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asp.net中js合并，压缩

2018年10月27日  | 移动技术网IT编程  | 我要评论

紧接着上一篇文章js文件 合并 压缩 去掉重复引用 缓存 延迟加载来说，遗留了一个很大的问题那就是js文本怎么合并与压缩了，上一篇文章中的

[csharp]
public static void appendjsfile(this htmlhelper htmlhelper, string jsfile, int group = 1) 
      public static mhtmlstring renderjsfile(this htmlhelper htmlhelper) 
都只限于mvc中使用，我们能不能搞一个更通用的东东了，答案是肯定的。
先说说思路吧，其实很简单 就是我们自己接管输出流，如何接管了？在global.asax文件中添加以下代码：

[csharp]
public override void init() 
      { 
          base.init(); 
          this.releaserequeststate += new eventhandler(installresponsefilter); 
      } 
      private void installresponsefilter(object sender, eventargs e) 
      { 
          httpresponse response = httpcontext.current.response; 
 
          if (response.contenttype == "text/html") 
              response.filter = new pagefilter(response.filter); 
      } 
我还是沿用先前的项目做demo吧

\

和我们平时的开发没有任何区别，但是返回结果却是如下

\
我们看到js文件和js文本都合并 并且也是压缩了的。

关键的一切还是pagefilter的功劳啊

代码如下：

[html]
public class pagefilter : stream 
   { 
       stream responsestream; 
       long position; 
       stringbuilder responsehtml; 
 
       public pagefilter(stream inputstream) 
       { 
           responsestream = inputstream; 
           responsehtml = new stringbuilder(); 
       } 
 
       #region filter overrides 
       public override bool canread 
       { 
           get { return true; } 
       } 
 
       public override bool canseek 
       { 
           get { return true; } 
       } 
 
       public override bool canwrite 
       { 
           get { return true; } 
       } 
 
       public override void close() 
       { 
           responsestream.close(); 
       } 
 
       public override void flush() 
       { 
           responsestream.flush(); 
       } 
 
       public override long length 
       { 
           get { return 0; } 
       } 
 
       public override long position 
       { 
           get { return position; } 
           set { position = value; } 
       } 
 
       public override long seek(long offset, seekorigin origin) 
       { 
           return responsestream.seek(offset, origin); 
       } 
 
       public override void setlength(long length) 
       { 
           responsestream.setlength(length); 
       } 
 
       public override int read(byte[] buffer, int offset, int count) 
       { 
           return responsestream.read(buffer, offset, count); 
       } 
       #endregion 
 
       #region dirty work 
       public override void write(byte[] buffer, int offset, int count) 
       { 
           httpresponse response = httpcontext.current.response; 
           string charset = response.charset ?? "utf-8"; 
           string strbuffer = encoding.getencoding(charset).getstring(buffer, offset, count); 
          
 
           int bodyindex = strbuffer.tolower().lastindexof("</body>"); 
             //js文本 
           regex reg = new regex("<script[^>]*>(?<content>[^<]*)</script>",regexoptions.ignorecase|regexoptions.multiline); 
           //js引用 
           regex regsrc = new regex("src=\"?(?<src>[^'\">]*)\"?",regexoptions.ignorecase|regexoptions.multiline); 
           stringbuilder jscontent = new stringbuilder(); 
           list<string> jssrc = new list<string>(); 
 
           matchcollection mc = reg.matches(strbuffer); 
 
           if (mc.count > 0) 
           { 
               #region 找出js部分 
 
               foreach (match m in mc) 
               { 
                   string str = m.groups["content"].value; 
                   if (!string.isnullorempty(str)) 
                   { 
                       jscontent.appendline(str);//找出js文本 
                   } 
                   else 
                   { 
                       //找出js引用 
                       match msrc = regsrc.match(m.value); 
                       if (msrc != null && msrc.success) 
                       { 
                           string temp = msrc.groups["src"].value; 
                           if (!jssrc.contains(temp)) 
                               jssrc.add(temp); 
                       } 
                   } 
               } 
               #endregion 
 
               strbuffer = reg.replace(strbuffer, string.empty); 
               if (bodyindex < 0) 
               { 
                   //html 文档还没有结束 
                   mergerjs(jscontent, jssrc); 
               } 
               else 
               { 
                   #region 带结束标签的html 
                   mergerjs(jscontent, jssrc); 
                   //生成新的js引用 
                   string jsfileformat = "<script type=\"text/javascript\" src=\"{0}\"></script>"; 
                   string jshref = string.format(jsfileformat, "=" + string.join(",", jssrc)); 
                   //生成新的js文本 
                   string jstextformat = "<script type=\"text/javascript\">{0}</script>"; 
                   //压缩js文本 
                   string jscontentstr = javascriptcompressor.compress(jscontent.tostring()); 
                   string jstext = string.format(jstextformat, jscontentstr); 
                   //插入新生成的js 
                   bodyindex = strbuffer.tolower().lastindexof("</body>"); 
                   strbuffer = strbuffer.insert(bodyindex, jshref + environment.newline + jstext);             
                   #endregion 
               } 
               byte[] data = encoding.getencoding(charset).getbytes(strbuffer); 
               responsestream.write(data, 0, data.length); 
           } 
           else { 
               responsestream.write(buffer, offset, count); 
           } 
         
 
       } 
       void mergerjs(stringbuilder jscontent, list<string> jssrc) 
       { 
           string jstextkey = "jstextkey"; 
           string jsfilekey = "jsfilekey"; 
           if (!httpcontext.current.items.contains(jstextkey)) 
               httpcontext.current.items.add(jstextkey, jscontent); 
           else 
           { 
               stringbuilder jstexttemp = httpcontext.current.items[jstextkey] as stringbuilder; 
               jscontent.insert(0, jstexttemp.tostring()); 
           } 
           if (!httpcontext.current.items.contains(jsfilekey)) 
               httpcontext.current.items.add(jsfilekey, jssrc); 
           else 
           { 
               list<string> jsfiletemp = httpcontext.current.items[jstextkey] as list<string>; 
               jssrc.insertrange(0, jsfiletemp); 
           } 
       } 
       #endregion 
   } 
说了这么多，这里只是提供一个思想，一个js合并的思想，在真实的项目中还有很多细节需要注意啊。

 

摘自 dz45693的专栏

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