Add WriteLiteral(ReadOnlyMemory<byte>) for UTF-8 HTML literal support#66429
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Add WriteLiteral(ReadOnlyMemory<byte>) for UTF-8 HTML literal support#66429DamianEdwards wants to merge 4 commits intomainfrom
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DamianEdwards
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Apr 23, 2026
| else | ||
| { | ||
| // For non-UTF-8 encodings or non-buffered writers, decode to string | ||
| // and use the existing string-based write path. |
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Might be better to defer this to the writer chain so that adjacent UTF8 literals could be coalesced and encoded in as a single block?
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Implements UTF-8 HTML literal support for MVC Razor views (issue #65605) with a direct byte write path through the entire writer chain so that UTF-8 literal bytes from Razor-compiled views flow directly to the response stream without ever being converted to a string. Changes: - Add Utf8HtmlLiteralContent: internal IHtmlContent wrapper that carries ReadOnlyMemory<byte> UTF-8 literal bytes through the ViewBuffer pipeline - Add RazorPageBase.WriteLiteral(ReadOnlyMemory<byte>): new public API overload that buffers UTF-8 content when encoding is UTF-8, or decodes to string for non-UTF-8 encodings - Add HttpResponseStreamWriter.WriteUtf8/WriteUtf8Async: public methods that flush pending char data then write raw UTF-8 bytes directly to the underlying stream, bypassing char-to-byte encoding entirely - Add PagedBufferedTextWriter.WriteUtf8/WriteUtf8Async: internal methods that flush buffered chars then forward UTF-8 bytes to the inner writer - Special-case Utf8HtmlLiteralContent in ViewBuffer.WriteTo/WriteToAsync to route through the direct UTF-8 write path when the writer chain supports it, avoiding both string conversion and per-item flush penalty - Add comprehensive unit tests and end-to-end tests verifying bytes flow directly to the response stream - Add example manually-authored generated view classes that simulate what the Razor compiler will emit when it supports u8 string literals Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Apr 23, 2026
| /// The writer's encoding is not UTF-8. | ||
| /// </exception> | ||
| [SuppressMessage("ApiDesign", "RS0027:Public API with optional parameter(s) should have the most parameters amongst its public overloads.", Justification = "Required to maintain compatibility")] | ||
| public Task WriteUtf8Async(ReadOnlyMemory<byte> utf8Value, CancellationToken cancellationToken = default) |
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Wonder if we should use ValueTask
- Update WriteLiteral method to accept ReadOnlyMemory<byte> directly. - Remove Utf8HtmlLiteralContent class and integrate its functionality into ViewBuffer. - Modify ViewBufferValue to support UTF-8 encoded values. - Update tests to reflect changes in UTF-8 handling and remove obsolete tests. - Enhance benchmarks for UTF-8 writing performance. Co-authored-by: Copilot <copilot@github.com>
This was referenced Apr 24, 2026
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Summary
Implements UTF-8 HTML literal support for MVC Razor views per #65605, with a direct byte write path through the entire writer chain so that UTF-8 literal bytes from Razor-compiled views flow directly to the response stream without ever being converted to a string.
The direct UTF-8 write path
At flush time, when
ViewBufferencounters aUtf8HtmlLiteralContententry:ViewBuffer.WriteToAsyncdetects the writer is aPagedBufferedTextWriterPagedBufferedTextWriter.WriteUtf8Asyncflushes any buffered chars, then forwards to the inner writerHttpResponseStreamWriter.WriteUtf8Asyncflushes any pending char buffer (with encoder finalization), then writes the raw UTF-8 bytes directly to the responseStreamResult: zero string allocations, zero char-to-byte encoding — the compile-time UTF-8 bytes are copied directly to the output.
Changes
Utf8HtmlLiteralContent— InternalIHtmlContentwrapper carryingReadOnlyMemory<byte>through theViewBufferRazorPageBase.WriteLiteral(ReadOnlyMemory<byte>)— New public API. When UTF-8 +ViewBufferTextWriter, buffers asUtf8HtmlLiteralContent. Otherwise decodes to string.HttpResponseStreamWriter.WriteUtf8/WriteUtf8Async— New public methods that flush pending chars then write raw UTF-8 bytes directly to the underlying stream. ThrowsInvalidOperationExceptionif encoding is not UTF-8.PagedBufferedTextWriter.WriteUtf8/WriteUtf8Async— Internal methods that flush buffered chars then forward UTF-8 bytes to the innerHttpResponseStreamWriter(falls back to string for other writers).ViewBuffer.WriteTo/WriteToAsync— RoutesUtf8HtmlLiteralContentthrough the direct UTF-8 path when the writer chain supports it. Avoids both string conversion and per-itemFlushAsyncpenalty.u8literalsTesting
HttpResponseStreamWriter.WriteUtf8tests: direct writes, ordering, non-UTF-8 rejection, disposed state (11 tests)PagedBufferedTextWriter.WriteUtf8tests: forwarding, ordering, fallback (5 tests)ViewBufferend-to-end tests: bytes flow directly to stream through full writer chain (3 tests)Utf8HtmlLiteralContentunit tests (6 tests)RazorPageBase.WriteLiteral(ReadOnlyMemory<byte>)unit tests (5 tests)Fixes #65605