SelectObjectContent.cs

/*
 * MinIO .NET Library for Amazon S3 Compatible Cloud Storage, (C) 2020 MinIO, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using System.Text;
using CommunityToolkit.HighPerformance;
using Minio.DataModel.Args;
using Minio.DataModel.Select;

namespace Minio.Examples.Cases;

internal static class SelectObjectContent
{
    // Get object in a bucket
    public static async Task Run(IMinioClient minio,
        string bucketName = "my-bucket-name",
        string objectName = "my-object-name")
    {
        if (minio is null) throw new ArgumentNullException(nameof(minio));

        var newObjectName = "new" + objectName;
        try
        {
            Console.WriteLine("Running example for API: SelectObjectContentAsync");

            var csvString = new StringBuilder();
            _ = csvString.AppendLine("Employee,Manager,Group");
            _ = csvString.AppendLine("Employee4,Employee2,500");
            _ = csvString.AppendLine("Employee3,Employee1,500");
            _ = csvString.AppendLine("Employee1,,1000");
            _ = csvString.AppendLine("Employee5,Employee1,500");
            _ = csvString.AppendLine("Employee2,Employee1,800");
            ReadOnlyMemory<byte> csvBytes = Encoding.UTF8.GetBytes(csvString.ToString());
            using var stream = csvBytes.AsStream();
            var putObjectArgs = new PutObjectArgs()
                .WithBucket(bucketName)
                .WithObject(newObjectName)
                .WithStreamData(stream)
                .WithObjectSize(stream.Length);
            _ = await minio.PutObjectAsync(putObjectArgs).ConfigureAwait(false);

            var queryType = QueryExpressionType.SQL;
            var queryExpr = "select count(*) from s3object";
            var inputSerialization = new SelectObjectInputSerialization
            {
                CompressionType = SelectCompressionType.NONE,
                CSV = new CSVInputOptions
                {
                    FileHeaderInfo = CSVFileHeaderInfo.None, RecordDelimiter = "\n", FieldDelimiter = ","
                }
            };
            var outputSerialization = new SelectObjectOutputSerialization
            {
                CSV = new CSVOutputOptions { RecordDelimiter = "\n", FieldDelimiter = "," }
            };
            var args = new SelectObjectContentArgs()
                .WithBucket(bucketName)
                .WithObject(newObjectName)
                .WithExpressionType(queryType)
                .WithQueryExpression(queryExpr)
                .WithInputSerialization(inputSerialization)
                .WithOutputSerialization(outputSerialization);
            var resp = await minio.SelectObjectContentAsync(args).ConfigureAwait(false);
            using var standardOutput = Console.OpenStandardOutput();
            await resp.Payload.CopyToAsync(standardOutput).ConfigureAwait(false);
            Console.WriteLine("Bytes scanned:" + resp.Stats.BytesScanned);
            Console.WriteLine("Bytes returned:" + resp.Stats.BytesReturned);
            Console.WriteLine("Bytes processed:" + resp.Stats.BytesProcessed);
            if (resp.Progress is not null) Console.WriteLine("Progress :" + resp.Progress.BytesProcessed);
        }
        catch (Exception e)
        {
            Console.WriteLine($"[Bucket]  Exception: {e}");
        }
    }
}