在 Node.js 中使用 POST 请求上传文件

小开

最佳答案

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.

小开

Leonid Beschastny's answer works but I also had to convert ArrayBuffer to Buffer that is used in the Node's request module. After uploading file to the server I had it in the same format that comes from the HTML5 FileAPI (I'm using Meteor). Full code below - maybe it will be helpful for others.

function toBuffer(ab) {
var buffer = new Buffer(ab.byteLength);
var view = new Uint8Array(ab);
for (var i = 0; i < buffer.length; ++i) {
buffer[i] = view[i];
}
return buffer;
}


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', toBuffer(file.data), {
filename: file.name,
contentType: file.type
});

小开

You can also use the "custom options" support from the request library. This format allows you to create a multi-part form upload, but with a combined entry for both the file and extra form information, like filename or content-type. I have found that some libraries expect to receive file uploads using this format, specifically libraries like multer.

This approach is officially documented in the forms section of the request docs - https://github.com/request/request#forms

//toUpload is the name of the input file: <input type="file" name="toUpload">


let fileToUpload = req.file;


let formData = {
toUpload: {
value: fs.createReadStream(path.join(__dirname, '..', '..','upload', fileToUpload.filename)),
options: {
filename: fileToUpload.originalname,
contentType: fileToUpload.mimeType
}
}
};
let options = {
url: url,
method: 'POST',
formData: formData
}
request(options, function (err, resp, body) {
if (err)
cb(err);


if (!err && resp.statusCode == 200) {
cb(null, body);
}
});

小开

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.

小开

 const remoteReq = request({
method: 'POST',
uri: 'http://host.com/api/upload',
headers: {
'Authorization': 'Bearer ' + req.query.token,
'Content-Type': req.headers['content-type'] || 'multipart/form-data;'
}
})
req.pipe(remoteReq);
remoteReq.pipe(res);

小开

I did it like this:

// Open file as a readable stream
const fileStream = fs.createReadStream('./my-file.ext');


const form = new FormData();
// Pass file stream directly to form
form.append('my file', fileStream, 'my-file.ext');