\label{Authoring_ExternalResponse}


\textbf{externalresponse} is an advanced type of response tag that
implements the ability to have an external program grade a response.
It expects either a \textbf{textline} or \textbf{textfield} inside
the tag. Possible attributes are:

\begin{itemize}
\item \textbf{url}\index{url}: url to submit the answer form to. It does
not need to be a LON-CAPA machine.
\item \textbf{answer}\index{answer}:  string or scalar variable that can
encode something that should encode the correct answer. In some cases,
this may be nothing. 
\item \textbf{form}\index{form}: hash variable name that will be submitted
to the remote site as a HTTP form.
\end{itemize}
The response of the remote server needs to be in XML as follows: 

\begin{itemize}
\item \textbf{loncapagrade}\index{loncapagrade}: takes no attributes, but
must surround the response.
\item \textbf{awardetail}\index{awardetail}: required. The delimited text
inside must be one of the detailed results that appears in the data
storage documentation. CVS:loncapa/doc/homework/datastorage, look
for \textbf{resource.partid.responseid.awarddetail}.
\item \textbf{message}\index{message}: optional message to have shown to
the student.
\end{itemize}
Example: \begin{verbatim} <loncapagrade>
    <awardetail>INCORRECT</awardetail>
    <message>
A message to be shown to the students
    </message>
</loncapagrade>
\end{verbatim}