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I assume you mean in the example at the top of the page. In theory, a view function should just take a request object and return a response object that encodes 200 OK if all went well, and something wilder like 404 Not Found or 500 Internal Server Error if something goes awry. In practice, problems can happen at a much lower level than HTTP error codes are designed to handle, like "database connection refused" or "template file not found". Rust's general-purpose error-handling system is the Result<T, E> type, where T is some useful return type, and E is some type representing an error. A function that does error-handling is declared as returning, say, Result<String, MyError>, and then in the body of the function you can "return Ok(somestring)" or "return Err(someerror)". I see that the example function returns an instance of type IronResult<Response>, which I assume is a wrapper around Result<T, E> that hard-codes E to be some Iron-specific error type (in the same way that Rust's std::io::Result<T> is shorthand for Result<T, std::io::Error>), so the Ok() is telling the framework "this is an actual legitimate response you should send to the browser", as opposed to an excuse for not producing a response. |