/Script ODB tree

Links

• Online Database
• mhttpd status page
• ODB
• /Customscript ODB tree

Purpose

The optional /Script ODB tree provides the user with a way to execute a script when a button on the mhttpd status page is clicked, including the capability of passing parameters from the ODB to the user-written script.

Creating the /Script tree

The /Script ODB tree is created by the user. This tree is optional, and apart from the tree name /Script, names of any keys in this tree are chosen by the user.

If the user creates a new ODB tree named /Script , then any key /Script/<button name> created in this tree will appear as a script-button named <button name> on the default mhttpd status page. Each subtree /Script/<button name>/ should contain at least one key which contains the path and name of the script. This key should be the first in the list of keys in the subtree, and will be used to execute the script when the script-button is pressed. Any further keys will be passed as arguments to the script. MIDAS symbolic links are permitted.

Example /Script tree

The example below shows the ODB /Script/DAC subtree. The presence of the DAC subtree will cause the system to created a script-button labelled DAC on the mhttpd status page.

The first key in the DAC subtree is the key cmd which contains the name and path of the script to be executed (in this case, a perl script). This script is located on the local host computer on which the experiment is running. The subsequent keys are parameters input to the script. The key experiment name is a soft-link to the ODB key /experiment/name.

[local:pol:R]/>ls "/script/DAC"
cmd                             /home/pol/online/perl/change_mode.pl
include path                    /home/pol/online/perl
experiment name -> /experiment/name
                                pol
select mode                     1h
mode file tag                   none
[local:pol:R]/>  

When the script-button "DAC" is pressed, the script "change_mode.pl" will be executed with the following key contents as parameters, equivalent to the command:

 /home/pol/online/perl/change_mode.pl  /home/pol/online/perl pol 1h mode