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Visual InterDev 6

 

Web Dev Process

  • Planning Phase – determine content, feasibility (time, cost, budget, benefits), localization

  • Analysis and Design – define structure of site, navigation, app tasks, data requirements

    1. Services application model –functionality defined as services user, business and data

    2. Clear development goals, better manageability, isolation of functionality, and division of labor

    3. Application models e.g. n-tier

    4. Define technical requirements, identify tradeoffs; e.g., integrate with other systems

    5. Build working prototype

  • Implementation and Testing – create components, HTML pages, scripts and databases

    • Implementation and Testing – create components, HTML pages, scripts and databases

      • Web developer – designs architecture; creates client & server scripts

      • Programmer – creates and maintains apps and components

      • HTML author – authors content, gathers graphics and other media

      • Graphic artist – designs/creates graphics

      • Test/documentation specialist – documents web site, tests content, navigation etc.

      • Web administrator – installs and maintains server

      • Database administrator – installs and maintains dbms

  • Production Deployment and implementation of application on server

  • Support Handle outdated content, optimize code – bottlenecks, bandwidth

 

Project Management

  • Scope Identify business needs, determine high-level requirements, critical dates, and assumptions

  • Conceptual Design Complete and accurate business requirements (workflow, tasks, phys. Environment, business goals.) Business rules, structure relationships. Important phase because creates accurate business requirements that addresses the problem, needs and capabilities, desired state of the work, whether upgrading existing solution is viable

  • Logical Design Visual Modeler. Data, user interface, components, services. Specification doc. Prototypes

  • Physical design

 

Browser History

  • 1G Static - Webmaster

  • 2G Dynamic; e.g., CGI

  • 3G Integration; e.g., component technology. – Web development team (InterDev – local mode, source code control, interoperability with other dev tools)

 

Web Projects

  • Master –updates local and master at same time

  • Local-changes not made to master web services. Get latest version, release working copy. Refresh project view, synchronise files.

Project name\project location
Server name (SSL?)
Enable site searching?

.sln – project & other files that make application
.vip – project – interdev specific
.asa – active server application

layouts – navigation
themes – css

 

Toolboxes

  • Design-time controls – usually data-bound

  • ActiveX controls; e.g., Treeview

  • Server Objects; e.g., dictionary

  • HTML – standard HTML elements

  • General – e.g., HTML fragments

  • Source view (middle tab) – design time controls, Java applets, edit scripts, text & HTML tags (HTML outline, Properties window, script outline, debugging.)

  • Design view (left tab) WYSIWYG – apply formatting; e.g., using toolbars & menu (HTML outline & properties window.)

  • Quick view (right tab) test quickly (but not asp script!)

HTML

NOFRAMES <FRAMESET COLS “*, 2*”>
DIV groups tags (line inserted after)
SPAN (line not inserted after)
FORM - Form handler – action attribute
Elements need a name attribute to be submitted
ActiveX control – use hidden HTML control value attribute and onsubmit event

 

DHTML

ID attribute of HTML tags
DOM – interface that permits scripts to update content, structure and style
All DOM collections have ITEM and LENGTH (number of elements)

(for definition of DHTML)

 

DOM Hierarchy

  • WINDOW – top-level object represents browser window – IE4

  • Event –exposes the information about a user's actions

  • History

  • Location - URL

  • Navigator – browser version, appName, appVersion

  • Screen

WINDOW

  • Document (container for objects in a particular web-page)

    1. Frames

    2. Forms

    3. Etc.

  • Frames

Each element object (e.g., input, form etc.) is accessed through document collections (e.g., All, Children, StyleSheets) by using index or ID. All elements have tagName, ID, ClassName

 

Event Procedures

<SCRIPT> block

Assign procedure in HTML tag <INPUT onclick=”procedure”>
Include script in tag that defines object <INPUT onclick=”msgbox..”>
Name a procedure objectname_onclick

Event bubbling to top element (document) -means that events can be handled centrally through the event object - reduces code & code changes

 

Dynamic styles/positioning

Style object div.style.fontsize
Zindex
Absolute – xy to parent element
Display – none
Visibility – hidden
Relative – xy to preceding element

 

Dynamic content

Add/remove content
Text properties innerText or HTML properties innerHTML

 

Scriptlets (DHTML & server)

right-click .htm and mark as scriptlet
Reusable UI components
Easy to create/maintain
Small and efficient
Prototype quickly
Raise Event, Bubble Event – expose to browser through window. Standard events can also be fired
Frozen, SetContextMenu, event, readystate
Public read/write variable – declare
Public_get (read)
Public_put (write)
Public function/sub (method)

(for definition of Scriptlets)

 

ASP

NT4 NT4 9x
IIS Peer Web Services Personal Web Server

Can use any language if appropriate engine installed on server
Browser independent – sends HTML
Uses server-side components (system, data or business)
Scripts cannot be read – on server

  • CGI – lots of processes (lots of clients), RAM, time consuming, performance, wait times

  • IIS also supports ISAPI (low o/head, fast, scaleable C++ slow dev time), CGI, IDC & SSI

  • ASP – runs in same process as web server, easy to develop, familiar framework, can retain user info between sessions, starting point directory, global data (active server application)

Application – collection of files in a directory whose properties can be set & can be run in a separate process space

HTTP – stateless

Global.asa – located in root directory, processed automatically (application & session)

ASP Session object (special user id)

Sessions begin ...

  • on first request of asp page & global asa has session_onstart

  • user stores variable in session object

  • object tag with session scope called from page

Sessions end ...

  • If no request for timeout period (default 20 mins)

  • Session.abandon

Sessionid sent to client as cookie
Cookie reused to track session
<% or <SCRIPT RUNAT=SERVER

(for more resources on ASP)

 

ASP Objects

Based on HTTP headers and body fields. GET retrieves page. PUT sends back.

  • Request (Retrieve info about user & HTTP request & forms)

    1. ClientCertificate

    2. Cookies Path attribute “/” cookies sent in each request. Maintain state

    3. Form. Need name attribute on HTML control (HTTP body.)

    4. QueryString. HTTP header appended parameters

    5. ServerVariables

  • Response Return info in HTTP response (MIME encoded)

    1. Buffer – enabled by default

    2. Expires

    3. ExpiresAbsolute

    4. IsClientConnected

    5. Status

    6. Clear

    7. End

    8. Flush

    9. Redirect – can only be used before info sent to client (ASP 2.0)

    10. Write – adds text to HTTP response

  • Session. Timeout, abandon. State data management. New object created for each user

  • Application. Lock/unlock (multi-user change)

  • Server

  • ObjectContext

  • Debug. If IIS running on PC (enable debugging). Local mode – test
    Remote debugging – one user at a time with right components on server (remote machine debug & Interdev server.) Admin level permissions

 

COM Components

<OBJECT > or Server.CreateObject – instantiate
RUNAT attribute
SCOPE application/session (default is page)
PROGID
CLASSID

Server objects tab of toolbox

  • ADO Cmd, connection

  • CDONTS

  • BrowserCapabilities (looks at HTTP headers and compares to browcap.ini)

  • FileAccess (FileSystemObject) text stream

 

Page Objects

Design time control based on scripting object model

  • Simplifies navigation

  • Easy way to execute specific script on another page

  • Maintain state

  • Execute server script from browser

Define methods and properties – navigate, execute and return value

ADO

Based on COM and UDA strategy. Application-level interface on OLEDB (extends ODBC by accessing all data sources not just RDBMS)

  • Not complex – flat object model

  • Standard Microsoft model across tools

  • Can be used in ASP

(ADO in the real world)

7 ADO Objects

  • Command defines info about what data is retrieved from a db connection. Cmd.CreateParam

  • Connection establishes connection (OLE DB or ODBC) DSN while adding connection or through ODBC in Control Panel. Establishes connection (ADODB.Connection)
    Cnn.Open Connectstring
    Cnn.close
    Set cnn=nothing
    Managing number of connections is important

  • Error

  • Field

  • Parameter

  • Property

  • Recordset Represents results of executed command working with cursor dynamic, forward only, keyset or static. Can create by command object or by itself

ADODB.Recordset

Rs.Open Source (e.g., sql or table), ActiveConnection (open object – better for pooling or connect string – not scalable), CursorType, LockType, Options

Can also create by execute method of connection (sql) or command objects (sql, stored procedure, table)

Use SQL commands where possible & business objects to access db to simplify maintenance & isolate logic

 

RDS

Web based extends ADO. Caches records on user’s pc – traffic times (only works in ie4, win9x, or nt4)
Binds data from a recordset to HTML elements or ActiveX controls on a web page
Data updates isolated in business objects instead of data-update code in HTML documents
RDS.DataControl object - Add to HTML document. Runs queries, makes recordsets available to controls
RDS.DataSpace.CreateObject – creates instances of bus. Objects on server
ADOR.Recordset – fewer features than ADO but faster
RDSServer.DataFactory – bus object runs queries (server)

(for definition of RDS)

 

Data-binding

Data Service Objects (DSO) – RDS
Data consumers – HTML elements in IE4 support DSO

 

Data Environment

  • Is the repository for storing & reusing data connections & commands in an InterDev project. Contains the info required to access data in a db and contains one or more connections

  • Is a sub-folder of global.asa – connections stored in application-level variables

  • Can use DE objects to access data. Stores data connections and data commands. Add connections at design time and then add commands

 

Database Projects

Create, modify & execute and save queries and stored procedures. Tools for building and managing databases separate from web-pages. Database diagrams, view relations alter structures. Save to script or direct to db.

Data-view window

Live view of databases, objects and props. Provides sophisticated development and admin. Can use data-view to open, edit and delete db objects

 

Query Designer

Diagram, grid, sql, results. Can differentiate between different breeds of sql (e.g., sql server, oracle)

Data-bound controls

Bound using a recordset control
RecordsetNavBar
Form Manager –based on script objects e.g. listbox, recordset design-time controls, can ‘advise’/’unadvise’ events

Can change script platform to take advantage of RDS if IE

Script object is an object that can be manipulated with code; e.g., design-time control. Set its properties, call its methods & respond to associated events

(for more information on creating a Data-Bound Control)

 

COM Components (apartment threaded)

Business rules – algorithms that companies use to help them operate. Can be used together to complete a business process

Business components are objects that contain business rules

Advantages of ActiveX COM components:

  • Work with MTS

  • Simplify complex processes

  • Enable natural modeling techniques

  • Encapsulation

  • Reuse

  • Variety of languages can create (VB, VC++, J++)

(for definition of Apartment Threaded)

DLL – in process, efficient – runs in same process as client. Fast. Less fault tolerant than EXE

EXE – out of process. Runs in own address space. Slower. Need to minimize calls. Fault tolerant

Process – win app residing in an address space that OS assigned. Has one or more threads running in the context of the process. Threads are used to run the application

Thread – basic unit to which OS allocates processor time. A thread runs in the address space of the process and uses resources allocated to the process

Instancing Private, PublicNotCreatable, MultiUse, GlobalMultiUse

 

CLASSID

A class is a template for an object
An object is an instance of a class (initialise/terminate.)

Project name and Class name make PROGID
PROGID, CLSID and TypeLib are referenced by applications to use objects
Binary compatibility must be set for MTS (project compatibility is not backwards compatible)
Restart IIS to release object
To register a component - run setup, compile dll, or run regsvr32.exe
Add components to web project – properties – custom – register on server
Copy Web Application -> Register Server Components

 

Debug

in process – add project to group

out of process - use second instance of VB

 

MTS

ACID – atomicity, consistency, isolation, durability
Simplifies development of n-tier apps
Provides transaction and resource management for server-based components. Provides infrastructure and admin. Support for building scalable, robust, enterprise apps

MTS components execute in MTS run-time environment

  • Must be compiled as ActiveX DLL

  • Must provide a type library & be self-registering (VB auto does this)

  • Components can run on multiple computers for higher availability, scalability and performance (DCOM installed with Win98, NT4 SP3, 95 sep. install.) DCOM required for communication

  • Share database connections

  • Secured centrally

  • Scalable – thread pooling, JIT object instantiation

  • Less complexity

MTS Services provide:

  • Component transactions – two phase commit

  • Object brokering

  • Resource pooling – connections and threads

  • JIT activation – server resources efficient

Admin – MTS Explorer

  • Create & manage packages – package consists of one or more components – administer them as a group. Process isolation, automatic thread pooling, transactions, security (declarative NT or programmatic roles)

Create MTS package for deploying -> export from MTS Explorer *.PAK. Client’s folder is also created which contains an exe file for client pc to access component

 

MTS Security

Packages define security boundaries
Roles used in securing COM components execute in MTS run-time environment
Map users to application functionality to determine security
Declarative security configured with MTS explorer (cannot use on 9x)
MTS roles (logical group of users that define access to component of a package (created at development time)
Roles mapped to NT accounts during deployment (declarative.) Security can be enabled at package & component level (both if component)

By default, package impersonates interactive user but, if set to specific NT account, can pool

Programmatic security – provided by code; e.g., IsCallerInRole(“rolename”) or IsSecurityEnabled

Configure component properties.
Each component has transaction property. If ObjectContext required during init or terminate, implement ObjectControl interface (-otherwise events not available)

Use CreateInstance to instantiate objects
GetObjectContext – requires transaction/uses transaction
SetComplete on ObjectContext
SetAbort on ObjectContext

(for more information on MTS Security)

 

MTS & ASP

Instantiate in ASP using Server.CreateObject ( - do not use <OBJECT>)
<% Transaction = Required or Requires_New or Supported or Not Supported
Transaction ends when page ends and can only involve one page. A transaction completes only if all components call SetComplete

 

Security

All computers connected to the Internet or indirectly through a proxy are potential victims

Security is a combination of technology and policy; e.g., physically securing access to sensitive resources & local logon rights only given to trusted individuals

Determine who has access to site/part of site. Can use InterDev to manage security – web project -> web permissions

Integrate with NT Access Control security using Access Control lists – authentication and authorization

Access control methods

  • Anonymous (can be set through IIS) e.g. IUSER_servername guest account

  • Basic (can be set through IIS) userid and password

  • Digest Authentication – hashes password

  • Content Rating – client side

  • NTFS

  • NT LAN Manager (can be set through IIS) NT challenge/response requires IE4 clients

  • SiteServer Membership - scalability

  • TCP/IP Address

 

Web security issues

  • Authentication

    1. Prove identity – authenticating user identity

    2. Client certificates (need server certificate & secure connection)

  • Controlling user access to files and resources (protect from loss, corruption and unauthorized use.)

    1. IIS – read, write, execute, script, none

    2. FrontPage server extensions

    3. NTFS

    4. Database – standard (recommended – pooling app connections) integrated

 

Security auditing

  • NT event log

  • IIS logs

  • Custom logs

 

Security Strategies

  • Server Solutions

    1. Privacy & data integrity – ensure unauthorized users do not access secure communications (data can’t be altered) via encryption

    2. MTS – transactions

    3. Private Communication Technology (PCT) – more advanced than SSL

    4. Secure Sockets Layer – provides secure channel by providing security handshake to initiate TCP/IP connection. Encrypts all info in request & response

  • Client solutions (IE Admin. kit)

    1. IE4 internet options – Java applets, ActiveX controls, cookies, scripts etc.

    2. JVM –sandbox

    3. Authenticode

  • Shared Solutions

    1. Certificates

    2. SSL, PCT & SET

    3. Don’t forget to secure global.asa

 

Mail Services

SMTP (layered on top of TCP)
POP(3)
Exchange Server
CDO (calendaring etc)
CDONTS
CDO rendering library (displays exchange data in HTML format)
MAPI

 

CDONTS

CDONTS works by itself on IIS & Exchange

  • Smaller and faster than CDO

  • Can be used by VB, VBScript, C, C++, and Jscript

  • Supports plain text, HTML, file attachments, URL’s etc

  • Quick and easy

CDONTS.NewMail object

Can also do via place message in pickup directory (plain text)

(for advanced CDONTS techniques)

 

SEARCH SERVICES

Index Server 2.0 – searching and indexing

  • Indexes content of website– content index service creates master index

  • Allows queries against that content (text, HTML + via filters e.g. Adobe)

    1. Basic query – multiple words

    2. Complex query – Boolean, fuzzy

    3. Free text – English language

    4. Document property query – file size etc

Administered through IIS, logging via IIS, security via NT. Obtain status, stats, which directories to exclude etc. Stop/start service.

Query form passes info to index server – reconciled against master index, returns results

  • Can use ASP

  • Index extension files (*.idq - query parameters & *.htx - results)

  • SQL queries via OLE DB provider

Can update content index automatically as background process, or administratively, or programmatically.

 

MULTIMEDIA DELIVERY

Speed limitations of modems
Streaming – don’t have to wait for whole file to download

IE supports many formats

Interactive Music Control – dynamic musical accompaniment via software wave-table synthesis (consistent & configurable via any soundcard)

Liquid Motion multimedia application tool (works on any platform that supports Java.

 

NetShow

  • Integration of audio and video.

  • Integrated with NT server

  • Client/server

  • Efficient, reliable, scalable & secure

  • Can stream over low bandwidth

  • Powerful broadcast system

  • Ease of use (integrated with IIS, NT Server & IE)

  • High quality audio and video

  • Instant play

Compressed and encoded using codecs – NetShow is codec independent

Unicast – each client requests separately
Multicast – send single copy to multiple people.

Active Streaming Format (ASF)

  • Foundation of all NetShow components

  • Open standards based

  • Adds error correction over unreliable networks

  • Synchronises different data-types

  • Multimedia content must be converted to ASF before delivery

  • Can be hosted on HTTP server, local drive or specialised media server such as NetShow

NetShow channels

  • Set up channel before broadcast to establish communications

  • Users connect via NetShow player or web page

  • They see whatever’s being played at the time

 

NetShow program

  • Channel is populated with programs (live or on-demand)

  • Programs can be scheduled at specific times

  • Can’t skip ahead or back but can switch off or change channels (like TV)



 
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