Overview

Node.js SDK provides APIs for getting object URLs and pre-signed request URLs. For details, see the descriptions and samples below.

Signature Calculation

In all COS XML API requests, the authentication credential Authorization is required for all operations on private resources for COS to determine whether a request is valid.

There are two ways to use the authentication credential:

1. Put it in the header parameter; field name: authorization.
2. Put it in the URL parameter; field name: sign.

The COS.getAuthorization method is used to calculate the authentication credential (Authorization), which is the signing information used to verify the request validity.

Note：

It is recommended that this method is only used for frontend debugging but not in actual projects, as it may disclose keys.

Use case

Obtaining the authentication credential for file download:

// Log in to the [CAM console](https://console.cloud.tencent.com/cam/capi) to check and manage the `SecretId` and `SecretKey` of your project.
var COS = require('cos-nodejs-sdk-v5');
var Authorization = COS.getAuthorization({
   SecretId: 'SECRETID',
   SecretKey: 'SECRETKEY',
   Method: 'get',
   Key: 'a.jpg',
   Expires: 60,
   Query: {},
   Headers: {}
});

Parameter description

Returned value

The returned value is the calculated authentication credential string authorization.

Getting a Pre-signed Request URL

Samples for download requests

Sample 1. Get an unsigned object URL

var url = cos.getObjectUrl({
   Bucket: 'examplebucket-1250000000',
   Region: 'COS_REGION',
   Key: '1.jpg',
   Sign: false
});

Sample 2. Get a signed object URL

var url = cos.getObjectUrl({
   Bucket: 'examplebucket-1250000000',
   Region: 'COS_REGION',
   Key: '1.jpg'
});

Sample 3. If the signing process is asynchronous, you need to get the signed URL through a callback

cos.getObjectUrl({
   Bucket: 'examplebucket-1250000000',
   Region: 'COS_REGION',
   Key: '1.jpg',
   Sign: false
}, function (err, data) {
   console.log(err || data.Url);
});

Sample 4. Specify the validity period of a link

cos.getObjectUrl({
   Bucket: 'examplebucket-1250000000',
   Region: 'COS_REGION',
   Key: '1.jpg',
   Sign: true,
   Expires: 3600, // Unit: second
}, function (err, data) {
   console.log(err || data.Url);
});

Sample 5. Get the file URL and download the file

var request = require('request');
var fs = require('fs');
cos.getObjectUrl({
   Bucket: 'examplebucket-1250000000',
   Region: 'COS_REGION',
   Key: '1.jpg',
   Sign: true
}, function (err, data) {
   if (err) return console.log(err);
   console.log(data.Url);
   var req = request(data.Url, function (err, response, body) {
       console.log(err || body);
   });
   var writeStream = fs.createWriteStream(__dirname + '/1.jpg');
   req.pipe(writeStream);
});

Samples for upload requests

Sample 1. Get a pre-signed URL for Put Object upload

var request = require('request');
var fs = require('fs');
cos.getObjectUrl({
   Bucket: 'examplebucket-1250000000',
   Region: 'COS_REGION',
   Method: 'PUT',
   Key: '1.jpg',
   Sign: true
}, function (err, data) {
   if (err) return console.log(err);
   console.log(data.Url);
   var readStream = fs.createReadStream(__dirname + '/1.jpg');
   var req = request({
       method: 'PUT',
       url: data.Url,
   }, function (err, response, body) {
       console.log(err || body);
   });
   readStream.pipe(req);
});

Parameter description

Returned value description

A string is returned in one of the two ways:

1. If the signature can be calculated synchronously (for example, the SecretId and SecretKey have been passed in during instantiation), the signed URL will be returned by default.
2. Otherwise, an unsigned URL will be returned.

Callback function description

function(err, data) { ... }