8 - Web Informationsystems

• Communication (data exchange) between computer and hosts takes place in the internet or through a Virtual Private Network (VPN) based on the internet standards (Protokolls)

• Access to information and services is supported by a program that manages the user interface, known as browser

• B2B - business to business

  • collaboration among companies

• B2C - business to consumer

  • online shops

• C2C - consumer to consumer

  • auctions, buy-sell notices

• G2B - Government to business

  • on line taxes, services to companies

• G2C - Government to citizens

  • online taxes

• Informative sites - Minimum

  • Who we are / Products/ Services / Contacts

  • Newsletter, Journal, Blog, …

• Ordering sites

  • Selection, configuration, purchase

• Management systems

  • CRM, SCM, ERP, MRP, …

• Autonomous systems

  • Negotiation, transaction, monitoring

• Portals, marketplace, marketspace

  • Aggregate many related companies / products

• Web 1.0

  • E-commerce

  • Deskop browser Access

  • Dedicated Infrastructure

• Web 2.0

  • Social Networks

  • “Mobile-first” always on

  • Cloud-diven computing

• Web 3.0

  • AI-driven services

  • Decentralisied data achritectur

  • Edge computing infratsructure

Application Architecture

• Browser / Client

• Internet infrastructure

• WebServer

• Application Server

• Database Server / 3rd party services

• Communication Structure - Typical Client-Server architecture

Set of rules to transfer information between two (or +) parties

• HTTP, HTTPS

  • Transfer of content (HTML-Pages)

• TCP

  • Reliable transfer of variable length data

• IP

  • Allow transfer of data though a network

• WiFi, Ethernet, Bluetooth, 4G, 5G

  • Local networking (logical access, medium access, physical details)

• Logical = Software

  • A process that runs on a host that relays information to a client upon the client sending it a request

  • Belongs to on of the three server roles of the n-tier architecture (Web, Application, Database)

• Physical = Hrdware

  • A host computer on a network that holds information (e.g., web sites) and responds to requests for information

• Manages the HTTP protocol

  • Receives client requests

  • Reads static pages from the file system

  • Activates the application server for dynamic pages (server side)

  • Sends an HTML file back to the client

• One HTTP connection for each request

• Multiprocess, Multi threaded or Process pool

• Provides static webpages

• URL (uniform resource locator) for finding web pages

• HTTP (hyper text transfer protocol) for client server interaction

• HTML (hyper text markup language) for writing web pages

• Host

• Scheme

• Query

• Userinfo

• Port

• Fragment

• Latency

  • time required for providing a 0 byte http page

  • Includes the server activation time, the request decoding time, the file access time, the transmission time and the time for closing the connection.

  • Unit of measure: http/s or s/http

• Throughput

  • maximum speed at which infinite infinite-sized pages can be sent.

  • Unit of measure: Bytes (Mbytes)/s

• RPS

  • max( #Requests / s)

• Dynamic page generation

• Manages the site business logic

• It's the middle tier between the client browser and the data residing on a database

• Implements the session mechanisms

• Different technologies and architectures are available

• A session is a set of related HTTP transactions performed by the same user

• They allow a continuous (state-full) interaction with the web application upon a state-less protocol (HTTP/S)

• Each HTTP exchange is independent

• They are usually based on cookies

• A cookie is a pair name and value

• Cookies are sent by the web server

• Usually upon the first interaction

• The browser keep a list of

  • Host – Cookie ( name + value )

• When a browser sends an request to a host is sends along all the cookies previously received from that host

• Stores the data on which the application server works.

• Executes the queries issued by the application server:

• Updates stored data

• Inserts new data

• Provides back query results

• The most frequent/complex queries can be implemented internally as stored procedures

• SQL (structured query language)

• ODBC (open database connectivity) to access data bases

• No-SQL

  • for non relational databases

  • SPARQL for triple based knowledge bases

• Infrastructure as a Service (IaaS)

• Platform as a Service (PaaS)

• Software as a Service (SaaS)

• Infrastructure as a Service (IaaS) is a cloud computing offering in which a vendor provides users access to computing resources such as servers, storage, and networking.

• Organizations use their own platform and applications within a service provider's infrastructure.

• Benefits

  • Instead of purchasing hardware, users pay for IaaS on demand

  • Scalability

  • No single point of failure

• provides users a cloud environment in which they can develop, manage and deliver applications, in addition to storage and other computing resources

• Prebuilt tools to develop are available

• Benefits:

  • Focus on development without having to worry about underlying infrastructure

  • The providers manage security, operating systems, server softwares and backups

  • Useful for remote development

• provides users with access to a vendor's cloud based software.

• Users do not install applications on their local devices, instead the applications reside on a remote cloud network accessed through the web or an API

• Benefits:

  • Users do not have to manage or install software

  • Data is secure in the cloud (???)

  • Use of resources can be scaled

• Drive down costs

• Accessibility

• Productivity

• Scalability

• Access to automatic updates

• Business continuity