UIMessageStreamResult

Namespace: Vercel.AI.AspNetCore

public sealed class UIMessageStreamResult : IResult

SSE result for the AI SDK UI message protocol.

Inheritance: object

Implements: IResult

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Constructors

`UIMessageStreamResult(StreamTextResult, int?, Func<string, string>?)`

public UIMessageStreamResult(StreamTextResult result, int? keepAliveMs = null, Func<string, string>? onError = null)

Creates a result that writes <code class=“paramref”>result</code>.

Parameters

Name	Type	Description
`result`	StreamTextResult	The stream to write.
`keepAliveMs`	int?	Optional idle interval, in milliseconds. Null sends no SSE comments.
`onError`	Func<string, string>	Optional mapper for `error` chunk text. Null writes `An error occurred.`.

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Methods

ExecuteAsync(HttpContext)

public Task ExecuteAsync(HttpContext httpContext)

Write an HTTP response reflecting the result.

Parameters

Name	Type	Description
`httpContext`	HttpContext	The HttpContext for the current request.

Returns: Task — A task that represents the asynchronous execute operation.

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`WriteAsync(StreamTextResult, Stream, int?, CancellationToken, Func<string, string>?)`

public static Task WriteAsync(StreamTextResult result, Stream destination, int? keepAliveMs = null, CancellationToken cancellationToken = default, Func<string, string>? onError = null)

Writes the UI message stream to <code class=“paramref”>destination</code>.

Parameters

Name	Type	Description
`result`	StreamTextResult	The stream to write.
`destination`	Stream	The response body or another writable stream.
`keepAliveMs`	int?	Optional idle interval, in milliseconds. Null sends no SSE comments. A positive value up to 2147483647 writes `: stream-open` before the start event and `: keep-alive` while the next part is still pending.
`cancellationToken`	CancellationToken	Cancels the write and stops keep-alive comments. ASP.NET Core passes `HttpContext.RequestAborted`.
`onError`	Func<string, string>	Optional mapper for `error` chunk text. Null writes `An error occurred.`.

Returns: Task

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`WriteChunksAsync(IReadOnlyList<JsonObject>, Stream, CancellationToken)`

public static Task WriteChunksAsync(IReadOnlyList<JsonObject> chunks, Stream destination, CancellationToken cancellationToken = default)

Writes already-built UI message chunks as SSE, then data: [DONE].

Parameters

Name	Type	Description
`chunks`	IReadOnlyList<JsonObject>	Chunk objects. Each one is one `data:` frame.
`destination`	Stream	The response body or another writable stream.
`cancellationToken`	CancellationToken	Cancels the write.

Returns: Task

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