Address remaining Blazor integration PR feedback by javiercn · Pull Request #17384 · microsoft/aspire

javiercn · 2026-05-22T15:37:04Z

Summary

Addresses remaining unresolved review threads from #15691 and adds Docker Compose publish support for the Blazor gateway.

PR Feedback Fixes

Add [ResourceName] attribute to AddBlazorGateway, AddBlazorWasmProject<T>, and AddBlazorWasmApp name parameters
Replace null-forgiving operator with explicit ?? throw in EndpointsManifestTransformer
Use StringComparison.OrdinalIgnoreCase for route comparison
Fix '.NET Aspire' phrasing in playground README files
Extract "Aspire:Store:Path" magic string to a const
Re-add OTLP misconfiguration warning at call site (where logger is available)

Docker Compose Publish Support

The ClientConfigValueProvider class (IValueProvider + IManifestExpressionProvider) is replaced with a static BuildConfigExpression() method that returns a ReferenceExpression. This makes the ConfigResponse environment variable natively understood by all publishers.

How it works:

Build JSON with a brace-free __ORIGIN__ token in place of the gateway URL
Serialize with UnsafeRelaxedJsonEscaping (we control all values, no braces present)
Escape structural JSON braces ({ -> {{) for string.Format safety
Replace __ORIGIN__ with {0} to create the format string
Build a ReferenceExpression with GatewayOriginReference as the argument

Result:

Dev mode: endpoint resolves to https://localhost:PORT — ConfigResponse contains absolute URLs
Docker Compose publish: publisher emits $${GATEWAY_BINDINGS_HTTPS_URL} — deployer fills .env

New file: GatewayOriginReference.cs — lightweight IValueProvider + IManifestExpressionProvider that wraps an EndpointReference, trims trailing slashes, and emits manifest expressions for publishers.

github-actions · 2026-05-22T15:42:41Z

🚀 Dogfood this PR with:

⚠️ WARNING: Do not do this without first carefully reviewing the code of this PR to satisfy yourself it is safe.

curl -fsSL https://raw.githubusercontent.com/microsoft/aspire/main/eng/scripts/get-aspire-cli-pr.sh | bash -s -- 17384

Or

Run remotely in PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/microsoft/aspire/main/eng/scripts/get-aspire-cli-pr.ps1) } 17384"

Copilot

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

This PR refactors how the Blazor gateway generates the WASM client configuration response, aiming to produce deployer-configurable manifest expressions while keeping dev-time behavior working, and also improves gateway publish/build inputs (image tag stamping, file locations).

Changes:

Replace the per-app IValueProvider config generator with a ReferenceExpression-based JSON builder using a gateway-origin placeholder.
Improve manifest processing robustness (explicit deserialization failure) and make the index.html route match case-insensitive.
Stamp/control the .NET Docker image tag via assembly metadata and adjust where gateway/publish artifacts are written/copied.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
src/Aspire.Hosting.Blazor/Scripts/Gateway.cs.in	Tighten nullability for `ConfigResponse` emission in the gateway script.
src/Aspire.Hosting.Blazor/Manifests/EndpointsManifestTransformer.cs	Add explicit deserialize failure and case-insensitive `index.html` detection.
src/Aspire.Hosting.Blazor/GatewayOriginReference.cs	New helper to emit a deployer-resolvable origin placeholder while resolving dev-time values.
src/Aspire.Hosting.Blazor/GatewayConfigurationBuilder.cs	Major refactor: build config JSON as a `ReferenceExpression` and remove logger-based warning path.
src/Aspire.Hosting.Blazor/BlazorHostedExtensions.cs	Adjust call site for the new config builder signature.
src/Aspire.Hosting.Blazor/BlazorGatewayExtensions.cs	Add `[ResourceName]`, change artifact paths, and revise .NET image tag resolution logic.
src/Aspire.Hosting.Blazor/Aspire.Hosting.Blazor.csproj	Add `BlazorGatewayDotNetImageTag` property and stamp it into assembly metadata.
playground/BlazorStandalone/README.md	Documentation wording update (“Aspire” instead of “.NET Aspire”).
playground/BlazorHosted/README.md	Documentation wording update (“Aspire” instead of “.NET Aspire”).

PR feedback from microsoft#15691: - Add [ResourceName] attribute to all Add* API name parameters - Replace null-forgiving operator with explicit throw in EndpointsManifestTransformer - Use StringComparison.OrdinalIgnoreCase for route comparison - Fix '.NET Aspire' phrasing in README files Docker Compose publish fixes for Blazor gateway: - Add GatewayOriginReference (IValueProvider + IManifestExpressionProvider) - Use ReferenceExpression for ConfigResponse so publishers emit proper placeholders - Use TextEncoderSettings to escape braces in JSON string values - Simplify Gateway.cs.in (serve ConfigResponse directly, no Replace logic) - Add System.Text.Unicode dependency for brace-escaping encoder Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

JamesNK

One issue found: missing OTLP misconfiguration warning in the hosted Blazor path (BlazorHostedExtensions.cs). The rest of the changes look correct.

JamesNK · 2026-05-25T13:41:53Z

@@ -99,7 +99,6 @@ private static void EnsureEnvironmentCallback(
                annotation.Services,


The OTLP misconfiguration warning was re-added at the call site in BlazorGatewayExtensions.cs (standalone gateway path), but the equivalent warning is missing here in the hosted Blazor path. When httpOtlpEndpointUrl is null and annotation.ProxyBlazorTelemetry is true, the user gets no diagnostic indicating that WASM client telemetry won't be forwarded.

The old ClientConfigValueProvider.LogOtlpWarningIfNeeded() covered both paths; now only the standalone gateway warns.

var httpOtlpEndpointUrl = BlazorGatewayExtensions.ResolveHttpOtlpEndpointUrl(context, host.ApplicationBuilder.Configuration); if (httpOtlpEndpointUrl is null && annotation.ProxyBlazorTelemetry) { context.Logger.LogWarning( "OTLP telemetry proxying was requested but no dashboard HTTP endpoint could be resolved. " + "WASM client telemetry will not be forwarded."); }

Ensure there are tests for both scenarios that check a warning is logged.

Done — added in 9759ffb:

\ProxyTelemetry_LogsWarning_WhenOtlpEndpointNotResolvable\ — verifies the warning fires when ProxyBlazorTelemetry is true but no HTTP OTLP endpoint is available.

\ProxyTelemetry_DoesNotLogWarning_WhenOtlpEndpointIsConfigured\ — verifies no spurious warning when the endpoint is properly configured.

Added the equivalent warning in the hosted path in 9759ffb. Both standalone and hosted paths now log when telemetry proxying is requested but no OTLP endpoint is resolvable.

JamesNK · 2026-05-25T13:52:28Z

+        var format = json
+            .Replace("{", "{{")
+            .Replace("}", "}}")
+            .Replace(OriginToken, "{0}");


Yuck. It works I guess.

JamesNK · 2026-05-25T13:59:38Z

+            // Send only the OTLP path so the WASM client resolves it against its own
+            // page origin (HostEnvironment.BaseAddress). This avoids cross-origin issues
+            // when the user navigates via HTTP but the gateway also exposes HTTPS.
+            environment["ASPIRE_OTLP_PATH_BASE"] = $"{pathBase}/{otlpPrefix}";


I didn't notice before, but this basically replaces OTEL_EXPLORTER_OTLP_ENDPOINT.

I would prefer that the standard endpoint env var was still used, and then clients replaced the scheme/host with the current web page scheme/host.

Done — renamed ASPIRE_OTLP_PATH_BASE to OTEL_EXPORTER_OTLP_ENDPOINT in 3832dea. The value remains a relative path that the WASM client resolves against its page origin (HostEnvironment.BaseAddress) to stay same-origin and avoid CORS issues.

The standalone gateway path already logged a warning when telemetry proxying was requested but no HTTP OTLP endpoint could be resolved. The hosted model (ProxyBlazorTelemetry via BlazorHostedExtensions) was missing the equivalent diagnostic. - Add LogWarning in BlazorHostedExtensions.EnsureEnvironmentCallback - Add tests verifying the warning fires (and does not fire) in both scenarios Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Use the standard OpenTelemetry environment variable name instead of a custom Aspire-specific one. The value remains a relative path that the WASM client resolves against its page origin to stay same-origin. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

javiercn force-pushed the javiercn/blazor-integration-follow-ups branch from 0fa6022 to 910da9e Compare May 22, 2026 15:41

github-actions Bot mentioned this pull request May 22, 2026

[repo-pulse] 📊 Repo Pulse — Daily Activity Dashboard #16404

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javiercn force-pushed the javiercn/blazor-integration-follow-ups branch 2 times, most recently from 9b4238d to 4be1b69 Compare May 22, 2026 17:07

javiercn marked this pull request as ready for review May 22, 2026 18:08

Copilot AI review requested due to automatic review settings May 22, 2026 18:08

Copilot AI reviewed May 22, 2026

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javiercn force-pushed the javiercn/blazor-integration-follow-ups branch from 4be1b69 to ae9ce87 Compare May 22, 2026 18:20

JamesNK reviewed May 25, 2026

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javiercn and others added 2 commits May 25, 2026 18:18

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Address remaining Blazor integration PR feedback#17384

Address remaining Blazor integration PR feedback#17384
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		@@ -99,7 +99,6 @@ private static void EnsureEnvironmentCallback(
		annotation.Services,

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Summary

PR Feedback Fixes

Docker Compose Publish Support

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