Office Automation

1
Office Automation Intranets

• BUSS 909

Lecture 10 Intranet Functionality 2 Textual
Media and Database Integration
2
Agenda

• we will consider a number of issues relating to
  text resources- how intranets can provide
  information
• re-purposing texts documents into HTML
• the development and operation of doc bases
• integrating databases with Intranet applications
  (and the associated technical issues of state and
  persistence)

3
Quick Publishing
4
Quick PublishingBefore Intranets

• traditional print publications
• requires designers, printers, bindings, shipping,
  receiving- many professionals
• requires may expensive and time consuming
  decisions
• often source materials are out of date (risking
  professional legal difficulties)

5
Quick Publishing

• quick publishing is typically an organisations
  first major intranet activity
• there is an overlay between quick publishing and
  information management (the latter generally
  involves database publishing- refer to Lecture 3)

6
Quick Publishing

• circumvents the time taken to print and publish
  material by creating digital documents for web
  publication straight from the document source
  applications (word processors and DTP
  applications)
• digital documents are posted on the intranet. Eg
  NetObjects TeamFusion (1992) Acrobat file on the
  BUSS909 Intranet

7
Quick Publishing

• information is available for viewing, downloading
  and printing
• some of these kinds of documents are referred to
  as brochure-ware
• but may include more substantial materials such
  as policy documents
• this use of intranets treats the WWW like an
  information parts store

8
Quick Publishing

• information parts stores are more than just a
  collection of files- they invite use- eg. PPT
  files in the BUSS909 Intranet
• information on intranets can be
• updated and re-published very quickly bypassing
  mailrooms and printing agencies
• removes the need for multiple physical copies- no
  costs for additional copies

9
Quick Publishing

• some companies have measurable cost reductions
  normally intranets can reduce some paper use but
  that will not happen immediately
• copying costs may in fact increase
• while it would be expected that overall paper use
  will decrease
• additional costs may be incurred internally while
  the IT/IS department tools up for Quick Publishing

10
Quick Publishing

• generally really quick publishing is
  accomplished by using an electronic publishing
  application like Acrobat (see BUSS909 Intranet)
• but as soon as you want to create real digital
  documents (with hyperlinks etc) then you are
  looking at converting documents to HTML
• very soon problems can emerge!

11
Web/Database Integration
12
Client/Server DB ApplicationsTraditional -vs-
Web-based

• Platform-dependent
• Client is natively compiled and therefore
  executes fast
• Installation necessary
• Fat client maintenance needs incurred
• New, unfamiliar interface
• Rich, custom GUI constructs possible
• Difficult to integrate- existing applications
• Difficult to add multimedia
• Persistent connection to database

• Platform-independent
• Client is an interpreter (HTML, Java, JavaScript,
  Microsoft Active X, etc) and is therefore slower
• No installation necessary, depending on model
  used
• Thin Client, maintenance is minimized
• One common, familiar interface across
  applications
• Limited set of GUI constructs with Java applets,
  custom-coded ones add to download time
• Easy to integrate with existing applications
• Easy to add multimedia
• Nonpersistent connection to databases

13
IntranetsWeb Database Applications- Components

• fundamental components of web database
  applications for the architecture of a web
  database application
• a database gateway is a combination of one or
  more of the first three layers of the
  architecture browser, application logic, and
  database connection

14
IntranetsWeb Database Applications- Components

• web database applications are composed of four
  components or layers
• browser layer
• application logic layer
• database connection layer
• database layer

15
IntranetsWeb Database Applications- Components
External helper program
Browser Layer Application Logic Layer Databa
se Gateway Layer Database Layer
HTML Document
Java Application
Java applet
CGI program
Proprietary Web Server
Web Server API module
Vendors Database API
Command-line interface to database
JDBC
ODBC
Database (RDMS)
16
IntranetsWeb Database Applications- Two tiered

• web database applications can consist of multiple
  tiers- there are two varieties
• two-tiered applications
• three-tiered applications
• two-tiered applications consist of client which
  supplies the user interface and the database
  connection and the database

17
IntranetsWeb Database Applications- Three tiered

• three tiered applications consist of a client
  which supplies the user interface, a middle tier
  which supports the database connection, and the
  database
• additional tiers can be used for operations such
  as security and state management (see Technical
  Note 4)

18
Web-Database Integration

• there are two ways to integrate Web database
  applications with other applications
• by directly linking applications of one
  technology base- generally involves
  straight-forward coding
• passing data between two applications- generally
  involves CGI (Common Gateway Interface) scripts

19
Web-Database IntegrationCGI Protocol

• CGI Protocol is generally the heart of
  integration- it was designed to do this in web
  applications
• CGI scripting was the first way that web sites
  were able to be integrated with databases and
  other resources external to the Web

20
Web-Database IntegrationMethods for Passing Data

• Integration of Web database applications with
  other applications can be accomplished with CGI
  coupled with one of several methods for passing
  data
• Hidden Fields
• URL Parameters
• Cookies
• JavaScript

21
Web-Database IntegrationPassing Data Hidden
Fields (1)

• a hidden HTML form field is commonly used as a
  simple storage container for data that needs to
  be passed from page to page of an HTML-based and
  CGI application
• For example
• ltinput typehidden namesessionID
  valuejwsr438kowkmgl

22
Web-Database IntegrationPassing Data Hidden
Fields (2)

• CGI programs automatically populate the field
  with a session ID that can be used to look up
  session information stored in a database
• suppose an intranet requires employees to
  authenticate their identity by logging in with a
  user name and password

23
Web-Database IntegrationPassing Data Hidden
Fields (3)

• at login
• employee can be assigned a randomly generated
  unique key that is stored in the database along
  with the users name
• the authentication procedure stores the key in a
  hidden HTML form field
• during the session
• the employee moves within the site the hidden
  field can be referenced by new resources to
  determine who is accessing them

24
Web-Database IntegrationPassing Data Hidden
Fields (4)

• this functionality can be used in contexts other
  than simply authenticating users
• they are also an ideal way of passing data
  between Lotus Domino applications and straight
  CGI or Web Server API applications because
  Dominos collaborative document management system
  is written in HTML

25
Web-Database IntegrationPassing Data URL
Parameters (1)

• within the URL, the string following the question
  mark (?) in a GET request, are another storage
  area for data that can be accessed by Web
  database applications (see Lecture 8)
• like HTML hidden form fields, the URL parameter
  string can be retrieved by CGI programs, web
  server API programs etc

26
Web-Database IntegrationPassing Data URL
Parameters (2)

• the URL parameters can be used in the same way
  that HTML hidden fields are used
• for example, a session key can be stored in the
  URL and used to access user authentication, user
  privaledges, and session state information

27
Web-Database IntegrationPassing Data Cookies (1)

• Cookies are pieces of information sent by the Web
  server in HTTP headers and stored on the client
  machine
• are used for the same purposes as HTML hidden
  form fields, and URL parameters but have an
  additional features...

28
Web-Database IntegrationPassing Data Cookies (2)

• the data stored in a Cookie can be retrieved
  across multiple Web browsing sessions
• when a user quits an instance of a Web browser,
  any data stored in a HTML hidden field or URL
  parameter during the session is lost, but if...

29
Web-Database IntegrationPassing Data Cookies (3)

• if the data is stored in a cookie on the client
  machine then the information is retrievable even
  after the user quits the browser
• as a consequence the data will be ready to be
  accessed during a later session

30
Web-Database IntegrationPassing Data Cookies (4)

• cookies relevant to a URL are sent back to the
  server and accessible via the environment
  variable HTTP_COOKIE
• Cookies are retrievable from Java (via
  JavaScript), JavaScript, CGI, and Web server
  modules such as Lotus Domino

31
Web-Database IntegrationPassing Data JavaScript
(1)

• JavaScript can be accessed from Java
• provides a bridge between a Java applet and the
  document on which it lives- adds new capabilities
  to Web database application programming
• an applet can know about any forms residing on
  the same page as its own and can access these
  fields

32
Web-Database IntegrationPassing Data JavaScript
(2)

• higher than JDK1.1, if an applet resides with a
  frame, then it can access parent and sibling
  frames
• reading data from them
• executing JavaScript functions defined in them,
  or
• overwriting the framed documents completely

33
Persistence State
34
Persistence

• persistent database connections are highly
  efficient data channels between a database client
  and the DBMS- ideal for database applications
• they allow single applications to exhaust these
  valuable data channels as applications may
  require more than one constant connection

35
Non-Persistence

• however Web-based database applications and the
  web applications in general do not have
  persistence
• the non-persistent connection architecture of the
  Web is a mixed blessing

36
State

• non-persistent connections mean that programmers
  take care of the application state management
• in order to understand persistence we must
  understand state
• the state of a system is expressed through the
  values that it current holds as a result of its
  execution

37
Persistence and State

• persistence is the result or remembering or
  tracking all the incremental intermediate changes
  in the state of the system (its objects,
  movements, or the actions of various media)
• persistence is the capabilty of remembering a
  state across different applications or time
  periods

38
Persistence and Statefor Traditional Applications

• for traditional applications, managing
  persistence is easy- the applications state can
  be kept in memory as long as the computer has
  enough memory
• stand-alone applications do not interact with any
  other applications, clients, or servers, and so
  do not need to make their state available or
  dependent on external factors

39
Resource Allocation ModelTraditional Databases
Connections are maintained to the database idle
sessions waster resources
40
Persistence and Statefor Web Applications (1)

• state maintenance in Web database applications
  adds another level of complexity which must be
  handled by programmers
• HTTP- the main protocol of the Web, is
  connectionless- which means that once an HTTP
  request is sent and the response is received the
  connection for the communication is closed

41
Persistence and Statefor Web Applications (2)

• if a connection could be kept open between the
  client and the server, the server could at any
  time query the client for state information and
  vise versa
• the server would know the identity of the client
  user throughout the session once the user had
  logged in

42
Persistence and Statefor Web Applications (3)

• the server has no constant memory of the users
  identity even after the user has logged in
• therefore, HTTP clients must make a new
  connection for each server request
• in a stateless request, the transaction is atomic

43
Persistence and Statefor Web Applications (4)

• programmers must also address the added overhead
  of creating new database connections each time a
  CGI program or Web server module requires
  database access
• database connections are expensive because they
  take time- which is a problem when implementing
  Web applications

44
Resource Allocation ModelWeb Databases
Persistent connections reduce the overhead of
accessing databases from the WWW or Intranet
Non-persistent connections optimize the number of
available database connections at any time
which promotes the sharing database resources
45
Doc Bases
46
Doc BasesIntroduction...

• I have mentioned in previous lectures that the
  success of the Internet owes much to its
  simplicity
• internet protocols connect clients to servers
  using standard ASCII text.
• programmers can write distributed programs using
  almost any programming or scripting languages-
  all languages can be applied to produce and
  consumed text-based protocols.

47
Doc BasesIntroduction...

• Why bother developing when you can buy
  distributed computing from Microsoft?
• simply assume that developing distributed
  applications will be difficult
• the reason is that these proprietary solutions
  use proprietary APIs, packaged into proprietary
  components that speak inaccessible binary
  protocols to other proprietary components.

48
Doc BasesIntroduction

• looking at the news group mail message (NNTP)
  shows how simple it can be...
• each NNTP transaction consists of a few
  elements...

• Path localhost!not-for-mail
• From Rodney Clarke ltrclarke_at_nimnet.netgt
• Newsgroups test
• Subject sample message
• Date Tue, 14 Apr 1999 222959 -0400
• Message-ID lt35760488.F61E274_at_nimnet.netgt
• NNTP-Posting-host localhost
• MIME-Version 1.0
• Content-type text/plain charsetus-ascii
• Content-Transfer-Encoding 7bit
• X-Mailer Mozilla 4.5 en (WinNT I)
• This is the body of the sample message!

49
Doc Bases

• Newsgroups header which identifies which group
  the message was posted to,
• Message-ID is automatically generated by the
  news server and uniquely identifies the specific
  message, and
• there are of course other fields including From,
  Subject, Date and so on whose meanings are
  familiar to you.

50
Doc BasesGeneral Definition...

• a collection of these news messages in a tree of
  subdirectories is the news servers' primary
  message data base
• this collection of messages is an example of
  Internet style data store or document data base
  which is being given the name of docbase (see
  Udell, 1999)

51
Doc BasesGeneral Definition...

• docbase is used to define ASCII text is
  structured according to some specific rules
• in the case of news messages these rules of
  defined by the appropriate standard for USENET
  messages (RFC 1036)

52
Doc BasesGeneral Definition...

• this kind of Internet data store holds
  semi-structured information defined as a
  combination of data that is
• structured- for example news messages defined
  key dimensions such as author, subject, date),
  together with,
• unstructured- for example a message body
  contains free form text.

53
Doc BasesImpose Rules on Web Page Collections (1)

• a collection of web pages wont hold the same
  kind of semi structured data
• web pages are not required to carry headers for
  example
• nor are they required to exhibit more complex
  structures than can be expressed in XML
• but you can choose to impose these kinds of rules
  on a collection of web pages

54
Doc BasesImpose Rules on Web Page Collections (2)

• imposing rules on web pages converts them into
  containers for semi-structured data and
  collections of them form a web doc base.
• semi-structured data is at the heart of groupware
  and requires the kind of skills necessary in
  publishing as well as conventional data management

55
Doc BasesProduce, Transform and Delivery

• it is possible to develop programs which produce,
  transform and deliver web doc bases.
• using exactly the same Internet protocols that we
  are already familiar with, these web doc bases
  can then be turned into CSCW/groupware
  applications

56
Doc BasesStructure (1)

• Doc bases consist of several elements including a
  repository format
• defines a doc base- the repository format for
  mail and news data stores is usually the copies
  of the headers and message bodies
• for web doc bases the repository format is often
  a markup language, eg. HTML, XHTML- a new
  standard which requires HTML documents to be
  well formed, SGML, or XML

57
Doc BasesStructure (2) Input and Delivery Format

• an input tool moves content into the repository-
  often a text editor, export filter or a web form
  and its handler
• the delivery format is the data store that is
  server application uses to deliver a document to
  apply application

58
Doc BasesStructure (3) Transformation Viewing
Tools

• when repository and delivery format differ a
  transformation tool bridges the gap between them-
  is usually true for web doc bases but not always
• a viewing tool is a client application that reads
  and displays a delivery format generally by means
  of a web browser, news reader or on occasion and
  mail reader.

59
Doc BasesImplementation (1) XML Query Languages

• there are several ways in which docbases can be
  implemented
• XML compatible Query Languages are now emerging
  although some of these are not stable (still
  experimental, but they will become increasingly
  viable in the next 2 yrs)
• there are some practical ways for implementing
  scalable, real world doc bases, now

60
Doc BasesImplementation (2) XML and Perl

• perhaps the most practical way to implement a web
  based docbase is to
• use XML as the repository format and then
• develop a translator in Perl using the
  XMLParser module that connects Perl to an XML
  parser called expat.
• Perl is considered to be one of the few languages
  of choice for web masters

61
Doc BasesHow they work- Programmers Analogy

• if you program then developing these kinds of
  systems are like
• turning the repository into a form of source code
• the translator becomes a compiler, and
• the deliverable HTML pages can be thought of as a
  form of object code

62
Doc BasesExample of Help Desk Doc Base (1)

• a hypothetical doc base
• could be created with information on how to
  create web pages and perform procedures using
  NetObjects
• this kind of archive of helpful tips is added to
  when new solutions are found to interesting
  problems in the company involving an
  Intranet/Extranet Site

63
Doc BasesExample of Help Desk Doc Base (2)

• web content in almost any form provides
  opportunities for creating groupware
• possibilities to connect internal groups (product
  development, support, marketing and other groups)
  with external groups (existing and prospective
  customers, business partners)

64
Doc BasesExample of Help Desk Doc Base (2)

• eg. a link on a web page
• lta hrefmailtorclarke_at_nimnet.comgtAuthorlt/agt
• can rendered automatically by the translator
  into a parametised mailto
• lta hrefmailtorclarke_at_nimnet.com?subjectTechni
  calFeedback\August1998NetObjectsClientPage
  Layoutgtrclarke_at_nimnet.netlt/agt
• this allows the reader of a technical paper to
  contact the systems support officer- the mail
  header is automatically filled out for them

65
Doc BasesExample of Help Desk Doc Base (3)

• the translator can do this because it knows about
  the doc base structure
• automatic translator substitution ensures that
  the context of the message is provided and
  consistent
• the recipient could use a client-side mail filter
  to manage the messages from the doc base,
  organise then and count them by technical paper
  or weblet section (as with messages to me about
  A2 and A3)

66
References

• Greer, T. (1998) Understanding Intranets
  Strategic Technology Series Microsoft Press
• Ju, P. (1997) Databases on the Web- Designing and
  Programming for Network Access Pencom Web Works/
  MT Books
• Udell, J. (1999) Practical Internet Groupware
  Building Tools for Collaboration Cambridge
  OReilly Associates Inc.