How to deal with the error reported when Node.js calls fs.renameSync (Error: EXDEV, cross-device link not permitted)-JS Tutorial-php.cn

How to deal with the error reported when Node.js calls fs.renameSync (Error: EXDEV, cross-device link not permitted)

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Release： 2017-12-27 13:43:32

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This article mainly introduces the error reported when Node.js calls fs.renameSync (Error: EXDEV, cross-device link not permitted). It is of great practical value. Friends who need it can refer to it. I hope it can help everyone.

When writing a file upload function, there is an error in calling the fs.renameSync method

The error code is as follows:

 function upload(response,request){
 console.log("upload called");
 var form = new formidable.IncomingForm();
 console.log("about to parse");
 form.parse(request, function(error, fields, files) {
  console.log("parsing done");
  fs.renameSync(files.upload.path, "./tmp/test.jpg");
  response.writeHead(200, {"Content-Type": "text/html"});
  response.write("received image:<br/>");
  response.write("<img src=&#39;/show&#39; />");
  response.end();
 });
 }

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Brief analysis Finally, it is expected that there will be permission issues when moving or operating files across disk partitions.

Two solutions are provided below:

Method 1:

Mainly use the createReadStream, createWriteSream and unlinkSync methods of fs

The specific code is as follows:

 function upload(response,request){
 console.log("upload called");
 var form = new formidable.IncomingForm();
 console.log("about to parse");
 form.parse(request, function(error, fields, files) {
  console.log("parsing done");

 // fs.renameSync(files.upload.path, "./tmp/test.jpg");
  var readStream=fs.createReadStream(files.upload.path);
  var writeStream=fs.createWriteStream("./tmp/test.jpg");
  readStream.pipe(writeStream);
  readStream.on(&#39;end&#39;,function(){
  fs.unlinkSync(files.upload.path);
  });

  response.writeHead(200, {"Content-Type": "text/html"});
  response.write("received image:<br/>");
  response.write("<img src=&#39;/show&#39; />");
  response.end();
 });
 }

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PS: The node version I use is 0.10.69. If you are using a version below 0.6, you can use util .pump

The corresponding code only needs to change the readStream.on in the above code to: (note the introduction of the util module)

util.pump(readStream,writeStream, function() {
 fs.unlinkSync(&#39;files.upload.path&#39;);
});

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method Two:

This is much simpler

Just add a form.uploadDir='tmp' (write a temporary path)

 function upload(response,request){
 console.log("upload called");
 var form = new formidable.IncomingForm();
 form.uploadDir=&#39;tmp&#39;;
 console.log("about to parse");
 form.parse(request, function(error, fields, files) {
  console.log("parsing done");
  fs.renameSync(files.upload.path, "./tmp/test.jpg");
  response.writeHead(, {"Content-Type": "text/html"});
  response.write("received image:<br/>");
  response.write("<img src=&#39;/show&#39; />");
  response.end();
 });
 }

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Related recommendations:

Instructions for using the fs.renameSync method in node.js_node.js

Detailed explanation of node .js uses websocket based on express

How to use the async function in Node.js

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