Feature Overview
This document provides an overview of APIs and SDK code samples for object content extraction.
API | Operation | Description |
Extracting Object Content | Extracts the content of a specified object |
Extracting Object Content
Note
This API is used to extract content from a specific object.
Method prototype
select_object_content(Bucket, Key, Expression, ExpressionType, InputSerialization, OutputSerialization, RequestProgress=None, **kwargs)
Sample Request
# -*- coding=utf-8from qcloud_cos import CosConfigfrom qcloud_cos import CosS3Clientimport sysimport osimport logging# Under normal circumstances, use the INFO log level. To locate issues, change it to DEBUG, and the SDK will print communication information with the server.logging.basicConfig(level=logging.INFO, stream=sys.stdout)# 1. Set user attributes, including secret_id, secret_key, region, etc. Appid has been removed from CosConfig, please include Appid in the Bucket parameter. Bucket is composed of BucketName-Appid.secret_id = os.environ['COS_SECRET_ID'] # User <1>SecretId</1>. We recommend that you use a sub-account key and follow the principle of least privilege to reduce risks. For more information on how to obtain a sub-account key, visit https://cloud.tencent.com/document/product/598/37140.secret_key = os.environ['COS_SECRET_KEY'] # User <1>SecretKey</1>. We recommend that you use a sub-account key and follow the principle of least privilege to reduce risks. For more information on how to obtain a sub-account key, visit https://cloud.tencent.com/document/product/598/37140.region = 'ap-beijing' # Replace it with the actual region, which can be viewed in the console at https://console.cloud.tencent.com/cos5/bucket.For a list of all regions supported by COS, visit https://cloud.tencent.com/document/product/436/6224token = None # Token is required for temporary keys but not permanent keys. For more information about how to generate and use a temporary key, see https://cloud.tencent.com/document/product/436/14048.scheme = 'https' # Specify whether to use HTTP or HTTPS protocol to access COS. This is optional and is https by default.config = CosConfig(Region=region, SecretId=secret_id, SecretKey=secret_key, Token=token, Scheme=scheme)client = CosS3Client(config)response = client.select_object_content(Bucket='examplebucket-1250000000',Key='exampleobject',Expression='Select * from COSObject',ExpressionType='SQL',InputSerialization={'CompressionType': 'NONE','JSON': {'Type': 'LINES'}},OutputSerialization={'CSV': {'RecordDelimiter': '\n'}})# Obtain the EventStream instance encapsulated in the response resultevent_stream = response['Payload']# Retrieve All Search Results at Once# Note: Since EventStream retrieves the results in a streaming manner, calling the get_select_result() method again will return an empty set.result = event_stream.get_select_result()print(result)
Sample request with all parameters
response = client.select_object_content(Bucket='examplebucket-1250000000',Key='exampleobject',Expression='Select * from COSObject',ExpressionType='SQL',InputSerialization={'CompressionType': 'GZIP','JSON': {'Type': 'LINES'}},OutputSerialization={'CSV': {'RecordDelimiter': '\n'}},RequestProgress={'Enabled': 'FALSE'})
Description
Parameter name | ParameterDescription | Local Disk Types | Required |
Bucket | Bucket name in the format of BucketName-APPID | String | Required |
Key | ObjectKey is the unique identifier of the object in the bucket. For example, in the object's access domain name examplebucket-1250000000.cos.ap-guangzhou.myqcloud.com/doc/pic.jpg, the ObjectKey is doc/pic.jpg | String | Required |
Expression | SQL statement, which represents the extract operation you want to perform | String | Required |
ExpressionType | Expression type, which is an extension. Currently, only SQL expressions and parameters are supported. | String | Required |
InputSerialization | Format of the object to extract. For more information, see Sample request | Dict | Required |
OutputSerialization | Output format of the extraction results. For more information, see Sample request | Dict | Required |
RequestProgress | Specifies whether to return the query progress information (QueryProgress). If this parameter is used, COS Select will periodically return the query progress. | Dict | Not required |
Response description
The extraction result is in dict format.
{'Payload': EventStream()}
In the response, there is only one key-value pair where the key is
'Payload' and the value is the EventStream instance. The extraction result of the object is encapsulated in the EventStream instance. You can call the next_event(), get_select_result(), and get_select_result_to_file() methods to get the extraction result.