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Checking Whether Objects Exist

Last updated: 2022-03-21 14:20:53

    Overview

    This document provides sample code for quickly checking whether an object exists in a bucket.

    The sample code actually calls the HEAD Object COS API and is a simplified version of the API.

    In addition to checking whether an object exists, HEAD Object returns object metadata. To view the SDK API that contains the full functionality of HEAD Object, please see Querying Object Metadata.

    Checking Whether an Object Exists

    Description

    You can check whether an object exists by using the shortcut API provided by the SDK.

    Note:

    The COS Go SDK version should not be earlier than v0.7.33.

    Method prototype

    func (s *ObjectService) IsExist(ctx context.Context, key string, id ...string) (isExist bool, err error)
    

    Sample code

    package main
    import (
      "context"
      "fmt"
      "github.com/tencentyun/cos-go-sdk-v5"
      "net/http"
      "net/url"
      "os"
    )
    func main() {
      // 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
      // Replace it with your region, which can be viewed in the COS console at https://console.cloud.tencent.com/. For more information about regions, see https://intl.cloud.tencent.com/document/product/436/6224.
      u, _ := url.Parse("https://examplebucket-1250000000.cos.ap-guangzhou.myqcloud.com")
      b := &cos.BaseURL{BucketURL: u}
      client := cos.NewClient(b, &http.Client{
          Transport: &cos.AuthorizationTransport{
              // Get the key from environment variables
              // Environment variable `SECRETID` refers to the user's SecretId, which can be viewed at https://console.cloud.tencent.com/cam/capi
              SecretID: os.Getenv("SECRETID"),
              // Environment variable `SECRETKEY` refers to the user's SecretKey, which can be viewed at https://console.cloud.tencent.com/cam/capi
              SecretKey: os.Getenv("SECRETKEY"),
          },
      })
      key := "exampleobject"
      ok, err := client.Object.IsExist(context.Background(), key)
      if err == nil && ok {
          fmt.Printf("object exists\n")
      } else if err != nil {
          fmt.Printf("head object failed: %v\n", err)
      } else {
          fmt.Printf("object does not exist\n")
      }
    }
    

    Parameter description

    Parameter Description Type Required
    key Object key, unique identifier of an object in a bucket. For example, if the object endpoint is examplebucket-1250000000.cos.ap-guangzhou.myqcloud.com/doc/pic.jpg, its object key is doc/pic.jpg. String Yes
    id VersionId of the object String No

    Response description

    Parameter Description Type
    isExist Whether the object exists Bool
    err Whether the request is successful Struct
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