Web API性能优化（一）压缩

简单的应用场景：分页获取日志JSON信息。

很简单的实现，简单的记录一下

未压缩时候

使用PostMan请求http://localhost:34390/api/gpm/syslog/page?pageindex=1&pagesize=10

上图用到了一些技术：AOP、IOC、Request/Response模式（个人觉得十分适合WebAPI），这里不介绍。ApiResullt是我封装的一个类（自动序列化），至于为什么自己造一个，只是本人觉得舒服！这个最重要。

响应结果：可以看到Size:2.04KB，Content-Length:1607

使用压缩

使用DotNetZip压缩，当然使用AOP方式，使用默认压缩级别

/// <summary>
/// 压缩返回信息
/// </summary>
[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, Inherited = true, AllowMultiple = true)]
public class CompressionAttribute : ActionFilterAttribute
{
    public override void OnActionExecuted(HttpActionExecutedContext actionExecutedContext)
    {
        var content = actionExecutedContext.Response.Content;
        var acceptEncoding = actionExecutedContext.Request.Headers.AcceptEncoding.
            Where(x => x.Value == "gzip" || x.Value == "deflate").ToList();
        if (acceptEncoding.HasItems() && content != null && actionExecutedContext.Request.Method != HttpMethod.Options)
        {
            var first = acceptEncoding.FirstOrDefault();
            if (first != null)
            {
                var bytes = content.ReadAsByteArrayAsync().Result;
                switch (first.Value)
                {
                    case "gzip":
                        actionExecutedContext.Response.Content = new ByteArrayContent(CompressionHelper.GZipBytes(bytes));
                        actionExecutedContext.Response.Content.Headers.Add("Content-Encoding", "gzip");
                        break;
                    case "deflate":
                        actionExecutedContext.Response.Content = new ByteArrayContent(CompressionHelper.DeflateBytes(bytes));
                        actionExecutedContext.Response.Content.Headers.Add("Content-encoding", "deflate");
                        break;
                }
            }
        }
        base.OnActionExecuted(actionExecutedContext);
    }
}
/// <summary>
/// 压缩帮助类
/// </summary>
internal static class CompressionHelper
{
    public static byte[] DeflateBytes(byte[] bytes)
    {
        if (!bytes.HasItems())
        {
            return null;
        }
        using (var output = new MemoryStream())
        {
            using (var compressor = new Ionic.Zlib.DeflateStream(output, Ionic.Zlib.CompressionMode.Compress, Ionic.Zlib.CompressionLevel.Default))
            {
                compressor.Write(bytes, 0, bytes.Length);
            }
            return output.ToArray();
        }
    }

    public static byte[] GZipBytes(byte[] bytes)
    {
        if (!bytes.HasItems())
        {
            return null;
        }
        using (var output = new MemoryStream())
        {
            using (var compressor = new Ionic.Zlib.GZipStream(output, Ionic.Zlib.CompressionMode.Compress, Ionic.Zlib.CompressionLevel.Default))
            {
                compressor.Write(bytes, 0, bytes.Length);
            }
            return output.ToArray();
        }
    }
}

请求响应结果：Size:833B，Content-Length:329，提升效果十分明显，细心的朋友会发现响应时间变长了，当然这是由于压缩需要时间造成的，但是影响不大