\label{Docs_Adding_External_Tool}

External tools which support the LTI (Learning Tool Interoperability)
standard can be included within a LON-CAPA course.  Which tools are available,
as well as the options which can be set by a Coordinator when including 
one of the available tools within a course or community, are set by the Domain 
Coordinator at a domain level. 

The full range of options which may be available to the Coordinator in the course
or community are:

\begin{itemize}

\item Display type 
\begin{itemize}
\item iframe -- the tool will be launched within the standard interface, (i.e.,
inline menu including navigation controls, and links/icons)

\item tab -- a page containing a link to launch the tool will be displayed
in a separate web browser tab.

\item window -- a page containing a link to launch the tool will be displayed
in a separate web browser window.

\end{itemize}

\item Display options -- if display is tab or window, additional options may be available:

\begin{itemize}

\item Link Text -- the text used in the link which launches the tool
\item Explanation -- optional text block (HTML mark-up can be used)
displayed below the link
\item Width/Height -- if display is window, width and height of the new window
can be set by specifying the number of pixels to use for each. 

\end{itemize}

\item Course label -- e.g., institutional course code (sent on launch of tool)
\item Course title -- Course Title

\item Title -- title to use for tool instance on the Course Contents page.

\end{itemize}

If external LTI tools can be used in the course's domain, you will select the
name of the tool you wish to use from the ``Select'' drop-down list. Doing 
so will cause the options for the tool to be displayed. If display is in
an iframe, by default, but you are permitted to choose one of the other types,
then click tab or window will cause additional elements to be displayed.

Your domain coordinator can tell you what data are sent to the external tool
when it is displayed. Typically, though, this will include the username of the
user, as well as the user's current ``LTI'' role. LTI uses a more restricted
set of roles -- Instructor, Content Developer, Teaching Assistant or Learner --
than are available in LON-CAPA. Your domain coordinator will have decided on
the mapping to an LTI role to be used for each standard LON-CAPA role. At a minimum
you can expect that Course Coordinator (LON-CAPA) will map to Instructor (LTI),
Student (LON-CAPA) will map to Learner (LTI).

Under the LTI protocol, the user's identity, as well as the course context, will
be sent to the external tool in an encrypted form, and the tool (the LTI Provider)
will trust the user's identity and role sent from LON-CAPA (the LTI Consumer),
and then assign appropriate privileges to the user within the tool.