(module $wasi_experimental_http
  (typename $http_error
    (enum (@witx tag u32)
      ;;; Success
      $success
      ;;; Invalid handle
      $invalid_handle
      ;;; Memory not found
      $memory_not_found
      ;;; Memory access error
      $memory_access_error
      ;;; Buffer too small
      $buffer_too_small
      ;;; Header not found
      $header_not_found
      ;;; UTF-8 error
      $utf8_error
      ;;; Destination not allowed
      $destination_not_allowed
      ;;; Invalid method
      $invalid_method
      ;;; Invalid encoding
      $invalid_encoding
      ;;; Invalid URL
      $invalid_url
      ;;; Request error
      $request_error
      ;;; Runtime error
      $runtime_error
      ;;; Too many sessions
      $too_many_sessions
    )
  )

  ;;; Handles for the HTTP extensions
  (resource $http_handle)

  ;;; HTTP status code
  (typename $status_code u16)

  ;;; An HTTP body being sent
  (typename $outgoing_body (in-buffer u8))

  ;;; Buffer for an HTTP body being received
  (typename $incoming_body (out-buffer u8))

  ;;; A response handle
  (typename $response_handle (handle $http_handle))

  ;;; Buffer to store a header value
  (typename $header_value_buf (out-buffer u8))

  ;;; Number of bytes having been written
  (typename $written_bytes (@witx usize))

  ;;; Send a request
    (@interface func (export "req")
        (param $url string)
        (param $method string)
        (param $headers string)
        (param $body $outgoing_body)
        (result $error (expected (tuple $status_code $response_handle) (error $http_error)))
    )

  ;;; Close a request handle
    (@interface func (export "close")
        (param $response_handle $response_handle)
        (result $error (expected (error $http_error)))
    )

  ;;; Get the value associated with a header
    (@interface func (export "header_get")
        (param $response_handle $response_handle)
        (param $header_name string)
        (param $header_value_buf $header_value_buf)
        (result $error (expected $written_bytes (error $http_error)))
    )

  ;;; Fill a buffer with the streamed content of a response body
    (@interface func (export "body_read")
        (param $response_handle $response_handle)
        (param $body_buf $incoming_body)
        (result $error (expected $written_bytes (error $http_error)))
    )
)