transfer files between two node.js servers over ht

问题:

I have two node.js/express servers that communicate with each other with http. server A is also communicates with the browser and can handle file upload requests. When file is uploaded to server A i want to transfer it as is to server B for further processing. what is the best way to do so? preferably with request-promise module which is what i'm using for communication between the two servers.

This is what i got so far, but i am unable to transfer the file between the servers, the file is uploaded successfully to server A, and there is no Error while sending it to server B, but server B is doesn't recognise the request as file. what am i missing here?

Server A Routes:

'use strict';

// Routes

 const express = require('express');
 const router = express.Router();
 const multer = require('multer');
 const upload = multer();

 const uploadController = require('./controllers/file/upload');

 router.post('/upload',upload.single('file'),uploadController); 

 module.exports = router;

Server A uploadController:

'use strict';

const RP = require('request-promise');

module.exports = (req, res) => {

  const body = req.body;

  if(req.file) {

    const file = req.file;

    RP('http://serverB.net/process', { 
      method: 'POST',
      formData: {file_buffer: file.buffer},
      body: body
    })
    .then((response) => {
      return res.status(200).send(response);
    })
    .catch((e) => {
      return res.status(500).send(e.message);
    })
  }
  else {
     return res.status(500).send('unable to upload file');
  }
};

Server B Routes:

'use strict';

// Routes

 const express = require('express');
 const router = express.Router();
 const multer = require('multer');
 const process = multer();

 const processFile = require('./controllers/file/processFile');

 router.post('/process', process.single('file'), processFile); 

 module.exports = router;

Server B processFile:

here i want to process the file from Server A but req.file is undefined

'use strict';

module.exports = (req, res) => {

  if(req.file) {
  // here i want to do something with the file.
  }

};

回答1:

The encoding that you are using so send the file may not be multipart/form-data. Try setting that header in your file send request. Express req.files will only be populated with a multipart/form-data Express req.files will only be populated with a multipart/form-data . You're already using multer so I'm guessing the sending encoding is not quite right.

RP({
    method: "POST",
    uri: "serverB.net",
    form: {
        file: file.buffer
    },
    headers: {
        "Content-Type": "multipart/form-data"
    }
});

回答2:

router.post('/process', process.single('file'), processFile);

This line, specifically process.single('file') tells multer to look for a field file which will contain the actual file data. However, in your request you never specify a value for file. Change the name file_buffer to just file in your request. Or change your process.single() to process.single('file_buffer')

RP('http://serverB.net/process', { 
  method: 'POST',
  formData: {
    file: file.buffer,
    body: body
  }
})
.then((response) => {
  return res.status(200).send(response);
})
.catch((e) => {
  return res.status(500).send(e.message);
})

Now on Server B, inside processFile you should see a req.body with a field body that contains your entire body passed in your request and you should have a req.file now that contains your multer file object.