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Checking Whether Objects Exist

Last updated: 2024-02-02 15:51:37

    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

    Feature 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.tencentcloud.com/cos5/bucket.
    // Replace it with your region, which can be viewed in the COS console at https://console.tencentcloud.com/. For more information about regions, visit https://www.tencentcloud.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 in the CAM console at https://console.tencentcloud.com/cam/capi.
    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/598/37140?from_cn_redirect=1.
    // Environment variable `SECRETKEY` refers to the user's `SecretKey`, which can be viewed in the CAM console at https://console.tencentcloud.com/cam/capi.
    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/598/37140?from_cn_redirect=1.
    },
    })
    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")
    }
    }

    Field description

    Parameter
    Description
    Type
    Required
    key
    Object key, the 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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