Download and Installation

Relevant resources

• Download the COS XML SDK source code for WeChat Mini Programs here.
• SDK quick download address: XML Mini Program SDK.
• Download the demo here.

Environmental dependency

1. This SDK is only applicable to WeChat Mini Programs.
2. Log in to the COS Console, create a bucket, and get the bucket name and region information.
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’s Glossary.

Installing the SDK

There are two ways to install the SDK for WeChat Mini Programs: manual installation and installation through npm as detailed below.

Installing manually

Copy the cos-wx-sdk-v5.js file in the source code directory to any path in the root directory of your WeChat Mini Program code and reference it using a relative path:

var COS = require('./lib/cos-wx-sdk-v5.js')

Installing through npm

If the code of your WeChat Mini Program is packaged using webpack, install the dependencies via npm:

npm install cos-wx-sdk-v5

The WeChat Mini Program code is referenced with var COS = require('cos-wx-sdk-v5');.

Getting Started

Configuring domain name whitelist for WeChat Mini Programs

To request COS in your WeChat Mini Program, you need to log in to the WeChat Official Accounts Platform and configure the domain name whitelist in Development > Basic Configuration. The SDK uses the following two APIs:

1. For cos.postObject, use the wx.uploadFile API.
2. For other methods, use the wx.request API.

For both methods, you need to configure the COS domain name. There are two forms of domain name whitelists.

1. For standard requests, you can configure the bucket domain name as the whitelist domain name, for example:
   examplebucket-1250000000.cos.ap-guangzhou.myqcloud.com.
2. If multiple buckets are used in your WeChat Mini Program, you can choose to use suffixed COS requests by passing in ForcePathStyle: true when instantiating the SDK. In this case, you need to configure the region domain name as the whitelisted domain name, such as cos.ap-guangzhou.myqcloud.com.

Initialization

var COS = require('./lib/cos-wx-sdk-v5.js')

var cos = new COS({
    // ForcePathStyle: true, // If multiple buckets are used, you can use suffixed requests to reduce the number of whitelisted domain names to be configured; the region domain name will be used for requests
    getAuthorization: function (options, callback) {
        // Get a temporary key asynchronously
        wx.request({
            url: 'https://example.com/server/sts.php',
            data: {
                bucket: options.Bucket,
                region: options.Region,
            },
            dataType: 'json',
            success: function (result) {
                var data = result.data;
                var credentials = data && data.credentials;
                if (!data || !credentials) return console.error('credentials invalid');
                callback({
                    TmpSecretId: credentials.tmpSecretId,
                    TmpSecretKey: credentials.tmpSecretKey,
                    XCosSecurityToken: credentials.sessionToken,
                    // We recommend using the time the server receives the credentials as the StartTime, so as to avoid signature error due to time deviations. 
                    StartTime: data.startTime, // Timestamp in seconds, such as 1580000000
                    ExpiredTime: data.expiredTime, // Timestamp in seconds, such as 1580000900
                });
            }
        });
    }
});

// The COS instance can then be used to call a COS request
// TODO

Configuration Items

Use cases

Create a COS SDK instance in the following methods:

• Method 1 (recommended). The backend gets a temporary key and sends it to the frontend for signature calculation.

var cos = new COS({
    // Required parameters
    getAuthorization: function (options, callback) {
        // Server examples for JS and PHP: https://github.com/tencentyun/cos-js-sdk-v5/blob/master/server/
        // For server examples for other programming languages, please see the [COS SDK for STS](https://github.com/tencentyun/qcloud-cos-sts-sdk)
        // For the STS documentation, please visit https://intl.cloud.tencent.com/document/product/436/14048
        wx.request({
            url: 'https://example.com/server/sts.php',
            data: {
                // You can obtain the required parameters from options
            },
            success: function (result) {
                var data = result.data;
                var credentials = data && data.credentials;
                if (!data || !credentials) return console.error('credentials invalid');
                callback({
                    TmpSecretId: credentials.tmpSecretId,
                    TmpSecretKey: credentials.tmpSecretKey,
                    XCosSecurityToken: credentials.sessionToken,
                    // We recommend using the time the server receives the credentials as the StartTime, so as to avoid signature error due to time deviations. 
                    StartTime: data.startTime, // Timestamp in seconds, such as 1580000000
                    ExpiredTime: data.expiredTime, // Timestamp in seconds, such as 1580000900
                });
            }
        });
    }
});

Note：

For more information on how to generate and use a temporary key, please see Generating and Using Temporary Keys.

• Method 2 (recommended). Permissions are controlled in a more refined manner. The backend gets a temporary key and sends it to the frontend. The frontend reuses the key only for the same request, and the backend can granularly manage permissions through Scope.

var cos = new COS({
    // Required parameters
    getAuthorization: function (options, callback) {
        // Server example: https://github.com/tencentyun/qcloud-cos-sts-sdk/edit/master/scope.md
        wx.request({
            url: 'https://example.com/server/sts-scope.php',
            data: JSON.stringify(options.Scope),
            success: function (result) {
                var data = result.data;
                var credentials = data && data.credentials;
                if (!data || !credentials) return console.error('credentials invalid');
                callback({
                    TmpSecretId: credentials.tmpSecretId,
                    TmpSecretKey: credentials.tmpSecretKey,
                    XCosSecurityToken: credentials.sessionToken,
                    // We recommend using the time the server receives the credentials as the StartTime, so as to avoid signature error due to time deviations. 
                    StartTime: data.startTime, // Timestamp in seconds, such as 1580000000
                    ExpiredTime: data.expiredTime, // Timestamp in seconds, such as 1580000900
                    ScopeLimit: true, // Refined permission control needs to be set to true, limiting the key to be reused only for the same request
                });
            }
        });
    }
});

Note：

For more information on how to generate and use a temporary key, please see Generating and Using Temporary Keys.

• Method 3 (not recommended). The frontend needs to get a signature through getAuthorization before each request, and the backend uses a fixed or temporary key to calculate the signature and returns it to the frontend. This method makes it difficult to control permissions for multipart upload and thus is not recommended.

var cos = new COS({
    // Required parameters
    getAuthorization: function (options, callback) {
        // The server obtains a signature. For more information, please see the COS SDK for the corresponding programming language: https://intl.cloud.tencent.com/document/product/436/6474
        // Note: there may be a security risk associated with this method. The backend needs to strictly control permissions through method and pathname, such as prohibiting put /
        wx.request({
            url: 'https://example.com/server/auth.php',
            data: JSON.stringify(options.Scope),
            success: function (result) {
                var data = result.data;
                if (!data || !data.authorization) return console.error('authorization invalid');
                callback({
                    Authorization: data.authorization,
                    // XCosSecurityToken: data.sessionToken, // If a temporary key is used, sessionToken needs to be passed to XCosSecurityToken
                });
            }
        });
    },
});

• Method 4 (not recommended). The frontend uses a fixed key to calculate a signature. This method is suitable for frontend debugging. If you use this method, be sure to avoid key disclosure.

var cos = new COS({
    SecretId: 'COS_SECRETID',
    SecretKey: 'COS_SECRETKEY',
});

Constructor Parameters

getAuthorization callback function description (using method 1)

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

getAuthorization Callback Parameters

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

getAuthorization callback function description (using method 2)

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

getAuthorization callback parameters:

After getAuthorization is calculated, the callback parameter supports two formats:
Format 1. The authentication credential string Authorization is called back.
Format 2. An object is called back with the following attributes:

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 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 for signature calculation within the instance during each request.

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

Creating a bucket

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

Note：

If you need to create a bucket in your WeChat Mini Program, but the bucket name is unknown, you cannot configure the bucket name as a domain name whitelist. Instead, you can use the suffix to call it. For applicable measures, please see FAQs.

Querying a bucket list

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

Uploading an object

The WeChat Mini Program upload API "wx.uploadFile" only supports POST requests. To upload files with the SDK, you need to use the postObject API. If only the file uploading API is needed in your WeChat Mini Program, we do not recommended referencing the SDK. For more information, please see the demo.

// First, select the file to get the temporary path
wx.chooseImage({
    count: 1, // Default value: 9
    sizeType: ['original'], // You can specify whether to use the original or compressed image. The original is used by default
    sourceType: ['album', 'camera'], // You can specify whether the source is an album or camera. Both can be used as the default source 
    success: function (res) {
        var filePath = res.tempFiles[0].path;
        var filename = filePath.substr(filePath.lastIndexOf('/') + 1);
        cos.postObject({
            Bucket: 'examplebucket-1250000000',
            Region: 'ap-beijing',
            Key: 'destination path/' + filename,
            FilePath: filePath,
            onProgress: function (info) {
                console.log(JSON.stringify(info));
            }
        }, function (err, data) {
            console.log(err || data);
        });
    }
});

Querying object list

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

Downloading an object

Note：

This API is used to read object content. If you need to launch a browser to download the file, you can get the URL through cos.getObjectUrl and then start the download in the browser. For more information, please see Pre-signed URL.

cos.getObject({
    Bucket: 'examplebucket-1250000000',
    Region: 'ap-beijing',
    Key: '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);
});