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The Antelope Interface to PHP and Applications: Web-based Real-time Monitoring

Lindquist Consulting, Inc.
59 College Road Suite 7
Fairbanks, Alaska 99701 USA
kent{at}lindquistconsulting.com
(K.L.)

R.L. Newman and F.L. Vernon

Scripps Institution of Oceanography
University of California, San Diego
9500 Gilman Drive
La Jolla, California 92093 USA
rlnewman{at}ucsd.edu
(R. N.)
flvernon{at}ucsd.edu
(F. V.)

View larger version (19K): [in this window] [in a new window]   Figure 1. Schematic of the underlying software layers. Data are retrieved from Datascope databases and Antelope orbservers by the Antelope libds.so and liborb.so shared-object libraries, respectively. These native Antelope libraries are linked to the PHP interpreter by the new Datascope.so and Orb.so PHP extension libraries, allowing data to be displayed on Web pages using PHP code embedded in HTML. A parallel sysinfo.so extension library provides access to a number of Antelope system-information utilities.

View larger version (48K): [in this window] [in a new window]   Figure 2. The compile structure of the Antelope contributed-code repository (left, "SOURCE") and the built structure after make install (right, "BUILT"). An example application, weborbstat, is shown in all its component parts, in the initial compile and the resultant built structure. Weborbstat is a simple application that connects to an ORB, displaying a table of station names and respective data-latencies (Figure 4). Each application is required to have a) a Unix manual page, b) a user-defined parameter file, c) the application itself (.php), and d) a css file. Client-side interaction is provided by a optional js file. Applications are often provided optional image files as well. Note how each component part is distributed into a different directory. Further detail on this and other applications in the text. css: Cascading Style Sheet, js: Javascript.

View larger version (38K): [in this window] [in a new window]   Figure 3. Weborbstat is a Web-based display of station data latencies in an ORB. (A) The configurable simple parameter file allows full customization, including images and a CSS file. (B) Screen dump of the running application in a Web browser. Note how different data-latency levels are color-coded to allow easy diagnostics. This installation is displaying data from the Transportable Array (TA) data of the Earthscope USArray project. More information in the text.

View larger version (35K): [in this window] [in a new window]   Figure 4. Examples of Web-based applications driven by the Antelope interface to PHP. (A) Pfexplorer—an interactive tool to open and explore the node tree of any Antelope parameter file. (B) Webdbe—a tool to interact with Datascope databases designed to replicate the behavior of the standard Tcl/Tk dbe application that ships with Antelope. Both these applications are in the contributed code for Antelope.

View larger version (64K): [in this window] [in a new window]   Figure 5. Screen dumps of the ROADNet Realtime Imagebank. (A) A list of cameras that provide images are listed in the "Camera Selector" drop-down menu in the top-left. If available for the selected camera, a time-lapse movie of the last day is displayed in the "Pre-made movies" panel. The main panel ("Requested Image") displays the latest image from the selected camera, with associated metadata including the camera description and time that the photograph was taken. In addition, a link at the top of the panel provides a search function for photographs taken by the camera and a link at the bottom of the panel provides access to the highest resolution version of the selected photograph. Beneath this is a table ("Database Table Entries") displaying the most recent 20 photographs taken at the site. Many of the display options (color scheme, number of recent photographs, if movies are created) are customizable via a parameter file. The application has been running continuously since August 2003. (B) Really Simple Syndication (RSS 2.0) feed of the latest photographs taken by the cameras in the ROADNet Realtime Imagebank project. The feed is updated with the latest images every five minutes and has been in operation since September 2006.

View larger version (83K): [in this window] [in a new window]   Figure 6. Screen dumps of two versions of the application webdbshow. (A) The default layout that is in the contributed software repository and (B) a modified local version. The differences in layout and formatting are achieved through modifications to the Cascading Style-Sheet (.css) file only.