HEAD Object
returns object metadata. To view the SDK API that contains the full functionality of HEAD Object
, please see Querying Object Metadata.API | Operation | Description |
Querying object metadata | Queries the metadata of an object. |
cos.headObject
method.function doesObjectExist() {cos.headObject({Bucket: 'examplebucket-1250000000', /* Your bucket name. Required. */Region: 'COS_REGION', /* Bucket region, such as `ap-beijing`. Required. */Key: '1.jpg', /* Object key stored in the bucket (such as `1.jpg` and `a/b/test.txt`). Required. */}, function(err, data) {if (data) {console.log('The object exists.');} else if (err.statusCode == 404) {console.log('The object does not exist.');} else if (err.statusCode == 403) {console.log ('no permission to read the object');}});}
Parameter | Description | Type | Required |
Bucket | Bucket name in the format of BucketName-APPID . | String | Yes |
Region | String | Yes | |
Key | Object key (object name), the unique ID of an object in a bucket. For more information, please see Object Overview. | String | Yes |
IfModifiedSince | If the object is modified after the specified time, the corresponding object metadata will be returned; otherwise, 304 will be returned. | String | No |
function(err, data) { ... }
Parameter | Description | Type |
err | Object returned when an error (network error or service error) occurs. If the request is successful, this is null. For more information, see Error Codes. | Object |
- statusCode | HTTP status code, such as 200 , 403 , and 404 . | Number |
- headers | Headers. | Object |
data | Content returned when the request is successful. If the request fails, this parameter is empty. | Object |
- statusCode | HTTP status code, such as 200 and 304 . 304 is returned if no modification is made after the specified time. | Number |
- headers | Headers. | Object |
- x-cos-object-type | Whether an object is appendable. Enumerated values: normal , appendable . The default value normal is not displayed. | String |
- x-cos-storage-class | Storage class of the object. Enumerated values: STANDARD (default), STANDARD_IA , ARCHIVE . STANDARD is not displayed if returned. | String |
- x-cos-meta-* | User-defined metadata | String |
- NotModified | Whether an object hasn’t been modified after the specified time. | Boolean |
- ETag | MD5 checksum of the object. The value of ETag can be used to check whether the object was corrupted during the upload. Example: "09cba091df696af91549de27b8e7d0f6" Note that double quotation marks are required at the beginning and the end. | String |
- VersionId | Version ID of the uploaded object if versioning is enabled for its bucket. If versioning is not enabled, this parameter is not returned. | String |
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