+                if (line.match('[\d]*-([\d]*-[\d]* [\d]*:[\d]*:[\d]*) \w+ -- Started GET ') != nil)
+                  if !begin_flag
+                    begin_flag = true
+                    paragraph.concat(line)
+                  else
+                    # 另一个paragraph的开头
+                    if (paragraph.match(response_regex) != nil)
+                        csv << get_status(paragraph)
+                    end
+                    begin_flag = true
+                    paragraph = line
+                  end
+                else
+                  if begin_flag
+                    paragraph.concat(line)
+                  else
+                  end
+                end
+              end
+           end
+          end
+          csv
+        end
       end
     end
   end