UIMessageStreamExtensions

Namespace: Vercel.AI.AspNetCore

public static class UIMessageStreamExtensions

Writes a StreamTextResult as an AI SDK UI message stream.

Inheritance: object

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Methods

ToUIMessageStreamResult(StreamTextResult, int?, Func<string, string>?)

public static IResult ToUIMessageStreamResult(this StreamTextResult result, int? keepAliveMs = null, Func<string, string>? onError = null)

Returns a text/event-stream result a JavaScript useChat client can consume. Emitted chunks are start, text, reasoning, tool input/output, tool approval request, source-url, step boundaries, finish, abort, and error. Finish reasons use the protocol values stop, length, content-filter, tool-calls, error, and other.

Parameters

Name	Type	Description
result	StreamTextResult	The stream to write.
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.
onError	Func<string, string>	Optional mapper for error chunk text. Null writes An error occurred.. Errors of provider-executed tools are not masked.

Returns: IResult

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