tencent cloud

Download and Installation

Relevant resources

• Download the source code for the COS XML Go SDK here.
• Download the demo here.
• For more information, see GitHub.
• For the complete sample code, see SDK Sample Code.
• For the SDK changelog, see Changelog.
• For SDK FAQs, see Go SDK.

Note：

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

Environmental dependencies

Golang is used to download and install the Go operating environment; it can be downloaded from the Golang official website.

Installing SDK

Execute the following command to install the COS Go SDK:

go get -u github.com/tencentyun/cos-go-sdk-v5

Getting Started

The section below describes how to use the COS Go SDK to perform basic operations, such as initializing a client, creating a bucket, querying a bucket list, uploading an object, querying an object list, downloading an object, or deleting an object.

Initialization

Note：

• We recommend you use a sub-account key and environment variables to call the SDK for security purposes. When authorizing a sub-account, follow the Notes on Principle of Least Privilege to avoid leaking resources besides your buckets and objects.
• If you must use a permanent key, we recommend you follow the Notes on Principle of Least Privilege to limit the scope of permission on the permanent key.

A COS GO client is generated using the COS domain name.

Method prototype

func NewClient(uri *BaseURL, httpClient *http.Client) *Client

Field description

// `BaseURL` indicates the base URL required for accessing APIs
type BaseURL struct {
   // Base URL (excluding `path`) for accessing bucket and object related APIs: https://examplebucket-1250000000.cos.<Region>.myqcloud.com
   BucketURL *url.URL
   // Base URL (excluding `path`) for accessing service APIs: https://cos.<Region>.myqcloud.com
   ServiceURL *url.URL
   // Base URL (excluding `path`) for accessing batch APIs: https://<UIN>.cos-control.<Region>.myqcloud.com
   BatchURL *url.URL
   // Base URL (excluding `path`) for accessing CI: https://examplebucket-1250000000.ci.<Region>.myqcloud.com
   CIURL *url.URL
}

Parameter	Description	Type	Required
BucketURL	Base URL (excluding path) for accessing bucket and object related APIs	String	Yes
ServiceURL	Base URL (excluding path) for accessing service APIs	String	No
BatchURL	Base URL (excluding path) for accessing batch APIs	String	No
CIURL	Base URL (excluding path) for accessing CI	String	No

Sample request 1: using a permanent key

// Replace `examplebucket-1250000000` and `COS_REGION` with the actual information of users
// Bucket name in the format of `BucketName-APPID` (`APPID` is required), which can be viewed in the COS console at https://console.tencentcloud.com/cos5/bucket.
// `COS_REGION` can be viewed in the COS console at https://console.tencentcloud.com/cos5/bucket/. For more information about regions, visit https://www.tencentcloud.com/document/product/436/6224.
u, _ := url.Parse("https://examplebucket-1250000000.cos.COS_REGION.myqcloud.com")
// The following calls the `Get Service` API. By default, all regions (service.cos.myqcloud.com) will be queried.
su, _ := url.Parse("https://cos.COS_REGION.myqcloud.com")
b := &cos.BaseURL{BucketURL: u, ServiceURL: su}
// 1. Permanent key
client := cos.NewClient(b, &http.Client{
   Transport: &cos.AuthorizationTransport{
       SecretID: os.Getenv("SECRETID"),  // User `SecretId`. We recommend you use a sub-account key and follow the principle of least privilege to reduce risks. For information about how to obtain a sub-account key, visit https://www.tencentcloud.com/document/product/598/32675.
       SecretKey: os.Getenv("SECRETKEY"),  // User `SecretKey`. We recommend you use a sub-account key and follow the principle of least privilege to reduce risks. For information about how to obtain a sub-account key, visit https://www.tencentcloud.com/document/product/598/32675.
   },
})

Sample request 2: using a temporary key

// Replace `examplebucket-1250000000` and `COS_REGION` with the actual information
// Bucket name in the format of `BucketName-APPID` (`APPID` is required), which can be viewed in the COS console at https://console.tencentcloud.com/cos5/bucket.
// `COS_REGION` can be viewed in the COS console at https://console.tencentcloud.com/cos5/bucket/. For more information about regions, visit https://www.tencentcloud.com/document/product/436/6224.
u, _ := url.Parse("https://examplebucket-1250000000.cos.COS_REGION.myqcloud.com")
b := &cos.BaseURL{BucketURL: u}
// 2. Temporary key
client := cos.NewClient(b, &http.Client{
   Transport: &cos.AuthorizationTransport{
       // If a temporary key is required, see the instructions at https://www.tencentcloud.com/document/product/436/14048 for generating and using a temporary key.
       SecretID:     "SECRETID",
       SecretKey:    "SECRETKEY",
       SessionToken: "SECRETTOKEN",
   },
})
if client != nil {
   // Call the COS request
}

Note：

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

Sample request 3: setting a domain name

By modifying BaseURL, you can directly use a custom domain name or global acceleration domain name to access COS.

// Use a global acceleration domain name to access COS
u, _ := url.Parse("http://<BucketName-APPID>.cos.accelerate.myqcloud.com")
b := &cos.BaseURL{BucketURL: u}
// 2. Temporary key
client := cos.NewClient(b, &http.Client{
   Transport: &cos.AuthorizationTransport{
       // If a temporary key is required, see the instructions at https://www.tencentcloud.com/document/product/436/14048 for generating and using a temporary key.
       SecretID:     "SECRETID",
       SecretKey:    "SECRETKEY",
       SessionToken: "SECRETTOKEN",
   },
})

Sample request 4: CRC64 verification

By default, CRC64 verification is enabled in the COS Go SDK for the uploaded objects.

Note：

• The COS Go SDK version should be or later than v0.7.23.
• You are strongly advised not to disable CRC64 verification.

// Replace `examplebucket-1250000000` and `COS_REGION` with the actual information
// Bucket name in the format of `BucketName-APPID` (`APPID` is required), which can be viewed in the COS console at https://console.cloud.tencent.com/cos5/bucket.
// `COS_REGION` can be viewed in the COS console at https://console.cloud.tencent.com/cos5/bucket/. For more information about regions, visit https://intl.cloud.tencent.com/document/product/436/6224.
u, _ := url.Parse("https://examplebucket-1250000000.cos.COS_REGION.myqcloud.com")
b := &cos.BaseURL{BucketURL: u}
// 2. Temporary key
client := cos.NewClient(b, &http.Client{
  Transport: &cos.AuthorizationTransport{
      // If a temporary key is required, see the instructions at https://intl.cloud.tencent.com/document/product/436/14048 for generating and using a temporary key.
      SecretID:     "SECRETID",
      SecretKey:    "SECRETKEY",
      SessionToken: "SECRETTOKEN",
  },
})
// Disable CRC64 verification.
client.Conf.EnableCRC = false

Creating a bucket

package main
import (
  "context"
  "net/http"
  "net/url"
  "os"
    "github.com/tencentyun/cos-go-sdk-v5"
)
func main(){
  // Replace `examplebucket-1250000000` and `COS_REGION` with the actual information
  // Bucket name in the format of `BucketName-APPID` (`APPID` is required), which can be viewed in the COS console at https://console.tencentcloud.com/cos5/bucket.
  // `COS_REGION` can be viewed in the COS console at https://console.tencentcloud.com/cos5/bucket/. For more information about regions, visit https://www.tencentcloud.com/document/product/436/6224.
  u, _ := url.Parse("https://examplebucket-1250000000.cos.COS_REGION.myqcloud.com")
  b := &cos.BaseURL{BucketURL: u}
  c := cos.NewClient(b, &http.Client{
      Transport: &cos.AuthorizationTransport{
          SecretID: os.Getenv("SECRETID"),  // User `SecretId`. We recommend you use a sub-account key and follow the principle of least privilege to reduce risks. For information about how to obtain a sub-account key, visit https://www.tencentcloud.com/document/product/598/32675.
          SecretKey: os.Getenv("SECRETKEY"),  // User `SecretKey`. We recommend you use a sub-account key and follow the principle of least privilege to reduce risks. For information about how to obtain a sub-account key, visit https://www.tencentcloud.com/document/product/598/32675.
      },
  })
    _, err := c.Bucket.Put(context.Background(), nil)
  if err != nil{
      panic(err)
  }
}

Querying the bucket list

package main

import (
   "context"
   "fmt"
   "net/http"
   "os"

   "github.com/tencentyun/cos-go-sdk-v5"
)

func main(){
   c := cos.NewClient(nil, &http.Client{
       Transport: &cos.AuthorizationTransport{
           SecretID: os.Getenv("SECRETID"),  // User `SecretId`. We recommend you use a sub-account key and follow the principle of least privilege to reduce risks. For information about how to obtain a sub-account key, visit https://www.tencentcloud.com/document/product/598/32675.
           SecretKey: os.Getenv("SECRETKEY"),  // User `SecretKey`. We recommend you use a sub-account key and follow the principle of least privilege to reduce risks. For information about how to obtain a sub-account key, visit https://www.tencentcloud.com/document/product/598/32675.
       },
   })

   s, _, err := c.Service.Get(context.Background())
   if err != nil{
       panic(err)
   }

   for _, b := range s.Buckets {
       fmt.Printf("%#v\n", b)
   }
}

Uploading an object

package main

import (
   "context"
   "net/http"
   "net/url"
   "os"
   "strings"
    "github.com/tencentyun/cos-go-sdk-v5"
)

func main(){
   // Replace `examplebucket-1250000000` and `COS_REGION` with the actual information
   // Bucket name in the format of `BucketName-APPID` (`APPID` is required), which can be viewed in the COS console at https://console.tencentcloud.com/cos5/bucket.
   // `COS_REGION` can be viewed in the COS console at https://console.tencentcloud.com/cos5/bucket/. For more information about regions, visit https://www.tencentcloud.com/document/product/436/6224.
   u, _ := url.Parse("https://examplebucket-1250000000.cos.COS_REGION.myqcloud.com")
   b := &cos.BaseURL{BucketURL: u}
   c := cos.NewClient(b, &http.Client{
       Transport: &cos.AuthorizationTransport{
           SecretID: os.Getenv("SECRETID"),  // User `SecretId`. We recommend you use a sub-account key and follow the principle of least privilege to reduce risks. For information about how to obtain a sub-account key, visit https://www.tencentcloud.com/document/product/598/32675.
           SecretKey: os.Getenv("SECRETKEY"),  // User `SecretKey`. We recommend you use a sub-account key and follow the principle of least privilege to reduce risks. For information about how to obtain a sub-account key, visit https://www.tencentcloud.com/document/product/598/32675.
       },
   })
   // An object key is the unique identifier of an object in a bucket
   // For example, in the access domain name `examplebucket-1250000000.cos.COS_REGION.myqcloud.com/test/objectPut.go`, the object key is `test/objectPut.go`
   name := "test/objectPut.go"
   // 1. Upload the object with a string.
   f := strings.NewReader("test")

   _, err := c.Object.Put(context.Background(), name, f, nil)
   if err != nil{
       panic(err)
   }
   // 2. Upload the object with a local file.
   _, err = c.Object.PutFromFile(context.Background(), name, "../test", nil)
   if err != nil{
       panic(err)
   }
   // 3. Upload the object with a file stream.
   fd, err := os.Open("./test")
   if err != nil{
       panic(err)
   }
   defer fd.Close()
   _, err = c.Object.Put(context.Background(), name, fd, nil)
   if err != nil{
       panic(err)
   }
}

Querying objects

package main

import (
   "context"
   "fmt"
   "net/http"
   "net/url"
   "os"
    "github.com/tencentyun/cos-go-sdk-v5"
)

func main(){
   // Replace `examplebucket-1250000000` and `COS_REGION` with the actual information
   // Bucket name in the format of `BucketName-APPID` (`APPID` is required), which can be viewed in the COS console at https://console.tencentcloud.com/cos5/bucket.
   // `COS_REGION` can be viewed in the COS console at https://console.tencentcloud.com/cos5/bucket/. For more information about regions, visit https://www.tencentcloud.com/document/product/436/6224.
   u, _ := url.Parse("https://examplebucket-1250000000.cos.COS_REGION.myqcloud.com")
   b := &cos.BaseURL{BucketURL: u}
   c := cos.NewClient(b, &http.Client{
       Transport: &cos.AuthorizationTransport{
           SecretID: os.Getenv("SECRETID"),  // User `SecretId`. We recommend you use a sub-account key and follow the principle of least privilege to reduce risks. For information about how to obtain a sub-account key, visit https://www.tencentcloud.com/document/product/598/32675.
           SecretKey: os.Getenv("SECRETKEY"),  // User `SecretKey`. We recommend you use a sub-account key and follow the principle of least privilege to reduce risks. For information about how to obtain a sub-account key, visit https://www.tencentcloud.com/document/product/598/32675.
       },
   })

   opt := &cos.BucketGetOptions{
       Prefix:  "test",
       MaxKeys: 3,
   }
   v, _, err := c.Bucket.Get(context.Background(), opt)
   if err != nil{
       panic(err)
   }

   for _, c := range v.Contents {
       fmt.Printf("%s, %d\n", c.Key, c.Size)
   }
}

Download an object

package main

import (
   "context"
   "fmt"
   "io/ioutil"
   "net/http"
   "net/url"
   "os"
    "github.com/tencentyun/cos-go-sdk-v5"
)

func main(){
   // Replace `examplebucket-1250000000` and `COS_REGION` with the actual information
   // Bucket name in the format of `BucketName-APPID` (`APPID` is required), which can be viewed in the COS console at https://console.tencentcloud.com/cos5/bucket.
   // `COS_REGION` can be viewed in the COS console at https://console.tencentcloud.com/cos5/bucket/. For more information about regions, visit https://www.tencentcloud.com/document/product/436/6224.
   u, _ := url.Parse("https://examplebucket-1250000000.cos.COS_REGION.myqcloud.com")
   b := &cos.BaseURL{BucketURL: u}
   c := cos.NewClient(b, &http.Client{
       Transport: &cos.AuthorizationTransport{
           SecretID: os.Getenv("SECRETID"),  // User `SecretId`. We recommend you use a sub-account key and follow the principle of least privilege to reduce risks. For information about how to obtain a sub-account key, visit https://www.tencentcloud.com/document/product/598/32675.
           SecretKey: os.Getenv("SECRETKEY"),  // User `SecretKey`. We recommend you use a sub-account key and follow the principle of least privilege to reduce risks. For information about how to obtain a sub-account key, visit https://www.tencentcloud.com/document/product/598/32675.
       },
   })
   // 1. Obtain the object through response body
   name := "test/objectPut.go"
   resp, err := c.Object.Get(context.Background(), name, nil)
   if err != nil{
       panic(err)
   }
   bs, _ := ioutil.ReadAll(resp.Body)
   resp.Body.Close()
   fmt.Printf("%s\n", string(bs))
   // 2. Download the object to the local file system
   _, err = c.Object.GetToFile(context.Background(), name, "exampleobject", nil)
   if err != nil{
       panic(err)
   }
}

Deleting an object

package main

import (
   "context"
   "net/http"
   "net/url"
   "os"
    "github.com/tencentyun/cos-go-sdk-v5"
)

func main(){
   // Replace `examplebucket-1250000000` and `COS_REGION` with the actual information
   // Bucket name in the format of `BucketName-APPID` (`APPID` is required), which can be viewed in the COS console at https://console.tencentcloud.com/cos5/bucket.
   // `COS_REGION` can be viewed in the COS console at https://console.tencentcloud.com/cos5/bucket/. For more information about regions, visit https://www.tencentcloud.com/document/product/436/6224.
   u, _ := url.Parse("https://examplebucket-1250000000.cos.COS_REGION.myqcloud.com")
   b := &cos.BaseURL{BucketURL: u}
   c := cos.NewClient(b, &http.Client{
       Transport: &cos.AuthorizationTransport{
           SecretID: os.Getenv("SECRETID"),  // User `SecretId`. We recommend you use a sub-account key and follow the principle of least privilege to reduce risks. For information about how to obtain a sub-account key, visit https://www.tencentcloud.com/document/product/598/32675.
           SecretKey: os.Getenv("SECRETKEY"),  // User `SecretKey`. We recommend you use a sub-account key and follow the principle of least privilege to reduce risks. For information about how to obtain a sub-account key, visit https://www.tencentcloud.com/document/product/598/32675.
       },
   })
   name := "test/objectPut.go"
   _, err := c.Object.Delete(context.Background(), name)
   if err != nil{
       panic(err)
   }
}