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Entry  17 Jun 2008, Stefan Ritt, Info, Improvement of custom pages Capture.png
    Reply  31 Jul 2008, Stefan Ritt, Info, Improvement of custom pages location.png
Message ID: 492     Entry time: 17 Jun 2008     Reply to this: 496
Author: Stefan Ritt 
Topic: Info 
Subject: Improvement of custom pages 
Some improvement of custom pages have been implemented. The idea behind is that
a custom page would contain a large background image containing indicators but
also controls. While indicators (values, bars) are already available, the field
of controls have been improved.

Edit boxes floating on top of a graphic

The first option has been there from the beginning, but was never documented. It
makes it possible to put an edit box right on top of a graphic by means of a CSS
style tag. The custom page code could look like this:

<div style="position:absolute; top:100px; left:50px;">
<odb src="/Runinfo/run number" edit=1>
<img src="cusgom.gif">

The "div" tag surrounding the "odb" tag places this directly on top of the
"custom.gif" image, where it can be clicked to be edited.

Password protection of an edit box

Being able to control an experiment through a web interface of course rises the
question about safety. This is not so much about external access (for which we
have other protection schemes like host lists etc.) but it's about accidental
access by the normal shift crew. If a single click on a web page opens a
critical valve, this might be a problem. In order to restrict access to some
"experts", an additional password can be chosen for all or some controls on a
custom page. This is done by a new option in the "odb" tag and by adding a small
JavaScript function into the custom page:

<script type="text/javascript">
function promptpwd(path)
    pwd = prompt('Please enter password', '');
    document.cookie = "cpwd=" + pwd;
    location.href = path;


<odb src="/..." edit=1 pwd="CustomPwd">


If the "pwd" option is present in the "odb" tag, mhttpd establishes a call to
the promptpwd() function if one click on the value. The password is then asked
from the user and submitted as a cookie. mhttpd then check this password against
the ODB entry


and shows an error if they don't match. By using an explicit name ("CustomPwd"
in the above example) one can use a single password for all controls on a page,
or one could use several passwords on the same page. Like a shift crew password
for the less severe controls (/Custom/Pwd/ShiftPwd), and an "expert" password
(/Custom/Pwd/ExpertPwd) for the critical things. This password is of course not
secure in the sense that it's placed in plain text into the ODB, it's more to
prevent accidental modifications of things.

Area map to toggle values

Sometimes it's desirable to toggle a value, like the state of a valve. This can
be done now with a new function like this:

<map name="Custom1">
<area shape="rect" coords="40,200,100,300" alt="Main Valve"
<img src="cusgom.gif" usemap="#Custom1">

This defines a clickable map on top of the custom image. The area(s) should
match with some areas on the image like the box of a valve. By clicking on it,
the supplied path to the ODB is used (in this case
"/Equpiment/Environment/Variables[2]") and it's value is toggled (set to 0 if it
is 1, set to 0 if it is 1). If the valve value is then used in the image via a
"fill" statement to change the color of the valve, it can turn green or red
depending on it's state.

Are map with password check

The above area map can be combined with the password check. To do so, one needs:

<area shape="rect" coords="40,200,100,300" alt="Main Valve"

in combination with the JavaScript from above.

An example of the are map technology is shown in the attachment. This page from the MEG experiment at PSI
shows a complex gas system. The valves are represented as green circles. If they are clicked, they close
and become red (after the user successfully supplied the correct password).
Attachment 1: Capture.png  44 kB  Uploaded 17 Jun 2008  | Show | Show all
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