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《Nodejs入门》一书确实很好的入门工具书，不过其中的一些代码还是和我们的实际开发环境不同。比如该书中的最后一个例子，上传图片到服务器。

\n\n

其中存在的问题的一部分源代码如下（处理上传文件）：

\n\n

Js代码

\n\n

function upload( res, req){  \n    console.log(\"request upload mehtod\");  \n    var form = new formidable.IncomingForm();  \n    form.parse( req, function( error, fields, files){     \n        fs.renameSync(files.upload.path, \"tmp/\"+filename+\".png\");   \n        res.writeHead(200,{\"Content-Type\":\"text/html\"});  \n        res.write(\"<img src='/show'/>\");   //发送/show请求  \n        res.end();  \n    });  \n}  \n

\n\n

这里用到了formidable第三方模块，上面的代码总是报错“can not find File or Directory: c:\\......”;\n原因是formidable默认上传文件的保存路径与项目路径不在同一相同路径中。如我的工程是在e盘。所以需要设置form.uploadDir = \"tmp\";//指向工程中的tmp文件夹

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另外，fs.renameSync()保存文件会抛出异常，为了能让程序正常运行，这里需要添加try{}catch(e){}

\n\n

如果我们像上传图片的同时，想在前台的一个输入框内设置一下名称，后台通过formidable如何获取这个字段的值呢？

\n\n

Js代码

\n\n

...  \nform.parse(req, function(error, fields, files){  \n\n    //filename为<input>标签中name属相的值  \n    var filename = fields[\"filename\"];    \n\n     ...  \n\n});  \n...  \n

\n\n

综上所述下面是upload方法完整的代码：

\n\n

Js代码

\n\n

function upload( res, req){  \n    console.log(\"request upload mehtod\");  \n\n    var form = new formidable.IncomingForm();  \n    form.uploadDir = \"tmp\"; \n    form.parse( req, function( error, fields, files){  \n        console.log(\"parsing done\");  \n        var filename = fields['filename'];  \n        console.log(\"filename = \" + filename);  \n\n       try{  \n            fs.renameSync(files.upload.path, \"tmp/\"+filename+\".png\");  \n        }catch( e){  \n            console.log(e);  \n        }\n        res.writeHead(200,{\"Content-Type\":\"text/html\"});  \n        res.write(\"<img src='/show'/>\");   //发送/show请求  \n        res.end();  \n    });  \n}  \n

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