/// <summary>
/// Allows configuring the <see cref="SocketsHttpHandler"/> instance. The base implementation
/// applies settings from <see cref="ProxyHttpClientContext.NewConfig"/>.
/// <see cref="SocketsHttpHandler.UseProxy"/>, <see cref="SocketsHttpHandler.AllowAutoRedirect"/>,
/// <see cref="SocketsHttpHandler.AutomaticDecompression"/>, and <see cref="SocketsHttpHandler.UseCookies"/>
/// are disabled prior to this call.
/// </summary>
protected virtual void ConfigureHandler(ProxyHttpClientContext context, SocketsHttpHandler handler)
{
var newConfig = context.NewConfig;
if (newConfig.SslProtocols.HasValue)
{
handler.SslOptions.EnabledSslProtocols = newConfig.SslProtocols.Value;
}
if (newConfig.MaxConnectionsPerServer != null)
{
handler.MaxConnectionsPerServer = newConfig.MaxConnectionsPerServer.Value;
}
if (newConfig.DangerousAcceptAnyServerCertificate ?? false)
{
handler.SslOptions.RemoteCertificateValidationCallback = delegate { return(true); };
}
#if NET
handler.EnableMultipleHttp2Connections = newConfig.EnableMultipleHttp2Connections.GetValueOrDefault(true);
if (newConfig.RequestHeaderEncoding != null)
{
var encoding = Encoding.GetEncoding(newConfig.RequestHeaderEncoding);
handler.RequestHeaderEncodingSelector = (_, _) => encoding;
}
#endif
var webProxy = TryCreateWebProxy(newConfig.WebProxy);
if (webProxy != null)
{
handler.Proxy = webProxy;
handler.UseProxy = true;
}
}
/// <inheritdoc/>
public HttpMessageInvoker CreateClient(ProxyHttpClientContext context)
{
if (CanReuseOldClient(context))
{
Log.ProxyClientReused(_logger, context.ClusterId);
return(context.OldClient !);
}
var handler = new SocketsHttpHandler
{
UseProxy = false,
AllowAutoRedirect = false,
AutomaticDecompression = DecompressionMethods.None,
UseCookies = false
// NOTE: MaxResponseHeadersLength = 64, which means up to 64 KB of headers are allowed by default as of .NET Core 3.1.
};
ConfigureHandler(context, handler);
var middleware = WrapHandler(context, handler);
Log.ProxyClientCreated(_logger, context.ClusterId);
return(new HttpMessageInvoker(middleware, disposeHandler: true));
}
/// <summary>
/// Adds any wrapping middleware around the <see cref="HttpMessageHandler"/>.
/// The base implementation conditionally includes the <see cref="ActivityPropagationHandler"/>.
/// </summary>
protected virtual HttpMessageHandler WrapHandler(ProxyHttpClientContext context, HttpMessageHandler handler)
{
var activityContextHeaders = context.NewConfig.ActivityContextHeaders.GetValueOrDefault(ActivityContextHeaders.BaggageAndCorrelationContext);
if (activityContextHeaders != ActivityContextHeaders.None)
{
handler = new ActivityPropagationHandler(activityContextHeaders, handler);
}
return(handler);
}
protected override void ConfigureHandler(ProxyHttpClientContext context, SocketsHttpHandler handler)
{
base.ConfigureHandler(context, handler);
_configureClient(context, handler);
}
/// <summary>
/// Checks if the options have changed since the old client was created. If not then the
/// old client will be re-used. Re-use can avoid the latency of creating new connections.
/// </summary>
protected virtual bool CanReuseOldClient(ProxyHttpClientContext context)
{
return(context.OldClient != null && context.NewConfig == context.OldConfig);
}