Blazor Web can use BasePath component instead of <base href="">
#64590
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Pull request overview
This PR introduces a new BasePath component that allows Blazor Web applications to dynamically set the <base href=""> element based on the current request path base, providing an alternative to hardcoded base tags. The component intelligently determines the base path from multiple sources with a clear precedence order.
Key changes:
- Added
BasePathcomponent with automatic path base detection fromIHttpContextAccessor,NavigationManager, and fallback options - Introduced a new dependency on
Microsoft.AspNetCore.Http.Abstractionsfor accessing request context - Exposed new public API surface including the
BasePathclass and itsHrefandFallbackHrefproperties
Reviewed changes
Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.
| File | Description |
|---|---|
| src/Components/Web/src/Head/BasePath.cs | New sealed component that renders a <base> element with href computed from request PathBase, explicit parameters, or NavigationManager |
| src/Components/Web/src/PublicAPI.Unshipped.txt | Adds public API entries for the new BasePath component and its properties |
| src/Components/Web/src/Microsoft.AspNetCore.Components.Web.csproj | Adds reference to Microsoft.AspNetCore.Http.Abstractions for IHttpContextAccessor support |
javiercn
requested changes
Dec 2, 2025
src/Components/Web/test/Microsoft.AspNetCore.Components.Web.Tests.csproj
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src/Components/Web/src/Microsoft.AspNetCore.Components.Web.csproj
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ilonatommy
commented
Dec 2, 2025
src/Components/Endpoints/test/Microsoft.AspNetCore.Components.Endpoints.Tests.csproj
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javiercn
approved these changes
Dec 3, 2025
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Summary
Proposal addressing #6818 by introducing a reusable
BasePathcomponent that centralizes how Blazor apps compute their<base>URI when hosted under subpaths.Background
Routing case preservation for apps mounted at
/dashboardor similar previously required manual<base href>edits or per-app JavaScript. Those workarounds were inconsistent across hosting models and easy to break during deployment. Moving the logic into the Endpoints package givesBlazor Weba single, framework-owned solution while standaloneWebAssemblyapps keep using their static<base />.This gives developers a first-class, framework-supported answer instead of per-app workarounds mentioned throughout #6818.
Changes
Public API
Implementation Details
BasePathimplementsIComponent, renders a<base>element viaRenderHandle, and resolves the href fromNavigationManager.BaseUri./if the base URI cannot be parsed, but otherwise mirrors both casing and multi-segment paths exposed by the endpoint pipeline.NavigationManager.src/Components/Endpoints/src/Routing/BasePath.csand will share the directory with future routing-related document helpers.Tests
The component is covered with unit tests and passed manual testing. Adding e2e test seems too heavy for this kind of change.
API usage
Fixes #6818.