Creating Rich Web-Based LIMS With Programmable XML Technologies by sus16053


									                                    Reprinted from American Laboratory September 2005

Creating Rich Web-Based LIMS With
Programmable XML Technologies
                                                                                                            by Dinu Toiba
Laboratory information management sys-          Web-enabled solutions to the arrival         Throughout the late 1980s and early
tems convert mass amounts of data into          of rich, scalable Web-based LIMS             1990s, client/server was an industry
analytical information useful throughout        applications. This technology is illus-      buzzword, as applications were migrated
the enterprise. Traditionally based on          trated by the version 10 Web-based           from centralized minicomputers and
familiar client/server technology               LIMS application (STARLIMS                   mainframes to networks of desktop
deployed in a local area network/wide           Corp., Hollywood, FL).                       computers.1 Client/server architecture
area network (LAN/WAN) environ-                                                              requires software installation and updat-
ment, these mission-critical computing                                                       ing on all clients and is generally limited
systems have generally been isolated and        Deployment options for                       to LAN or WAN environments.
fully accessible only to users connected to
the laboratory’s LIMS network.                  commercial LIMS                              Thin client—terminal
In the rush to develop products that
                                                solutions                                    services based
deliver laboratory automation features          Thick client—client/server                   To quickly deploy applications over
through a Web browser interface, several                                                     the Web, many software developers,
LIMS vendors added browser front ends           applications                                 LIMS vendors included, adopted the
to existing products, offering Web-             The familiar client/server model has         terminal services approach—also
enabled software. A number of these             powered LIMS and most other enter-           referred to as server-based computing.
packages integrate HTML-based por-                                                               An example of this is Terminal
tal-like features that allow data con-                                                           Services, in which all application
sumers to prelog-in requests for test-                                                           execution, data processing, and
ing, view sample status, and access            XML and SOAP-based                                data storage take place on the
reports. Other vendors offer server-                                                             server. Applications and user
based options by employing emula-               Web services are now                             desktops are displayed on clients
tion technology such as Microsoft                                                                using terminal-emulation soft-
Corp. (Redmond, WA) Windows™
Terminal Services (WTS) and Citrix
                                               allowing developers to                            ware. 2 The advantage of this
                                                                                                 approach for LIMS and other
Systems, Inc. (Fort Lauderdale, FL)
MetaFram® enabling LIMS deploy-
                                               provide the scalability                           enterprise system vendors was the
                                                                                                 ability to expand the reach of
ment over the Web.
                                              and usability required by                          applications to user desktops and
                                                                                                 devices located throughout the
Both of these methods focus on                                                                   network or beyond it via the Web.
extending the existing application              complex systems such                             However, this approach requires
reach, making LIMS accessible to                                                                 upfront investments in robust
enterprise clients. These approaches                 as LIMS.                                    servers and uncompromised net-
presented limited graphical user                                                                 work availability.
interfaces (GUIs), and in some cases
complex configuration management,               prise business and manufacturing sys-        Thick client—Web-enabled
with less than optimal response times.          tems over the years. Impressive progress
Shortcomings have fueled demand for             in PC hardware and system technology         applications
true Web-based solutions purposely built        has enabled comprehensive client-side        Originally written for client/server
to utilize advanced Internet technology         computing with enhanced usability, flex-      environments, several LIMS products
as their computing platform. A true             ibility, and scalability. In client/server   were modified to allow connectivity
Web-based application delivers an               LIMS architecture, the client processes      through the Web. By replacing direct
uncompromising “rich” user experience,          the user interface and performs some or      client–database connection (i.e., open
together with unlimited enterprise reach.       all of the application processing. Servers   database connectivity [ODBC]) with
                                                maintain databases and process requests      Web services protocols (i.e., simple
This article examines currently avail-          from clients to extract data or update       object access protocol [SOAP]), remote
able Internet deployment options and            databases. A LIMS application server         access to databases was made possible.
illustrates the historical development          provides additional business processing      The advantages of this approach are
of LIMS software from standard                  for clients. Servers and clients are con-    accessibility to a central database from
client/server technology through                nected via a LAN or WAN.                     multiple sites and a familiar, rich user
                                                                                                 SOAP-based Web services. This tech-
                                                                                                 nical infrastructure is powered by the
                                                                                                 configurable LIMS business logic
                                                                                                 developed over 15 years by STAR-
                                                                                                 LIMS Corp.

                                                                                                 Key technical requirements
                                                                                                 for Web-based applications
                                                                                                 Version 10 was built to meet the fol-
                                                                                                 lowing technological requirements:
                                                                                                 • Rich, fully functional GUI leading
                                                                                                    to a rich user experience compara-
                                                                                                    ble to or better than client/server
                                                                                                 • Built to Internet standards, com-
                                                                                                    prising design norms users have
                                                                                                    grown accustomed to on the Web,
                                                                                                    to significantly decrease training
                                                                                                    duration and complexity
                                                                                                 • Zero client side installs, eliminat-
                                                                                                    ing the costly process of installing
Figure 1     Evolution of Internet technology.                                                      and maintaining every potential
                                                                                                    client machine both on the intra-
                                                                                                    and extra-nets
interface. The inherent disadvantage is          engines, such as the integrated XML             • Scalable, easily configurable addi-
the need to install and update client            STARLIMS Form Definition (XFD)                     tional hardware resources and abil-
software on every user machine,                  designer (STARLIMS), can now                       ity to employ load balancing algo-
thereby increasing IT management bur-            replace static HTML pages with a rich,             rithms to supply uninterruptible
den and limiting portability.                    fully functional GUI equivalent to that            service to a growing number of users
                                                 achieved by thick client versions.              • A single application for both design
                                                                                                    and run time, eliminating the need
Early Web-based                                  Leveraging these developments, Web-                to maintain special power user ver-
applications                                     based version 10 was written for the               sions on non-Web-based platforms
                                                 Microsoft .NET platform using XML               • Full enterprise integration via
Early Web-based applications offered effi-        GUIs and Web services. The .NET                    Web services
cient HTML tools for navigating the              platform was chosen because of its              • Separation of user interface from
Web, and provided broad access to a              majority status in the enterprise mar-             business logic with standard Web
wealth of content. These applications            ket, accessibility to scores of program-           services used to communicate
aim for reach—not rich—which means               mers, strong framework for building                between the two
supporting the widest number of clients at       rich GUIs, and built-in support of              • Predictable response times
the cost of some functionality.3 For exam-
ple, the requisite from a LIMS results
entry screen is that upon editing a cell, a
set of simultaneous processes would be
triggered including calculations, valida-
tions, and screen. In a pure HTML envi-
ronment, complex solutions such as those
described above could not be designed
and constructed (see Figure 1).

Modern Web-based
Recent developments in programmable
eXtensible Markup Language (XML)
and SOAP-based Web services are now
allowing developers to provide the scal-
ability and usability required by com-
plex systems such as LIMS. Rich user
interfaces created with XML form                 Figure 2    STARLIMS version 10 architecture.
                                                                                        and-drop design tools, the STAR-
                                                                                        LIMS XFD designer dynamically cre-
                                                                                        ates XML forms containing both lay-
                                                                                        out tags, used in a declarative way for
                                                                                        describing the user interface, and
                                                                                        JScript.NET code, used to program-
                                                                                        matically handle these elements, their
                                                                                        corresponding events, and make
                                                                                        remote calls to business logic services
                                                                                        located on the server. Communica-
                                                                                        tions between the GUI and the busi-
                                                                                        ness logic are achieved via standard
                                                                                        Web services. The integrated designer
                                                                                        is also used for creating Web services
                                                                                        that are made available to third-party
                                                                                        client applications for seamless inter-
                                                                                        operability between enterprise appli-
                                                                                        cations to STARLIMS.

   Figure 3    STARLIMS version 10 screen.
                                                                                        Impressive advances in the technol-
                                                                                        ogy continuum over the past few years
• Easy-to-use design tools that allow        ing server, which analyzes the work-       have ushered in an era of demand for
  client system administrators to            load and directs requests to the opti-     enterprise-wide LIMS data availabil-
  enhance or modify system func-             mal server.                                ity. This data availability, coupled
  tionality as required by changing                                                     with the emergence of rich, full-
  business requirements.                     The STARLIMS client is a standard          featured Web-based LIMS, is facilitat-
                                             Web browser that hosts a .NET con-         ing timely enterprise action, reducing
                                             trol charged with dynamically pre-         the total cost of ownership, and
Architecture                                 senting the user interface. The con-       enabling multisite organizations to
As demonstrated in Figure 2, version         trol, named the STARLIMS XFD               conform to best practices.
10 architecture follows that of stan-        Renderer, is automatically deployed
dard Web-based applications, where           on the client every time a new ver-
the client side is a Web browser and         sion is available. In addition to the      References
the server side is composed of a scal-       classic GUI controls, such as labels,      1. Computer desktop encyclopedia.
able and extensible application and          buttons, and textboxes, this technol-         Retrieved Jul 12, 2005, from
database server “farm.” Communica-           ogy supports more complex controls  
tions between the client and server          such as hierarchical data grids, tab       2.
are achieved through standard Web            controls, and selection boxes. For            nol/windowsserver2003/library/TechRef/
service messaging over hypertext             data-aware components, special busi-          2cb5c8c9-cadc-44a9-bf39-
transfer protocol (HTTP) or option-          ness actions called data providers are        856127f4c827.mspx.
ally secure HTTP (HTTPS) for a               used to interface the GUI with the         3.
more protected environment.                  data model that resides on the server.        default.asp?url=/library/en-us/
                                             For increased security, client-side           dnwinforms/html/clickonce.asp.
To take advantage of all available pro-      scripting code is run in an isolated
cessing power and allow for a rich user      (sand-boxed) environment, and the
experience, version 10 splits its code       server side business logic code is sepa-
into business logic, which is executed       rated from the client-side code. The
on the server side, and presentation         STARLIMS XFD Renderer uses the
code run by a .NET control residing          local machine’s computational capa-
on the Web client.                           bilities, resulting in reduced server
                                             and network loads (see Figure 3).
To provide scalability, STARLIMS
application servers utilize hardware         The same STARLIMS client when set
resources by dynamically creating exe-       to design mode exposes the STAR-           Mr. Toiba is Vice President, Research & Devel-
cution threads that concurrently han-        LIMS XFD designer, built to allow          opment, STARLIMS Corp., 4000 Hollywood
dle business logic requests. The scal-       authorized users to intuitively config-    Blvd., Ste. 515 S., Hollywood, FL 33021-
able distributed server farm is              ure business rules and processes as        6755, U.S.A.; tel.: 954-964-8663; fax: 954-
continuously monitored by a balanc-          requirements change. Through drag-         964-8113; e-mail:

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