Trait elastic_responses::parsing::IsOk [−] [src]

pub trait IsOk {
    fn is_ok<B: ResponseBody>(
        head: HttpResponseHead, 
        unbuffered: Unbuffered<B>
    ) -> Result<MaybeOkResponse<B>, ParseResponseError>;
}

Convert a response message into a either a success or failure result.

This is the main trait that drives response parsing by inspecting the http status and potentially buffering the response to determine whether or not it represents a successful operation. This trait doesn't do the actual deserialisation, it just passes on a MaybeOkResponse.

Some endpoints may not map success or error responses directly to a status code. In this case, the Unbuffered body can be buffered into an anonymous json object and inspected for an error node. The Unbuffered type takes care of response bodies that can only be buffered once.

Any type that implements IsOk can be deserialised by parse. Implementations should behave in the following way:

  • If the response is successful, this trait should return Ok(MaybeOkResponse::ok).
  • If the response is an error, this trait should return Ok(MaybeOkResponse::err).
  • If the response isn't recognised or is otherwise invalid, this trait should return Err.

Examples

Implement IsOk for a custom response type, where a http 404 might still contain a valid response:

impl IsOk for MyResponse {
    fn is_ok<B: ResponseBody>(head: HttpResponseHead, unbuffered: Unbuffered<B>) -> Result<MaybeOkResponse<B>, ParseResponseError> {
        match head.status() {
            200...299 => Ok(MaybeOkResponse::ok(unbuffered)),
            404 => {
                // If we get a 404, it could be an IndexNotFound error or ok
                // Check if the response contains a root 'error' node
                let (body, buffered) = unbuffered.body()?;

                let is_ok = body.as_object()
                    .and_then(|body| body.get("error"))
                    .is_none();

                Ok(MaybeOkResponse::new(is_ok, buffered))
            }
            _ => Ok(MaybeOkResponse::err(unbuffered)),
        }
    }
}

Required Methods

Inspect the http response to determine whether or not it succeeded.

Implementors