Download and Installation

Relevant resources

• Download the COS XML SDK resources for Node.js here.
• Fast SDK download: XML Node.js SDK.
• Download the demo here.
• For the complete sample code, please see SDK Sample Code.
• For the SDK changelog, please see Changelog.

Note：

If you encounter errors such as non-existent functions or methods when using the SDK, please update the SDK to the latest version and try again.

Environmental dependencies

1. The SDK requires your runtime environment to include Node.js (v6 or later) 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.

Note：

For the definition of parameters such as SecretId, SecretKey, and Bucket, please see COS’s Glossary.

Installing SDK

Install the SDK through npm which can be downloaded here.

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

Getting Started

Initialization

Initializing with permanent key

First, log into the CAM console, and get your SecretId and SecretKey from the Access Key page.
Replace SecretId, SecretKey, bucket, and region with the actual values in your development environment. To test file upload, please see the following sample code.

// 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 cos = new COS({
   SecretId: 'SECRETID',
   SecretKey: 'SECRETKEY'
});

Initializing with temporary key

For more information on how to generate and use a temporary key, please see Generating and Using Temporary Keys. 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 = require('cos-nodejs-sdk-v5');
var cos = new COS({
   getAuthorization: function (options, callback) {
       // Get a temporary key asynchronously.
       request({
           url: 'https://example.com/sts',
           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) {}
           if (!data || !credentials) return console.error('credentials invalid');
           callback({
               TmpSecretId: credentials.tmpSecretId, // tmpSecretId of the temporary key
               TmpSecretKey: credentials.tmpSecretKey, // tmpSecretKey of the temporary key
               SecurityToken: credentials.sessionToken, // sessionToken of the temporary key
               ExpiredTime: data.expiredTime, // Expiration timestamp of the temporary key, which is calculated by adding durationSeconds to the timestamp when applying for the temporary key 
           });
       });
   }
});

Below are some examples of common APIs. For more detailed initialization methods, please see the Demo.

Configuration items

Constructor parameters

Parameter	Description	Type	Required
SecretId	User SecretId	String	Yes
SecretKey	User SecretKey. We recommend you only use the SecretKey for frontend debugging to avoid key exposure	String	Yes
FileParallelLimit	Number of concurrent file uploads in the same instance. Default value: 3	Number	No
ChunkParallelLimit	Number of concurrent part uploads for the same uploaded file. Default value: 3	Number	No
ChunkRetryTimes	Number of retries upon multipart upload/copy failure. Default value: 3 (a request will be made 4 times in total, including the initial one)	Number	No
ChunkSize	Part size in the multipart upload in bytes. Default value: 1048576 (1 MB)	Number	No
SliceSize	When files are uploaded in batches using uploadFiles, if the file size is greater than the value of this parameter (measured in bytes), multipart upload is used; otherwise, simple upload is used. Default value: 1048576 (1 MB)	Number	No
CopyChunkParallelLimit	Number of concurrent part uploads for the same multipart copy operation. Default value: 20	Number	No
CopyChunkSize	Number of bytes in each part during a multipart copy operation with sliceCopyFile. Default value: 10485760 (10 MB)	Number	No
CopySliceSize	When a file is copied using sliceCopyFile, if the file size is greater than the value of this parameter, multipart copy is used; otherwise, simple copy is used. Default value: 10485760 (10 MB)	Number	No
ProgressInterval	Callback frequency of the upload progress callback method onProgress in milliseconds. Default value: 1000	Number	No
Protocol	Protocol used when the request is made. Valid values: https:, http:. By default, http: is used when the current page is determined to be in http: format; otherwise, https: is used	String	No
ServiceDomain	The request domain name when getService is called, such as service.cos.myqcloud.com	String	No
Domain	Custom request domain name used to call a bucket or object API. You can use a template such as "{Bucket}.cos.{Region}.myqcloud.com" which will use the bucket and region information passed in the replacement parameters when an API is called.	String	No
UploadQueueSize	The maximum size of the upload queue. If the maximum is exceeded, failed, completed, and canceled tasks will be cleared. Default value: 1000	Number	No
ForcePathStyle	Forces the use of a suffix when sending requests. The suffixed bucket will be placed in the pathname after the domain name, and the bucket will be added to the signature pathname for calculation. Default value: false	Boolean	No
UploadCheckContentMd5	Forces the verification of Content-MD5 for file uploads, which calculates the MD5 checksum of the file request body and places it in the Content-MD5 field of the header. Default value: false	Boolean	No
Timeout	Timeout period in milliseconds. Default value: 0, indicating no timeout period.	Number	No
KeepAlive	Indicates that more than one request is sent over one TCP connection. Default value: true. This parameter is recommended for a large number of concurrent requests.	Boolean	No
StrictSsl	Strict verification of the HTTPS certificate. Default value: true	Boolean	No
Proxy	Uses an HTTP proxy when making requests, such as: http://127.0.0.1:8080	String	No
getAuthorization	Callback method for getting the signature. If there is no SecretId or SecretKey, this parameter is required	Function	No

getAuthorization Callback function description (Format 1)

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

getAuthorization function parameters:

Parameter	Description	Type
options	Required for getting the signature	Object
- Bucket	Bucket name in the format of BucketName-APPID. The bucket name entered here must be in this format	String
- Region	Bucket region. For the enumerated values, see Regions and Access Domain Names.	String
callback	Callback method after the temporary key is obtained	Function

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

Attribute	Description	Type	Required
TmpSecretId	tmpSecretId of the obtained temporary key	String	Yes
TmpSecretKey	tmpSecretKey of the obtained temporary key	String	No
SecurityToken	sessionToken of the obtained temporary key, which corresponds to the x-cos-security-token field in the header	String	Yes
StartTime	The timestamp in seconds of when you obtained the key, such as 1580000000. Passing in this parameter as the signature start time can avoid signature expiration issues due to time deviation on the frontend.	String	No
ExpiredTime	expiredTime of the obtained temporary key measured in seconds, i.e., the timeout timestamp, such as 1580000900	String	Yes

getAuthorization Callback function description (Format 2)

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

getAuthorization function parameters:

Parameter	Description	Type
options	Parameter object necessary for getting the signature	Object
- Method	Method of the current request	String
- Pathname	Request path used for signature calculation	String
- Key	ObjectKey (object name) is the unique ID of an object in a bucket. For more information, see Object Overview.	String
- Query	Query parameter in the current request. Format: {key: 'val'}	Object
- Headers	Headers in the current request. Format: {key: 'val'}	Object
callback	Callback after the temporary key is obtained	Function

Once the getAuthorization callback function is finished, it returns one of the following:
An Authorization string.
An object whose attributes are listed as follows:

Attribute	Description	Type	Required
Authorization	Calculated signature string	String	Yes
SecurityToken	sessionToken of the obtained temporary key, which corresponds to the x-cos-security-token field in the header	String	No

Getting an authentication credential

There are three ways to get the authentication credentials for your instance by passing in different parameters during instantiation:

1. During instantiation, pass in your 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 function, 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 for signature calculation within the instance during each request.

Creating a bucket

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

Querying the bucket list

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

Uploading an object

This API is used to upload small files. For large files, please use the multipart upload API. For more information, see Actions on Objects.

cos.putObject({
   Bucket: 'examplebucket-1250000000', /* Required */
   Region: 'COS_REGION',    /* Required */
   Key: 'exampleobject', /* Required */
   StorageClass: 'STANDARD',
   Body: fs.createReadStream('./exampleobject'), // Uploading file object
   onProgress: function(progressData) {
       console.log(JSON.stringify(progressData));
   }
}, function(err, data) {
   console.log(err || data);
});

Query objects

cos.getBucket({
   Bucket: 'examplebucket-1250000000', /* Required */
   Region: 'COS_REGION', /* Required */
   Prefix: 'a/', /*Optional*/
}, function(err, data) {
   console.log(err || data.Contents);
});

Download an object

cos.getObject({
   Bucket: 'examplebucket-1250000000', /* Required */
   Region: 'COS_REGION',    /* Required */
   Key: 'exampleobject', /* Required */
   Output: fs.createWriteStream('./exampleobject'),
}, function(err, data) {
   console.log(err || data);
});

Delete an object

cos.deleteObject({
   Bucket: 'examplebucket-1250000000', /* Required */
   Region: 'COS_REGION',    /* Required */
   Key: 'exampleobject'       /* Required */
}, function(err, data) {
   console.log(err || data);
});