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Do not send binary gRPC metadata on InvokeBinding calls #1901

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Merged
WhitWaldo merged 1 commit into from
Aug 25, 2026
Merged

Do not send binary gRPC metadata on InvokeBinding calls #1901

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23 changes: 23 additions & 0 deletions src/Dapr.Client/DaprClientGrpc.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -349,6 +349,7 @@ public override async Task<BindingResponse> InvokeBindingAsync(BindingRequest re
}

var options = CreateCallOptions(headers: null, cancellationToken);
RemoveBinaryMetadata(options.Headers);
try
{
return await client.InvokeBindingAsync(envelope, options);
Expand Down Expand Up @@ -2308,6 +2309,28 @@ private CallOptions CreateCallOptions(Metadata headers, CancellationToken cancel
return options;
}

/// <summary>
/// Removes binary gRPC metadata entries (keys ending in "-bin", such as grpc-trace-bin) because
/// the runtime copies InvokeBinding call metadata into string binding component metadata, where
/// raw bytes break components that require text values. Trace context still propagates via the
/// traceparent and tracestate headers.
/// </summary>
private static void RemoveBinaryMetadata(Metadata headers)
{
if (headers is null)
{
return;
}

for (var i = headers.Count - 1; i >= 0; i--)
{
if (headers[i].Key.EndsWith("-bin", StringComparison.OrdinalIgnoreCase))

@WhitWaldo WhitWaldo Aug 25, 2026

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@JoshVanL Should this look for endswith("bin") instead of "-bin" given the example here of "x-ms-meta-daprgrpctracebin"?

@JoshVanL JoshVanL Aug 25, 2026

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@WhitWaldo no I think keeping the -bin is correct:

https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md

Note that HTTP2 does not allow arbitrary octet sequences for header values so binary header values must be encoded using Base64 as per https://tools.ietf.org/html/rfc4648#section-4. Implementations MUST accept padded and un-padded values and should emit un-padded values. Applications define binary headers by having their names end with "-bin". Runtime libraries use this suffix to detect binary headers and properly apply base64 encoding & decoding as headers are sent and received.

x-ms-meta-daprgrpctracebin is not a proper gRPC binary header AFAIK

{
headers.RemoveAt(i);
}
}
}

/// <summary>
/// Makes Grpc call using the cancellationToken and handles Errors.
/// All common exception handling logic will reside here.
Expand Down
31 changes: 31 additions & 0 deletions test/Dapr.Client.Test/InvokeBindingApiTest.cs
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Expand Up @@ -16,6 +16,7 @@ namespace Dapr.Client.Test;

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text.Json;
using System.Threading;
Expand Down Expand Up @@ -156,6 +157,36 @@ public async Task InvokeBindingAsync_WithRequest_ValidateRequest()
});
}

[Fact]
public async Task InvokeBindingAsync_StripsBinaryHeadersButKeepsTraceparent()
{
await using var client = TestClient.CreateForDaprClient();

var previousActivity = Activity.Current;
using var activity = new Activity("test-binding");
activity.SetIdFormat(ActivityIdFormat.W3C);
activity.Start();

try
{
var invokeRequest = new InvokeRequest() { RequestParameter = "Hello " };
var request = await client.CaptureGrpcRequestAsync(async daprClient =>
{
await daprClient.InvokeBindingAsync<InvokeRequest>("test", "create", invokeRequest);
});

request.Dismiss();

// The runtime copies InvokeBinding call metadata into string binding component metadata,
// which must be valid text, so binary (-bin) gRPC metadata must not be sent on this call.
request.Request.Headers.Any(h => h.Key.EndsWith("-bin", StringComparison.OrdinalIgnoreCase)).ShouldBeFalse();
request.Request.Headers.Contains("traceparent").ShouldBeTrue();
}
finally
{
Activity.Current = previousActivity;
}
}

[Fact]
public async Task InvokeBindingAsync_WithCancelledToken()
Expand Down
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