Question

在我的应用程序中，我们从客户端发送大小合适的数据包，并收到相当大的响应，所以我想在上升和返回的过程中实现一些压缩。

在回来的路上很好，因为我可以依靠IIS的动态压缩为我做这件事，但在上升的过程中，我发现了以下问题。

我有一个代理处理程序，可以解压缩传入的请求：（此代码的大部分内容基于Fabrik.Common（https://github.com/benfoster/Fabrik.Common））

的部分内容

public class DecompressionHandler : DelegatingHandler
{
    public Collection<ICompressor> Compressors;

    public DecompressionHandler()
    {
        Compressors = new Collection<ICompressor> {new GZipCompressor(), new DeflateCompressor()};
    }

    protected async override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, System.Threading.CancellationToken cancellationToken)
    {
        if (request.Content.Headers.ContentEncoding.IsntNullOrEmpty() && request.Content != null)
        {
            var encoding = request.Content.Headers.ContentEncoding.First();

            var compressor = Compressors.FirstOrDefault(c => c.EncodingType.Equals(encoding, StringComparison.InvariantCultureIgnoreCase));

            if (compressor != null)
            {
                request.Content = await DecompressContentAsync(request.Content, compressor).ConfigureAwait(true);
            }
        }

        var response = await base.SendAsync(request, cancellationToken).ConfigureAwait(true);

        return response;
    }

    private static async Task<HttpContent> DecompressContentAsync(HttpContent compressedContent, ICompressor compressor)
    {
        using (compressedContent)
        {
            var decompressed = new MemoryStream();
            await compressor.Decompress(await compressedContent.ReadAsStreamAsync(), decompressed).ConfigureAwait(true);

            // set position back to 0 so it can be read again
            decompressed.Position = 0;

            var newContent = new StreamContent(decompressed);
            // copy content type so we know how to load correct formatter
            newContent.Headers.ContentType = compressedContent.Headers.ContentType;
            return newContent;
        }
    }
}

public class DeflateCompressor : Compressor
{
    private const string DeflateEncoding = "deflate";

    public override string EncodingType
    {
        get { return DeflateEncoding; }
    }

    public override Stream CreateCompressionStream(Stream output)
    {
        return new DeflateStream(output, CompressionMode.Compress, leaveOpen: true);
    }

    public override Stream CreateDecompressionStream(Stream input)
    {
        return new DeflateStream(input, CompressionMode.Decompress, leaveOpen: true);
    }
}
public abstract class Compressor : ICompressor
{
    public abstract string EncodingType { get; }
    public abstract Stream CreateCompressionStream(Stream output);
    public abstract Stream CreateDecompressionStream(Stream input);

    public virtual Task Compress(Stream source, Stream destination)
    {
        var compressed = CreateCompressionStream(destination);

        return Pump(source, compressed)
            .ContinueWith(task => compressed.Dispose());
    }

    public virtual Task Decompress(Stream source, Stream destination)
    {
        var decompressed = CreateDecompressionStream(source);

        return Pump(decompressed, destination)
            .ContinueWith(task => decompressed.Dispose());
    }

    protected virtual Task Pump(Stream input, Stream output)
    {
        return input.CopyToAsync(output);
    }
}

public interface ICompressor
{
    string EncodingType { get; }
    Task Compress(Stream source, Stream destination);
    Task Decompress(Stream source, Stream destination);
}

public class GZipCompressor : Compressor
{
    private const string GZipEncoding = "gzip";

    public override string EncodingType
    {
        get { return GZipEncoding; }
    }

    public override Stream CreateCompressionStream(Stream output)
    {
        return new GZipStream(output, CompressionMode.Compress, leaveOpen: true);
    }

    public override Stream CreateDecompressionStream(Stream input)
    {
        return new GZipStream(input, CompressionMode.Decompress, leaveOpen: true);
    }
}

解压缩工作正常，我有我的request.Content填充结果是我的解压缩JSON。

当我将它传递给base.SendAsync并且它命中我的控制器方法时，模型为null，而在我实现压缩之前，它一切都很好。

我已经读过，当您阅读内容流时，它是一次性的事情，但我认为将request.content设置为解压缩的结果应该让它再次被读取？

Answer 1

我解决了这个问题。

我的HTTPClient实现中出现错误，我已经从使用PostAsJsonAsync转移到PostAsync来执行压缩客户端，但是没有添加Content-Type标头来指定application / json。

在客户端完成此操作后，所有操作都按计划进行。

DelegatingHandler在WebApi中解压缩传入的请求

1 个答案: