Uploading file using POST request in Node.js

Question

I have problem uploading file using POST request in Node.js. I have to use request module to accomplish that (no external npms). Server needs it to be multipart request with the file field containing file's data. What seems to be easy it's pretty hard to do in Node.js without using any external module.

I've tried using this example but without success:

request.post({   uri: url,   method: 'POST',   multipart: [{     body: '<FILE_DATA>'   }] }, function (err, resp, body) {   if (err) {     console.log('Error!');   } else {     console.log('URL: ' + body);   } }); 

Answer 1

Looks like you're already using request module.

in this case all you need to post multipart/form-data is to use its form feature:

var req = request.post(url, function (err, resp, body) {   if (err) {     console.log('Error!');   } else {     console.log('URL: ' + body);   } }); var form = req.form(); form.append('file', '<FILE_DATA>', {   filename: 'myfile.txt',   contentType: 'text/plain' }); 

but if you want to post some existing file from your file system, then you may simply pass it as a readable stream:

form.append('file', fs.createReadStream(filepath)); 

request will extract all related metadata by itself.

For more information on posting multipart/form-data see node-form-data module, which is internally used by request.

Answer 2

An undocumented feature of the formData field that request implements is the ability to pass options to the form-data module it uses:

request({   url: 'http://example.com',   method: 'POST',   formData: {     'regularField': 'someValue',     'regularFile': someFileStream,     'customBufferFile': {       value: fileBufferData,       options: {         filename: 'myfile.bin'       }     }   } }, handleResponse); 

This is useful if you need to avoid calling requestObj.form() but need to upload a buffer as a file. The form-data module also accepts contentType (the MIME type) and knownLength options.

This change was added in October 2014 (so 2 months after this question was asked), so it should be safe to use now (in 2017+). This equates to version v2.46.0 or above of request.