Overview

This document provides an overview of the API and SDK code samples related to extracting object content.

SDK API Reference

For the parameters and method descriptions of all the APIs in the SDK, see Api Documentation.

Extracting Object Content

API description

This API is used by the COS Select feature to extract objects in the following formats:

• CSV: an object is stored in CSV format with its data records separated with a specific delimiter.
• JSON: an object is stored in JSON format, which can be either a JSON file or a JSON list.

Note：

• To use COS Select, you must have the permission for cos:GetObject.
• CSV- or JSON-formatted objects need to be encoded in UTF-8.
• COS Select can extract CSV- or JSON-formatted objects compressed by gzip or bzip2.
• COS Select can extract CSV- or JSON-formatted objects encrypted with SSE-COS.

Sample code

try
{
    string bucket = "examplebucket-1250000000"; // Bucket name in the format: BucketName-APPID
    string key = "exampleobject"; // Object key

    SelectObjectRequest request = new SelectObjectRequest(bucket, key);

    ObjectSelectionFormat.JSONFormat jSONFormat = new ObjectSelectionFormat.JSONFormat();
    jSONFormat.Type = "DOCUMENT";
    jSONFormat.RecordDelimiter = "\n";

    string outputFile = "select_local_file.json";

    request.setExpression("Select * from COSObject")
            .setInputFormat(new ObjectSelectionFormat(null, jSONFormat))
            .setOutputFormat(new ObjectSelectionFormat(null, jSONFormat))
            .SetCosProgressCallback(delegate (long progress, long total) {
                Console.WriteLine("OnProgress : " + progress + "," + total);
            })
            .outputToFile(outputFile)
            ;

    SelectObjectResult selectObjectResult =  cosXml.selectObject(request);
    Console.WriteLine(selectObjectResult.stat);
}
catch (COSXML.CosException.CosClientException clientEx)
{
    Console.WriteLine("CosClientException: " + clientEx.StackTrace);
    Console.WriteLine("CosClientException: " + clientEx.Message);
}
catch (COSXML.CosException.CosServerException serverEx)
{
    Console.WriteLine("CosServerException: " + serverEx.GetInfo());
}

Note：

For the complete sample, go to GitHub.