The response model

pub record Response {
  status: Int,
  reason: String,
  headers: List Header,
  body: BitString,
}

Response represents a response received from the server. HTTP status codes are not transport errors in Rata, so 404, 409, and 500 all arrive as Ok(response) when the network request completed successfully.

Status helpers

pub fun is_success : Response -> Bool
pub fun is_redirect : Response -> Bool
pub fun is_client_error : Response -> Bool
pub fun is_server_error : Response -> Bool
pub fun expect_status : Int -> Response -> Result Response FetchStatusError
pub fun expect_success : Response -> Result Response FetchStatusError

Use expect_success when an application branch wants to reject non-2xx responses:

case Fetch.get "https://example.com/data.json" {
  Err error -> dbg error
  Ok response -> case Fetch.expect_success response {
    Ok successful -> dbg successful.status
    Err status_error -> dbg status_error
  }
}

Headers

Response headers are preserved as a list of Header records:

pub record Header {
  name: String,
  value: String,
}

Lookup helpers are case-insensitive:

pub fun header : String -> Response -> Maybe String
pub fun headers : String -> Response -> List String
pub fun content_type : Response -> Maybe String
pub fun content_length : Response -> Maybe Int

header returns the first matching value. Use headers for values that may repeat, such as Set-Cookie.

Bodies

Response bodies are raw BitString values:

response.body

For UTF-8 text responses, use:

pub fun body_text : Response -> Result String String

The conversion can fail because HTTP bodies can be arbitrary bytes. JSON decoding belongs in your JSON library or application layer:

case Fetch.expect_success response {
  Ok successful -> decode_json successful.body
  Err status_error -> Err status_error
}