使用C＃模拟mysql压缩功能

Question

I'd like to insert some byte data into a mysql blob column. The data is large so I want to store it in a compressed way.

I'm using Entity Framework 3.5SP1 to insert the data into the mysql database using the latest mysql .net connector. Is there a way to either use the entitiy framework to insert a blob into the mysql database (like insert into testtable (blobcolumn) values (compress('aaa')) ) or to emulate the compress function of mysql in c# and then insert the result in the database?

Thanks

Answer 1

Please find below my implementation using Ionic zip . Hope that helps!

using System;
using System.IO;
using Ionic.Zlib;
using System.Text;

namespace Qobuz
{
    public static class MySqlCompressHelper
    {
        public static byte[] MySqlCompress(this string str, CompressionLevel level = CompressionLevel.BestCompression)
        {
            return UTF8Encoding.UTF8.GetBytes(str).MySqlCompress(level);
        }

        public static byte[] MySqlCompress(this byte[] buffer, CompressionLevel level = CompressionLevel.BestCompression)
        {
            using (var output = new MemoryStream())
            {
                output.Write(BitConverter.GetBytes((int)buffer.Length), 0, 4);
                using (var compressor = new ZlibStream(output, CompressionMode.Compress, level))
                {
                    compressor.Write(buffer, 0, buffer.Length);
                }

                return output.ToArray();
            }
        }

        public static string MySqlUncompressString(this byte[] buffer)
        {
            return UTF8Encoding.UTF8.GetString(buffer.MySqlUncompressBuffer());
        }

        public static byte[] MySqlUncompressBuffer(this byte[] buffer)
        {
            using (var output = new MemoryStream())
            {
                using (var decompressor = new ZlibStream(output, CompressionMode.Decompress))
                {
                    decompressor.Write(buffer, 4, buffer.Length - 4);
                }

                return output.ToArray();
            }
        }
    }
}

Answer 2

在连接字符串中指定“ UseCompression”选项以启用数据包压缩。