Getting Started

Last updated: 2020-12-21 10:35:08

    Download and Installation

    Relevant resources

    • Download the COS XML SDK resources for Node.js here.
    • Download the XML SDK for Node.js here.
    • Download the demo here.
    • Find the complete sample code here.
    • For the SDK changelog, please see Changelog.

    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.

    Note:

    For the definitions of parameters such as SecretId, SecretKey, and Bucket, please see COS 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.

    var COS = require('cos-nodejs-sdk-v5');
    var cos = new COS({
        SecretId: 'COS_SECRETID',
        SecretKey: 'COS_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
                    XCosSecurityToken: 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 parameter description

    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 time 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 the getService method 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 descriptions (using method 1)

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

    getAuthorization function parameters:

    Parameter Description Type
    options Parameter object necessary for getting a temporary key 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, please see Regions and Access Endpoints 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 Yes
    XCosSecurityToken sessionToken of the obtained temporary key, which corresponds to the x-cos-security-token field in the header String No
    StartTime Key acquisition start time measured in seconds, i.e., the timestamp of the key acquisition time, such as 1580000000. This parameter is used as the signature start time. Passing in this parameter can avoid signature expiration issues due to time deviation on the frontend
    ExpiredTime expiredTime of the obtained temporary key measured in seconds, i.e., the timeout timestamp, such as 1580000900 String No

    getAuthorization callback function description (using method 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 Object key (object name), which is the unique identifier of the object in the bucket. For more information, please see Object Overview String
    - Query Query parameter object of the current request in the format of {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:
    Format 1. An Authorization string.
    Format 2. An object whose attributes are listed as follows:

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

    Getting 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 by this callback for signature calculation within the instance during each request.

    Creating bucket

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

    Querying bucket list

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

    Uploading object

    This API is used to upload small files. For large files, please use the multipart upload API. For more information, please see Object Operations.

    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);
    });

    Querying object list

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

    Downloading 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);
    });

    Deleting object

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

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