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extractor

A handler argument that pulls one piece of data out of the request, like the path or the JSON body.

In axum, handler parameters implement FromRequestParts/FromRequest (Path, Query, Json, State); a failed extraction rejects the request with a 4xx response.

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Examples

  • async fn one(Path(id): Path<u32>) pulls id from /tools/{id}; for /tools/abc axum rejects the request with 400 Bad Request before the handler runs.

See also

middleware HTTP status code serialization
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