Web Services = Client/Server + OO

Web Services = Client/Server + OO

Host

Terminal (dumb)

n
.
One that furnishes
facilities and resources
for a function or event

n
.
A point or part
that forms the end

Host

Terminal (dumb)

n
.
One that furnishes
facilities and resources
for a function or event

n
.
A point or part
that forms the end

CPU



CPU

Server

n
.
One that
performs
a service

n
.
A p
arty for whom
services are rendered

CPU

CPU

Client

Server

Client

192.168.0.1

192.168.0.102

TCP/IP

Xerox IPX/SPX

M$ LAN Manager

Novell NCP

International
Standards
Organization
(ISO)


Open

Systems

Interconnect

(OSI)

Web

Mail

File

Name

Chat

Database

Terminal

Screen

Time

Web

Mail

File

Name

Chat

Database

Terminal

Screen

Time

cat /etc/services

Port (Canonical)

Protocol

Server

42

DNS

/
usr/sbin/named
,

WINS

123

NTP

/
usr/sbin/ntpd

25, 110/995, 143/993

SMTP, POP3, IMAP

Sendmail
, Courier,
Postfix, Exchange

21/115, 2049, 3020

FTP,

SMB/CIFS, NFS ,
AFP,
WebDAV


iDrive
, Samba, NFS

22, 23

SSH, telnet

OpenSSH,
telnetd

5900

VNC

Vine,
RealVNC
, Olivetti

6667,5050,5190,1863

IRC, Yahoo, ICQ, MSN

…

80

HTTP

Apache, IIS

3306,1433

TDS,

etc.

SQL

Server,
MySQL
,
Oracle

•

Semantics

•

Transcript structure

n
. An agreement on how to have a conversation

•

Data formats

a lexicon (dictionary) of
acceptable terms e.g. nouns,
verbs, etc.

Rules of dialogue e.g. in SMTP an
EHLO must be issued immediately
after connection

Format of data, e.g. HTML,
tabular, XML

S: <wait for connection on TCP port 110>

C: <open connection>

S: +OK POP3 server ready <1896.697170952@dbc.mtview.ca.us>

C: APOP
mrose

c4c9334bac560ecc979e58001b3e22fb

S: +OK
mrose's

maildrop

has 2 messages (320 octets)

C: STAT

S: +OK 2 320

C: LIST

S: +OK 2 messages (320 octets)

S: 1 120

S: 2 200

S: .

C: RETR 1

S: +OK 120 octets

S: <the POP3 server sends message 1>

S: .

C: DELE 1

S: +OK message 1 deleted

C: RETR 2

S: +OK 200 octets

S: <the POP3 server sends message 2>

C: QUIT

S: +OK
dewey

POP3 server signing off (
maildrop

empty)

C: <close connection>

S: <wait for next connection>

void fn1 (


int

PersonId
,


double Height,


double Width,


int

Age,


char *Address,


char *Children[],


bool

IsReachable


)

int

PersonId

= 3;

double Height = 6.2;

double Weight = 140.5;

int

Age = 42;

char *Address = “101 Main St. …”;


fn1 (
PersonId
, Height, Weight,


Age, Address, Children,
IsReachable


);


fn2 (
PersonId
, Height, Weight,


Age, Address, Children,
IsReachable


);



class Person {


int

PersonId
;


double Height;


double Weight;

Public:


void Retire();


int

MakeTaller(int
);

}

Person
p
;


p.Height

= 6.2;

p.Weight

= 140.5;


p.MakeTaller(6.3);

p.Retire
();

Thing

Person

Accountant

Woman

Furniture

Table

Seat

Sofa

Couch

Divan

Process

Manufacturing

Retail

Investment

•

Inheritance

•

Abstraction

•

Code Reuse

Thing

Person

Accounta
nt

Woman

Furniture

Table

Seat

Sofa

Couch

Divan

Process

Manufact
uring

Retail

Investme
nt

MyLibrary.dll

Sharepoint.dll

Exchange.dll

SQL
Server.dll

Network

Filesystem

Device drivers

WMI
-

Instrumentation

Fat Clients

•

Compiled

•

Architecture
-
bound

•

Local installation

•

Security issues

MyLibrary.dll

Person
p


=
Remote(‘Hostname
’);


p.Height

= 6.2;

p.Weight

= 140.5;


p.MakeTaller(6.3);

p.Retire
();

SOAP = HTTP + XML

•

Self
-
describing


•

Human readable


•

Solid security
model


•

Portable


•

Wide adoption


•

Easy to use