Getting Started

Download and Installation

Relevant Resources

• The COS XML SDK for JS source code can be downloaded here.
• The demo can be downloaded here.

Environmental Dependency

1. To use the SDK, your operating environment should have Node.js and npm.
2. Log in to the COS Console, create a bucket, and get the bucket name and region name.
3. Log in to the CAM Console and get your project's SecretId and SecretKey.

For more information on the meanings of parameters such as SecretId, SecretKey, and Bucket contained herein and how to get them, see COS Glossary.

Installing the SDK

Install the SDK via npm which can be downloaded here.

npm i cos-nodejs-sdk-v5 --save

Getting Started

Initialization

Initializing with a Permanent Key

Replace the SecretId, SecretKey, bucket, and region with actual values in your development environment. To test file upload, see the following sample code.

var COS = require('cos-nodejs-sdk-v5');
var cos = new COS({
    SecretId: 'COS_SECRETID',
    SecretKey: 'COS_SECRETKEY'
});

Initializing with a Temporary Key

For more information on how to generate and use a temporary key, see Temporary Key Generation and Usage Guide. The SDK for Node.js supports initialization by passing in a temporary key as shown in the sample code below:

var request = require('request');
var cos = new COS({
    getAuthorization: function (options, callback) {
        // Get a temporary key asynchronously
        request({
            url: '../server/sts.php',
            data: {
                // The required parameters can be obtained from options
            }
        }, function (err, response, body) {
            try {
                var data = JSON.parse(body);
                var credentials = data.credentials;
            } catch(e) {}
            callback({
                    TmpSecretId: credentials.tmpSecretId,
                    TmpSecretKey: credentials.tmpSecretKey,
                    XCosSecurityToken: credentials.sessionToken,
                    ExpiredTime: data.expiredTime,
            });
        });
    }
});

Below are some samples of commonly used APIs. For more detailed initialization methods, see the samples in the demo.

Configuration Items

Constructor Parameter Descriptions

getAuthorization Callback Function Descriptions (Using Method 1)

getAuthorization: function(options, callback) { ... }

getAuthorization callback parameter descriptions

After the temporary key is obtained, the callback returns an object. The attributes of the returned object are as shown below:

getAuthorization Callback Function Descriptions (Using Method 2)

getAuthorization: function(options, callback) { ... }

getAuthorization function callback parameter descriptions

After the getAuthorization calculation is completed, the callback returns a signature string or an object:
If a signature string is returned, the string type is the credential field "Authorization" to be used by the authentication header of the request.
If an object is returned, the attributes of the object are as shown below:

Getting an Authentication Credential

You have three ways to obtain the authentication credentials for your instance by passing in different parameters during instantiation:

1. During instantiation, pass in the SecretId and SecretKey, and each time a signature is required, it will be internally calculated by the instance.
2. During instantiation, pass in the getAuthorization callback, and each time a signature is required, it will be calculated and returned to the instance through this callback.
3. During instantiation, pass in the getSTS callback, and each time a temporary key is required, it will be returned to the instance by this callback for signature calculation within the instance during each request.

Creating a Bucket

cos.putBucket({
    Bucket: 'examplebucket-1250000000',
    Region: 'ap-beijing',
}, function (err, data) {
    console.log(err || data);
});

Querying Bucket List

cos.getService(function (err, data) {
    console.log(data && data.Buckets);
});

Uploading an Object

This API is suitable for uploading small files. For large files, use the multipart upload API. For more information, see Object Operations.

cos.putObject({
    Bucket: 'examplebucket-1250000000',
    Region: 'ap-beijing',
    Key: 'destination path/picture.jpg',
    Body: fs.createReadStream('./picture.jpg'), // Pass in the prefix here
}, function (err, data) {
    console.log(err || data);
});

Querying Object List

cos.getBucket({
    Bucket: 'examplebucket-1250000000',
    Region: 'ap-beijing',
    Prefix: 'exampledir/', // Pass in the prefix of files to be listed here
}, function (err, data) {
    console.log(err || data.Contents);
});

Downloading an Object

cos.getObject({
    Bucket: 'examplebucket-1250000000',
    Region: 'ap-beijing',
    Key: 'exampleobject.txt',
    Output: fs.createWriteFile(__dirname + '/exampleobject.txt'),
}, function (err, data) {
    console.log(err || data.Body);
});

Deleting an Object

cos.deleteObject({
    Bucket: 'examplebucket-1250000000',
    Region: 'ap-beijing',
    Key: 'picture.jpg',
}, function (err, data) {
    console.log(err || data);
});