Modifying an Object¶

Function¶

This API modifies the content of an object in a parallel file system from the specified position.

Restrictions¶

This API is currently available only for parallel file systems, not for object buckets. For details about how to create a parallel file system, see Creating a Bucket.
To modify an object, you must have the obs:object:PutObject permission.

Method¶

func (obsClient ObsClient) ModifyObject(input *ModifyObjectInput) (output *ModifyObjectOutput, err error)

Request Parameters¶

**Table 1** List of request parameters¶
Parameter	Type	Mandatory (Yes/No)	Description
input	*ModifyObjectInput	Yes	Explanation: Input parameters for modifying an object. For details, see Table 2.

**Table 2** ModifyObjectInput¶
Parameter	Type	Mandatory (Yes/No)	Description
Bucket	string	Yes	Explanation: Bucket name Restrictions: A bucket name must be unique across all accounts and regions. A bucket name: Must be 3 to 63 characters long and start with a digit or letter. Lowercase letters, digits, hyphens (-), and periods (.) are allowed. Cannot be formatted as an IP address. Cannot start or end with a hyphen (-) or period (.). Cannot contain two consecutive periods (..), for example, my..bucket. Cannot contain a period (.) and a hyphen (-) adjacent to each other, for example, my-.bucket or my.-bucket. If you repeatedly create buckets of the same name in the same region, no error will be reported and the bucket attributes comply with those set in the first creation request. Default value: None
Key	string	Yes	Explanation: Object name. An object is uniquely identified by an object name in a bucket. An object name is a complete path that does not contain the bucket name. Value range: The value must contain 1 to 1,024 characters. Default value: None
Position	int64	Yes	Explanation: Position from which the object is modified Value range: 1 to (2⁶³ - 1), in bytes Default value: 1, indicating the modification starts from the first byte of the object
ContentLength	int64	No	Explanation: Size of the object to be modified Value range: 1 to (2⁶³ - 1), in bytes Default value: None
Body	io.Reader	No	Explanation: Data stream of the object to be modified Default value: None

Responses¶

**Table 3** List of returned results¶
Parameter	Type	Description
output	*ModifyObjectOutput	Explanation: Returned results. For details, see Table 4.
err	error	Explanation: Error messages returned by the API

**Table 4** ModifyObjectOutput¶
Parameter	Type	Description
StatusCode	int	Explanation: HTTP status code Value range: A status code is a group of digits that can be 2xx (indicating successes) or 4xx or 5xx (indicating errors). It indicates the status of a response. Default value: None
RequestId	string	Explanation: Request ID returned by the OBS server Default value: None
ResponseHeaders	map[string][]string	Explanation: HTTP response headers Default value: None
ETag	string	Explanation: Base64-encoded, 128-bit MD5 value of an object. ETag is the unique identifier of the object content. It can be used to determine whether the object content is changed. For example, if the ETag value is A when an object is uploaded, but changes to B when the object is downloaded, it indicates that the object content has been changed. The ETag reflects changes to the object content, rather than the object metadata. An uploaded or copied object has a unique ETag after being encrypted using MD5. Restrictions: If an object is encrypted using server-side encryption, the ETag is not the MD5 value of the object. Value range: The value must contain 32 characters. Default value: None

Code Examples¶

This example modifies object example/objectname in bucket examplebucket.

package main
import (
    "fmt"
    "os"
    "strings"
    "obs-sdk-go/obs"
)
func main() {
    //Obtain an AK/SK pair using environment variables or import an AK/SK pair in other ways. Using hard coding may result in leakage.
    //Obtain an AK/SK pair on the management console.
    ak := os.Getenv("AccessKeyID")
    sk := os.Getenv("SecretAccessKey")
    // (Optional) If you use a temporary AK/SK pair and a security token to access OBS, you are advised not to use hard coding to reduce leakage risks. You can obtain an AK/SK pair using environment variables or import an AK/SK pair in other ways.
    // securityToken := os.Getenv("SecurityToken")
    // Enter the endpoint of the region where the bucket locates.
    endPoint := "https://your-endpoint"
    // Create an obsClient instance.
    // If you use a temporary AK/SK pair and a security token to access OBS, use the obs.WithSecurityToken method to specify a security token when creating an instance.
    obsClient, err := obs.New(ak, sk, endPoint/*, obs.WithSecurityToken(securityToken)*/)
    if err != nil {
        fmt.Printf("Create obsClient error, errMsg: %s", err.Error())
    }
    input := &obs.ModifyObjectInput{}
    // Specify a bucket name.
    input.Bucket = "examplebucket"
    // Specify an object (example/objectname as an example).
    input.Key = "example/objectname"
    input.Position = 0
    input.Body = strings.NewReader("Modify Hello OBS")
    // Modify the object.
    output, err := obsClient.ModifyObject(input)
    if err == nil {
        fmt.Printf("Modify object(%s) under the bucket(%s) successful!\n", input.Key, input.Bucket)
        fmt.Printf("ETag:%s\n", output.ETag)
        return
    }
    fmt.Printf("Modify object(%s) under the bucket(%s) fail!\n", input.Key, input.Bucket)
    if obsError, ok := err.(obs.ObsError); ok {
        fmt.Println("An ObsError was found, which means your request sent to OBS was rejected with an error response.")
        fmt.Println(obsError.Error())
    } else {
        fmt.Println("An Exception was found, which means the client encountered an internal problem when attempting to communicate with OBS, for example, the client was unable to access the network.")
        fmt.Println(err)
    }
}

last updated: 2025-08-28 14:06 UTC - commit: 39882e2dd8910deda6bee60c54bef141ea2cac76